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Sample records for metodo spin coating

  1. Comparison of additive amount used in spin-coated and roll-coated organic solar cells

    DEFF Research Database (Denmark)

    Cheng, Pei; Lin, Yuze; Zawacka, Natalia Klaudia

    2014-01-01

    All-polymer and polymer/fullerene inverted solar cells were fabricated by spin-coating and roll-coating processes. The spin-coated small-area (0.04 cm(2)) devices were fabricated on indium tin oxide (ITO) coated glass substrates in nitrogen. The roll-coated large-area (1.0 cm(2)) devices were...

  2. Spin coated versus dip coated electrochromic tungsten oxide films: Structure, morphology, optical and electrochemical properties

    International Nuclear Information System (INIS)

    Deepa, M.; Saxena, T.K.; Singh, D.P.; Sood, K.N.; Agnihotry, S.A.

    2006-01-01

    A sol-gel derived acetylated peroxotungstic acid sol encompassing 4 wt.% of oxalic acid dihydrate (OAD) has been employed for the deposition of tungsten oxide (WO 3 ) films by spin coating and dip coating techniques, in view of smart window applications. The morphological and structural evolution of the as-deposited spin and dip coated films as a function of annealing temperature (250 and 500 o C) has been examined and compared by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). A conspicuous feature of the dip coated film (annealed at 250 o C) is that its electrochromic and electrochemical properties ameliorate with cycling without degradation in contrast to the spin coated film for which these properties deteriorate under repetitive cycling. A comparative study of spin and dip coated nanostructured thin films (annealed at 250 o C) revealed a superior performance for the cycled dip coated film in terms of higher transmission modulation and coloration efficiency in solar and photopic regions, faster switching speed, higher electrochemical activity as well as charge storage capacity. While the dip coated film could endure 2500 color-bleach cycles, the spin coated film could sustain only a 1000 cycles. The better cycling stability of the dip coated film which is a repercussion of a balance between optimal water content, porosity and grain size hints at its potential for electrochromic window applications

  3. Effect of Annealing Temperature and Spin Coating Speed on Mn-Doped ZnS Nanocrystals Thin Film by Spin Coating

    Directory of Open Access Journals (Sweden)

    Noor Azie Azura Mohd Arif

    2017-01-01

    Full Text Available ZnS:Mn nanocrystals thin film was fabricated at 300°C and 500°C via the spin coating method. Its sol-gel was spin coated for 20 s at 3000 rpm and 4000 rpm with metal tape being used to mold the shape of the thin film. A different combination of these parameters was used to investigate their influences on the fabrication of the film. Optical and structural characterizations have been performed. Optical characterization was analyzed using UV-visible spectroscopy and photoluminescence spectrophotometer while the structural and compositional analysis of films was measured via field emission scanning electron microscopy and energy dispersive X-ray. From UV-vis spectra, the wavelength of the ZnS:Mn was 250 nm and the band gap was within the range 4.43 eV–4.60 eV. In room temperature PL spectra, there were two emission peaks centered at 460 nm and 590 nm. Under higher annealing temperature and higher speed used in spin coating, an increase of 0.05 eV was observed. It was concluded that the spin coating process is able to synthesize high quality spherical ZnS:Mn nanocrystals. This conventional process can replace other high technology methods due to its synthesis cost.

  4. Cellulose nanocrystal submonolayers by spin coating

    NARCIS (Netherlands)

    Kontturi, E.J.; Johansson, L.S.; Kontturi, K.S.; Ahonen, P.; Thune, P.C.; Laine, J.

    2007-01-01

    Dilute concentrations of cellulose nanocrystal solutions were spin coated onto different substrates to investigate the effect of the substrate on the nanocrystal submonolayers. Three substrates were probed: silica, titania, and amorphous cellulose. According to atomic force microscopy (AFM) images,

  5. A high performance ceria based interdiffusion barrier layer prepared by spin-coating

    DEFF Research Database (Denmark)

    Plonczak, Pawel; Joost, Mario; Hjelm, Johan

    2011-01-01

    A multiple spin-coating deposition procedure of Ce0.9Gd0.1O1.95 (CGO) for application in solid oxide fuel cells (SOFCs) was developed. The thin and dense CGO layer can be employed as a barrier layer between yttria stabilised zirconia (YSZ) electrolyte and a (La, Sr)(Co, Fe)O3 based cathode....... The decomposition of the polymer precursor used in the spin-coating process was studied. The depositions were performed on anode supported half cells. By controlling the sintering temperature between each spin-coating process, dense and crack-free CGO films with a thickness of approximately 1 μm were obtained....... The successive steps of dense layer production was investigated by scanning electron microscopy. X-ray diffraction was employed to monitor the crystal structure of the CGO layer sintered at different temperatures. The described spin coated barrier layer was evaluated using an anode supported cell...

  6. Enhanced corrosion protective PANI-PAA/PEI multilayer composite coatings for 316SS by spin coating technique

    Energy Technology Data Exchange (ETDEWEB)

    Syed, Junaid Ali; Lu, Hongbin; Tang, Shaochun; Meng, Xiangkang, E-mail: mengxk@nju.edu.cn

    2015-01-15

    Highlights: • PANI-PAA/PEI multilayers with controllable thickness were fabricated by spin assembly. • PAA matrix results in the homogeneous dispersion of PANI in the composite coatings. • Spin coating combined with heating assures the linear increase in thickness with n. • The corrosion protection property of PANI-PAA/PEI coatings were optimized at n = 20. • Enhanced protection owing to multilayer structure that lengthens the diffusion pathway of ions. - Abstract: In the present study, polyaniline-polyacrylic acid/polyethyleneimine (PANI-PAA/PEI) composite coatings with a multilayer structure for corrosion protection of 316 stainless steels (316SS) were prepared by an alternate deposition. Spin coating combined with heating assists removal of residual water that result in a linear increase in thickness with layer number (n). The combination of PANI-PAA composite with PEI and their multilayer structure provides a synergistic enhancement of corrosion resistance properties as determined by electrochemical measurements in 3.5% NaCl solution. Importantly, the PANI-PAA/PEI coating with an optimized layer number of n = 20 shows improved corrosion protection. The superior performance was attributed to the formation of an interfacial oxide layer as well as the multilayer structure that extend the diffusion pathway of corrosive ions.

  7. Robust and thermal-healing superhydrophobic surfaces by spin-coating of polydimethylsiloxane.

    Science.gov (United States)

    Long, Mengying; Peng, Shan; Deng, Wanshun; Yang, Xiaojun; Miao, Kai; Wen, Ni; Miao, Xinrui; Deng, Wenli

    2017-12-15

    Superhydrophobic surfaces easily lose their excellent water-repellency after damages, which limit their broad applications in practice. Thus, the fabrication of superhydrophobic surfaces with excellent durability and thermal healing should be taken into consideration. In this work, robust superhydrophobic surfaces with thermal healing were successfully fabricated by spin-coating method. To achieve superhydrophobicity, cost-less and fluoride-free polydimethylsiloxane (PDMS) was spin-coated on rough aluminum substrates. After being spin-coated for one cycle, the superhydrophobic PDMS coated hierarchical aluminum (PDMS-H-Al) surfaces showed excellent tolerance to various chemical and mechanical damages in lab, and outdoor damages for 90days. When the PDMS-H-Al surfaces underwent severe damages such as oil contamination (peanut oil with high boiling point) or sandpaper abrasion (500g of force for 60cm), their superhydrophobicity would lose. Interestingly, through a heating process, cyclic oligomers generating from the partially decomposed PDMS acted as low-surface-energy substance on the damaged rough surfaces, leading to the recovery of superhydrophobicity. The relationship between the spin-coating cycles and surface wettability was also investigated. This paper provides a facile, fluoride-free and efficient method to fabricate superhydrophobic surfaces with thermal healing. Copyright © 2017. Published by Elsevier Inc.

  8. Thin film coatings which inhibit spin relaxation of polarized potassium atoms

    International Nuclear Information System (INIS)

    Thomas, G.E.; Holt, R.J.; Boyer, D.; Green, M.C.; Kowalczyk, R.S.; Young, L.

    1986-01-01

    A prototype of a polarized deuterium target which employs the spin exchange method is being developed. The mixing cell for mixing deuterium atoms and potassium vapor requires a surface that will reflect these atoms without being destroyed by the corrosive potassium. Thin film coating methods and a technique for coating pyrex are described. Results of spin relaxation measurements are given

  9. Surface spins disorder in uncoated and SiO2 coated maghemite nanoparticles

    International Nuclear Information System (INIS)

    Zeb, F.; Nadeem, K.; Shah, S. Kamran Ali; Kamran, M.; Gul, I. Hussain; Ali, L.

    2017-01-01

    We studied the surface spins disorder in uncoated and silica (SiO 2 ) coated maghemite (γ-Fe 2 O 3 ) nanoparticles using temperature and time dependent magnetization. The average crystallite size for SiO 2 coated and uncoated nanoparticles was about 12 and 29 nm, respectively. Scanning electron microscopy (SEM) showed that the nanoparticles are spherical in shape and well separated. Temperature scans of zero field cooled (ZFC)/field cooled (FC) magnetization measurements showed lower average blocking temperature (T B ) for SiO 2 coated maghemite nanoparticles as compared to uncoated nanoparticles. The saturation magnetization (M s ) of SiO 2 coated maghemite nanoparticles was also lower than the uncoated nanoparticles and is attributed to smaller average crystallite size of SiO 2 coated nanoparticles. For saturation magnetization vs. temperature data, Bloch's law (M(T)= M(0).(1− BT b )) was fitted well for both uncoated and SiO 2 coated nanoparticles and yields: B =3×10 −7 K -b , b=2.22 and B=0.0127 K -b , b=0.57 for uncoated and SiO 2 coated nanoparticles, respectively. Higher value of B for SiO 2 coated nanoparticles depicts decrease in exchange coupling due to enhanced surface spins disorder (broken surface bonds) as compared to uncoated nanoparticles. The Bloch's exponent b was decreased for SiO 2 coated nanoparticles which is due to their smaller average crystallite size or finite size effects. Furthermore, a sharp increase of coercivity at low temperatures (<25 K) was observed for SiO 2 coated nanoparticles which is also due to contribution of increased surface anisotropy or frozen surface spins in these smaller nanoparticles. The FC magnetic relaxation data was fitted to stretched exponential law which revealed slower magnetic relaxation for SiO 2 coated nanoparticles. All these measurements revealed smaller average crystallite size and enhanced surface spins disorder in SiO 2 coated nanoparticles than in uncoated γ-Fe 2 O 3 nanoparticles

  10. Transition from Spin Dewetting to continuous film in spin coating of Liquid Crystal 5CB.

    Science.gov (United States)

    Dhara, Palash; Bhandaru, Nandini; Das, Anuja; Mukherjee, Rabibrata

    2018-05-08

    Spin dewetting refers to spontaneous rupture of the dispensed solution layer during spin coating, resulting in isolated but periodic, regular sized domains of the solute and is pre-dominant when the solute concentration (C n ) is very low. In this article we report how the morphology of liquid crystal (LC) 5CB thin films coated on flat and patterned PMMA substrate transform from spin dewetted droplets to continuous films with increase in C n . We further show that within the spin dewetted regime, with gradual increase in the solute concentration, periodicity of the isotropic droplets (λ D ) as well as their mean diameter (d D ), gradually decreases, till the film becomes continuous at a critical concentration (C n *). Interestingly, the trend that λ D reduces with increase in C n is exact opposite to what is observed in thermal/solvent vapor induced dewetting of a thin film. The spin dewetted droplets exhibit transient Radial texture, in contrast to Schlieren texture observed in elongated threads and continuous films of 5CB, which remains in the Nematic phase at room temperature. Finally we show that by casting the film on a grating patterned substrate it becomes possible to align the spin dewetted droplets along the contours substrate patterns.

  11. Transparent nanocrystalline ZnO films prepared by spin coating

    Energy Technology Data Exchange (ETDEWEB)

    Berber, M. [SusTech GmbH and Co. KG, Petersenstr. 20, 64287 Darmstadt, Hessen (Germany)]. E-mail: mete.berber@sustech.de; Bulto, V. [SusTech GmbH and Co. KG, Petersenstr. 20, 64287 Darmstadt, Hessen (Germany); Kliss, R. [SusTech GmbH and Co. KG, Petersenstr. 20, 64287 Darmstadt, Hessen (Germany); Hahn, H. [SusTech GmbH and Co. KG, Petersenstr. 20, 64287 Darmstadt, Hessen (Germany); Forschungszentrum Karlsruhe, Institute for Nanotechnology, Postfach 3640, 76021 Karlsruhe (Germany); Joint Research Laboratory Nanomaterials, TU Darmstadt, Institute of Materials Science, Petersenstr. 23, 64287 Darmstadt (Germany)

    2005-09-15

    Dispersions of zinc oxide nanoparticles synthesized by the electrochemical deposition under oxidizing conditions process with organic surfactants, were spin coated on glass substrates. After sintering, the microstructure, surface morphology, and electro-optical properties of the transparent nanocrystalline zinc oxide films have been investigated for different coating thicknesses and organic solvents.

  12. Transparent nanocrystalline ZnO films prepared by spin coating

    International Nuclear Information System (INIS)

    Berber, M.; Bulto, V.; Kliss, R.; Hahn, H.

    2005-01-01

    Dispersions of zinc oxide nanoparticles synthesized by the electrochemical deposition under oxidizing conditions process with organic surfactants, were spin coated on glass substrates. After sintering, the microstructure, surface morphology, and electro-optical properties of the transparent nanocrystalline zinc oxide films have been investigated for different coating thicknesses and organic solvents

  13. Silica-sol-based spin-coating barrier layer against phosphorous diffusion for crystalline silicon solar cells.

    Science.gov (United States)

    Uzum, Abdullah; Fukatsu, Ken; Kanda, Hiroyuki; Kimura, Yutaka; Tanimoto, Kenji; Yoshinaga, Seiya; Jiang, Yunjian; Ishikawa, Yasuaki; Uraoka, Yukiharu; Ito, Seigo

    2014-01-01

    The phosphorus barrier layers at the doping procedure of silicon wafers were fabricated using a spin-coating method with a mixture of silica-sol and tetramethylammonium hydroxide, which can be formed at the rear surface prior to the front phosphorus spin-on-demand (SOD) diffusion and directly annealed simultaneously with the front phosphorus layer. The optimization of coating thickness was obtained by changing the applied spin-coating speed; from 2,000 to 8,000 rpm. The CZ-Si p-type silicon solar cells were fabricated with/without using the rear silica-sol layer after taking the sheet resistance measurements, SIMS analysis, and SEM measurements of the silica-sol material evaluations into consideration. For the fabrication of solar cells, a spin-coating phosphorus source was used to form the n(+) emitter and was then diffused at 930°C for 35 min. The out-gas diffusion of phosphorus could be completely prevented by spin-coated silica-sol film placed on the rear side of the wafers coated prior to the diffusion process. A roughly 2% improvement in the conversion efficiency was observed when silica-sol was utilized during the phosphorus diffusion step. These results can suggest that the silica-sol material can be an attractive candidate for low-cost and easily applicable spin-coating barrier for any masking purpose involving phosphorus diffusion.

  14. High-mobility ultrathin semiconducting films prepared by spin coating

    Science.gov (United States)

    Mitzi, David B.; Kosbar, Laura L.; Murray, Conal E.; Copel, Matthew; Afzali, Ali

    2004-03-01

    The ability to deposit and tailor reliable semiconducting films (with a particular recent emphasis on ultrathin systems) is indispensable for contemporary solid-state electronics. The search for thin-film semiconductors that provide simultaneously high carrier mobility and convenient solution-based deposition is also an important research direction, with the resulting expectations of new technologies (such as flexible or wearable computers, large-area high-resolution displays and electronic paper) and lower-cost device fabrication. Here we demonstrate a technique for spin coating ultrathin (~50Å), crystalline and continuous metal chalcogenide films, based on the low-temperature decomposition of highly soluble hydrazinium precursors. We fabricate thin-film field-effect transistors (TFTs) based on semiconducting SnS2-xSex films, which exhibit n-type transport, large current densities (>105Acm-2) and mobilities greater than 10cm2V-1s-1-an order of magnitude higher than previously reported values for spin-coated semiconductors. The spin-coating technique is expected to be applicable to a range of metal chalcogenides, particularly those based on main group metals, as well as for the fabrication of a variety of thin-film-based devices (for example, solar cells, thermoelectrics and memory devices).

  15. Active Layer Spin Coating Speed Dependence of Inverted Organic Solar Cell Based on Eosin-Y-Coated ZnO Nanorod Arrays

    Science.gov (United States)

    Ginting, R. T.; Yap, C. C.; Yahaya, M.; Fauzia, V.; Salleh, M. M.

    2013-04-01

    The active layer spin coating speed dependence of the performance of inverted organic solar cells (OSCs) based on Eosin-Y-coated ZnOnanorods has been investigated. An active layer consisted of poly(2-methoxy-5-(2'-ethyl)-hexyloxy-p-phenylenevinylene) (MEH-PPV) as donor and phenyl-c61-butyric acid methyl ester (PCBM) as acceptor was employed, whereas ZnO nanorods were utilized as electron transporting layer. The active layer was deposited on top of Eosin-Y-coated ZnO nanorods with various spin coating speeds (1000-4000 rpm). Inverted OSCs with a structure of FTO/Eosin-Y-coated ZnO nanorods/MEH-PPV:PCBM /Ag were characterized through the current density-voltage (J-V) measurement under illumination intensity of 100 mW/cm2. Based on the investigation, the short circuit current density (Jsc) and the power conversion efficiency (PCE) enhanced significantly, where as fill factor slightly increased with spin coating speed. The two-diode equivalent model was found to fit the experimental J-V curves very well. The optimum PCE of 1.18 ± 0.07% was achieved at the highest spin coating speed of 4000 rpm, as a result of the decrement of diffusion current density (Jdiff), recombination current density (Jrec), and ideality factor, thus further confirms the strong built-in electric field in thinner photoactive layer.

  16. The importance of spinning speed in fabrication of spin-coated organic thin film transistors: Film morphology and field effect mobility

    International Nuclear Information System (INIS)

    Kotsuki, Kenji; Tanaka, Hiroshige; Obata, Seiji; Stauss, Sven; Terashima, Kazuo; Saiki, Koichiro

    2014-01-01

    We have investigated the film morphology and the field effect mobility of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) thin films which were formed by spin coating on the SiO 2 substrate with solution-processed graphene electrodes. The domain size and the density of aggregates in the C8-BTBT film showed the same dependence on the spinning speed. These competitive two factors (domain size and density of aggregates) give an optimum spinning speed, at which the field effect mobility of C8-BTBT transistor showed a maximum (2.6 cm 2 /V s). This result indicates the importance of spinning speed in the fabrication of solution processed organic thin film transistors by spin coating.

  17. High-mobility ultrathin semiconducting films prepared by spin coating.

    Science.gov (United States)

    Mitzi, David B; Kosbar, Laura L; Murray, Conal E; Copel, Matthew; Afzali, Ali

    2004-03-18

    The ability to deposit and tailor reliable semiconducting films (with a particular recent emphasis on ultrathin systems) is indispensable for contemporary solid-state electronics. The search for thin-film semiconductors that provide simultaneously high carrier mobility and convenient solution-based deposition is also an important research direction, with the resulting expectations of new technologies (such as flexible or wearable computers, large-area high-resolution displays and electronic paper) and lower-cost device fabrication. Here we demonstrate a technique for spin coating ultrathin (approximately 50 A), crystalline and continuous metal chalcogenide films, based on the low-temperature decomposition of highly soluble hydrazinium precursors. We fabricate thin-film field-effect transistors (TFTs) based on semiconducting SnS(2-x)Se(x) films, which exhibit n-type transport, large current densities (>10(5) A cm(-2)) and mobilities greater than 10 cm2 V(-1) s(-1)--an order of magnitude higher than previously reported values for spin-coated semiconductors. The spin-coating technique is expected to be applicable to a range of metal chalcogenides, particularly those based on main group metals, as well as for the fabrication of a variety of thin-film-based devices (for example, solar cells, thermoelectrics and memory devices).

  18. Surface spins disorder in uncoated and SiO{sub 2} coated maghemite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zeb, F. [Nanoscience and Technology Laboratory, International Islamic University, H-10, 44000 Islamabad (Pakistan); Nadeem, K., E-mail: kashif.nadeem@iiu.edu.pk [Nanoscience and Technology Laboratory, International Islamic University, H-10, 44000 Islamabad (Pakistan); Shah, S. Kamran Ali; Kamran, M. [Nanoscience and Technology Laboratory, International Islamic University, H-10, 44000 Islamabad (Pakistan); Gul, I. Hussain [School of Chemical & Materials Engineering, National University of Sciences and Technology (NUST), H-12, 44000 Islamabad, Pakistan (Pakistan); Ali, L. [Materials Research Laboratory, International Islamic University, H-10, 44000 Islamabad (Pakistan)

    2017-05-01

    We studied the surface spins disorder in uncoated and silica (SiO{sub 2}) coated maghemite (γ-Fe{sub 2}O{sub 3}) nanoparticles using temperature and time dependent magnetization. The average crystallite size for SiO{sub 2} coated and uncoated nanoparticles was about 12 and 29 nm, respectively. Scanning electron microscopy (SEM) showed that the nanoparticles are spherical in shape and well separated. Temperature scans of zero field cooled (ZFC)/field cooled (FC) magnetization measurements showed lower average blocking temperature (T{sub B}) for SiO{sub 2} coated maghemite nanoparticles as compared to uncoated nanoparticles. The saturation magnetization (M{sub s}) of SiO{sub 2} coated maghemite nanoparticles was also lower than the uncoated nanoparticles and is attributed to smaller average crystallite size of SiO{sub 2} coated nanoparticles. For saturation magnetization vs. temperature data, Bloch's law (M(T)= M(0).(1− BT{sup b})) was fitted well for both uncoated and SiO{sub 2} coated nanoparticles and yields: B =3×10{sup −7} K{sup -b}, b=2.22 and B=0.0127 K{sup -b}, b=0.57 for uncoated and SiO{sub 2} coated nanoparticles, respectively. Higher value of B for SiO{sub 2} coated nanoparticles depicts decrease in exchange coupling due to enhanced surface spins disorder (broken surface bonds) as compared to uncoated nanoparticles. The Bloch's exponent b was decreased for SiO{sub 2} coated nanoparticles which is due to their smaller average crystallite size or finite size effects. Furthermore, a sharp increase of coercivity at low temperatures (<25 K) was observed for SiO{sub 2} coated nanoparticles which is also due to contribution of increased surface anisotropy or frozen surface spins in these smaller nanoparticles. The FC magnetic relaxation data was fitted to stretched exponential law which revealed slower magnetic relaxation for SiO{sub 2} coated nanoparticles. All these measurements revealed smaller average crystallite size and enhanced surface

  19. Sprayed and Spin-Coated Multilayer Antireflection Coating Films for Nonvacuum Processed Crystalline Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Abdullah Uzum

    2017-01-01

    Full Text Available Using the simple and cost-effective methods, spin-coated ZrO2-polymer composite/spray-deposited TiO2-compact multilayer antireflection coating film was introduced. With a single TiO2-compact film on the surface of a crystalline silicon wafer, 5.3% average reflectance (the reflectance average between the wavelengths of 300 nm and 1100 nm was observed. Reflectance decreased further down to 3.3% after forming spin-coated ZrO2 on the spray-deposited TiO2-compact film. Silicon solar cells were fabricated using CZ-Si p-type wafers in three sets: (1 without antireflection coating (ARC layer, (2 with TiO2-compact ARC film, and (3 with ZrO2-polymer composite/TiO2-compact multilayer ARC film. Conversion efficiency of the cells improved by a factor of 0.8% (from 15.19% to 15.88% owing to the multilayer ARC. Jsc was improved further by 2 mA cm−2 (from 35.3 mA cm−2 to 37.2 mA cm−2 when compared with a single TiO2-compact ARC.

  20. Spin-coating: A new approach for improving dispersion of cellulose nanocrystals and mechanical properties of poly (lactic acid) composites.

    Science.gov (United States)

    Shojaeiarani, Jamileh; Bajwa, Dilpreet S; Stark, Nicole M

    2018-06-15

    This study systematically evaluated the influence of masterbatch preparation techniques, solvent casting and spin-coating methods, on composite properties. Composites were manufactured by combining CNCs masterbatches and PLA resin using twin screw extruder followed by injection molding. Different microscopy techniques were used to investigate the dispersion of CNCs in masterbatches and composites. Thermal, thermomechanical, and mechanical properties of composites were evaluated. Scanning electron microscopy (SEM) images showed superior dispersion of CNCs in spin-coated masterbatches compared to solvent cast masterbatches. At lower CNCs concentrations, both SEM and optical microscope images confirmed more uniform CNCs dispersion in spin-coated composites than solvent cast samples. Degree of crystallinity of PLA exhibited a major enhancement by 147% and 380% in solvent cast and spin-coated composites, respectively. Spin-coated composites with lower CNCs concentration exhibited a noticeable improvement in mechanical properties. However, lower thermal characteristics in spin-coated composites were observed, which could be attributed to the residual solvents in masterbatches. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Freestanding films of crosslinked gold nanoparticles prepared via layer-by-layer spin-coating

    Science.gov (United States)

    Schlicke, Hendrik; Schröder, Jan H.; Trebbin, Martin; Petrov, Alexey; Ijeh, Michael; Weller, Horst; Vossmeyer, Tobias

    2011-07-01

    A new, extremely efficient method for the fabrication of films comprised of gold nanoparticles (GNPs) crosslinked by organic dithiols is presented in this paper. The method is based on layer-by-layer spin-coating of both components, GNPs and crosslinker, and enables the deposition of films several tens of nanometers in thickness within a few minutes. X-ray diffraction and conductance measurements reveal the proper adjustment concentration of the crosslinker solution of the critical is in order to prevent the destabilization and coalescence of particles. UV/vis spectroscopy, atomic force microscopy, and conductivity measurements indicate that films prepared via layer-by-layer spin-coating are of comparable quality to coatings prepared via laborious layer-by-layer self-assembly using immersion baths. Because spin-coated films are not bound chemically to the substrate, they can be lifted-off by alkaline underetching and transferred onto 3d-electrodes to produce electrically addressable, freely suspended films. Comparative measurements of the sheet resistances indicate that the transfer process does not compromise the film quality.

  2. Freestanding films of crosslinked gold nanoparticles prepared via layer-by-layer spin-coating

    International Nuclear Information System (INIS)

    Schlicke, Hendrik; Schroeder, Jan H; Trebbin, Martin; Petrov, Alexey; Ijeh, Michael; Weller, Horst; Vossmeyer, Tobias

    2011-01-01

    A new, extremely efficient method for the fabrication of films comprised of gold nanoparticles (GNPs) crosslinked by organic dithiols is presented in this paper. The method is based on layer-by-layer spin-coating of both components, GNPs and crosslinker, and enables the deposition of films several tens of nanometers in thickness within a few minutes. X-ray diffraction and conductance measurements reveal the proper adjustment concentration of the crosslinker solution of the critical is in order to prevent the destabilization and coalescence of particles. UV/vis spectroscopy, atomic force microscopy, and conductivity measurements indicate that films prepared via layer-by-layer spin-coating are of comparable quality to coatings prepared via laborious layer-by-layer self-assembly using immersion baths. Because spin-coated films are not bound chemically to the substrate, they can be lifted-off by alkaline underetching and transferred onto 3d-electrodes to produce electrically addressable, freely suspended films. Comparative measurements of the sheet resistances indicate that the transfer process does not compromise the film quality.

  3. Cellulose model surfaces - simplified preparation by spin coating and characterization by X-ray photoelectron spectroscopy, infrared spectroscopy, and atomic force microscopy

    NARCIS (Netherlands)

    Kontturi, E.J.; Thuene, P.C.; Niemantsverdriet, J.W.

    2003-01-01

    Spin coating is introduced as a simplified method to prep. model surfaces of cellulose. Prior to spin coating, trimethylsilyl cellulose (TMSC), a nonpolar deriv. of cellulose, is synthesized in order to dissolve the otherwise immiscible cellulose. After the spin coating deposition of TMSC on an

  4. Thin films of La{sub 0,78}Sr{sub 0,22}MnO{sub 3} by the spin coating method; Filmes finos de La{sub 0,78}Sr{sub 0,22}MnO{sub 3} pelo metodo spin coating

    Energy Technology Data Exchange (ETDEWEB)

    Macedo, Daniel Araujo de; Cela, Beatriz; Silva, Brena Kelly Oliveira da; Souza, Graziele Lopes de; Paskocimas, Carlos Alberto; Nascimento, Rubens Maribondo do [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Nucleo de Tecnologia. Lab. de Ceramica]. E-mail: damaced@gmail.com

    2008-07-01

    22% Strontium-doped lanthanum manganite (La{sub 0,78}Sr{sub 0,22}MnO{sub 3} - LSM 22) thin films were prepared using microscope slide cover glass as a substrate. The polymeric resin was obtained by Pechini method and deposited by spin coating technical. The films were made using 1500, 2000 and 2500 rpm speeds and sintered at 500 deg C for 2 hours. X-ray diffraction measures confirmed the presence of LSM 22 at the substrates surface. The morphologic characterization was performed by scanning electronic microscopy in Philips/XL-30 equipment. The deposition method made possible the obtaining of films with good adherence and thickness varying between 322 and 900 nanometers. (author)

  5. Titanium-silicon films prepared by spin and dip-coating

    International Nuclear Information System (INIS)

    Nassar, Eduardo J.; Ciuffi, Katia J.; Goncalves, Rogeria R.; Messaddeq, Younes; Ribeiro, Sidney J.L.

    2003-01-01

    The conditions for the preparation of luminescent materials, consisting of Eu 3+ ions entrapped in a titanium matrix, in the form of a thin film, using the sol-gel process, are described. The films were obtained from sols prepared with TEOS and TEOT, in the presence of acetylacetone as the hydrolysis-retarding agent, using the dip-coating and spin-coating techniques. The influence of these techniques on the films based on titanium and silicon are presented. The Eu 3+ was used as a luminescent probe. The films have been characterized by luminescence, reflection and transmittance. The thickness of the films could be related to the preparation procedure. Transparent thin films have been prepared by dip-coating technique. (author)

  6. Formation of ordered microphase-separated pattern during spin coating of ABC triblock copolymer.

    Science.gov (United States)

    Huang, Weihuan; Luo, Chunxia; Zhang, Jilin; Han, Yanchun

    2007-03-14

    In this paper, the authors have systematically studied the microphase separation and crystallization during spin coating of an ABC triblock copolymer, polystyrene-b-poly(2-vinylpyridine)-b-poly(ethylene oxide) (PS-b-P2VP-b-PEO). The microphase separation of PS-b-P2VP-b-PEO and the crystallization of PEO blocks can be modulated by the types of the solvent and the substrate, the spinning speed, and the copolymer concentration. Ordered microphase-separated pattern, where PEO and P2VP blocks adsorbed to the substrate and PS blocks protrusions formed hexagonal dots above the P2VP domains, can only be obtained when PS-b-P2VP-b-PEO is dissolved in N,N-dimethylformamide and the films are spin coated onto the polar substrate, silicon wafers or mica. The mechanism of the formation of regular pattern by microphase separation is found to be mainly related to the inducement of the substrate (middle block P2VP wetting the polar substrate), the quick vanishment of the solvent during the early stage of the spin coating, and the slow evaporation of the remaining solvent during the subsequent stage. On the other hand, the probability of the crystallization of PEO blocks during spin coating decreases with the reduced film thickness. When the film thickness reaches a certain value (3.0 nm), the extensive crystallization of PEO is effectively prohibited and ordered microphase-separated pattern over large areas can be routinely prepared. When the film thickness exceeds another definite value (12.0 nm), the crystallization of PEO dominates the surface morphology. For films with thickness between these two values, microphase separation and crystallization can simultaneously occur.

  7. Synthesis and characterization of uniform silica nanoparticles on nickel substrate by spin coating and sol-gel method

    Science.gov (United States)

    Ngoc Thi Le, Hien; Jeong, Hae Kyung

    2014-01-01

    Spin coating and sol-gel methods are proposed for the preparation of silica nanoparticles on a nickel substrate using silicon tetrachloride, 2-methoxyethanol, and four different types of alkaline solutions. The effects of the type of alkaline solution, concentration of silica solution, and speed of spin coating on the properties of silica nanoparticles are investigated systematically. Uniform spherical shape of silica nanoparticles on Ni with the smallest size are obtained with sodium carbonate among the alkaline solutions after stirring at 70 °C for 6 h and spin-coating at 7000 rpm. Physical and electrochemical properties of the silica particles are investigated.

  8. Hybrid Perovskite Thin Film Formation: From Lab Scale Spin Coating to Large Area Blade Coating

    KAUST Repository

    Munir, Rahim

    2017-11-22

    Our reliance on semiconductors is on the rise with the ever growing use of electronics in our daily life. Organic-inorganic hybrid lead halide perovskites have emerged as a prime alternative to current standard and expensive semiconductors because of its use of abundant elements and the ease of solution processing. This thesis has shed light on the ink-to-solid conversion during the one-step solution process of hybrid perovskite formulations from DMF. We utilize a suite of in situ diagnostic probes including high speed optical microscopy, optical reflectance and absorbance, and grazing incidence wide angle x-ray scattering (GIWAXS), all performed during spin coating, to monitor the solution thinning behavior, changes in optical absorbance, and nucleation and growth of crystalline phases of the precursor and perovskite. The starting formulation experiences solvent-solute interactions within seconds of casting, leading to the formation of a wet gel with nanoscale features visible by in situ GIWAXS. The wet gel subsequently gives way to the formation of ordered precursor solvates (equimolar iodide and chloride solutions) or disordered precursor solvates (equimolar bromide or 3:1 chloride), depending upon the halide and MAI content. The ordered precursor solute phases are stable and retain the solvent for long durations, resulting in consistent conversion behavior to the perovskite phase and solar-cell performance. In this thesis, we develop a firm understanding of the solvent engineering process in which an anti-solvent is used during the coating process through the solvent mixture of GBL and DMSO in different ratios. It has been shown that solvent engineering produce pin hole-free films, justifying its wide adoption across the field. We then translate our learnings from the lab scale spin coating process to the industrial friendly blade coating process. Here we compare the ink solidification and film formation mechanisms of CH3NH3PbI3 in solutions we used to

  9. In situ UV-visible absorption during spin-coating of organic semiconductors: A new probe for organic electronics and photovoltaics

    KAUST Repository

    Abdelsamie, Maged; Zhao, Kui; Niazi, Muhammad Rizwan; Chou, Kang Wei; Amassian, Aram

    2014-01-01

    Spin-coating is the most commonly used technique for the lab-scale production of solution processed organic electronic, optoelectronic and photovoltaic devices. Spin-coating produces the most efficient solution-processed organic solar cells and has

  10. Magnetic field dependence of the current flowing in the spin-coated chlorophyll thin films

    Science.gov (United States)

    Aji, J. R. P.; Kusumandari; Purnama, B.

    2018-03-01

    The magnetic dependence of the current flowing in the spin coated chlorophyll films on a patterned Cu PCB substrate has been presented. Chlorophyll was isolated from Spirulina sp and deposited by spin coated methods. The reducing of current by the change of magnetic field (magneto conductance effect) was performed by inducing the magnetic field parallel to the inplane of film at room temp. The magnetoconductance ratio decreases as the increase of voltage. It was indicated that the origin of carrier charge in chlorophyll films should be different with the carrier charge injection (electron).

  11. Fabrication of Antireflection Nanodiamond Particle Film by the Spin Coating Deposition Technique

    Directory of Open Access Journals (Sweden)

    Chii-Ruey Lin

    2014-01-01

    Full Text Available Diamond-based antireflective (AR coatings were fabricated using a spin coating of diamond suspension at room temperature as nucleation enhancement procedure and microwave plasma enhanced chemical vapour deposition. Various working pressures were used to investigate their effect on the optical characterization of the as-deposited diamond films. Scanning electron microscopy (SEM and atomic forced microscopy (AFM were employed to analyze the surface properties of the diamond films. Raman spectra and transmission electron microscopy (TEM also were used for analysis of the microstructure of the films. The results showed that working pressure had a significant effect on thickness, surface roughness, and wettability of the as-deposited diamond films. Deposited under 35 Torr or working pressure, the film possessed a low surface roughness of 13.8 nm and fine diamond grain sizes of 35 nm. Reflectance measurements of the films also were carried out using UV-Vis spectrometer and revealed a low reflectance value of the diamond films. The achievement demonstrated feasibility of the proposed spin-coating procedure for large scale production and thus opens up a prospect application of diamond film as an AR coating in industrial optoelectronic device.

  12. Using mixed solvent and changing spin-coating parameters to increase the efficiency and lifetime of organic solar cells.

    Science.gov (United States)

    Tsai, Yu Sheng; Chu, Wei-Ping; Tang, Rong-Ming; Juang, Fuh-Shyang; Chang, Ming-Hua; Liu, Mark O; Hsieh, Tsung-Eong

    2008-10-01

    The derivative of C60, i.e., PCBM, and P3HT (3-hexylthiophene) were dissolved in chloroform:dichlorobenzene mixed solvent, then spin-coated as the active layer for organic solar cells (OSC). The experimental parameters were studied carefully to obtain the optimum power conversion efficiency (PCE), including the solvent mixing ratio, spin-coating speed, annealing conditions for the active layer, etc. The OSC devices were packaged with glass and a newly developed UV-glue to improve the lifetime and PCE. Dichlorobenzene solvent has great effect upon the PCE. Changing the spin-coating speed and increasing the number of steps increased the PCE apparently to 1.4%.

  13. Optimization of spin-coated electrodes for electrolyte-supported solid oxide fuel cells

    International Nuclear Information System (INIS)

    Nobrega, Shayenne Diniz da; Monteiro, Natalia Kondo; Tabuti, Francisco; Fonseca, Fabio Coral; Florio, Daniel Zanetti de

    2017-01-01

    Electrodes for electrolyte-supported solid oxide fuel cells (SOFC’s) were fabricated by spin coating. Strontium-doped lanthanum manganite (LSM) cathode and nickel yttria-stabilized zirconia cermet anodes were synthesized and processed for enhanced deposition conditions. The influence of electrode microstructural parameters was investigated by a systematic experimental procedure aiming at optimized electrochemical performance of single cells. Polarization curves showed a strong dependence on both electrode thickness and sintering temperature. By a systematic control of such parameters, the performance of single cells was significantly enhanced due to decreasing of polarization resistance from 26 Ω cm² to 0.6 Ω cm² at 800°C. The results showed that spin-coated electrodes can be optimized for fast and cost effective fabrication of SOFCs. (author)

  14. Optimization of spin-coated electrodes for electrolyte-supported solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Nobrega, Shayenne Diniz da; Monteiro, Natalia Kondo; Tabuti, Francisco; Fonseca, Fabio Coral, E-mail: shaynnedn@hotmail.com, E-mail: nataliakm@usp.br, E-mail: fntabuti@ipen.br, E-mail: fabiocf@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil); Florio, Daniel Zanetti de, E-mail: daniel.florio@ufabc.edu.br [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil)

    2017-01-15

    Electrodes for electrolyte-supported solid oxide fuel cells (SOFC’s) were fabricated by spin coating. Strontium-doped lanthanum manganite (LSM) cathode and nickel yttria-stabilized zirconia cermet anodes were synthesized and processed for enhanced deposition conditions. The influence of electrode microstructural parameters was investigated by a systematic experimental procedure aiming at optimized electrochemical performance of single cells. Polarization curves showed a strong dependence on both electrode thickness and sintering temperature. By a systematic control of such parameters, the performance of single cells was significantly enhanced due to decreasing of polarization resistance from 26 Ω cm² to 0.6 Ω cm² at 800°C. The results showed that spin-coated electrodes can be optimized for fast and cost effective fabrication of SOFCs. (author)

  15. Highly efficient polymer solar cells with printed photoactive layer: rational process transfer from spin-coating

    KAUST Repository

    Zhao, Kui

    2016-09-05

    Scalable and continuous roll-to-roll manufacturing is at the heart of the promise of low-cost and high throughput manufacturing of solution-processed photovoltaics. Yet, to date the vast majority of champion organic solar cells reported in the literature rely on spin-coating of the photoactive bulk heterojunction (BHJ) layer, with the performance of printed solar cells lagging behind in most instances. Here, we investigate the performance gap between polymer solar cells prepared by spin-coating and blade-coating the BHJ layer for the important class of modern polymers exhibiting no long range crystalline order. We find that thickness parity does not always yield performance parity even when using identical formulations. Significant differences in the drying kinetics between the processes are found to be responsible for BHJ nanomorphology differences. We propose an approach which benchmarks the film drying kinetics and associated BHJ nanomorphology development against those of the champion laboratory devices prepared by spin-coating the BHJ layer by adjusting the process temperature. If the optimization requires the solution concentration to be changed, then it is crucial to maintain the additive-to-solute volume ratio. Emulating the drying kinetics of spin-coating is also shown to help achieve morphological and performance parities. We put this approach to the test and demonstrate printed PTB7:PC71BM polymer solar cells with efficiency of 9% and 6.5% PCEs on glass and flexible PET substrates, respectively. We further demonstrate performance parity for two other popular donor polymer systems exhibiting rigid backbones and absence of a long range crystalline order, achieving a PCE of 9.7%, the highest efficiency reported to date for a blade coated organic solar cell. The rational process transfer illustrated in this study should help the broader and successful adoption of scalable printing methods for these material systems.

  16. Structural features of spin-coated thin films of binary AsxS100−x chalcogenide glass system

    International Nuclear Information System (INIS)

    Cook, J.; Slang, S.; Golovchak, R.; Jain, H.; Vlcek, M.; Kovalskiy, A.

    2015-01-01

    Spin-coating technology offers a convenient method for fabricating photostable chalcogenide glass thin films that are especially attractive for applications in IR optics. In this paper we report the structure of spin-coated As x S 100−x (x = 30, 35, 40) thin films as determined using high resolution X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, especially in relation to composition (i.e. As/S ratio) and preparation process variables. It was observed that As atoms during preparation have a tendency to precipitate out in close to stoichiometric compositions. The mechanism of bonding between the inorganic matrix and organic residuals is discussed based on the experimental data. A weak interaction between S ions and amine-based clusters is proposed as the basis of structural organization of the organic–inorganic interface. - Highlights: • As–S spin-coated chalcogenide thin films with different As/S were fabricated. • XPS measurements support the cluster-like structure of spin-coated films. • As 2 O 3 was confirmed as the composition of precipitate formed during dissolution. • Lack of As–As bonds explains the observed photostability of the thin films

  17. Third-order optical susceptibility in polythiophene thin films prepared by spin-coating from high-boiling-point solvents

    International Nuclear Information System (INIS)

    Kobayashi, Takashi; Shinke, Wataru; Nagase, Takashi; Murakami, Shuichi; Naito, Hiroyoshi

    2014-01-01

    We examined the enhancements in the third-order optical susceptibility (χ (3) ) of spin-coated thin films of poly(3-hexylthiophene) using an anhydrous solvent with a high boiling point. The χ (3) value was found to be enhanced as the boiling point of the solvent increased. In this study, the largest value of χ (3) was obtained for thin films that were spin-coated in an inert atmosphere using anhydrous dichlorobenzene and then was subsequently exposed to its vapor for 1 h. The maximum value of the imaginary part of χ (3) was determined to be 1.8 × 10 -9 esu, which is more than three times greater than that of thin films spin-coated in an ambient atmosphere using a solvent with a low boiling point, such as chloroform. - Highlights: • Enhancements in nonlinear optical properties of a conjugated polymer were examined. • Thin films were fabricated by spin-coating using a solvent with a high boiling point. • The third-order optical susceptibility increased with increasing boiling point. • An additional enhancement was obtained by the vapor-treatment technique. • These thin films were sufficiently homogeneous for use in nonlinear optical devices

  18. Titanium dioxide antireflective coating for silicon solar cells by spinning technique

    Energy Technology Data Exchange (ETDEWEB)

    Murozono, M; Kitamura, S

    1982-01-01

    Antireflective (AR) TiO2 films for Si solar cells are presently obtained by coating a solution that is derived from organotitanium compounds (with an acetylacetone ligand and an ethanol solvent) on the Si surface using a spinning technique, and then firing at high temperature. AR film thickness can be controlled by up to 1200 A by changing solution concentration and spin speed. Si solar cells with these AR films exhibit as much as a 50 percent improvement in conversion efficiency over uncoated cells. 12 references.

  19. Stabilization of 2D assemblies of silver nanoparticles by spin-coating polymers

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Longyu; Pfirman, Aubrie; Chumanov, George, E-mail: gchumak@clemson.edu

    2015-12-01

    Graphical abstract: - Highlights: • Spin-coating of polymers onto 2D assemblies of Ag NPs was used to stabilize the assemblies against aggregation. • The polymer filled the space between the particles leaving the metal surface uncoated and accessible to various chemical reactions. • Etching nanoparticles produced crater-like structures. - Abstract: Silver nanoparticles self-assembled on poly(4-vinylpyridine) modified surfaces were spin-coated with poly(methyl methacrylate), poly(butyl methacrylate) and polystyrene from anisole and toluene solutions. The polymers filled the space between the particles thereby providing stabilization of the assemblies against particle aggregation when dried or chemically modified. The polymers did not coat the top surface of the nanoparticles offering the chemical accessibility to the metal surface. This was confirmed by converting the stabilized nanoparticles into silver sulfide and gold clusters. Etching the nanoparticles resulted in crater-like polymeric structures with the cavities extending down to the underlying substrate. Electrochemical reduction of silver inside the craters was performed. The approach can be extended to other nanoparticle assemblies and polymers.

  20. Late stage crystallization and healing during spin-coating enhance carrier transport in small-molecule organic semiconductors

    KAUST Repository

    Chou, Kang Wei

    2014-01-01

    Spin-coating is currently the most widely used solution processing method in organic electronics. Here, we report, for the first time, a direct investigation of the formation process of the small-molecule organic semiconductor (OSC) 6,13-bis(triisopropylsilylethynyl) (TIPS)-pentacene during spin-coating in the context of an organic thin film transistor (OTFT) application. The solution thinning and thin film formation were monitored in situ by optical reflectometry and grazing incidence wide angle X-ray scattering, respectively, both of which were performed during spin-coating. We find that OSC thin film formation is akin to a quenching process, marked by a deposition rate of ∼100 nm s-1, nearly three orders of magnitude faster than drop-casting. This is then followed by a more gradual crystallization and healing step which depends upon the spinning speed. We associate this to further crystallization and healing of defects by residency of the residual solvent trapped inside the kinetically trapped film. The residency time of the trapped solvent is extended to several seconds by slowing the rotational speed of the substrate and is credited with improving the carrier mobility by nearly two orders of magnitude. Based on this insight, we deliberately slow down the solvent evaporation further and increase the carrier mobility by an additional order of magnitude. These results demonstrate how spin-coating conditions can be used as a handle over the crystallinity of organic semiconductors otherwise quenched during initial formation only to recrystallize and heal during extended interaction with the trapped solvent. This journal is © the Partner Organisations 2014.

  1. Spin coating and plasma process for 2.5D integrated photonics on multilayer polymers

    International Nuclear Information System (INIS)

    Zebda, A.; Camberlein, L.; Beche, B.; Gaviot, E.; Beche, E.; Duval, D.; Zyss, J.; Jezequel, G.; Solal, F.; Godet, C.

    2008-01-01

    Polymer spin coating, surface plasma treatment and selective UV-lithography processes have been developed to realize 2.5D photonic micro-resonators, made of disk- or ring-shaped upper rib waveguides, using common polymers such as SU8 (biphenol A ether glycidyl), PS233 (polymeric silane) and SOG (siloxane Spin on Glass). Both oxygen and argon plasma treatments, applied to PS233 and SOG before spin-coating the SU8, improve substantially the grip of multilayer devices (SU8 / PS233 or SU8 / SOG). Surface energy components derived from contact angle measurements have been used to optimize the processing conditions. In such integrated photonic devices, the both single-electromagnetic-modes called transverse electric (TE 00 ) and transverse magnetic (TM 00 ) have been excited in a SU8 micro-disk, with a single mode propagation strongly localized near the edge of the disk (i.e. the so called whispering gallery modes)

  2. Fabrication of Nanoplasmonic Arrays with Square Symmetry Using Spin-Coating Method

    Czech Academy of Sciences Publication Activity Database

    Friedl, Alexandra; Adam, Pavel; Leshkov, Sergey; Homola, Jiří

    2011-01-01

    Roč. 11, č. 3 (2011), s. 2528-2532 ISSN 1533-4880 R&D Projects: GA AV ČR KAN200670701; GA MŠk OC09058 Institutional research plan: CEZ:AV0Z20670512 Keywords : ordered nanoparticles * spin-coating * lithography Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.563, year: 2011

  3. In situ UV-visible absorption during spin-coating of organic semiconductors: A new probe for organic electronics and photovoltaics

    KAUST Repository

    Abdelsamie, Maged

    2014-01-01

    Spin-coating is the most commonly used technique for the lab-scale production of solution processed organic electronic, optoelectronic and photovoltaic devices. Spin-coating produces the most efficient solution-processed organic solar cells and has been the preferred approach for rapid screening and optimization of new organic semiconductors and formulations for electronic and optoelectronic applications, both in academia and in industrial research facilities. In this article we demonstrate, for the first time, a spin-coating experiment monitored in situ by time resolved UV-visible absorption, the most commonly used, simplest, most direct and robust optical diagnostic tool used in organic electronics. In the first part, we successfully monitor the solution-to-solid phase transformation and thin film formation of poly(3-hexylthiophene) (P3HT), the de facto reference conjugated polymer in organic electronics and photovoltaics. We do so in two scenarios which differ by the degree of polymer aggregation in solution, prior to spin-coating. We find that a higher degree of aggregation in the starting solution results in small but measurable differences in the solid state, which translate into significant improvements in the charge carrier mobility of organic field-effect transistors (OFET). In the second part, we monitor the formation of a bulk heterojunction photoactive layer based on a P3HT-fullerene blend. We find that the spin-coating conditions that lead to slower kinetics of thin film formation favour a higher degree of polymer aggregation in the solid state and increased conjugation length along the polymer backbone. Using this insight, we devise an experiment in which the spin-coating process is interrupted prematurely, i.e., after liquid ejection is completed and before the film has started to form, so as to dramatically slow the thin film formation kinetics, while maintaining the same thickness and uniformity. These changes yield substantial improvements to the

  4. The fabrication of highly uniform ZnO/CdS core/shell structures using a spin-coating-based successive ion layer adsorption and reaction method

    International Nuclear Information System (INIS)

    Joo, Jinmyoung; Kim, Darae; Yun, Dong-Jin; Jun, Hwichan; Rhee, Shi-Woo; Lee, Jae Sung; Yong, Kijung; Jeon, Sangmin; Kim, Sungjee

    2010-01-01

    We developed a successive ion layer adsorption and reaction method based on spin-coating (spin-SILAR) and applied the method to the fabrication of highly uniform ZnO/CdS core/shell nanowire arrays. Because the adsorption, reaction, and rinsing steps occur simultaneously during spin-coating, the spin-SILAR method does not require rinsing steps between the alternating ion adsorption steps, making the growth process simpler and faster than conventional SILAR methods based on dip-coating (dip-SILAR). The ZnO/CdS core/shell nanowire arrays prepared by spin-SILAR had a denser and more uniform structure than those prepared by dip-SILAR, resulting in the higher power efficiency for use in photoelectrochemical cells.

  5. The fabrication of highly uniform ZnO/CdS core/shell structures using a spin-coating-based successive ion layer adsorption and reaction method

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Jinmyoung; Kim, Darae; Yun, Dong-Jin; Jun, Hwichan; Rhee, Shi-Woo; Lee, Jae Sung; Yong, Kijung; Jeon, Sangmin [System on Chip Chemical Process Research, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang (Korea, Republic of); Kim, Sungjee, E-mail: jeons@postech.ac.kr [Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang (Korea, Republic of)

    2010-08-13

    We developed a successive ion layer adsorption and reaction method based on spin-coating (spin-SILAR) and applied the method to the fabrication of highly uniform ZnO/CdS core/shell nanowire arrays. Because the adsorption, reaction, and rinsing steps occur simultaneously during spin-coating, the spin-SILAR method does not require rinsing steps between the alternating ion adsorption steps, making the growth process simpler and faster than conventional SILAR methods based on dip-coating (dip-SILAR). The ZnO/CdS core/shell nanowire arrays prepared by spin-SILAR had a denser and more uniform structure than those prepared by dip-SILAR, resulting in the higher power efficiency for use in photoelectrochemical cells.

  6. Probing the chemistry of adhesion between a 316L substrate and spin-on-glass coating

    DEFF Research Database (Denmark)

    Lampert, Felix; Kadkhodazadeh, Shima; Kasama, Takeshi

    2018-01-01

    Hydrogen silsesquioxane ([HSiO3/2]n) based "spin-on-glass" has been deposited on 316L substrate and cured in Ar/H2 gas atmosphere at 600 ºC to form a continuous surface coating with sub-micrometer thickness. The coating functionality depends primarily on the adhesion to the substrate, which...... is largely affected by the chemical interaction at the interface between the coating and the substrate. We have investigated this interface by transmission electron microscopy and electron energy loss spectroscopy. The analysis identified a 5-10 nm thick interaction zone containing signals from O, Si, Cr....... In agreement with computational thermodynamics, it is proposed that the spin-on-glass forms a chemically bonded silicate-rich interaction zone with the substrate. It was further suggested that this zone is composed of a corundum-type oxide at the substrate surface, followed by an olivine-structure intermediate...

  7. Structural features of spin-coated thin films of binary As{sub x}S{sub 100−x} chalcogenide glass system

    Energy Technology Data Exchange (ETDEWEB)

    Cook, J. [Austin Peay State University, Clarksville, TN 37075 (United States); Slang, S. [Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice (Czech Republic); Golovchak, R. [Austin Peay State University, Clarksville, TN 37075 (United States); Jain, H. [International Materials Institute for New Functionality in Glass, Lehigh University, Bethlehem, PA 18015 (United States); Vlcek, M. [Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice (Czech Republic); Kovalskiy, A., E-mail: kovalskyya@apsu.edu [Austin Peay State University, Clarksville, TN 37075 (United States)

    2015-08-31

    Spin-coating technology offers a convenient method for fabricating photostable chalcogenide glass thin films that are especially attractive for applications in IR optics. In this paper we report the structure of spin-coated As{sub x}S{sub 100−x} (x = 30, 35, 40) thin films as determined using high resolution X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, especially in relation to composition (i.e. As/S ratio) and preparation process variables. It was observed that As atoms during preparation have a tendency to precipitate out in close to stoichiometric compositions. The mechanism of bonding between the inorganic matrix and organic residuals is discussed based on the experimental data. A weak interaction between S ions and amine-based clusters is proposed as the basis of structural organization of the organic–inorganic interface. - Highlights: • As–S spin-coated chalcogenide thin films with different As/S were fabricated. • XPS measurements support the cluster-like structure of spin-coated films. • As{sub 2}O{sub 3} was confirmed as the composition of precipitate formed during dissolution. • Lack of As–As bonds explains the observed photostability of the thin films.

  8. Passivation properties of alumina for multicrystalline silicon nanostructure prepared by spin-coating method

    Science.gov (United States)

    Jiang, Ye; Shen, Honglie; Yang, Wangyang; Zheng, Chaofan; Tang, Quntao; Yao, Hanyu; Raza, Adil; Li, Yufang; Huang, Chunlai

    2018-02-01

    In this paper, we report passivation properties of inverted pyramidal nanostructure based multi-crystalline silicon (mc-Si) by Al2O3 films with spin-coating method. Precursors AlCl3 and Al(acac)3 for Al2O3 films were chosen for comparison. Al2O3/SiO x stacks were found to be able to passivate the nanostructured surface well. With the number of spin-coating up to five, the Al2O3 films could conformally attach the nanostructure. The weighted average reflectance values (ranging from 400-900 nm) of the passivated silicon surface could be reduced to 10.74% (AlCl3) and 11.12% (Al(acac)3), and the effective carrier lifetime could reach 7.84 and 16.98 μs, respectively. This work presented a potential process to fabricate low cost high efficiency mc-Si solar cells.

  9. Spin coated graphene films as the transparent electrode in organic photovoltaic devices

    International Nuclear Information System (INIS)

    Kymakis, E.; Stratakis, E.; Stylianakis, M.M.; Koudoumas, E.; Fotakis, C.

    2011-01-01

    Many research efforts have been devoted to the replacement of the traditional indium–tin-oxide (ITO) electrode in organic photovoltaics. Solution-based graphene has been identified as a potential replacement, since it has less than two percent absorption per layer, relative high carrier mobility, and it offers the possibility of deposition on large area and flexible substrates, compatible with roll to roll manufacturing methods. In this work, soluble reduced graphene films with high electrical conductivity and transparency were fabricated and incorporated in poly(3-hexylthiophene) [6,6]-phenyl-C 61 -butyric acid methyl ester photovoltaic devices, as the transparent electrode. The graphene films were spin coated on glass from an aqueous dispersion of functionalized graphene, followed by a reduction process combining hydrazine vapor and annealing under argon, in order to reduce the sheet resistance. The photovoltaic devices obtained from the graphene films showed lower performance than the reference devices with ITO, due to the higher sheet resistance (2 kΩ/sq) and the poor hydrophilicity of the spin coated graphene films.

  10. Ultraviolet Stimulated Emission from Sol-Gel Spin Coated ZnO Thin Films

    Directory of Open Access Journals (Sweden)

    Ahmed S. Razeen

    2017-01-01

    Full Text Available Low cost ultraviolet stimulated emission has been generated using optical excitation of ZnO thin films deposited by sol-gel spin coating on n+ As-doped 100 Si-substrate. The number of deposited layers and the heat treatment have been investigated to obtain a film that can generate stimulated emission under optical excitation. The optimum condition for preparation of the film has been presented. X-ray diffraction and scanning electron microscope have been used for structural and morphological investigations. Input-output intensity dependence and spectral width, peak emission wavelength, and the quantum efficiency versus the pump intensity have been presented. A quantum efficiency of about 24.2% has been reported, a power exponent higher than 8 has been obtained in input-output intensity dependence, and a threshold of about 23 Mw/cm2 has been evaluated for the samples. The mechanism by which stimulated emission occurs has been discussed. The results show that sol-gel spin coating is a promising method for generating ultraviolet stimulated emission from ZnO thin films.

  11. METAL OXIDE DOPED ANTIBACTERIAL POLYMERIC COATED TEXTILE MATERIALS AND ASSESSEMENT OF ANTIBACTERIAL ACTIVITY WITH ELECTRON SPIN RESONANCE

    Directory of Open Access Journals (Sweden)

    GEDIK Gorkem

    2017-05-01

    Full Text Available Antibacterial activity of a food conveyor belt is an essential property in some cases. However, every antibacterial chemical is not suitable to contact with food materials. Many metal oxides are suitable option for this purpose. The aim of this study was to investigate antibacterial properties of zinc oxide doped PVC polymer coated with electron spin resonance technique. Therefore, optimum zinc oxide containing PVC paste was prepared and applied to textile surface. Coating construction was designed as double layered, first layer did not contain antibacterial agent, thin second layer contained zinc oxide at 10-35% concentration. Oxygen radicals released from zinc oxide containing polymeric coated surface were spin trapped with DMPO (dimethylpyrroline-N-oxide spin trap and measured with Electron Spin Resonance (ESR. Besides conveyor belt samples, oxygen radical release from zinc oxide surface was measured with ESR under UV light and dark conditions. Oxygen radical release was determined even at dark conditions. Antibacterial properties were tested with ISO 22196 standard using Listeria innocua species. Measured antibacterial properties were related with ESR results. Higher concentration of zinc oxide resulted in higher antibacterial efficiency. DCFH-DA flourometric assay was carried out to determine oxidative stress insidebacteria. It is tought that, this technique will lead to decrease on the labour and time needed for conventional antibacterial tests.

  12. DMF as an Additive in a Two-Step Spin-Coating Method for 20% Conversion Efficiency in Perovskite Solar Cells.

    Science.gov (United States)

    Wu, Jionghua; Xu, Xin; Zhao, Yanhong; Shi, Jiangjian; Xu, Yuzhuan; Luo, Yanhong; Li, Dongmei; Wu, Huijue; Meng, Qingbo

    2017-08-16

    DMF as an additive has been employed in FAI/MAI/IPA (FA= CH 2 (NH 2 ) 2 , MA = CH 3 NH 3 , IPA = isopropanol) solution for a two-step multicycle spin-coating method in order to prepare high-quality FA x MA 1-x PbI 2.55 Br 0.45 perovskite films. Further investigation reveals that the existence of DMF in the FAI/MAI/IPA solution can facilitate perovskite conversion, improve the film morphology, and reduce crystal defects, thus enhancing charge-transfer efficiency. By optimization of the DMF amount and spin-coating cycles, compact, pinhole-free perovskite films are obtained. The nucleation mechanisms of perovskite films in our multicycle spin-coating process are suggested; that is, the introduction of DMF in the spin-coating FAI/MAI/IPA solution can lead to the formation of an amorphous phase PbX 2 -AI-DMSO-DMF (X = I, Br; A = FA, MA) instead of intermediate phase (MA) 2 Pb 3 I 8 ·2DMSO. This amorphous phase, similar to that in the one-step method, can help FAI/MAI penetrate into the PbI 2 framework to completely convert into the perovskite. As high as 20.1% power conversion efficiency (PCE) has been achieved with a steady-state PCE of 19.1%. Our work offers a simple repeatable method to prepare high-quality perovskite films for high-performance PSCs and also help further understand the perovskite-crystallization process.

  13. Novel microstructure in spin coated polyaniline thin films

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Deepak; Dutta, V [Photovoltaic Laboratory, Centre for Energy Studies, Indian Institute of Technology Delhi, Hauz Khas, New Delhi-110016 (India)

    2007-05-08

    Polyaniline (Pani) thin films doped with camphor sulfonic acid (CSA) have been deposited on glass substrates using the spin coating technique. Pani is chemically synthesized by an oxidation method at {approx}0 deg. C. Pani-CSA films show a hexagonal structure in scanning electron micrographs, which occurs due to the crystalline growth of CSA. A dense hexagonal structure is visible for film deposited at 800 rpm, but it becomes sparser as the revolutions per minute are increased (1200, 1500 and 2000 rpm). Electronic transition of quinoid units cause an absorption shoulder at {approx}900 nm for films deposited at 1200, 1500 and 2000 rpm, which is not observed for film deposited at 800 rpm.

  14. Nanocluster formation by spin coating : quantitative atomic force microscopy and Rutherford backscattering spectrometry analysis

    NARCIS (Netherlands)

    Partridge, A.; Toussaint, S.L.G.; Flipse, C.F.J.; IJzendoorn, van L.J.; Oetelaar, van den L.C.A.

    1996-01-01

    A recently developed spin coating method has been employed to produce a homogeneous distribution of nanometer-sized metal clusters onto a flat oxidic support. The particle size and distribution, and the total amount of material deposited has been studied by comparing the results of atomic force

  15. Enhancement of ZnO nanorod arrays-based inverted type hybrid organic solar cell using spin-coated Eosin-Y

    International Nuclear Information System (INIS)

    Lim, Eng Liang; Yap, Chi Chin; Yahaya, Muhammad; Salleh, Muhamad Mat

    2013-01-01

    This paper reports the effect of Eosin-Y coating concentration on the performance of inverted type hybrid organic solar cell based on ZnO nanorod arrays and poly(3-hexylthiophene-2,5-diyl) (P3HT). The Eosin-Y solution with concentrations of 0.05, 0.2, 2.0 and 5.0 mM was spin-coated onto the ZnO nanorod arrays grown on the fluorine-doped tin oxide glass substrate. The P3HT film was then spin-coated onto Eosin-Y-coated ZnO nanorod arrays, followed by deposition of silver (Ag) as anode using magnetron sputtering technique. The short circuit current density increased with the Eosin-Y coating concentration up to 0.2 mM, after which it started to decrease, mainly due to the aggregation of Eosin-Y which reduced the charge extraction from P3HT to ZnO. Meanwhile, the open circuit voltage increased with the Eosin-Y coating concentration, indicating reduced back charge recombination of electron on the ZnO and hole on the P3HT, as well as reduced leakage current through the direct contact between the ZnO nanorods and the Ag metal contact. The power conversion efficiency of the device with the optimum coating concentration was approximately eight times higher than that without Eosin-Y modification. (paper)

  16. Enhancement of ZnO nanorod arrays-based inverted type hybrid organic solar cell using spin-coated Eosin-Y

    Science.gov (United States)

    Lim, Eng Liang; Yap, Chi Chin; Yahaya, Muhammad; Mat Salleh, Muhamad

    2013-04-01

    This paper reports the effect of Eosin-Y coating concentration on the performance of inverted type hybrid organic solar cell based on ZnO nanorod arrays and poly(3-hexylthiophene-2,5-diyl) (P3HT). The Eosin-Y solution with concentrations of 0.05, 0.2, 2.0 and 5.0 mM was spin-coated onto the ZnO nanorod arrays grown on the fluorine-doped tin oxide glass substrate. The P3HT film was then spin-coated onto Eosin-Y-coated ZnO nanorod arrays, followed by deposition of silver (Ag) as anode using magnetron sputtering technique. The short circuit current density increased with the Eosin-Y coating concentration up to 0.2 mM, after which it started to decrease, mainly due to the aggregation of Eosin-Y which reduced the charge extraction from P3HT to ZnO. Meanwhile, the open circuit voltage increased with the Eosin-Y coating concentration, indicating reduced back charge recombination of electron on the ZnO and hole on the P3HT, as well as reduced leakage current through the direct contact between the ZnO nanorods and the Ag metal contact. The power conversion efficiency of the device with the optimum coating concentration was approximately eight times higher than that without Eosin-Y modification.

  17. Efficiency enhancement of polymer solar cells by applying poly(vinylpyrrolidone) as a cathode buffer layer via spin coating or self-assembly.

    Science.gov (United States)

    Wang, Haitao; Zhang, Wenfeng; Xu, Chenhui; Bi, Xianghong; Chen, Boxue; Yang, Shangfeng

    2013-01-01

    A non-conjugated polymer poly(vinylpyrrolidone) (PVP) was applied as a new cathode buffer layer in P3HT:PCBM bulk heterojunction polymer solar cells (BHJ-PSCs), by means of either spin coating or self-assembly, resulting in significant efficiency enhancement. For the case of incorporation of PVP by spin coating, power conversion efficiency (PCE) of the ITO/PEDOT:PSS/P3HT:PCBM/PVP/Al BHJ-PSC device (3.90%) is enhanced by 29% under the optimum PVP spin-coating speed of 3000 rpm, which leads to the optimum thickness of PVP layer of ~3 nm. Such an efficiency enhancement is found to be primarily due to the increase of the short-circuit current (J(sc)) (31% enhancement), suggesting that the charge collection increases upon the incorporation of a PVP cathode buffer layer, which originates from the conjunct effects of the formation of a dipole layer between P3HT:PCBM active layer and Al electrodes, the chemical reactions of PVP molecules with Al atoms, and the increase of the roughness of the top Al film. Incorporation of PVP layer by doping PVP directly into the P3HT:PCBM active layer leads to an enhancement of PCE by 13% under the optimum PVP doping ratio of 3%, and this is interpreted by the migration of PVP molecules to the surface of the active layer via self-assembly, resulting in the formation of the PVP cathode buffer layer. While the formation of the PVP cathode buffer layer is fulfilled by both fabrication methods (spin coating and self-assembly), the dependence of the enhancement of the device performance on the thickness of the PVP cathode buffer layer formed by self-assembly or spin coating is different, because of the different aggregation microstructures of the PVP interlayer.

  18. Filmes de titânio-silício preparados por "spin" e "dip-coating"

    Directory of Open Access Journals (Sweden)

    Nassar Eduardo J.

    2003-01-01

    Full Text Available The conditions for the preparation of luminescent materials, consisting of Eu3+ ions entrapped in a titanium matrix, in the forma of a thin film, using the sol-gel process, are described. The films were obtained from sols prepared with TEOS and TEOT, in the presence of acetylacetone as the hidrolysis-retarding agent, using the dip-coating and spin-coating techniques. The influence of these techniques on the films based on titanium and silicon are presented. The Eu3+ was used as a luminescent probe. The films have been characterized by luminescence, reflection and transmittance. The thickness of the films could be related to the preparation procedure. Transparent thin films have been prepared by dip-coating technique.

  19. Surface morphology of spin-coated As-S-Se chalcogenide thin films

    Czech Academy of Sciences Publication Activity Database

    Kohoutek, T.; Wágner, T.; Orava, J.; Krbal, M.; Fejfar, Antonín; Mates, Tomáš; Kasap, S. O.; Frumar, M.

    2007-01-01

    Roč. 353, - (2007), s. 1437-1440 ISSN 0022-3093 R&D Projects: GA AV ČR IAA1010316; GA AV ČR IAA1010413 Grant - others:GA ČR(CZ) GA203/05/0524; GAMŠk(CZ) LC523 Program:LC Institutional research plan: CEZ:AV0Z10100521 Keywords : chemical properties * spin coating * infrared glasses * chalcogenides * atomic force and scanning tunneling microscopy * scanning electron microscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.319, year: 2007

  20. Late stage crystallization and healing during spin-coating enhance carrier transport in small-molecule organic semiconductors

    KAUST Repository

    Chou, Kang Wei; Khan, Hadayat Ullah; Niazi, Muhammad Rizwan; Yan, Buyi; Li, Ruipeng; Payne, Marcia M.; Anthony, John Edward; Smilgies, Detlef Matthias; Amassian, Aram

    2014-01-01

    Spin-coating is currently the most widely used solution processing method in organic electronics. Here, we report, for the first time, a direct investigation of the formation process of the small-molecule organic semiconductor (OSC) 6,13-bis

  1. Improved electron injection in spin coated Alq3 incorporated ZnO thin film in the device for solution processed OLEDs

    Science.gov (United States)

    Dasi, Gnyaneshwar; Ramarajan, R.; Thangaraju, Kuppusamy

    2018-04-01

    We deposit tris-(8-hydroxyquinoline)aluminum (Alq3) incorporated zinc oxide (ZnO) thin films by spin coating method under the normal ambient. It showed the higher transmittance (90% at 550 nm) when compared to that (80% at 550 nm) of spin coated pure ZnO film. SEM studies show that the Alq3 incorporation in ZnO film also enhances the formation of small sized particles arranged in the network of wrinkles on the surface. XRD reveals the improved crystalline properties upon Alq3 inclusion. We fabricate the electron-only devices (EODs) with the structure of ITO/spin coated ZnO:Alq3 as ETL/Alq3 interlayer/LiF/Al. The device showed the higher electron current density of 2.75 mA/cm2 at 12V when compared to that (0.82 mA/cm2 at 12V) of the device using pure ZnO ETL. The device results show that it will be useful to fabricate the low-cost solution processed OLEDs for future lighting and display applications.

  2. Fabrication of yttrium-doped barium zirconate thin films with sub-micrometer thickness by a sol–gel spin coating method

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Hanlin; Su, Pei-Chen, E-mail: peichensu@ntu.edu.sg

    2015-06-01

    A modified sol–gel process was developed for the fabrication of sub-micrometer scale yttrium-doped barium zirconate (BZY) thin film at much lower processing temperatures. The film was fabricated by direct spin-coating of the sol on a Si{sub 3}N{sub 4} passivated Si substrate, followed by low temperature thermal annealing at 1000 °C, and single BZY phase without barium carbonate residue was obtained. A 200 nm-thick thin film without obvious through-film cracks was fabricated with optimized process parameters of sol concentration and heating rate. The stoichiometry of the BZY thin film was well-controlled and no Ba evaporation was observed due to the low processing temperature. The combination of sol–gel and spin coating method can be a promising alternative to vacuum-based thin film deposition techniques for the fabrication of sub-micrometer scale BZY thin film. - Highlights: • A sol–gel spin coating method was developed for the fabrication of BZY thin films. • The processing temperature was much lower compared to powder-based sintering. • Sub-micrometer scale BZY thin film with well-controlled stoichiometry was obtained.

  3. LE «SOTTIGLIEZZE DI CERTA DIDATTICA SUPERLATIVA» DELLA GRAMMATICA ELEMENTARE: STORIA (ATTESTATA DEL METODO RAFFORZISTA (1814-1914

    Directory of Open Access Journals (Sweden)

    Michela Dota

    2018-03-01

    Full Text Available Il contributo ripercorre la storia e le peculiarità del metodo rafforzista, metodo glottodidattico per l’insegnamento della lettura e della scrittura. Il metodo, nato in Italia nel primo Ottocento, nell’epoca postunitaria era praticato nelle scuole elementari soprattutto dell’Italia meridionale, nonché nelle scuole reggimentali e in alcuni istituti per sordomuti. Le sue fondamenta, aberranti rispetto alla norma ortografica e ortoepica tradizionale, lo resero obiettivo di un tenace ostracismo da parte del Ministero dell’Istruzione pubblica, sostenuto per questa occasione da due tra i più eminenti glottologi dell’epoca: Graziadio Isaia Ascoli e Francesco Lorenzo Pullè. Il metodo finì per estinguersi nel secondo decennio del Novecento.   The history of the “metodo rafforzista” for teaching Italian (1814-1914 This article retraces the history and peculiarities of the “metodo rafforzista”, a language teaching method developed in Italy during the first part of 1800s. In the post-Unitarian period, it was used in elementary schools, especially in Southern Italy, and also in military schools and in some institutes for the Deaf and Dumb. Orthographic and orthoepic models proposed by the “metodo rafforzista” diverged from rules of traditional Italian grammar. The method, supported by Graziadio Isaia Ascoli and Francesco Lorenzo Pullè, two of the most distinguished Italian linguists at that time, was subsequently rejected by the Ministry of Public Education, and it vanished during the second half of 1900s.

  4. Scienza e conoscenza: sul valore del metodo scientifico

    Directory of Open Access Journals (Sweden)

    Riccardo Luciano Appolloni

    2014-05-01

    Full Text Available L’antico problema di riconoscere una forma di conoscenza oggettivae fondata è ancora vivo; in questo scritto cercheremo di capire se la scienza moderna possa essere una forma di conoscenza tale e, quindi, privilegiata. A tal fine ci serviremo del pensiero di alcuni epistemologi e scienziati. In particolare, nel trattare il problema del valore epistemologico del metodo scientifico, non potremo esimerci dal fare i conti con l’anarchismo metodologico di Paul K. Feyerabend, verso il quale l’esito del presente articolo sarà fondamentalmente critico. A partire dai fecondi spunti di questo filosofo, tenteremo dapprima di analizzare i caratteri distintivi della scienza e del suo metodo rispetto ad altre forme di sapere; quindi, cercheremo di individuare alcuni limiti della conoscenza razionale.

  5. Structural and optical studies on spin coated ZnO-graphene conjugated thin films

    Science.gov (United States)

    Srinatha, N.; Angadi, Basavaraj; Son, D. I.; Choi, W. K.

    2018-05-01

    ZnO-Graphene conjugated thin films were prepared using spin coating technique for different spin rates. Prior to the deposition, ZnO-Graphene nanoparticles were synthesized and their particle size and conjugation was studied through Transmission electron microscope (TEM). The deposited films were characterized using grazing incidence x-ray diffractometer (GIXRD), atomic force microscope (AFM) and UV-Visible spectrometer for their crystallinity, surface topographic features and optical properties. GIXRD patterns confirms the presence of both ZnO and Graphene related crystalline peaks supports the TEM results, which shows the quasi core-shell type conjugation of ZnO-Graphene particles. The crystallinity as well as thickness of the films found to decrease with increase of spin rate. AFM results reveal the uniform, smooth and homogeneity of films and also good adhesivity of ZnO-Graphene with glass substrates. No significant change in the transmittance and absorption with spin rate is observed, while the band gap energy found to decrease due to the reduction in the thickness of the films and conjugation of ZnO-Graphene. All films exhibit˜90 % transmittance in the visible wavelength region, could be potential candidates for optoelectronics and transparent conducting oxide (TCO) applications.

  6. Tribological properties of self-assembled monolayers of catecholic imidazolium and the spin-coated films of ionic liquids.

    Science.gov (United States)

    Liu, Jianxi; Li, Jinlong; Yu, Bo; Ma, Baodong; Zhu, Yangwen; Song, Xinwang; Cao, Xulong; Yang, Wu; Zhou, Feng

    2011-09-20

    A novel compound of an imidazolium type of ionic liquid (IL) containing a biomimetic catecholic functional group normally seen in mussel adhesive proteins was synthesized. The IL can be immobilized on a silicon surface and a variety of other engineering material surfaces via the catecholic anchor, allowing the tribological protection of these substrates for engineering applications. The surface wetting and adhesive properties and the tribological property of the synthesized self-assembled monolayers (SAMs) are successfully modulated by altering the counteranions. The chemical composition and wettability of the IL SAMs were characterized by means of X-ray photoelectron spectroscopy (XPS) and contact angle (CA) measurements. The adhesive and friction forces were measured with an atomic force microscope (AFM) on the nanometer scale. IL composite films were prepared by spin coating thin IL films on top of the SAMs. The macrotribological properties of these IL composite films were investigated with a pin-on-disk tribometer. The results indicate that the presence of IL SAMs on a surface can improve the wettability of spin-coated ionic liquids and thus the film quality and the tribological properties. These films registered a reduced friction coefficient and a significantly enhanced durability and load-carrying capacity. The tribological properties of the composite films are better than those of pure IL films because the presence of the monolayers improves the adhesion and compatibility of spin-coated IL films with substrates. © 2011 American Chemical Society

  7. Direct Observation on Spin-Coating Process of PS- b -P2VP Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Hiroki; Takenaka, Mikihito; Miyazaki, Tsukasa; Fujiwara, Akihiko; Lee, Byeongdu; Shimokita, Keisuke; Nishibori, Eiji; Takata, Masaki

    2016-05-10

    We studied the structural development of symmetric poly(styrene-b-2-vinylpyridine) (PS-b-P2VP) block copolymers during spin-coating using in situ grazing incidence small angle X-ray scattering (GISAXS) measurements. During the spin-coating process, after the formation of the micelles in dilute solution, the selective solvent induced two kinds of the morphological transition. Firstly, the disordered spherical micelles were transformed into a BCC lattice of spheres of which the (110) plane was oriented perpendicularly to the substrate surface. Secondly, further evaporation induced a transition from spheres on the BCC lattice into cylindrical structures. The orientation of the cylinders perpendicular to the substrate surface was induced by solvent convection perpendicular to the substrate, which occurs during rapid solvent evaporation. After this transition, vitrification of PS and P2VP prevented any further transition from cylinders to the more thermodynamically stable lamellar structures, as are generally observed as the bulk equilibrium state.

  8. Comparative Study of Deposit through a Membrane and Spin-Coated MWCNT as a Flexible Anode for Optoelectronic Applications

    Directory of Open Access Journals (Sweden)

    Walid Aloui

    2016-01-01

    Full Text Available We present a comparative study between multiwalled carbon nanotubes (MWCNTs thin films deposited on polyethylene terephthalate (PET substrates using (i spin-coating technique and (ii deposition through a membrane. We deduce from transparence, electrical properties, and AFM image that deposition through membrane presents better properties than spin-coating method. The concentration comparison shows that the optimum result was achieved at a concentration of 1.2 mg·mL−1 corresponding to a resistance (Rs of 180 Ω·cm−2 and an optical transparence of about 81% using a wavelength 550 nm. We will also demonstrate the use of the elaborated electrodes to fabricate the following flexible structure: PET-MWCNTs/MEH-PPV/Al. The series resistance Rs and the ideality factor n were calculated.

  9. Properties and performance of spin-on-glass coatings for the corrosion protection of stainless steels in chloride media

    DEFF Research Database (Denmark)

    Lampert, Felix; Jensen, Annemette H.; Din, Rameez U.

    2018-01-01

    Spin-on-glass deposition was investigated as viable alternative to increase the durability and performance of 316L steel in chloride environment. The buildup of a detrimental interface oxide was prevented by non-oxidative thermal curing of the coatings, which leads to a transformation...... silica. Electrochemical analysis by cyclic polarization indicated that the coatings behave as imperfect barrier coatings, which may enhance the passive properties of the substrates; however, there is still some statistical scatter in the quality of the coatings. While there is a tendency for an increase...... of the upper limit of the breakdown potential, there is also a decrease of the lower limit. It was found that such lower quality coatings showed, in association with substrate defects, unevenly distributed coating flaws, which may act as initiation points of pitting corrosion and decrease the corrosion...

  10. Morphology, conductivity, and wetting characteristics of PEDOT:PSS thin films deposited by spin and spray coating

    Energy Technology Data Exchange (ETDEWEB)

    Zabihi, F.; Xie, Y.; Gao, S.; Eslamian, M., E-mail: Morteza.Eslamian@sjtu.edu.cn

    2015-05-30

    Highlights: • Nanostructure of spun-on and spray-on PEDOT:PSS thin films is studied. • A correlation is established between the film nanostructure and electrical conductivity. • Effect of process parameters is studied on the film characteristics. • A high solution concentration, high process temperature and multiple deposition layers are recommended. - Abstract: The goal of this paper is to study the characteristics of PEDOT:PSS thin films and the effects of varying the processing parameters on the structure, functionality, and surface wetting of spun-on and spray-on PEDOT:PSS thin films. PEDOT:PSS is a polymer mixture, which is electrically conductive and transparent and, therefore, is an attractive material for some optoelectronic applications, such as organic and perovskite solar cells. In this work, the films are fabricated using spin coating (a lab-scale method) and spray coating (an up-scalable method). The effects of spinning speed, drying time, and post-annealing temperature on spun-on samples and the effects of the substrate temperature and number of spray passes (deposition layers) on spray-on samples, as well as the effect of precursor solution concentration on both cases are investigated. Various characterization tools, such as AFM, SEM, XRD, confocal laser scanning microscopy (CLSM), and electrical conductivity measurements are used to determine the film roughness, thickness, structure, and morphology. The solution precursor physical data, such as contact angle on glass substrates, viscosity, and interfacial tension, are also obtained within a practical range of temperatures and concentrations. It is found that in both spin and spray coating routes, only well-controlled operating conditions result in the formation of conductive and defect-free PEDOT:PSS films. The formation of PEDOT:PSS thin films with small grains composed of PEDOT forming the core of the grains and PSS forming a shell or coating, which are evenly distributed in a PSS

  11. Morphology, conductivity, and wetting characteristics of PEDOT:PSS thin films deposited by spin and spray coating

    International Nuclear Information System (INIS)

    Zabihi, F.; Xie, Y.; Gao, S.; Eslamian, M.

    2015-01-01

    Highlights: • Nanostructure of spun-on and spray-on PEDOT:PSS thin films is studied. • A correlation is established between the film nanostructure and electrical conductivity. • Effect of process parameters is studied on the film characteristics. • A high solution concentration, high process temperature and multiple deposition layers are recommended. - Abstract: The goal of this paper is to study the characteristics of PEDOT:PSS thin films and the effects of varying the processing parameters on the structure, functionality, and surface wetting of spun-on and spray-on PEDOT:PSS thin films. PEDOT:PSS is a polymer mixture, which is electrically conductive and transparent and, therefore, is an attractive material for some optoelectronic applications, such as organic and perovskite solar cells. In this work, the films are fabricated using spin coating (a lab-scale method) and spray coating (an up-scalable method). The effects of spinning speed, drying time, and post-annealing temperature on spun-on samples and the effects of the substrate temperature and number of spray passes (deposition layers) on spray-on samples, as well as the effect of precursor solution concentration on both cases are investigated. Various characterization tools, such as AFM, SEM, XRD, confocal laser scanning microscopy (CLSM), and electrical conductivity measurements are used to determine the film roughness, thickness, structure, and morphology. The solution precursor physical data, such as contact angle on glass substrates, viscosity, and interfacial tension, are also obtained within a practical range of temperatures and concentrations. It is found that in both spin and spray coating routes, only well-controlled operating conditions result in the formation of conductive and defect-free PEDOT:PSS films. The formation of PEDOT:PSS thin films with small grains composed of PEDOT forming the core of the grains and PSS forming a shell or coating, which are evenly distributed in a PSS

  12. Microstructures and Photovoltaic Properties of Zn(AlO/Cu2O-Based Solar Cells Prepared by Spin-Coating and Electrodeposition

    Directory of Open Access Journals (Sweden)

    Takeo Oku

    2014-03-01

    Full Text Available Copper oxide (Cu2O-based heterojunction solar cells were fabricated by spin-coating and electrodeposition methods, and photovoltaic properties and microstructures were investigated. Zinc oxide (ZnO and Cu2O were used as n- and p-type semiconductors, respectively, to fabricate photovoltaic devices based on In-doped tin oxide/ZnO/Cu2O/Au heterojunction structures. Short-circuit current and fill factor increased by aluminum (Al doping in the ZnO layer, which resulted in the increase of the conversion efficiency. The efficiency was improved further by growing ZnO and Cu2O layers with larger crystallite sizes, and by optimizing the Al-doping by spin coating.

  13. Advanced fabrication method for the preparation of MOF thin films: Liquid-phase epitaxy approach meets spin coating method.

    KAUST Repository

    Chernikova, Valeriya; Shekhah, Osama; Eddaoudi, Mohamed

    2016-01-01

    Here we report a new and advanced method for the fabrication of highly oriented/polycrystalline metal-organic framework (MOF) thin films. Building on the attractive features of the liquid-phase epitaxy (LPE) approach, a facile spin coating method

  14. Track-etched nanopores in spin-coated polycarbonate films applied as sputtering mask

    International Nuclear Information System (INIS)

    Nix, A.-K.; Gehrke, H.-G.; Krauser, J.; Trautmann, C.; Weidinger, A.; Hofsaess, H.

    2009-01-01

    Thin polycarbonate films were spin-coated on silicon substrates and subsequently irradiated with 1-GeV U ions. The ion tracks in the polymer layer were chemically etched yielding nanopores of about 40 nm diameter. In a second process, the nanoporous polymer film acted as mask for structuring the Si substrate underneath. Sputtering with 5-keV Xe ions produced surface craters of depth ∼150 nm and diameter ∼80 nm. This arrangement can be used for the fabrication of track-based nanostructures with self-aligned apertures.

  15. Polarized Emission from Conjugated Polymer Chains Aligned by Epitaxial Growth during Off-Center Spin-Coating

    Directory of Open Access Journals (Sweden)

    Takuya Anzai

    2017-01-01

    Full Text Available Due to their macromolecular nature, conjugated polymers can be relatively easily aligned by applying a variety of processes resulting in either elongation or ordering of their conjugated backbones. Processes that induce chain alignment include electrospinning, mechanical rubbing, epitaxial growth, and nanoconfinement and unidirectional deposition techniques such as off-center spin-coating. In this study, we compare these deposition techniques by applying them to a green-emitting conjugated polymer material that exhibits liquid crystalline phase behavior. Our study reveals that while methods such as electrospinning and mechanical rubbing can be useful to locally generate polymer chain alignment, the combination of epitaxial growth using 1,3,5-trichlorobenzene as crystallizing agent with off-center spin-coating results in the formation of anisotropic nanofiber-like structures with enhanced crystallinity degree and polarized light-emission properties. The unidirectional epitaxial growth was also applied to a red-emitting polymer that exhibits polarization ratios up to 4.1. Our results emphasize that this simple solution formulation and process can be used for the fabrication of polarized thin films of a variety of conjugated polymers with potential applications in the advanced display technologies or analytical equipment fields.

  16. Carbon decorative coatings by dip-, spin-, and spray-assisted layer-by-layer assembly deposition.

    Science.gov (United States)

    Hong, Jinkee; Kang, Sang Wook

    2011-09-01

    We performed a comparative surface analysis of all-carbon nano-objects (multiwall carbon nanotubes (MWNT) or graphene oxide (GO) sheets) based multilayer coatings prepared using three widely used nanofilm fabrication methods: dip-, spin-, and spray-assisted layer-by-layer (LbL) deposition. The resultant films showed a marked difference in their growth mechanisms and surface morphologies. Various carbon decorative coatings were synthesized with different surface roughness values, despite identical preparation conditions. In particular, smooth to highly rough all-carbon surfaces, as determined by atomic force microscopy (AFM) and scanning electron microscopy (SEM), were readily obtained by manipulating the LbL deposition methods. As was confirmed by the AFM and SEM analyses, this finding indicated the fundamental morphological evolution of one-dimensional nano-objects (MWNT) and two-dimensional nano-objects (GO) by control of the surface roughness through the deposition method. Therefore, an analysis of the three LbL-assembly methods presented herein may offer useful information about the industrial use of carbon decorative coatings and provide an insight into ways to control the structures of multilayer coatings by tuning the morphologies of carbon nano-objects.

  17. Investigation of optical band gap and device parameters of rubrene thin film prepared using spin coating technique

    International Nuclear Information System (INIS)

    Tuğluoğlu, Nihat; Barış, Behzad; Gürel, Hatice; Karadeniz, Serdar; Yüksel, Ömer Faruk

    2014-01-01

    Highlights: • Thin film of rubrene has been deposited by spin coating technique. • The band gap properties of the film were investigated in the range 200–700 nm. • The analysis of the absorption coefficient revealed indirect allowed transition. • The parameters such as barrier height and ideality factor were determined. -- Abstract: Rubrene thin film has been deposited by spin coating technique. The optical band gap properties of rubrene thin film have been investigated in the spectral range 200–700 nm. The results of the absorption coefficient (α) were analyzed in order to determine the optical band gap and Urbach energy of the film. The absorption spectra recorded in the UV–vis region shows two peaks at 250 nm and 300 nm. The analysis of the spectral behavior of the absorption coefficient (α) in the absorption region revealed indirect allowed transition with corresponding energy 2.31 eV. The value of Urbach energy (E U ) was determined to be 1.169 eV. The current–voltage (I–V) characteristics and electrical conduction properties of rubrene/n-Si device fabricated by spin coating method have also been investigated. The I–V characteristic in dark was showed the rectification effect due to the formation of Schottky barrier at rubrene/silicon interface. From analyzing the I-V measurement for the device, the basic device parameters such as barrier height, ideality factor and series resistance were determined. At the low-voltage region, the current conduction in Au/rubrene/n-Si device is ohmic type. The charge transport phenomenon appears to be space charge limited current (SCLC) at higher-voltage regions

  18. Investigation of optical band gap and device parameters of rubrene thin film prepared using spin coating technique

    Energy Technology Data Exchange (ETDEWEB)

    Tuğluoğlu, Nihat, E-mail: tugluo@gmail.com [Department of Technology, Sarayköy Nuclear Research and Training Center, 06983 Saray, Ankara (Turkey); Barış, Behzad; Gürel, Hatice [Department of Physics, Faculty of Arts and Sciences, Giresun University, Gazipaşa Campus, Giresun 28100 (Turkey); Karadeniz, Serdar [Department of Technology, Sarayköy Nuclear Research and Training Center, 06983 Saray, Ankara (Turkey); Yüksel, Ömer Faruk [Department of Physics, Faculty of Science, Selçuk University, Campus Konya 42075 (Turkey)

    2014-01-05

    Highlights: • Thin film of rubrene has been deposited by spin coating technique. • The band gap properties of the film were investigated in the range 200–700 nm. • The analysis of the absorption coefficient revealed indirect allowed transition. • The parameters such as barrier height and ideality factor were determined. -- Abstract: Rubrene thin film has been deposited by spin coating technique. The optical band gap properties of rubrene thin film have been investigated in the spectral range 200–700 nm. The results of the absorption coefficient (α) were analyzed in order to determine the optical band gap and Urbach energy of the film. The absorption spectra recorded in the UV–vis region shows two peaks at 250 nm and 300 nm. The analysis of the spectral behavior of the absorption coefficient (α) in the absorption region revealed indirect allowed transition with corresponding energy 2.31 eV. The value of Urbach energy (E{sub U}) was determined to be 1.169 eV. The current–voltage (I–V) characteristics and electrical conduction properties of rubrene/n-Si device fabricated by spin coating method have also been investigated. The I–V characteristic in dark was showed the rectification effect due to the formation of Schottky barrier at rubrene/silicon interface. From analyzing the I-V measurement for the device, the basic device parameters such as barrier height, ideality factor and series resistance were determined. At the low-voltage region, the current conduction in Au/rubrene/n-Si device is ohmic type. The charge transport phenomenon appears to be space charge limited current (SCLC) at higher-voltage regions.

  19. Efficiency improvement of flexible fluorescent and phosphorescent organic light emitting diodes by inserting a spin-coating buffer layer

    International Nuclear Information System (INIS)

    Tsai, Yu-Sheng; Wang, Shun-Hsi; Chen, Shen-Yaur; Su, Shin-Yuan; Juang, Fuh-Shyang

    2009-01-01

    We dissolved hole transport materials α-NPD and NPB in THF solvent, and spin-coated the α-NPD + THF or NPB + THF solution onto ITO anode surface to improve the luminance efficiency and lifetime of flexible fluorescent and phosphorescent organic light emitting diodes. Then the BCP and TPBi were employed as hole blocking layer (HBL) of phosphorescent device and its thickness was optimized. From the experimental results, the maximum luminance efficiency is 4.4 cd/A at 9 V of fluorescent device and 24.4 cd/A of phosphorescent device, respectively. Such an improvement in the device performance was attributed to the smoother surface and good contact between the interface of spin-coated HTL/ITO, the hole were effectively injected from the anode into the organic layer. And the deposited HTL can block excitons from diffusing into the anode to quench, thus improving the luminance efficiency and lifetime greatly.

  20. Fabrication of barium titanate nanoparticles/poly (methylmethacrylate composite films by a combination of deposition process and spin-coating technique

    Directory of Open Access Journals (Sweden)

    Yoshio Kobayashi

    2014-10-01

    Full Text Available The present work proposes a method for fabricating poly(methylmethacrylate (PMMA film containing barium titanate (BT nanoparticles (BT/PMMA film. BT particles with an average size of 77.6 ± 30.5 nm and a crystal size of 28.1 nm were synthesized by adding sodium hydroxide aqueous solution to titanium tetraisopropoxide/acetylacetone/i-propanol solution suspending barium hydroxide. A sodium glass plate, of which surface was modified with polyvinylpyrrolidone, was immersed into water suspending the BT particles, which resulted in deposition of the BT particles on the plate. A BT/PMMA film was fabricated by twice performance of a process composed of spin-coating of N-methyl-2-pyrrolidone (NMP dissolving PMMA on the plate, and then drying the coated plate in the atmosphere at room temperature. Spin-coating of a PMMA/NMP solution with a PMMA concentration of 150 g/L at a rotating speed of 5000 rpm provided fabrication of a BT/PMMA film with a BT volume fraction of 35.5%, a thickness of ca. 300 nm, and a transmittance of ca. 90% in the visible light region.

  1. Electrical characteristic of spin coated Fe-Porphyrin on Cu substrates

    Energy Technology Data Exchange (ETDEWEB)

    Utari, E-mail: utari@ugm.ac.id [Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Sebelas Maret, Jl. Ir. Sutami 36A Kentingan Surakarta 57126 (Indonesia); Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Bulaksumur BLS 21 Yogyakarta 55281 (Indonesia); Kusumandari,; Purnama, Budi, E-mail: bpurnama@mipa.uns.ac.id [Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Sebelas Maret, Jl. Ir. Sutami 36A Kentingan Surakarta 57126 (Indonesia); Mudasir [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Bulaksumur BLS 21 Yogyakarta 55281 (Indonesia); Abraha, Kamsul [Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Bulaksumur BLS 21 Yogyakarta 55281 (Indonesia)

    2016-06-17

    This paper describes the electrical-characteristics of Fe-Porphyrin thin films on Cu substrates. The thin layer samples used were deposited by spin coating methods on Cu-substrates at room temperature with and without induced magnetic field in the plane direction of the surface films. Fe-porphyrin was dissolved in chloroform and mixed with a magnetic stirrer for 60 min at a rotational speed of 200 rpm. The experimental results show that the mobility carrier charge of the Fe-Porphyrin layer with induced magnetic field during deposition has lower value than that without induced magnetic field case. The decrease of the mobility can be attribute to the change of the surface morphology in Fe-porphyrin films by means of increase in the nano-granular/nano-molecular size caused by the induce magnetic field.

  2. Use of resonance ionization spectroscopy to detect DNA bands on ultrathin spin-coated gels.

    Science.gov (United States)

    Doktycz, M J; Gibson, W A; Arlinghaus, H F; Allen, R C; Jacobson, K B

    1993-01-01

    Development of alternative electrophoresis procedures are necessary for large volume sequencing and mapping studies. The use of stable isotopes as DNA labels and ultrathin gels promises to greatly increase the rate of sequencing. Spin coating is presented as an alternative method for producing ultrathin polyacrylamide gels. The technique has the potential of producing gels of micron to submicron thicknesses by varying the viscosity of the acrylamide solution and the spinning speed. Thirty micron thick 6% (weight %) gels were produced in this manner. Tin-labeled DNA oligomers were electrophoresed and detected using sputter-initiated resonance ionization spectroscopy (SIRIS). The usefulness of SIRIS and laser atomization RIS (LARIS) to sample the surface and deeper layers of 240 microns thick gels was investigated. With LARIS, whole cross-sections of the gel can be atomized, possibly allowing complete sampling of labels.

  3. Fabrication of selenization-free superstrate-type CuInS{sub 2} solar cells based on all-spin-coated layers

    Energy Technology Data Exchange (ETDEWEB)

    Cheshme khavar, Amir Hossein [Department of Chemistry, Tarbiat Modares University, P.O. Box. 14155-4383, Gisha Bridge, Tehran (Iran, Islamic Republic of); Mahjoub, Alireza, E-mail: mahjouba@modares.ac.ir [Department of Chemistry, Tarbiat Modares University, P.O. Box. 14155-4383, Gisha Bridge, Tehran (Iran, Islamic Republic of); Samghabadi, Farnaz Safi [Physics Department, Sharif University of Technology, Tehran, 14588 (Iran, Islamic Republic of); Taghavinia, Nima, E-mail: taghavinia@sharif.edu [Physics Department, Sharif University of Technology, Tehran, 14588 (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran, 14588 (Iran, Islamic Republic of)

    2017-01-15

    Today manufacturing of high efficiency chalcogenide thin film solar cells is based on high cost vacuum-based deposition processes at high temperature (>500 °C) and in chalcogen -containing atmosphere. In this paper, we introduce a simple vacuum-free and selenization-free, solution processing for fabricating a superstrate-type CuInS{sub 2} (CIS) solar cell. The absorber, buffer and blocking layers were all deposited by spin coating of molecular precursor inks. We demonstrate the deposition of In{sub 2}S{sub 3} buffer layer by sol-gel spin casting for the first time. The rapid sintering process of CIS layer was carried out at 250 °C that is considered a very low temperature in CIGS thin-film technologies. A novel molecular-ink route to deposit In{sub 2}S{sub 3} type buffer layer is presented. For the back contact we employed carbon, deposited by simple knife coating method. Different parameters including type of buffer, thickness of absorber layer, CIS and In{sub 2}S{sub 3} annealing temperature and morphology were optimized. Our air stable simple device structure consisting of showed promising power conversion efficiency (PCE) of 2.67%. - Highlights: • This work is an effort on the fabrication of all spin-coated CIS solar cells. • A novel molecular-ink route to deposit In{sub 2}S{sub 3} type buffer layer is presented. • The best devices showed power conversion efficiency (PCE) of 2.67%.

  4. Observation of prolonged coherence time of the collective spin wave of an atomic ensemble in a paraffin-coated 87Rb vapor cell

    International Nuclear Information System (INIS)

    Jiang Shuo; Luo Xiaoming; Chen Liqing; Ning Bo; Chen Shuai; Wang Jingyang; Zhong Zhiping; Pan Jianwei

    2009-01-01

    We report a prolonged coherence time of the collective spin wave of a thermal 87 Rb atomic ensemble in a paraffin-coated cell. The spin wave is prepared through a stimulated Raman process. The long coherence time is achieved by prolonging the lifetime of the spins with paraffin coating and minimize dephasing with optimal experimental configuration. The observation of the long-time-delayed-stimulated Stokes signal in the writing process suggests the prolonged lifetime of the prepared spins; a direct measurement of the decay of anti-Stokes signal in the reading process shows the coherence time is up to 300 μs after minimizing dephasing. This is 100 times longer than the reported coherence time in the similar experiments in thermal atomic ensembles based on the Duan-Lukin-Cirac-Zoller and its improved protocols. This prolonged coherence time sets the upper limit of the memory time in quantum repeaters based on such protocols, which is crucial for the realization of long-distance quantum communication. The previous reported fluorescence background in the writing process due to collision in a sample cell with buffer gas is also reduced in a cell without buffer gas.

  5. Indium Sulfide and Indium Oxide Thin Films Spin-Coated from Triethylammonium Indium Thioacetate Precursor for n-Channel Thin Film Transistor

    Energy Technology Data Exchange (ETDEWEB)

    Tung, Duy Dao; Jeong, Hyun Dam [Chonnam Natioal University, Gwangju (Korea, Republic of)

    2014-09-15

    The In{sub 2}S{sub 3} thin films of tetragonal structure and In{sub 2}O{sub 3} films of cubic structure were synthesized by a spin coating method from the organometallic compound precursor triethylammonium indium thioacetate ([(Et){sub 3}NH]+ [In(SCOCH{sub 3}){sub 4}]''-; TEA-InTAA). In order to determine the electron mobility of the spin-coated TEA-InTAA films, thin film transistors (TFTs) with an inverted structure using a gate dielectric of thermal oxide (SiO{sub 2}) was fabricated. These devices exhibited n-channel TFT characteristics with a field-effect electron mobility of 10.1 cm''2 V''-1s''-1 at a curing temperature of 500 o C, indicating that the semiconducting thin film material is applicable for use in low-cost, solution-processed printable electronics.

  6. Characterization of nanocrystalline ZnO:Al films by sol-gel spin coating method

    Energy Technology Data Exchange (ETDEWEB)

    Gareso, P. L., E-mail: pgareso@gmail.com; Rauf, N., E-mail: pgareso@gmail.com; Juarlin, E., E-mail: pgareso@gmail.com [Department of Physics, Faculty of Mathematics and Natural Sciences, Hasanuddin University, Makassar 90245 (Indonesia); Sugianto,; Maddu, A. [Department of Physics, Faculty of Mathematics and Natural Sciences, Bogor Institute of Culture, IPB Bogor (Indonesia)

    2014-09-25

    Nanocrystalline ZnO films doped with aluminium by sol-gel spin coating method have been investigated using optical transmittance UV-Vis and X-ray diffraction (X-RD) measurements. ZnO films were prepared using zinc acetate dehydrate (Zn(CH{sub 3}COO){sub 2}@@‡2H{sub 2}O), ethanol, and diethanolamine (DEA) as a starting material, solvent, and stabilizer, respectively. For doped films, AlCl{sub 3} was added to the mixture. The ZnO:Al films were deposited on a transparent conductive oxide (TCO) substrate using spin coating technique at room temperature with a rate of 3000 rpm in 30 sec. The deposited films were annealed at various temperatures from 400°C to 600°C during 60 minutes. The transmittance UV-Vis measurement results showed that after annealing at 400°C, the energy band gap profile of nanocrystalline ZnO:Al film was a blue shift. This indicated that the band gap of ZnO:Al increased after annealing due to the increase of crystalline size. As the annealing temperature increased the bandgap energy was a constant. In addition to this, there was a small oscillation occurring after annealing compared to the as–grown samples. In the case of X-RD measurements, the crystalinity of the films were amorphous before annealing, and after annealing the crystalinity became enhance. Also, X-RD results showed that structure of nanocrystalline ZnO:Al films were hexagonal polycrystalline with lattice parameters are a = 3.290 Å and c = 5.2531 Å.

  7. Structural, compositional and optical properties of spin coated MoO3 thin film

    Science.gov (United States)

    Jain, Vishva; Shah, Dimple; Patel, K. D.; Zankat, Chetan

    2018-05-01

    The attraction towards the MoO3 thin film is due to its wide range of application base on its properties. Its application in the field of energy storage and conversion as a cathode material for rechargeable lithium ion battery, hole selective layer in solar cell and in pseudocapacitors makes it more attractive material. Taking in consideration, economical route and tailoring advantage of film formation we have used spin coating method for the synthesis of the film with Ammonium heptamolybdate (NH4)6Mo7O24 4H2O) and distilled water as the precursor and solvent respectively on the glass substrate. The method also provides the large area synthesis of the film which is beneficial for the commercial applications. The film was spin coated at 1600 rpm with 4 % weight per volume ratio. The film so formed was annealed at 300 °C for 3 hours. The structural investigation was done by the X-Ray diffraction technique which shows the thin film of polycrystalline type. The average crystallize size is about 50 nm. The composition of the film was studied with the help of EDAX. The optical properties were studied by the photoluminescence and UV Spectroscopy. The results from both the characterization are well matched with each other. Photoluminescence studies show band to band emission observed at 416 nm shown in the fig. 5. From UV spectroscopy, using transmission and absorption spectra we observed the band gap edge around 3 eV. This is in accordance with the photoluminescence result.

  8. Effects of annealing and plasma treatment on the electrical and optical properties of spin-coated ITZO films

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong-min; Kim, Jae-Kwan [Department of Materials Science and Metallurgical Engineering, Sunchon National University, Sunchon, Chonnam 540-742 (Korea, Republic of); Hao, Jinchen; Kim, Han-Ki [Department of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, Yongin-si, Gyeonggi-do 446-701 (Korea, Republic of); Yoon, Jae-Sik [Division of Materials Science, Korea Basic Science Institute, Daejeon 305-333 (Korea, Republic of); Lee, Ji-Myon, E-mail: jimlee@sunchon.ac.kr [Department of Printed Electronics Engineering, Sunchon National University, Sunchon, Chonnam 540-742 (Korea, Republic of)

    2014-01-15

    Highlights: • The resistivity of ITZO was enhanced by H{sub 2} gas plasma treatment. • The transmittance of H{sub 2} treated film was same as that of ref. after wet treatment. • The plasma process was carried out at room temperature. -- Abstract: This paper reports the effects on the optical and electrical properties of indium tin zinc oxide (ITZO) films by annealing and hydrogen plasma treatment. ITZO films were prepared by spin-coating using ITZO nanoink. The sheet resistance of the spin-coated ITZO was decreased to 155 Ω/square after annealing at 300 °C. Subsequent inductively-coupled hydrogen plasma decreased the sheet resistance of the ITZO film further to 88 Ω/square due to the formation of a high density of O–H bonds and oxygen vacancies leaving a metal cluster on the surface, which is comparable to that of solution-processed ITO films. Although the transmittance of the hydrogen plasma-treated sample was decreased considerable by the formation of metal clusters, the transmittance and optical band gap could be enhanced without a deteriorating the electrical properties by removing the metal clusters using a H{sub 2}SO{sub 4} solution.

  9. Characterisation and vapour sensing properties of spin coated thin films of anthracene labelled PMMA polymer

    Energy Technology Data Exchange (ETDEWEB)

    Capan, I., E-mail: inci.capan@gmail.com [Balikesir University, Faculty of Art and Sciences, Department of Physics, Cagis Campus, 10145 Balikesir (Turkey); Tarimci, C., E-mail: Celik.Tarimci@eng.ankara.edu.tr [Ankara University, Faculty of Engineering, Department of Engineering Physics, 06100, Ankara (Turkey); Erdogan, M., E-mail: merdogan@balikesir.edu.tr [Balikesir University, Faculty of Art and Sciences, Department of Physics, Cagis Campus, 10145 Balikesir (Turkey); Hassan, A.K., E-mail: A.Hassan@shu.ac.uk [Materials and Engineering Research Institute, Sheffield Hallam University, Sheaf Building, Pond Street, Sheffield S1 1WB (United Kingdom)

    2009-05-05

    In the present article thin films of poly (methyl methacrylate) (PMMA) polymer labelled with anthracene (Ant-PMMA) prepared by spin coating are characterised by UV-visible spectroscopy, surface plasmon resonance (SPR), spectroscopic ellipsometry (SE) and Atomic Force Microscopy (AFM) and their organic vapour sensing properties are investigated. Ant-PMMA films' thickness are determined by performing theoretical fitting to experimental data measured using SPR and SE. Results obtained show that the spin-cast films are of good uniformity with an average thickness of 6-8 nm. Organic vapour sensing properties are studied using SPR technique during exposures to different volatile organic compounds (VOCs). Ant-PMMA films' response to the selected VOCs has been examined in terms of solubility parameters and molar volumes of the solvents, and the films were found to be largely sensitive to benzene vapour compared to other studied analytes.

  10. Characterisation and vapour sensing properties of spin coated thin films of anthracene labelled PMMA polymer

    International Nuclear Information System (INIS)

    Capan, I.; Tarimci, C.; Erdogan, M.; Hassan, A.K.

    2009-01-01

    In the present article thin films of poly (methyl methacrylate) (PMMA) polymer labelled with anthracene (Ant-PMMA) prepared by spin coating are characterised by UV-visible spectroscopy, surface plasmon resonance (SPR), spectroscopic ellipsometry (SE) and Atomic Force Microscopy (AFM) and their organic vapour sensing properties are investigated. Ant-PMMA films' thickness are determined by performing theoretical fitting to experimental data measured using SPR and SE. Results obtained show that the spin-cast films are of good uniformity with an average thickness of 6-8 nm. Organic vapour sensing properties are studied using SPR technique during exposures to different volatile organic compounds (VOCs). Ant-PMMA films' response to the selected VOCs has been examined in terms of solubility parameters and molar volumes of the solvents, and the films were found to be largely sensitive to benzene vapour compared to other studied analytes.

  11. Bottom Extreme-Ultraviolet-Sensitive Coating for Evaluation of the Absorption Coefficient of Ultrathin Film

    Science.gov (United States)

    Hijikata, Hayato; Kozawa, Takahiro; Tagawa, Seiichi; Takei, Satoshi

    2009-06-01

    A bottom extreme-ultraviolet-sensitive coating (BESC) for evaluation of the absorption coefficients of ultrathin films such as extreme ultraviolet (EUV) resists was developed. This coating consists of a polymer, crosslinker, acid generator, and acid-responsive chromic dye and is formed by a conventional spin-coating method. By heating the film after spin-coating, a crosslinking reaction is induced and the coating becomes insoluble. A typical resist solution can be spin-coated on a substrate covered with the coating film. The evaluation of the linear absorption coefficients of polymer films was demonstrated by measuring the EUV absorption of BESC substrates on which various polymers were spin-coated.

  12. Nanostructured ZnO thin films prepared by sol–gel spin-coating

    Energy Technology Data Exchange (ETDEWEB)

    Heredia, E., E-mail: heredia.edu@gmail.com [UNIDEF (CONICET-MINDEF), J.B. de La Salle 4397, 1603 Villa Martelli, Pcia. de Buenos Aires (Argentina); Bojorge, C.; Casanova, J.; Cánepa, H. [UNIDEF (CONICET-MINDEF), J.B. de La Salle 4397, 1603 Villa Martelli, Pcia. de Buenos Aires (Argentina); Craievich, A. [Instituto de Física, Universidade de São Paulo, Cidade Universitária, 66318 São Paulo, SP (Brazil); Kellermann, G. [Universidade Federal do Paraná, 19044 Paraná (Brazil)

    2014-10-30

    Highlights: • ZnO films synthesized by sol–gel were deposited by spin-coating on flat substrates. • Structural features of ZnO films with several thicknesses were characterized by means of different techniques. • The thicknesses of different ZnO thin films were determined by means of FESEM and AFM. • The nanoporous structures of ZnO thin films were characterized by GISAXS using IsGISAXS software. • The average densities of ZnO thin films were derived from (i) the critical angle in 1D XR patterns, (ii) the angle of Yoneda peak in 2D GISAXS images, (iii) minimization of chi2 using IsGISAXS best fitting procedure. - Abstract: ZnO thin films deposited on silica flat plates were prepared by spin-coating and studied by applying several techniques for structural characterization. The films were prepared by depositing different numbers of layers, each deposition being followed by a thermal treatment at 200 °C to dry and consolidate the successive layers. After depositing all layers, a final thermal treatment at 450 °C during 3 h was also applied in order to eliminate organic components and to promote the crystallization of the thin films. The total thickness of the multilayered films – ranging from 40 nm up to 150 nm – was determined by AFM and FESEM. The analysis by GIXD showed that the thin films are composed of ZnO crystallites with an average diameter of 25 nm circa. XR results demonstrated that the thin films also exhibit a large volume fraction of nanoporosity, typically 30–40 vol.% in thin films having thicknesses larger than ∼70 nm. GISAXS measurements showed that the experimental scattering intensity is well described by a structural model composed of nanopores with shape of oblate spheroids, height/diameter aspect ratio within the 0.8–0.9 range and average diameter along the sample surface plane in the 5–7 nm range.

  13. Magnetism in spin-coated pristine TiO{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hassini, Awatef [IUT de Blois, 3 place Jean Jaures, C.S. 2903, 41029 Blois (France); Sakai, Joe [Laboratoire LEMA, UMR 6157 CNRS/CEA, Universite Francois Rabelais, Parc de Grandmont, 37200 Tours (France); Lopez, Josep Santiso [Institut de Ciencia de Materials de Barcelona, CSIC, Campus UAB, Bellaterra 08193 (Spain); Nguyen Hoa Hong [Laboratoire LEMA, UMR 6157 CNRS/CEA, Universite Francois Rabelais, Parc de Grandmont, 37200 Tours (France)], E-mail: nguyen.hoahong@univ-tours.fr

    2008-04-28

    Spin coated pristine TiO{sub 2} thin films show magnetic behaviors that are similar to those of pulsed laser ablated TiO{sub 2} thin films that were reported previously. It seems that in this kind of material, ferromagnetism (FM) is indeed intrinsic, and it can be achieved by various deposition techniques. The fact that oxygen annealing degrades the magnetic moment implies that the observed magnetism is likely due to defects or/and oxygen vacancies. Moreover, thick films that were deposited under the same growth conditions have the magnetic ordering degraded enormously. It is found that as for FM in undoped TiO{sub 2} films made by the chemical solution deposition, not only do defects/oxygen vacancies play a role, but also the confinement effects seem to be important.

  14. Comparison of barium titanate thin films prepared by inkjet printing and spin coating

    Directory of Open Access Journals (Sweden)

    Jelena Vukmirović

    2015-09-01

    Full Text Available In this paper, barium titanate films were prepared by different deposition techniques (spin coating, office Epson inkjet printer and commercial Dimatix inkjet printer. As inkjet technique requires special rheological properties of inks the first part of the study deals with the preparation of inks, whereas the second part examines and compares structural characteristics of the deposited films. Inks were synthesized by sol-gel method and parameters such as viscosity, particle size and surface tension were measured. Deposited films were examined by optical and scanning electron microscopy, XRD analysis and Raman spectroscopy. The findings consider advantages and disadvantages of the particular deposition techniques.

  15. Nondispersive hole transport in a spin-coated dendrimer film measured by the charge-generation-layer time-of-flight method

    Science.gov (United States)

    Markham, Jonathan P. J.; Anthopoulos, Thomas D.; Samuel, Ifor D. W.; Richards, Gary J.; Burn, Paul L.; Im, Chan; Bassler, Heinz

    2002-10-01

    Measurements of the mobility of a first-generation (G1) bis-fluorene cored dendrimer have been performed on spin-coated samples of 500 nm thickness using the charge-generation-layer time-of-flight (TOF) technique. A 10 nm perylene charge generation layer was excited by the 532 nm line of a Q-switched Nd:YAG laser and the generated carriers swept through the dendrimer film under an applied field. We observe nondispersive hole transport in the dendrimer layer with a room-temperature mobility mu=2.0 x10-4 cm2/V s at a field of 0.55 MV/cm. There is a weak field dependence of the mobility and it increases from mu=1.6 x10-4 cm2/V s at 0.2 MV/cm to mu=3.0 x10-4 cm2/V s at 1.4 MV/cm. These results suggest that the measurement of mobility by TOF in spin-coated samples on thickness scales relevant to organic light-emitting diodes can yield valuable information, and that dendrimers are promising materials for device applications.

  16. Nanoscale Morphology of Doctor Bladed versus Spin-Coated Organic Photovoltaic Films

    KAUST Repository

    Pokuri, Balaji Sesha Sarath

    2017-08-17

    Recent advances in efficiency of organic photovoltaics are driven by judicious selection of processing conditions that result in a “desired” morphology. An important theme of morphology research is quantifying the effect of processing conditions on morphology and relating it to device efficiency. State-of-the-art morphology quantification methods provide film-averaged or 2D-projected features that only indirectly correlate with performance, making causal reasoning nontrivial. Accessing the 3D distribution of material, however, provides a means of directly mapping processing to performance. In this paper, two recently developed techniques are integrated—reconstruction of 3D morphology and subsequent conversion into intuitive morphology descriptors —to comprehensively image and quantify morphology. These techniques are applied on films generated by doctor blading and spin coating, additionally investigating the effect of thermal annealing. It is found that morphology of all samples exhibits very high connectivity to electrodes. Not surprisingly, thermal annealing consistently increases the average domain size in the samples, aiding exciton generation. Furthermore, annealing also improves the balance of interfaces, enhancing exciton dissociation. A comparison of morphology descriptors impacting each stage of photophysics (exciton generation, dissociation, and charge transport) reveals that spin-annealed sample exhibits superior morphology-based performance indicators. This suggests substantial room for improvement of blade-based methods (process optimization) for morphology tuning to enhance performance of large area devices.

  17. Manufacturing PDMS micro lens array using spin coating under a multiphase system

    International Nuclear Information System (INIS)

    Sun, Rongrong; Yang, Hanry; Rock, D Mitchell; Danaei, Roozbeh; Panat, Rahul; Kessler, Michael R; Li, Lei

    2017-01-01

    The development of micro lens arrays has garnered much interest due to increased demand of miniaturized systems. Traditional methods for manufacturing micro lens arrays have several shortcomings. For example, they require expensive facilities and long lead time, and traditional lens materials (i.e. glass) are typically heavy, costly and difficult to manufacture. In this paper, we explore a method for manufacturing a polydimethylsiloxane (PDMS) micro lens array using a simple spin coating technique. The micro lens array, formed under an interfacial tension dominated system, and the influence of material properties and process parameters on the fabricated lens shape are examined. The lenses fabricated using this method show comparable optical properties—including surface finish and image quality—with a reduced cost and manufacturing lead time. (paper)

  18. Template-directed formation of functional complex metal-oxide nanostructures by combination of sol-gel processing and spin coating

    International Nuclear Information System (INIS)

    Choi, Y.C.; Kim, J.; Bu, S.D.

    2006-01-01

    We report the template-based formation of functional complex metal-oxide nanostructures by a combination of sol-gel processing and spin coating. This method employs the spin-coating of a sol-gel solution into an anodic aluminum oxide membrane (SSAM). Various metal-oxide nanowires and nanotubes with a high aspect-ratio were prepared. The aspect-ratios of the PbO 2 nanowires and Pb(Zr 0.52 Ti 0.48 )O 3 nanowires were about 300 and 400, respectively, and their diameters were about 50 nm. The fabricated PbTiO 3 nanotubes have a relatively constant wall thickness of about 20 nm with an outer diameter of about 60 nm. The deposition time for all of the fabricated metal-oxide nanowires and nanotubes is less than 120 s, which is far shorter than those required in both the sol-gel dipping and sol-gel electrophoretic methods. These results indicate that the SSAM method can be a versatile pathway to prepare functional complex metal-oxide nanowires and nanotubes with a high aspect-ratio. The possible formation process for the one-dimensional nanostructures by SSAM is discussed

  19. Saturable Absorption and Modulation Characteristics of Laser with Graphene Oxide Spin Coated on ITO Substrate

    OpenAIRE

    Li, Xin; Zhang, Haikun; Wang, Peiji; Li, Guiqiu; Zhao, Shengzhi; Wang, Jing; Chen, Lijuan

    2014-01-01

    The graphene oxide (GO) thin film has been obtained by mixture of GO spin coated on substrate of indium tin oxide (ITO). The experiment has shown that continuous-wave laser is modulated when the graphene oxide saturable absorber (GO-SA) is employed in the 1064 nm laser cavity. The shortest pulse width is 108 ns at the pump power of 5.04 W. Other output laser characteristics, such as the threshold pump power, the repetition rate, and the peak power, have also been measured. The results have de...

  20. Characterization and photocatalytic properties of cotton fibers modified with ZnO nanoparticles using sol–gel spin coating technique

    Directory of Open Access Journals (Sweden)

    Mohamed Shaban

    2016-09-01

    Full Text Available Zinc oxide nanoparticles (ZnO NPs were prepared using the sol–gel method. Cotton fibers were loaded with ZnO nanoparticles using sol–gel spin coating technique. The prepared ZnO NPs and ZnO-coated cotton were characterized by scanning electron microscope (SEM and energy dispersive X-ray spectroscopy (EDX. The self-cleaning property of ZnO-coated cotton and the photocatalytic removal of methyl orange dye from the contaminated water and cotton fibers were studied by measuring the optical absorbance after exposure to sunlight and Philips 200W lamp illumination. The results showed that the cotton loaded with ZnO nanoparticles could efficiently decompose 73% of methyl orange dye in the sunlight and 30.7% in the lamp illumination after 12 hours. ZnO nanoparticles decomposed methyl orange dye by 92.7% in the sunlight and 26.4% in the lamp illumination after 7 hours.

  1. Pentacene Active Channel Layers Prepared by Spin-Coating and Vacuum Evaporation Using Soluble Precursors for OFET Applications

    OpenAIRE

    Ochiai, Shizuyasu; Palanisamy, Kumar; Kannappan, Santhakumar; Shin, Paik-Kyun

    2012-01-01

    Pentacene OFETs of bottom-gate/bottom-contact were fabricated with three types of pentacene organic semiconductors and cross linked Poly(4-vinylphenol) or polycarbonate as gate dielectric layer. Two different processes were used to prepare the pentacene active channel layers: (1) spin-coating on dielectric layer using two different soluble pentacene precursors of SAP and DMP; (2) vacuum evaporation on PC insulator. X-ray diffraction studies revealed coexistence of thin film and bulk phase of ...

  2. Side chain effect on electronic structure of spin-coated films of [6,6]-phenyl-C61-butyric acid methyl ester and its bis-adduct

    International Nuclear Information System (INIS)

    Akaike, Kouki; Kanai, Kaname; Ouchi, Yukio; Seki, Kazuhiko

    2013-01-01

    Highlights: ► Electronic structure of spin-coated films of PCBM and bis-PCBM was investigated. ► Ionization energy and electron affinity of bis-PCBM are smaller than those of PCBM. ► Electron donation from the side chain to C 60 -backbone raises the HOMO and LUMO. ► Open circuit voltages of PCBM-based solar cells relates to electron affinities. - Abstract: We investigated the electronic structure of spin-coated films of two soluble fullerenes; [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM) and its bis-adduct (bis-PCBM) using ultraviolet photoelectron spectroscopy, inverse photoemission spectroscopy and molecular orbital calculations. The ionization energy and electron affinity of spin-coated films of bis-PCBM were determined to be 6.01 eV and 3.4 eV, respectively. Analysis of electron density suggested the stronger electron donation from the two side chains to fullerene-backbone in a bis-PCBM molecule, compared with PCBM. The electron donation raises the energies of the frontier orbitals of bis-PCBM, which mainly consist of π-orbitals of fullerene-backbone. As a result, the ionization energy and electron affinity of bis-PCBM are smaller than those of PCBM. Moreover, we also concluded that the larger open circuit voltage observed for bis-PCBM based organic photovoltaics was explained by the higher-lying unoccupied molecular orbital of bis-PCBM

  3. Spin coating of an evaporating polymer solution

    KAUST Repository

    Münch, Andreas

    2011-01-01

    We consider a mathematical model of spin coating of a single polymer blended in a solvent. The model describes the one-dimensional development of a thin layer of the mixture as the layer thins due to flow created by a balance of viscous forces and centrifugal forces and evaporation of the solvent. In the model both the diffusivity of the solvent in the polymer and the viscosity of the mixture are very rapidly varying functions of the solvent mass fraction. Guided by numerical solutions an asymptotic analysis reveals a number of different possible behaviours of the thinning layer dependent on the nondimensional parameters describing the system. The main practical interest is in controlling the appearance and development of a "skin" on the polymer where the solvent concentration reduces rapidly on the outer surface leaving the bulk of the layer still with high concentrations of solvent. In practice, a fast and uniform drying of the film is required. The critical parameters controlling this behaviour are found to be the ratio of the diffusion to advection time scales ε, the ratio of the evaporation to advection time scales δ and the ratio of the diffusivity of the pure polymer and the initial mixture exp(-1/γ). In particular, our analysis shows that for very small evaporation with δ

  4. Calcium phosphate/porous silicon biocomposites prepared by cyclic deposition methods: Spin coating vs electrochemical activation

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Montelongo, J., E-mail: jacobo.hernandez@uam.es [Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Gallach, D.; Naveas, N.; Torres-Costa, V. [Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Climent-Font, A. [Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Centro de Microanálisis de Materiales (CMAM), Universidad Autónoma de Madrid, Madrid 28049 (Spain); García-Ruiz, J.P. [Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, Madrid 28049 (Spain); Manso-Silvan, M. [Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain)

    2014-01-01

    Porous silicon (PSi) provides an excellent platform for bioengineering applications due to its biocompatibility, biodegradability, and bioresorbability. However, to promote its application as bone engineering scaffold, deposition of calcium phosphate (CaP) ceramics in its hydroxyapatite (HAP) phase is in progress. In that sense, this work focuses on the synthesis of CaP/PSi composites by means of two different techniques for CaP deposition on PSi: Cyclic Spin Coating (CSC) and Cyclic Electrochemical Activation (CEA). Both techniques CSC and CEA consisted on alternate Ca and P deposition steps on PSi. Each technique produced specific morphologies and CaP phases using the same independent Ca and P stem-solutions at neutral pH and at room temperature. The brushite (BRU) phase was favored with the CSC technique and the hydroxyapatite (HAP) phase was better synthesized using the CEA technique. Analyses by elastic backscattering spectroscopy (EBS) on CaP/PSi structures synthesized by CEA supported that, by controlling the CEA parameters, an HAP coating with the required Ca/P atomic ratio of 1.67 can be promoted. Biocompatibility was evaluated by bone-derived progenitor cells, which grew onto CaP/PSi prepared by CSC technique with a long-shaped actin cytoskeleton. The density of adhered cells was higher on CaP/PSi prepared by CEA, where cells presented a normal morphological appearance and active mitosis. These results can be used for the design and optimization of CaP/PSi composites with enhanced biocompatibility for bone-tissue engineering. - Highlights: • Proposed cyclic methods produce specific morphologies and CaP phases in biocomposites. • The brushite phase is favored in the biocomposite produced by Cyclic Spin Coating. • The hydroxyapatite phase is favored in the biocomposite produced by Cyclic Electrochemical Activation. • The Ca/P atomic ratio of hydroxyapatite was validated by elastic backscattering spectroscopy. • Cells grown showed morphological and

  5. Calcium phosphate/porous silicon biocomposites prepared by cyclic deposition methods: Spin coating vs electrochemical activation

    International Nuclear Information System (INIS)

    Hernandez-Montelongo, J.; Gallach, D.; Naveas, N.; Torres-Costa, V.; Climent-Font, A.; García-Ruiz, J.P.; Manso-Silvan, M.

    2014-01-01

    Porous silicon (PSi) provides an excellent platform for bioengineering applications due to its biocompatibility, biodegradability, and bioresorbability. However, to promote its application as bone engineering scaffold, deposition of calcium phosphate (CaP) ceramics in its hydroxyapatite (HAP) phase is in progress. In that sense, this work focuses on the synthesis of CaP/PSi composites by means of two different techniques for CaP deposition on PSi: Cyclic Spin Coating (CSC) and Cyclic Electrochemical Activation (CEA). Both techniques CSC and CEA consisted on alternate Ca and P deposition steps on PSi. Each technique produced specific morphologies and CaP phases using the same independent Ca and P stem-solutions at neutral pH and at room temperature. The brushite (BRU) phase was favored with the CSC technique and the hydroxyapatite (HAP) phase was better synthesized using the CEA technique. Analyses by elastic backscattering spectroscopy (EBS) on CaP/PSi structures synthesized by CEA supported that, by controlling the CEA parameters, an HAP coating with the required Ca/P atomic ratio of 1.67 can be promoted. Biocompatibility was evaluated by bone-derived progenitor cells, which grew onto CaP/PSi prepared by CSC technique with a long-shaped actin cytoskeleton. The density of adhered cells was higher on CaP/PSi prepared by CEA, where cells presented a normal morphological appearance and active mitosis. These results can be used for the design and optimization of CaP/PSi composites with enhanced biocompatibility for bone-tissue engineering. - Highlights: • Proposed cyclic methods produce specific morphologies and CaP phases in biocomposites. • The brushite phase is favored in the biocomposite produced by Cyclic Spin Coating. • The hydroxyapatite phase is favored in the biocomposite produced by Cyclic Electrochemical Activation. • The Ca/P atomic ratio of hydroxyapatite was validated by elastic backscattering spectroscopy. • Cells grown showed morphological and

  6. Effect of the Precursor Solution Concentration of CuI Thin Film Deposited By Spin Coating Method

    International Nuclear Information System (INIS)

    Nur Amalina Muhmmad; Atiq, A.M.; Rusop, M.

    2011-01-01

    Copper (I) Iodide is a p-type semiconductor with bandgap of 3.1 eV. It is water insoluble solid with three crystalline phases α, β, γ. In this research, the effect of precursor concentration of CuI thin film deposited by spin coating method was studied. The wide band gap p type semiconductor CuI thin film was prepared by mixing the CuI powder (ALDRICH, 98 %) with 50 ml of acetonitrile as a solvent. The CuI concentration varies from 0.025 M to 0.5 M. The speed for spin coating is 1000 rpm for 60 seconds. After the deposition the CuI thin films were annealed at 150 degree Celsius. The electrical and optical properties were characterized by current-voltage (I-V) measurement using Solar Simulator (Bukoh Keiki EP-2000) and ultraviolet visible- near infrared (UV-VIS-NIR) measurement (Jasco V-670). The result shows the CuI thin film properties strongly depends on its precursor concentration. Thickness between 33.65 nm - 441.25 nm was obtained as the concentration increases. The increment of thickness affects the electrical properties which is the resistivity and conductivity of CuI thin film. For optical properties, the transmittance decreases with high concentration as high amount of CuI particle were observed in the thin films. From the transmittance, the absorption coefficient and optical band gap of CuI was determined using Taucs plot. (author)

  7. Efficiency enhancement of perovskite solar cells by fabricating as-prepared film before sequential spin-coating procedure

    International Nuclear Information System (INIS)

    Jiang, Jiajia; Tao, Hai jun; Chen, Shanlong; Tan, Bin; Zhou, Ning; Zhu, Lumin; Zhao, Yuan; Wang, Yuqiao; Tao, Jie

    2016-01-01

    Graphical abstract: Schematic illustration of modified two-step spin-coating procedure for MAPbI 3 perovskite thin films. - Highlights: • An as-prepared CH 3 NH 3 PbI 3 and PbI 2 film was introduced before the traditional two-step process. • Smooth morphology and trace amount of remaining PbI 2 benefit the performance of solar cell. • The optimal as-prepared film introduced improves the efficiency of CH 3 NH 3 PbI 3 solar cells from 9.11% to 11.16%. - Abstract: Sequential spin-coating procedure is a widely adopted strategy to prepare CH 3 NH 3 PbI 3 on mesostructured TiO 2 electrode for organolead halide perovskite-based solar cells. However, this method suffers from the rough surface and excessively residual PbI 2 in the resulting perovskite film, deteriorating the device performance seriously. Herein, a facial modified sequential solution deposition method, by introducing an as-prepared CH 3 NH 3 PbI 3 and PbI 2 film before the traditional two-step process, was proposed to fabricate the perovskite-based solar cell with smooth morphology and trace amount of remaining PbI 2 . The optimal as-prepared film introduced improves the efficiency of CH 3 NH 3 PbI 3 solar cells from 9.11% to 11.16%. The enhancement of device performance can be attributed to the increased light absorption ability and decreased recombination rate of carriers in CH 3 NH 3 PbI 3 absorber.

  8. Side chain effect on electronic structure of spin-coated films of [6,6]-phenyl-C{sub 61}-butyric acid methyl ester and its bis-adduct

    Energy Technology Data Exchange (ETDEWEB)

    Akaike, Kouki, E-mail: akaike@riken.jp [Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan); Kanai, Kaname [Department of Physics, Faculty of Science and Technology, Tokyo University of Science, Yamazaki 2641, Noda 278-8510 (Japan); Ouchi, Yukio; Seki, Kazuhiko [Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan)

    2013-03-29

    Highlights: ► Electronic structure of spin-coated films of PCBM and bis-PCBM was investigated. ► Ionization energy and electron affinity of bis-PCBM are smaller than those of PCBM. ► Electron donation from the side chain to C{sub 60}-backbone raises the HOMO and LUMO. ► Open circuit voltages of PCBM-based solar cells relates to electron affinities. - Abstract: We investigated the electronic structure of spin-coated films of two soluble fullerenes; [6,6]-phenyl-C{sub 61}-butyric acid methyl ester (PCBM) and its bis-adduct (bis-PCBM) using ultraviolet photoelectron spectroscopy, inverse photoemission spectroscopy and molecular orbital calculations. The ionization energy and electron affinity of spin-coated films of bis-PCBM were determined to be 6.01 eV and 3.4 eV, respectively. Analysis of electron density suggested the stronger electron donation from the two side chains to fullerene-backbone in a bis-PCBM molecule, compared with PCBM. The electron donation raises the energies of the frontier orbitals of bis-PCBM, which mainly consist of π-orbitals of fullerene-backbone. As a result, the ionization energy and electron affinity of bis-PCBM are smaller than those of PCBM. Moreover, we also concluded that the larger open circuit voltage observed for bis-PCBM based organic photovoltaics was explained by the higher-lying unoccupied molecular orbital of bis-PCBM.

  9. Resistivity behavior of optimized PbTiO3 thin films prepared by spin coating method

    Science.gov (United States)

    Nurbaya, Z.; Wahid, M. H.; Rozana, M. D.; Alrokayan, S. A. H.; Khan, H. A.; Rusop, M.

    2018-05-01

    Th is study presents the resistivity behavior of PbTiO3 thin films which were prepared towards metal-insulator-metal capacitor device fabrication. The PbTiO3 thin films were prepared through sol-gel spin coating method that involved various deposition parameters that is (1) different molar concentration of PbTiO3 solutions, (2) various additional PbAc-content in PbTiO3 solutions, and (3) various annealing temperature on PbTiO3 thin films. Hence, an electrical measurement of current versus voltage was done to determine the resistivity behavior of PbTiO3 thin films.

  10. Influence of Heat Treatment on the Morphologies of Copper Nanoparticles Based Films by a Spin Coating Method

    Directory of Open Access Journals (Sweden)

    Wei Liu

    2017-01-01

    Full Text Available We have investigated the influence of heat treatment on the morphologies of copper nanoparticles based films on glass slides by a spin coating method. The experiments show that heat treatment can modify the sizes and morphologies of copper nanoparticles based films on glass slides. We suggest that through changing the parameters of heat treatment process may be helpful to vary the scattering and absorbing intensity of copper nanoparticles when used in energy harvesting/conversion and optical devices.

  11. Phase Transition Control for High-Performance Blade-Coated Perovskite Solar Cells

    KAUST Repository

    Li, Jianbo

    2018-05-07

    Summary Here, we have identified that the key issue for rational transitioning from spin-coating to blade-coating processes of perovskite films arises from whether intermediate phases participate in the phase transition. In situ characterizations were carried out to provide a comprehensive picture of structural evolution and crystal growth mechanisms. These findings present opportunities for designing an effective process for blade-coating perovskite film: a large-grained dense perovskite film with high crystal quality and photophysical properties can be obtained only via direct crystallization for both spin-coating and blade-coating processes. As a result, the blade-coated MAPbI3 films deliver excellent charge-collection efficiency at both short circuit and open circuit, and photovoltaic properties with efficiencies of 18.74% (0.09 cm2) and 17.06% (1 cm2) in planar solar cells. The significant advances in understanding how the phase transition links spin-coating and blade-coating processes should provide a path toward high-performance printed perovskite devices.

  12. Catalytic behaviors of ruthenium dioxide films deposited on ferroelectrics substrates, by spin coating process

    International Nuclear Information System (INIS)

    Khachane, M.; Nowakowski, P.; Villain, S.; Gavarri, J.R.; Muller, Ch.; Elaatmani, M.; Outzourhite, A.; Luk'yanchuk, I.; Zegzouti, A.; Daoud, M.

    2007-01-01

    Catalytic ruthenium dioxide films were deposited by spin-coating process on ferroelectric films mainly constituted of SrBi 2 Ta 2 O 9 (SBT) and Ba 2 NaNb 5 O 15 (BNN) phases. After thermal treatment under air, these ferroelectric-catalytic systems were characterized by X-ray diffraction and scanning electron microscopy (SEM). SEM images showed that RuO 2 film morphology depended on substrate nature. A study of CH 4 conversion into CO 2 and H 2 O was carried out using these catalytic-ferroelectric multilayers: the conversion was analyzed from Fourier transform infrared (FTIR) spectroscopy, at various temperatures. Improved catalytic properties were observed for RuO 2 films deposited on BNN oxide layer

  13. Effects of hot airflow during spin-coating process on CH3NH3PbI3-xClx perovskite solar cells

    Science.gov (United States)

    Tanaka, Hiroki; Ohishi, Yuya; Oku, Takeo

    2018-01-01

    CH3NH3PbI3-xClx photovoltaic devices were fabricated, and the effects of hot airflow during spin-coating were investigated. Cubic perovskite crystals that is a high temperature phase were obtained by the hot airflow method. The conversion efficiencies of the devices prepared by the hot airflow were remained even after 56 days.

  14. Estudio numerico y experimental del proceso de soldeo MIG sobre la aleacion 6063--T5 utilizando el metodo de Taguchi

    Science.gov (United States)

    Meseguer Valdenebro, Jose Luis

    improvement on mechanical properties in aluminum metal joint. Los procesos de soldadura por arco electrico representan unas de las tecnicas mas utilizadas en los procesos de fabricacion de componentes mecanicos en la industria moderna. Los procesos de soldeo por arco se han adaptado a las necesidades actuales, haciendose un modo de fabricacion flexible y versatil. Los resultados obtenidos numericamente en el proceso de soldadura son validados experimentalmente. Los principales metodos numericos mas empleados en la actualidad son tres, metodo por diferencias finitas, metodos por elementos finitos y metodo por volumenes finitos. El metodo numerico mas empleado para el modelado de uniones soldadas, es el metodo por elementos finitos, debido a que presenta una buena adaptacion a las condiciones geometricas y de contorno ademas de que existe una diversidad de programas comerciales que utilizan el metodo por elementos finitos como base de calculo. Este trabajo de investigacion presenta un estudio experimental de una union soldada mediante el proceso MIG de la aleacion de aluminio 6063-T5. El metodo numerico se valida experimentalmente aplicando el metodo de los elementos finitos con el programa de calculo ANSYS. Los resultados experimentales obtenidos son: las curvas de enfriamiento, el tiempo critico de enfriamiento t4/3, geometria del cordon, microdurezas obtenidas en la union soldada, zona afectada termicamente y metal base, dilucion del proceso, areas criticas intersecadas entre las curvas de enfriamiento y la curva TTP. Los resultados numericos son: las curvas del ciclo termico, que representan tanto el calentamiento hasta alcanzar la temperatura maxima y un posterior enfriamiento. Se calculan el tiempo critico de enfriamiento t4/3, el rendimiento termico y se representa la geometria del cordon obtenida experimentalmente. La zona afectada termicamente se obtiene diferenciando las zonas que se encuentran a diferentes temperaturas, las areas criticas intersecadas entre las

  15. Saturable Absorption and Modulation Characteristics of Laser with Graphene Oxide Spin Coated on ITO Substrate

    Directory of Open Access Journals (Sweden)

    Xin Li

    2014-01-01

    Full Text Available The graphene oxide (GO thin film has been obtained by mixture of GO spin coated on substrate of indium tin oxide (ITO. The experiment has shown that continuous-wave laser is modulated when the graphene oxide saturable absorber (GO-SA is employed in the 1064 nm laser cavity. The shortest pulse width is 108 ns at the pump power of 5.04 W. Other output laser characteristics, such as the threshold pump power, the repetition rate, and the peak power, have also been measured. The results have demonstrated that graphene oxide is an available saturable absorber for 1064 nm passive Q-switching laser.

  16. Advanced fabrication method for the preparation of MOF thin films: Liquid-phase epitaxy approach meets spin coating method.

    KAUST Repository

    Chernikova, Valeriya

    2016-07-14

    Here we report a new and advanced method for the fabrication of highly oriented/polycrystalline metal-organic framework (MOF) thin films. Building on the attractive features of the liquid-phase epitaxy (LPE) approach, a facile spin coating method was implemented to generate MOF thin films in a high-throughput fashion. Advantageously, this approach offers a great prospective to cost-effectively construct thin-films with a significantly shortened preparation time and a lessened chemicals and solvents consumption, as compared to the conventional LPE-process. Certainly, this new spin-coating approach has been implemented successfully to construct various MOF thin films, ranging in thickness from a few micrometers down to the nanometer scale, spanning 2-D and 3-D benchmark MOF materials including Cu2(bdc)2•xH2O, Zn2(bdc)2•xH2O, HKUST-1 and ZIF-8. This method was appraised and proved effective on a variety of substrates comprising functionalized gold, silicon, glass, porous stainless steel and aluminum oxide. The facile, high-throughput and cost-effective nature of this approach, coupled with the successful thin film growth and substrate versatility, represents the next generation of methods for MOF thin film fabrication. Thereby paving the way for these unique MOF materials to address a wide range of challenges in the areas of sensing devices and membrane technology.

  17. Cover layer technology and a new hard coat for cartridge-free Blu-ray disc

    Science.gov (United States)

    Kang, Tae-Sik; Han, Mi Young; Lee, Seong-Keun; Jang, Sung Hoon; Hong, Young Jun; Seo, Hun; Lee, Chang-Ho

    2004-09-01

    Spin coating method for cover layer of Blu-ray Disc (BD) has been studied and a new hard coat resin including antifouling property has been developed. A vacuum chuck was newly designed to minimize the ski-jump effect. 3 mm hard coat layer was stacked onto the 97 mm cover layer by spin coating method.

  18. Enhanced Response Speed of ZnO Nanowire Photodetector by Coating with Photoresist

    Directory of Open Access Journals (Sweden)

    Xing Yang

    2016-01-01

    Full Text Available Spin-coating photoresist film on ZnO nanowire (NW was introduced into the fabrication procedure to improve photoresponse and recovery speed of a ZnO NW ultraviolet photoelectric detector. A ZnO NW was first assembled on prefabricated electrodes by dielectrophoresis. Then, photoresist was spin-coated on the nanowire. Finally, a metal layer was electrodeposited on the nanowire-electrode contacts. The response properties and I-V characteristics of ZnO NW photodetector were investigated by measuring the electrical current under different conditions. Measurement results demonstrated that the detector has an enhanced photoresponse and recovery speed after coating the nanowire with photoresist. The photoresponse and recovery characteristics of detectors with and without spin-coating were compared to demonstrate the effects of photoresist and the enhancement of response and recovery speed of the photodetector is ascribed to the reduced surface absorbed oxygen molecules and binding effect on the residual oxygen molecules after photoresist spin-coating. The results demonstrated that surface coating may be an effective and simple way to improve the response speed of the photoelectric device.

  19. Scanning tunneling microscopy measurements of the spin Hall effect in tungsten films by using iron-coated tungsten tips

    Science.gov (United States)

    Xie, Ting; Dreyer, Michael; Bowen, David; Hinkel, Dan; Butera, R. E.; Krafft, Charles; Mayergoyz, Isaak

    2018-05-01

    Scanning tunneling microscopy experiments using iron-coated tungsten tips and current-carrying tungsten films have been conducted. An asymmetry of the tunneling current with respect to the change of the direction of the bias current through a tungsten film has been observed. It is argued that this asymmetry is a manifestation of the spin Hall effect in the current-carrying tungsten film. Nanoscale variations of this asymmetry across the tungsten film have been studied by using the scanning tunneling microscopy technique.

  20. Fluorine Based Superhydrophobic Coatings

    Directory of Open Access Journals (Sweden)

    Jean-Denis Brassard

    2012-05-01

    Full Text Available Superhydrophobic coatings, inspired by nature, are an emerging technology. These water repellent coatings can be used as solutions for corrosion, biofouling and even water and air drag reduction applications. In this work, synthesis of monodispersive silica nanoparticles of ~120 nm diameter has been realized via Stöber process and further functionalized using fluoroalkylsilane (FAS-17 molecules to incorporate the fluorinated groups with the silica nanoparticles in an ethanolic solution. The synthesized fluorinated silica nanoparticles have been spin coated on flat aluminum alloy, silicon and glass substrates. Functionalization of silica nanoparticles with fluorinated groups has been confirmed by Fourier Transform Infrared spectroscopy (FTIR by showing the presence of C-F and Si-O-Si bonds. The water contact angles and surface roughness increase with the number of spin-coated thin films layers. The critical size of ~119 nm renders aluminum surface superhydrophobic with three layers of coating using as-prepared nanoparticle suspended solution. On the other hand, seven layers are required for a 50 vol.% diluted solution to achieve superhydrophobicity. In both the cases, water contact angles were more than 150°, contact angle hysteresis was less than 2° having a critical roughness value of ~0.700 µm. The fluorinated silica nanoparticle coated surfaces are also transparent and can be used as paint additives to obtain transparent coatings.

  1. Microelectromechanical systems integrating molecular spin crossover actuators

    Energy Technology Data Exchange (ETDEWEB)

    Manrique-Juarez, Maria D. [LCC, CNRS and Université de Toulouse, UPS, INP, F-31077 Toulouse (France); LAAS, CNRS and Université de Toulouse, INSA, UPS, F-31077 Toulouse (France); Rat, Sylvain; Salmon, Lionel; Molnár, Gábor; Bousseksou, Azzedine, E-mail: liviu.nicu@laas.fr, E-mail: azzedine.bousseksou@lcc-toulouse.fr [LCC, CNRS and Université de Toulouse, UPS, INP, F-31077 Toulouse (France); Mathieu, Fabrice; Saya, Daisuke; Séguy, Isabelle; Leïchlé, Thierry; Nicu, Liviu, E-mail: liviu.nicu@laas.fr, E-mail: azzedine.bousseksou@lcc-toulouse.fr [LAAS, CNRS and Université de Toulouse, INSA, UPS, F-31077 Toulouse (France)

    2016-08-08

    Silicon MEMS cantilevers coated with a 200 nm thin layer of the molecular spin crossover complex [Fe(H{sub 2}B(pz){sub 2}){sub 2}(phen)] (H{sub 2}B(pz){sub 2} = dihydrobis(pyrazolyl)borate and phen = 1,10-phenantroline) were actuated using an external magnetic field and their resonance frequency was tracked by means of integrated piezoresistive detection. The light-induced spin-state switching of the molecules from the ground low spin to the metastable high spin state at 10 K led to a well-reproducible shift of the cantilever's resonance frequency (Δf{sub r} = −0.52 Hz). Control experiments at different temperatures using coated as well as uncoated devices along with simple calculations support the assignment of this effect to the spin transition. This latter translates into changes in mechanical behavior of the cantilever due to the strong spin-state/lattice coupling. A guideline for the optimization of device parameters is proposed so as to efficiently harness molecular scale movements for large-scale mechanical work, thus paving the road for nanoelectromechanical systems (NEMS) actuators based on molecular materials.

  2. Correlation between the fine structure of spin-coated PEDOT:PSS and the photovoltaic performance of organic/crystalline-silicon heterojunction solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Funda, Shuji; Ohki, Tatsuya; Liu, Qiming; Hossain, Jaker; Ishimaru, Yoshihiro; Ueno, Keiji; Shirai, Hajime [Graduate School of Science and Engineering, Saitama University, Saitama 338-8570 (Japan)

    2016-07-21

    We investigated the relationship between the fine structure of spin-coated conductive polymer poly(3,4-ethylenedioxythiphene):poly(styrene sulfonate) (PEDOT:PSS) films and the photovoltaic performance of PEDOT:PSS crystalline-Si (PEDOT:PSS/c-Si) heterojunction solar cells. Real-time spectroscopic ellipsometry revealed that there were two different time constants for the formation of the PEDOT:PSS network. Upon removal of the polar solvent, the PEDOT:PSS film became optically anisotropic, indicating a conformational change in the PEDOT and PSS chain. Polarized Fourier transform infrared attenuated total reflection absorption spectroscopy and Raman spectroscopy measurements also indicated that thermal annealing promoted an in-plane π-conjugated C{sub α} = C{sub β} configuration attributed to a thiophene ring in PEDOT and an out-of-plane configuration of -SO{sub 3} groups in the PSS chain with increasing composition ratio of oxidized (benzoid) to neutral (quinoid) PEDOT, I{sub qui}/I{sub ben}. The highest power conversion efficiency for the spin-coated PEDOT:PSS/c-Si heterojunction solar cells was 13.3% for I{sub qui}/I{sub ben} = 9–10 without employing any light harvesting methods.

  3. Scanning tunneling microscopy measurements of the spin Hall effect in tungsten films by using iron-coated tungsten tips

    Directory of Open Access Journals (Sweden)

    Ting Xie

    2018-05-01

    Full Text Available Scanning tunneling microscopy experiments using iron-coated tungsten tips and current-carrying tungsten films have been conducted. An asymmetry of the tunneling current with respect to the change of the direction of the bias current through a tungsten film has been observed. It is argued that this asymmetry is a manifestation of the spin Hall effect in the current-carrying tungsten film. Nanoscale variations of this asymmetry across the tungsten film have been studied by using the scanning tunneling microscopy technique.

  4. Efficiency enhancement of perovskite solar cells by fabricating as-prepared film before sequential spin-coating procedure

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Jiajia [Jiangsu Key Laboratory of Materials and Technology for Energy Conversion, College of material science and technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211100 (China); Tao, Hai jun, E-mail: taohaijun@nuaa.edu.cn [Jiangsu Key Laboratory of Materials and Technology for Energy Conversion, College of material science and technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211100 (China); Jiangsu Collaborative Innovation Center of Photovolatic Science and Engineering, Changzhou University, Changzhou 213164, Jiangsu (China); Chen, Shanlong; Tan, Bin [Jiangsu Key Laboratory of Materials and Technology for Energy Conversion, College of material science and technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211100 (China); Zhou, Ning [Shanghai Electrochemical Energy Devices Research Center, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhu, Lumin; Zhao, Yuan [Jiangsu Key Laboratory of Materials and Technology for Energy Conversion, College of material science and technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211100 (China); Wang, Yuqiao [Jiangsu Optoelectronic Functional Materials and Engineering Laboratory, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Tao, Jie [Jiangsu Key Laboratory of Materials and Technology for Energy Conversion, College of material science and technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211100 (China)

    2016-05-15

    Graphical abstract: Schematic illustration of modified two-step spin-coating procedure for MAPbI{sub 3} perovskite thin films. - Highlights: • An as-prepared CH{sub 3}NH{sub 3}PbI{sub 3} and PbI{sub 2} film was introduced before the traditional two-step process. • Smooth morphology and trace amount of remaining PbI{sub 2} benefit the performance of solar cell. • The optimal as-prepared film introduced improves the efficiency of CH{sub 3}NH{sub 3}PbI{sub 3} solar cells from 9.11% to 11.16%. - Abstract: Sequential spin-coating procedure is a widely adopted strategy to prepare CH{sub 3}NH{sub 3}PbI{sub 3} on mesostructured TiO{sub 2} electrode for organolead halide perovskite-based solar cells. However, this method suffers from the rough surface and excessively residual PbI{sub 2} in the resulting perovskite film, deteriorating the device performance seriously. Herein, a facial modified sequential solution deposition method, by introducing an as-prepared CH{sub 3}NH{sub 3}PbI{sub 3} and PbI{sub 2} film before the traditional two-step process, was proposed to fabricate the perovskite-based solar cell with smooth morphology and trace amount of remaining PbI{sub 2}. The optimal as-prepared film introduced improves the efficiency of CH{sub 3}NH{sub 3}PbI{sub 3} solar cells from 9.11% to 11.16%. The enhancement of device performance can be attributed to the increased light absorption ability and decreased recombination rate of carriers in CH{sub 3}NH{sub 3}PbI{sub 3} absorber.

  5. Research progress of fabricating polyvinyl alcohol coating on plastic microsphere

    International Nuclear Information System (INIS)

    Su Lin; Chen Sufen; Liu Meifang; Zhang Zhanwen; Yao Hong; Li Bo; Liu Yiyang

    2012-01-01

    In the procedures of designing polystyrene-polyvinyl alcohol-CH (carbon and hydrogen elements) (PS-PVA-CH) triple-layer microspheres, there are many methods such as drop-tower technique, emulsion micro-encapsulation, dip (spin) coating, interfacial polycondensation, and spraying technique to prepare the PVA coating. Drop-tower technique, emulsion micro-encapsulation and dip (spin) coating are most-commonly used. The advantages, disadvantages and the research progress of the three methods are summarized in this paper. Emulsion micro-encapsulation is suitable for preparing double-layer microspheres of sizes smaller then 500 μm, with high survival ratio and good quality. However, the preparation process is easily influenced by artificial factors. Small-sized double-layer microspheres can also be prepared by the drop-tower technique, and the preparation period is short. But there are still some problems such as the difficulty in designing the droplet generator, uneven PVA coating and the difficulty in preparing large-sized microspheres. Dip (spin) coating technique can be used to prepare PS-PVA microspheres with sizes larger than 1000 μm, but the spread of PVA coating is affected by many factors in this method, and the prepared PVA coating is too thin and not uniform. (authors)

  6. Spin-cast bulk heterojunction solar cells: A dynamical investigation

    KAUST Repository

    Chou, Kang Wei

    2013-02-22

    Spin-coating is extensively used in the lab-based manufacture of organic solar cells, including most of the record-setting solution-processed cells. We report the first direct observation of photoactive layer formation as it occurs during spin-coating. The study provides new insight into mechanisms and kinetics of bulk heterojunction formation, which may be crucial for its successful transfer to scalable printing processes. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Spin-cast bulk heterojunction solar cells: A dynamical investigation

    KAUST Repository

    Chou, Kang Wei; Yan, Buyi; Li, Ruipeng; Li, Erqiang; Zhao, Kui; Anjum, Dalaver H.; Alvarez, Steven; Gassaway, Robert; Biocca, Alan K.; Thoroddsen, Sigurdur T; Hexemer, Alexander; Amassian, Aram

    2013-01-01

    Spin-coating is extensively used in the lab-based manufacture of organic solar cells, including most of the record-setting solution-processed cells. We report the first direct observation of photoactive layer formation as it occurs during spin-coating. The study provides new insight into mechanisms and kinetics of bulk heterojunction formation, which may be crucial for its successful transfer to scalable printing processes. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Comparison of Y{sub 2}O{sub 3}:Bi{sup 3+} phosphor thin films fabricated by the spin coating and radio frequency magnetron techniques

    Energy Technology Data Exchange (ETDEWEB)

    Jafer, R.M.; Yousif, A. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa); Department of Physics, Faculty of Education, University of Khartoum, P.O. Box 321, Postal Code 11115 Omdurman (Sudan); Kumar, Vinod [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa); Photovoltaic Laboratory, Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi 110016 (India); Pathak, Trilok Kumar [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa); Semiconductor Physics Lab, Department of Physics, Gurukula Kangri University, Haridwar (India); Purohit, L.P. [Semiconductor Physics Lab, Department of Physics, Gurukula Kangri University, Haridwar (India); Swart, H.C., E-mail: swarthc@ufs.ac.za [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa); Coetsee, E., E-mail: CoetseeE@ufs.ac.za [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa)

    2016-09-15

    The reactive radio-frequency (RF) magnetron sputtering and spin coating fabrication techniques were used to fabricate Y{sub 2−x}O{sub 3}:Bi{sub x=0.5%} phosphor thin films. The two techniques were analysed and compared as part of investigations being done on the application of down-conversion materials for a Si solar cell. The morphology, structural and optical properties of these thin films were investigated. The X-ray diffraction results of the thin films fabricated by both techniques showed cubic structures with different space groups. The optical properties showed different results because the Bi{sup 3+} ion is very sensitive towards its environment. The luminescence results for the thin film fabricated by the spin coating technique is very similar to the luminescence observed in the powder form. It showed three obvious emission bands in the blue and green regions centered at about 360, 410 and 495 nm. These emissions were related to the {sup 3}P{sub 1}–{sup 1}S{sub 0} transition of the Bi{sup 3+} ion situated in the two different sites of the Y{sub 2}O{sub 3} matrix with I a-3(206) space group. Whereas the thin film fabricated by the radio frequency magnetron technique showed a broad single emission band in the blue region centered at about 416 nm. This was assigned to the {sup 3}P{sub 1}–{sup 1}S{sub 0} transition of the Bi{sup 3+} ion situated in one of the Y{sub 2}O{sub 3} matrix's sites with a Fm-3 (225) space group. The spin coating fabrication technique is suggested to be the best technique to fabricate the Y{sub 2}O{sub 3}:Bi{sup 3+} phosphor thin films. - Highlights: • RF sputtering and spin coating were used to fabricate Y{sub 2−x}O{sub 3}:Bi{sub x=0.5%} phosphor thin films. • XRD results of the two films showed cubic structures with different space groups. • PL showed different emission for the Bi{sup 3+} ions in the two films. • Three emission bands in the blue and green regions centered at about 360, 410 and 495 nm. • RF

  9. Osservazioni sul principio di legalità come idea e come metodo nell’esperienza giuridica della Chiesa

    Directory of Open Access Journals (Sweden)

    Beatrice Serra

    2012-10-01

    SOMMARIO: 1. Introduzione - 2. – La struttura essenziale del concetto di legalità e la sua realizzazione radicale nel diritto della Chiesa. - 3. L’idea di legalità come “regola che sta prima” nel ius commune e la sua coesistenza con un approccio empirico, essenzialmente giurisprudenziale e dottrinale, di costruzione del diritto. Il principio di legalità come metodo di produzione del diritto nel pensiero giuridico moderno- 4. Il legame storico-concettuale fra il principio di legalità e i Codici moderni - 5. Il Codex iuris canonici del 1917 e il principio di legalità come metodo di costruzione del ius ecclesiae in funzione della certezza del diritto - 6. (segueUlteriori riflessi della prima codificazione canonica sul principio di legalità.:

  10. Spin-Coating and Characterization of Multiferroic MFe2O4 (M=Co, Ni) / BaTiO3 Bilayers

    Science.gov (United States)

    Quandt, Norman; Roth, Robert; Syrowatka, Frank; Steimecke, Matthias; Ebbinghaus, Stefan G.

    2016-01-01

    Bilayer films of MFe2O4 (M=Co, Ni) and BaTiO3 were prepared by spin coating of N,N-dimethylformamide/acetic acid solutions on platinum coated silicon wafers. Five coating steps were applied to get the desired thickness of 150 nm for both the ferrite and perovskite layer. XRD, IR and Raman spectroscopy revealed the formation of phase-pure ferrite spinels and BaTiO3. Smooth surfaces with roughnesses in the order of 3 to 5 nm were found in AFM investigations. Saturation magnetization of 347 emu cm-3 for the CoFe2O4/BaTiO3 and 188 emu cm-3 for the NiFe2O4/BaTiO3 bilayer, respectively were found. For the CoFe2O4/BaTiO3 bilayer a strong magnetic anisotropy was observed with coercivity fields of 5.1 kOe and 3.3 kOe (applied magnetic field perpendicular and parallel to film surface), while for the NiFe2O4/BaTiO3 bilayer this effect is less pronounced. Saturated polarization hysteresis loops prove the presence of ferroelectricity in both systems.

  11. Synthesis and characterization of nanocomposite polymer blend electrolyte thin films by spin-coating method

    Energy Technology Data Exchange (ETDEWEB)

    Chapi, Sharanappa; Niranjana, M.; Devendrappa, H., E-mail: dehu2010@gmail.com [Department of Physics, Mangalore University, Mangalagangothri - 574 199 (India)

    2016-05-23

    Solid Polymer blend electrolytes based on Polyethylene oxide (PEO) and poly vinyl pyrrolidone (PVP) complexed with zinc oxide nanoparticles (ZnO NPs; Synthesized by Co-precipitation method) thin films have prepared at a different weight percent using the spin-coating method. The complexation of the NPs with the polymer blend was confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR). The variation in film morphology was examined by polarized optical micrographs (POMs). The thermal behavior of blends was investigated under non-isothermal conditions by differential thermal analyses (DTA). A single glass transition temperature for each blend was observed, which supports the existence of compatibility of such system. The obtained results represent that the ternary based thin films are prominent materials for battery and optoelectronic device applications.

  12. Enhancement of Lithium Niobate nanophotonic structures via spin-coating technique for optical waveguides application

    Directory of Open Access Journals (Sweden)

    Fakhri Makram A.

    2017-01-01

    Full Text Available This work is dedicated to investigation of temperature effects in Lithium Niobate (LiNbO3 nanostructures. The LiNbO3 nanostructures were deposited on glass substrate by spin-coating technique. LiNbO3 was set down at 3000 rpm for 30 sec and annealed from 100 to 600 °C. The structures were characterized and analyzed by scanning electron microscopy (SEM and ultra-violet visible (UV-vis spectrophotometer. The measured results have showed that by increasing annealing temperatures, the structures start to be more crystallized and be more homogenized until the optimum arrangement was achieved. Once this was accomplished, it's applicable for optical waveguides development. Eventually, it starts to be less crystallization and non-homogeneous. Energy gap was recorded to be at average value of 3.9 eV.

  13. Heat-resistant hydrophobic-oleophobic coatings

    OpenAIRE

    Uyanik, Mehmet; Arpac, Ertugrul; Schmidt, Helmut K.; Akarsu, Murat; Sayilkan, Funda; Sayilkan, Hikmet

    2006-01-01

    Thermally and chemically durable hydrophobic oleophobic coatings, containing different ceramic particles such as SiO2, SiC, Al 2O3, which can be alternative instead of Teflon, have been developed and applied on the aluminum substrates by spin-coating method. Polyimides, which are high-thermal resistant heteroaromatic polymers, were synthesized, and fluor oligomers were added to these polymers to obtain hydrophobic-oleophobic properties. After coating, Al surface was subjected to Taber-abrasio...

  14. Annealing temperature effect on electrical properties of MEH-PPV thin film via spin coating method

    Science.gov (United States)

    Azhar, N. E. A.; Shariffudin, S. S.; Alrokayan, Salman A. H.; Khan, Haseeb A.; Rusop, M.

    2018-05-01

    Organic semiconductor has been discovered in different application devices such as organic light emitting diodes (OLEDs). Poly [2-methoxy-5(2' -ethylhexyloxy)-1, 4-phenylenevinylene), MEH-PPV widely used in this device because its ability to produce a good optical quality films. The MEH-PPV was prepared on glass substrate by spin coating method. The thin film was investigated at different annealing temperatures. The scanning electron micrographs (SEM) revealed that sample annealed at 50°C showed uniformity and less aggregation on morphology polymer thin film. Optical properties showed the intensities of visible emission increased as temperatures increased. The current-voltage (I-V) measurement revealed that the temperature of 50°C showed high conductive and it is suitable for optoelectronic device.

  15. Properties-Adjustable Alumina-Zirconia Nanolaminate Dielectric Fabricated by Spin-Coating

    Directory of Open Access Journals (Sweden)

    Junbiao Peng

    2017-11-01

    Full Text Available In this paper, an alumina-zirconia (Al2O3-ZrO2 nanolaminate dielectric was fabricated by spin-coating and the performance was investigated. It was found that the properties of the dielectric can be adjusted by changing the content of Al2O3/ZrO2 in nanolaminates: when the content of Al2O3 was higher than 50%, the properties of nanolaminates, such as the optical energy gap, dielectric strength (Vds, capacitance density, and relative permittivity were relatively stable, while the change of these properties became larger when the content of Al2O3 was less than 50%. With the content of ZrO2 varying from 50% to 100%, the variation of these properties was up to 0.482 eV, 2.12 MV/cm, 135.35 nF/cm2, and 11.64, respectively. Furthermore, it was demonstrated that the dielectric strength of nanolaminates were influenced significantly by the number (n of bilayers. Every increment of one Al2O3-ZrO2 bilayer will enhance the dielectric strength by around 0.39 MV/cm (Vds ≈ 0.86 + 0.39n. This could be contributed to the amorphous alumina which interrupted the grain boundaries of zirconia.

  16. Regulation of the forming process and the set voltage distribution of unipolar resistance switching in spin-coated CoFe2O4 thin films.

    Science.gov (United States)

    Mustaqima, Millaty; Yoo, Pilsun; Huang, Wei; Lee, Bo Wha; Liu, Chunli

    2015-01-01

    We report the preparation of (111) preferentially oriented CoFe2O4 thin films on Pt(111)/TiO2/SiO2/Si substrates using a spin-coating process. The post-annealing conditions and film thickness were varied for cobalt ferrite (CFO) thin films, and Pt/CFO/Pt structures were prepared to investigate the resistance switching behaviors. Our results showed that resistance switching without a forming process is preferred to obtain less fluctuation in the set voltage, which can be regulated directly from the preparation conditions of the CFO thin films. Therefore, instead of thicker film, CFO thin films deposited by two times spin-coating with a thickness about 100 nm gave stable resistance switching with the most stable set voltage. Since the forming process and the large variation in set voltage have been considered as serious obstacles for the practical application of resistance switching for non-volatile memory devices, our results could provide meaningful insights in improving the performance of ferrite material-based resistance switching memory devices.

  17. Synthesis of dense TiO2 nanoparticle multilayers using spin coating technique

    Science.gov (United States)

    DeSilva, L. Ajith; Thakurdesai, Madhavi; Bandara, T. M. W. J.; Preston, Joshua; Johnson, Wyatt; Gaquere-Parker, Anne; Survase, Smita

    2018-04-01

    A stack of nine layers is prepared by sequential spun casting of commercially available colloidal TiO2 nanoparticles of average size of 10-15 nm. Scanning electron microscopy (SEM) is employed to investigate the surface morphology of the multilayers. SEM micrographs exhibit formation of highly uniform and dense TiO2 nanoparticle layers. The uniformity and density is found to be increasing with layer thickness. Structural characterization is carried out using X-ray diffraction (XRD) technique. XRD spectra indicate improvement in crystalline quality of all the layers with increasing layer thickness. All the layers are having mainly the anatase phase of TiO2. Optical characterization is carried out by UV-visible spectroscopy. The value of bandgap estimated on the basis of absorption coefficient is found to be 3.26 eV and approximately remains the same for the layers. The electrical characterization suggests that multilayer resistivity increases with increasing layer thickness. The good quality spin coated thin dense TiO2 layers have many applications in optoelectronics.

  18. Fabrication and electrochemical properties of cathode-supported solid oxide fuel cells via slurry spin coating

    International Nuclear Information System (INIS)

    Chen Min; Luo Jingli; Chuang, Karl T.; Sanger, Alan R.

    2012-01-01

    Highlights: ► LSM cathode-supported cell prepared by slurry spin coating. ► Optimizing porosity in CFL resulting in power density of 0.58 W cm −2 at 850 °C. ► Activation polarization govern the impedance arcs measured under the OCV condition. ► Concentration polarization can induce the change of activation polarization. ► Four kinds of polarizations of our cells are separated and investigated. - Abstract: A cathode-supported SOFC consisting of LSM (La 0.8 Sr 0.2 MnO 3−δ ) cathode supporter, LSM–Sm 0.2 Ce 0.8 O 2−δ (SDC) cathode functional layer (CFL), yttria stabilized zirconia (YSZ)/SDC bi-layered electrolyte and Ni-YSZ anode layer was fabricated by a slurry spin coating technique. The influence of the porosity in both the CFL and cathode supporter on the electrochemical properties of the cells has been investigated. It was found that properly controlling the porosity in the CFL would improve the performance of the cells using O 2 in the cathode side (O 2 -cells), with a maximum power density (MPD) value achieving as high as 0.58 W cm −2 at 850 °C. However, this improvement is not so evident for the cells using air in the cathode side (air-cells). When increasing the porosity in the cathode-supporter, a significant increase of the power density for the air cells due to the decreasing R conc,c (cathode concentration polarization to the cell resistance) can be ascertained. In terms of our analysis on various electrochemical parameters, the R act (activation polarization to the cell resistance) is assumed to be mainly responsible for the impedance arcs measured under the OCV condition, with a negligible R conc,c value being able to be detected in our impedances. In this case, a significant decreasing size of the impedance arcs due to the increasing porosity in the cathode supporter would correspond to a decrease of the R act values, which was proved to be induced by the decreasing R conc,c .

  19. Spin-Coating and Characterization of Multiferroic MFe{sub 2}O{sub 4} (M=Co, Ni) / BaTiO{sub 3} Bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Quandt, Norman [Institute of Chemistry, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 2, 06120 Halle (Germany); Roth, Robert [Institute of Physics, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 3, 06120 Halle (Germany); Syrowatka, Frank [Interdisciplinary Center of Materials Science, Martin Luther University Halle-Wittenberg, Heinrich-Damerow-Straße 4, 06120 Halle (Germany); Steimecke, Matthias [Institute of Chemistry, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Germany); Ebbinghaus, Stefan G., E-mail: stefan.ebbinghaus@chemie.uni-halle.de [Institute of Chemistry, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 2, 06120 Halle (Germany)

    2016-01-15

    Bilayer films of MFe{sub 2}O{sub 4} (M=Co, Ni) and BaTiO{sub 3} were prepared by spin coating of N,N-dimethylformamide/acetic acid solutions on platinum coated silicon wafers. Five coating steps were applied to get the desired thickness of 150 nm for both the ferrite and perovskite layer. XRD, IR and Raman spectroscopy revealed the formation of phase-pure ferrite spinels and BaTiO{sub 3}. Smooth surfaces with roughnesses in the order of 3 to 5 nm were found in AFM investigations. Saturation magnetization of 347 emu cm{sup −3} for the CoFe{sub 2}O{sub 4}/BaTiO{sub 3} and 188 emu cm{sup −3} for the NiFe{sub 2}O{sub 4}/BaTiO{sub 3} bilayer, respectively were found. For the CoFe{sub 2}O{sub 4}/BaTiO{sub 3} bilayer a strong magnetic anisotropy was observed with coercivity fields of 5.1 kOe and 3.3 kOe (applied magnetic field perpendicular and parallel to film surface), while for the NiFe{sub 2}O{sub 4}/BaTiO{sub 3} bilayer this effect is less pronounced. Saturated polarization hysteresis loops prove the presence of ferroelectricity in both systems. - Graphical abstract: The SEM image of the CoFe{sub 2}O{sub 4}/BaTiO{sub 3} bilayer on Pt–Si-substrate (left), magnetization as a function of the magnetic field perpendicular and parallel to the film plane (right top) and P–E and I–V hysteresis loops of the bilayer at room temperature. - Highlights: • Ferrite and perovskite oxides grown on platinum using spin coating technique. • Columnar growth of cobalt ferrite particle on the substrate. • Surface investigation showed a homogenous and smooth surface. • Perpendicular and parallel applied magnetic field revealed a magnetic anisotropy. • Switching peaks and saturated P–E hysteresis loops show ferroelectricity.

  20. Doctor Blade-Coated Polymer Solar Cells

    KAUST Repository

    Cho, Nam Chul

    2016-10-25

    In this work, we report polymer solar cells based on blade-coated P3HT:PC71BM and PBDTTT-EFT:PC71BM bulk heterojunction photoactive layers. Enhanced power conversion efficiency of 2.75 (conventional structure) and 3.03% (inverted structure) with improved reproducibility was obtained from blade-coated P3HT:PC71BM solar cells, compared to spin-coated ones. Furthermore, by demonstrating 3.10% efficiency flexible solar cells using blade-coated PBDTTT-EFT:PC71BM films on the plastic substrates, we suggest the potential applicability of blade coating technique to the high throughput roll-to-roll fabrication systems.

  1. Microscale adaptation of the potentiometric method with ion-selective electrode for the quantification of fluoride; Adaptacion a microescala del metodo potenciometrico con electrodo ion selectivo para la cuantificacion de fluoruro

    Energy Technology Data Exchange (ETDEWEB)

    Guevara Ruiz, Paulina; Ortiz Perez, Maria Deogracias [Laboratorio de Bioquimica, Facultad de de Medicina, Universidad Autonoma de San Luis Potosi, San Luis Potosi, San Luis Potosi, (Mexico)]. E-mail: mdortiz@uaslp.mx

    2009-05-15

    Similarly to other countries, ground water from Mexico is naturally polluted by fluoride. The main effects of fluoride at typical ground water concentrations are dental fluorosis, neurological deficits and reproductive disorders. In order to verify that the fluoride concentration is within the allowed guideline in Mexico (NOM 127 and 201), it is important to monitor fluoride levels in water and commercial beverages. The aim of this work is to develop a modification of the standard potentiometric method for fluoride determination in water, in order to reduce costs and amount of potentially toxic waste substances. Both methods were validated, the standard potentiometric method with the ion selective electrode and the microscale modification proposed in this paper. The methods were compared using statistic tests and graphics, followed by the comparison of 125 samples of commercial bottled water sold in the city of San Luis Potosi. Optimal results were obtained for the validation of both methods, and the microscale modification showed statistically identical results to those obtained with the standard method in all samples of bottled water. The microscale modification is a good alternative for fluoride assessment in water and beverages, and it represents a 95 % reduction of costs and chemical waste. [Spanish] En varios paises, incluido Mexico se presenta una contaminacion natural con fluoruro en agua subterranea; los principales efectos en la salud observados en poblacion expuesta a concentraciones mayores al valor permisible (que en Mexico es de 1.5 mg/L) son la fluorosis dental y esqueletica, asi como dano reproductivo y neurologico. En varios estados de la republica Mexicana, este problema es aun desconocido, de ahi la necesidad de evaluar las concentraciones de fluoruro en agua de consumo en varias comunidades. Asi, el objetivo de este trabajo es desarrollar un metodo a microescala para la determinacion de fluoruro en agua, que al reducir la cantidad de reactivo y

  2. Growth of long triisopropylsilylethynyl pentacene (TIPS-PEN) nanofibrils in a polymer thin film during spin-coating.

    Science.gov (United States)

    Park, Minwoo; Min, Yuho; Lee, Yu-Jeong; Jeong, Unyong

    2014-03-01

    This study demonstrates the growth of long triisopropylsilyethynyl pentacene (TIPS-PEN) nanofibrils in a thin film of a crystalline polymer, poly(ε-caprolactone) (PCL). During spin-coating, TIPS-PEN molecules are locally extracted around the PCL grain boundaries and they crystallize into [010] direction forming long nanofibrils. Molecular weight of PCL and weight fraction (α) of TIPS-PEN in PCL matrix are key factors to the growth of nanofibrils. Long high-quality TIPS-PEN nanofibrils are obtained with high-molecular-weight PCL and at the α values in the range of 0.03-0.1. The long nanofibrils are used as an active layer in a field-effect organic transistor. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Influence of pH on optoelectronic properties of zinc sulphide thin films prepared using hydrothermal and spin coating method

    Science.gov (United States)

    Choudapur, V. H.; Bennal, A. S.; Raju, A. B.

    2018-04-01

    The ZnS nanomaterial is synthesized by hydrothermal method under optimized conditions using Zinc acetate and sodium sulphide as precursors. The Zinc Sulphide thin films are obtained by simple spin coating method with high optical transmittance. The prepared thin films are adhesive and uniform. The x-ray diffraction analysis showed that the films are polycrystalline in cubic phase with the preferred orientation along (111) direction. Current-voltage curves were recorded at room temperature using Keithley 617 programmable electrometer and conductivity is calculated for the film coated on ITO by two probe method. The pH of the solution is varied by using ammonia and hydrochloric acid. The comparative studies of effect of pH on the morphology, crystallanity and optoelectronic properties of the films are studied. It is observed that the pH of the solution has large influence on optoelectronic properties. The thin film prepared with neutral pH has higher crystallanity, bandgap and conductivity as compared to the samples prepared in acidic or basic solutions.

  4. Kinetic study of formic acid oxidation on Ti/IrO{sub 2} electrodes prepared using the spin coating deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Fierro, Stephane, E-mail: stephane.fierro@epfl.c [Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology, ISIC-EPFL, CH-1015 Lausanne (Switzerland); Comninellis, Christos [Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology, ISIC-EPFL, CH-1015 Lausanne (Switzerland)

    2010-09-30

    In the first part of this paper, IrO{sub 2} electrodes produced by thermal decomposition of H{sub 2}IrCl{sub 6} precursor were manufactured using the spin coating deposition technique, where centrifugal forces spread the precursor solution with simultaneous evaporation of the solvent on the rotating Ti substrate. It was found using this technique, that it is possible to obtain thin and uniform IrO{sub 2} coatings with controlled loadings. The influence of the concentration of iridium salt in the precursor solution (c{sub 0}) as well as the influence of the rotation speed at which the substrate spins ({omega}) on the IrO{sub 2} loading have been studied using voltammetric charge measurements. From these results, a simple relation has been proposed for the estimation of the IrO{sub 2} loading for a given c{sub 0} and {omega}. In the second part of this paper and from measurements performed using different IrO{sub 2} loadings and formic acid concentrations, the kinetic parameters of the oxidation of formic acid have been quantitatively determined using a model that involves the redox couple IrO{sub 3}/IrO{sub 2} as mediator of this reaction. Furthermore, using the kinetic parameters obtained together with the Nernst equation and the I-V curves of the supporting electrolyte (1 M HClO{sub 4}), theoretical I-V curves could be constructed for different concentrations of formic acid and different IrO{sub 2} loadings.

  5. Phase Transition Control for High-Performance Blade-Coated Perovskite Solar Cells

    KAUST Repository

    Li, Jianbo; Munir, Rahim; Fan, Yuanyuan; Niu, Tianqi; Liu, Yucheng; Zhong, Yufei; Yang, Zhou; Tian, Yuansi; Liu, Bo; Sun, Jie; Smilgies, Detlef-M.; Thoroddsen, Sigurdur T; Amassian, Aram; Zhao, Kui; Liu, Shengzhong (Frank)

    2018-01-01

    with high crystal quality and photophysical properties can be obtained only via direct crystallization for both spin-coating and blade-coating processes. As a result, the blade-coated MAPbI3 films deliver excellent charge-collection efficiency at both short

  6. Friction Modifier Using Adherent Metallic Multilayered or Mixed Element Layer Conversion Coatings

    Science.gov (United States)

    Schramm, Harry F. (Inventor); Defalco, Francis G. (Inventor); Starks, Lloyd L., Sr. (Inventor)

    2013-01-01

    A process for creating conversion coatings and spin, drawing, and extrusion finishes for surfaces, wherein the conversion coatings and spin, drawing, and extrusion finishes contain potassium, phosphorus, nitrogen, and one or more non-alkaline metals and/or one or more metalloids. The process comprises forming an aqueous solution of water, phosphoric acid or sulfuric acid, ammonium hydroxide, an alkali metal hydroxide, and one or more non-alkaline metals and/or one or more metalloids. The aqueous solution forms an anti-friction multilayer conversion and/or mixed element coating or a spin, drawing, and extrusion finish on a surface when applied to the surface, either directly without the use of applied external electromotive force, or as an additive in lubricating fluids.

  7. Thermal-induced changes on the properties of spin-coated P3HT:C60 thin films for solar cell applications

    CSIR Research Space (South Africa)

    Motaung, DE

    2009-09-01

    Full Text Available on the properties of spin- coated P3HT:C60 thin films for solar cell applications David E. Motaung1, 2, Gerald F. Malgas1,*, Christopher J. Arendse1, Sipho E. Mavundla1, 3 Clive J. Oliphant 1, 2 and Dirk Knoesen2 1National Centre for Nano...-structured Materials, Council for Scientific Industrial Research, P. O. Box 395, Pretoria, 0001, South Africa 2Deparment of Physics, University of the Western Cape, Private Bag X17, Bellville, 7535, South Africa 3Deparment of Chemistry, University of the Western...

  8. Doped indium nitride thin film by sol-gel spin coating method

    Science.gov (United States)

    Lee, Hui San; Ng, Sha Shiong; Yam, Fong Kwong

    2017-12-01

    In this study, magnesium doped indium nitride (InN:Mg) thin films grown on silicon (100) substrate were prepared via sol-gel spin coating method followed by nitridation process. A custom-made tube furnace was used to perform the nitridation process. Through this method, the low dissociation temperature issue of InN:Mg thin films can be solved. The deposited InN:Mg thin films were investigated using various techniques. The X-rays diffraction results revealed that two intense diffraction peaks correspond to wurtzite structure InN (100), and InN (101) were observed at 29° and 33.1° respectively. Field emission scanning electron microscopy images showed that the surface of the films exhibits densely packed grains. The elemental composition of the deposited thin films was analyzed using energy dispersive X-rays spectroscopy. The detected atomic percentages for In, N, and Mg were 43.22 %, 3.28 %, and 0.61 % respectively. The Raman spectra showed two Raman- and infrared-active modes of E2 (High) and A1 (LO) of the wurtzite InN. The band gap obtained from the Tauc plot showed around 1.74 eV. Lastly, the average surface roughness measured by AFM was around 0.133 µm.

  9. Effect of surfactant coating on magnetic properties of Fe3O4 nanoparticles: ESR study

    International Nuclear Information System (INIS)

    Koeseoglu, Yueksel

    2006-01-01

    Magnetic properties of surfactant-coated and uncoated superparamagnetic iron oxide nanoparticles, Fe 3 O 4 (SPION) were investigated by electron spin resonance (ESR) technique. For all samples, a strong and broad single ESR signal has been observed at all temperatures. A strong temperature dependence of ESR linewidth and resonance field is observed. Also, there is a strong effect of surfactant coating on magnetic properties of Fe 3 O 4 nanoparticles. While the resonance field is decreasing by coating, the linewidth of the ESR spectra is increasing. These changes in resonance field and the linewidth are attributed to the decrease in effective magnetic moment due to a non-collinear spin structure originated from the pinning of the surface spins and coated surfactant at the interface of nanoparticles. Also, the changes are due to the contribution of the volume of the diamagnetic coating mass to the sample volume

  10. Sequential Dip-spin Coating Method: Fully Infiltration of MAPbI 3-x Cl x into Mesoporous TiO 2 for Stable Hybrid Perovskite Solar Cells

    KAUST Repository

    Kim, Woochul

    2017-05-31

    Organic-inorganic hybrid perovskite solar cells (PSCs) have reached a power conversion efficiency of 22.1% in a short period (∼7 years), which has been obtainable in silicon-based solar cells for decades. The high power conversion efficiency and simple fabrication process render perovskite solar cells as potential future power generators, after overcoming the lack of long-term stability, for which the deposition of void-free and pore-filled perovskite films on mesoporous TiO2 layers is the key pursuit. In this research, we developed a sequential dip-spin coating method in which the perovskite solution can easily infiltrate the pores within the TiO2 nanoparticulate layer, and the resultant film has large crystalline grains without voids between them. As a result, a higher short circuit current is achieved owing to the large interfacial area of TiO2/perovskite, along with enhanced power conversion efficiency, compared to the conventional spin coating method. The as-made pore-filled and void-free perovskite film avoids intrinsic moisture and air and can effectively protect the diffusion of degradation factors into the perovskite film, which is advantageous for the long-term stability of PSCs.

  11. Superpolarizing neutron coatings: Theory and first experiments

    International Nuclear Information System (INIS)

    Pleshanov, N.K.

    2010-01-01

    A new method for improving polarizing neutron coatings is theoretically substantiated and experimentally verified. It is based on the use of layers with a negative potential of definite thickness to suppress reflection of neutrons with the undesired spin from the potential barriers formed by structural imperfections. Estimations showed that Ti, Co or Ti/Co interlayers at the interfaces and a protective Ti/TiO 2 surface bilayer may increase the flipping ratio for reflection from polarizing neutron coatings by orders of magnitude. It opens the possibility to build polarizers and analyzers of new generation. Superpolarizing coatings not only will improve the performance and thus widen the range of applications of the polarizing devices, but also may be the basis for designing novel neutron instrumentation. Even ultra-cold neutron beams can be efficiently polarized and analyzed with new polarizing neutron optics. A method for precise measurements of NSF and SF reflectivities of the spin-down neutrons for polarizing coatings with the flipping ratios up to 10 3 -10 4 is suggested (method of two samples).

  12. Optical Properties of Fe3O4 Thin Films Prepared from the Iron Sand by Spin Coating Method

    Science.gov (United States)

    Yulfriska, N.; Rianto, D.; Murti, F.; Darvina, Y.; Ramli, R.

    2018-04-01

    Research on magnetic oxide is growing very rapidly. This magnetic oxide can be found in nature that is in iron sand. One of the beaches in Sumatera Barat containing iron sand is Tiram Beach, Padang Pariaman District, Sumatera Barat. The content of iron sand is generally in the form of magnetic minerals such as magnetite, hematite, and maghemit. Magnetite has superior properties that can be developed into thin films. The purpose of this research is to investigate the optical properties of transmittance, absorbance, reflectance and energy gap from Fe3O4 thin films. This type of research is an experimental research. The iron sand obtained from nature is first purified using a permanent magnet, then made in nanoparticle size using HEM-E3D with milling time for 30 hours. After that, the process of making thin film with sol-gel spin coating method. In this research, variation of rotation speed from spin coating is 1000 rpm, 2000 rpm and 3000 rpm. Based on XRD results indicated that the iron sand of Tiram beach contains magnetite minerals and the SEM results show that the thickness of the thin films formed is 25μm, 24μm and 11μm. The characterization tool used for characterizing optical properties is the UV-VIS Spectrophotometer. So it can be concluded that the greater the speed of rotation the thickness of the thin layer will be smaller, resulting in the transmittance and reflectance will be greater, while the absorbance will be smaller. Energy gap obtained from this research is 3,75eV, 3,75eV and 3,74eV. So the average energy gap obtained is 3,75eV.

  13. Experimental verification of the rotational type of chiral spin spiral structures by spin-polarized scanning tunneling microscopy.

    Science.gov (United States)

    Haze, Masahiro; Yoshida, Yasuo; Hasegawa, Yukio

    2017-10-16

    We report on experimental verification of the rotational type of chiral spin spirals in Mn thin films on a W(110) substrate using spin-polarized scanning tunneling microscopy (SP-STM) with a double-axis superconducting vector magnet. From SP-STM images using Fe-coated W tips magnetized to the out-of-plane and [001] directions, we found that both Mn mono- and double-layers exhibit cycloidal rotation whose spins rotate in the planes normal to the propagating directions. Our results agree with the theoretical prediction based on the symmetry of the system, supporting that the magnetic structures are driven by the interfacial Dzyaloshinskii-Moriya interaction.

  14. In situ scanning tunneling microscope tip treatment device for spin polarization imaging

    Science.gov (United States)

    Li, An-Ping [Oak Ridge, TN; Jianxing, Ma [Oak Ridge, TN; Shen, Jian [Knoxville, TN

    2008-04-22

    A tip treatment device for use in an ultrahigh vacuum in situ scanning tunneling microscope (STM). The device provides spin polarization functionality to new or existing variable temperature STM systems. The tip treatment device readily converts a conventional STM to a spin-polarized tip, and thereby converts a standard STM system into a spin-polarized STM system. The tip treatment device also has functions of tip cleaning and tip flashing a STM tip to high temperature (>2000.degree. C.) in an extremely localized fashion. Tip coating functions can also be carried out, providing the tip sharp end with monolayers of coating materials including magnetic films. The device is also fully compatible with ultrahigh vacuum sample transfer setups.

  15. Application techniques of coatings by thermal projection; Tecnicas de aplicacion de recubrimientos por proyeccion termica

    Energy Technology Data Exchange (ETDEWEB)

    Porcayo Calderon, Jesus [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1995-12-31

    The coatings applied by thermal projection have an important number of applications in different industries (chemical, oil, electric, nuclear, etc.). The main purpose of the protection by means of coatings is to alter the surface characteristics of a component so as to resist corrosive environments, abrasion and erosion, among others. The coatings can be applied by different methods, but due to the fact that its characteristics appreciably differ from the base metal, it is important the knowledge of its properties when a coating is selected for a specific use. In this article the characteristics of the applied coatings by thermal projection, the factors that affect its performance and the principal application techniques, are described. [Espanol] Los recubrimientos aplicados por proyeccion termica tienen un numero importante de aplicaciones en diferentes industrias (quimica, petrolera, electrica, nuclear, etc.). El proposito principal de la proteccion por medio de recubrimientos es alterar las caracteristicas de la superficie de un componente de manera que resista ambientes corrosivos, abrasion y erosion, entre otros. Los recubrimientos pueden aplicarse por diferentes metodos, pero debido a que sus propiedades difieren apreciablemente de las del metal base, es importante el conocimiento de sus propiedades cuando se selecciona un recubrimiento para un uso especifico. En este articulo se describen las caracteristicas de los recubrimientos aplicados por proyeccion termica, los factores que afectan su desempeno y las principales tecnicas de aplicacion.

  16. Application techniques of coatings by thermal projection; Tecnicas de aplicacion de recubrimientos por proyeccion termica

    Energy Technology Data Exchange (ETDEWEB)

    Porcayo Calderon, Jesus [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    The coatings applied by thermal projection have an important number of applications in different industries (chemical, oil, electric, nuclear, etc.). The main purpose of the protection by means of coatings is to alter the surface characteristics of a component so as to resist corrosive environments, abrasion and erosion, among others. The coatings can be applied by different methods, but due to the fact that its characteristics appreciably differ from the base metal, it is important the knowledge of its properties when a coating is selected for a specific use. In this article the characteristics of the applied coatings by thermal projection, the factors that affect its performance and the principal application techniques, are described. [Espanol] Los recubrimientos aplicados por proyeccion termica tienen un numero importante de aplicaciones en diferentes industrias (quimica, petrolera, electrica, nuclear, etc.). El proposito principal de la proteccion por medio de recubrimientos es alterar las caracteristicas de la superficie de un componente de manera que resista ambientes corrosivos, abrasion y erosion, entre otros. Los recubrimientos pueden aplicarse por diferentes metodos, pero debido a que sus propiedades difieren apreciablemente de las del metal base, es importante el conocimiento de sus propiedades cuando se selecciona un recubrimiento para un uso especifico. En este articulo se describen las caracteristicas de los recubrimientos aplicados por proyeccion termica, los factores que afectan su desempeno y las principales tecnicas de aplicacion.

  17. DOLOČITEV POVRŠINSKE NAPETOSTI Z METODO KAPILARNEGA DVIGA DVOFAZNIH SISTEMOV

    OpenAIRE

    Kravanja, Gregor

    2014-01-01

    Namen magistrske naloge je bil postavitev merilne naprave in razvoj nove metode merjenja površinske napetosti s kapilarnim dvigom dvofaznih sistemov v okolici kritične točke. Za pridobitev natančnih in primerljivih meritev je bilo potrebno poznati natančni notranji premer tankih kapilar. Določili smo ga z metodo laserskega tipanja na nemški koordinatni merilni napravi ZEISS tipa UMC-850 s pomočjo merilne programske opreme CALYPSO 5.1.4. Za merjenje ravnotežne višine smo uporabili računalniški...

  18. In vivo evaluation of CaO-SiO2-P2O5-B2O3 glass-ceramics coating on Steinman pins.

    Science.gov (United States)

    Lee, Jae Hyup; Hong, Kug Sun; Baek, Hae-Ri; Seo, Jun-Hyuk; Lee, Kyung Mee; Ryu, Hyun-Seung; Lee, Hyun-Kyung

    2013-07-01

    Surface coating using ceramics improves the bone bonding strength of an implant. We questioned whether a new type of glass-ceramics (BGS-7) coating (CaO-SiO2 -P2 O5 -B2 O3 ) would improve the osseointegration of Steinman pins (S-pins) both biomechanically and histomorphometrically. An in vivo study was performed using rabbits by inserting three S-pins into each iliac bone. The pins were 2.2-mm S-pins with a coating of 30-μm-thick BGS-7 and 550-nm-thick hydroxyapatite (HA), as opposed to an S-pin without coating. A tensile strength test and histomorphometrical evaluation was performed. In the 2-week group, the BGS-7 implant showed a significantly higher tensile strength than the S-pin. In the 4- and 8-week groups, the BGS-7 implants had significantly higher tensile strengths than the S-pins and HA implants. The histomorphometrical study revealed that the BGS-7 implant had a significantly higher contact ratio than the S-pin and HA implants in the 4-week group. The biomechanical and histomorphometrical tests showed that the BGS-7 coating had superior bone bonding properties than the groups without the coating from the initial stage of insertion. The BGS-7 coating of an S-pin will enhance the bone bonding strength, and there might also be an advantage in human bone bonding. © 2013, Copyright the Authors. Artificial Organs © 2013, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  19. Effects of fluorine contamination on spin-on dielectric thickness in semiconductor manufacturing

    Science.gov (United States)

    Kim, Hyoung-ryeun; Hong, Soonsang; Kim, Samyoung; Oh, Changyeol; Hwang, Sung Min

    2018-03-01

    In the recent semiconductor industry, as the device shrinks, spin-on dielectric (SOD) has been adopted as a widely used material because of its excellent gap-fill, efficient throughput on mass production. SOD film must be uniformly thin, homogeneous and free of particle defects because it has been perfectly perserved after chemical-mechanical polishing (CMP) and etching process. Spin coating is one of the most common techniques for applying SOD thin films to substrates. In spin coating process, the film thickness and uniformity are strong function of the solution viscosity, the final spin speed and the surface properties. Especially, airborne molecular contaminants (AMCs), such as HF, HCl and NH3, are known to change to surface wetting characteristics. In this work, we study the SOD film thickness as a function of fluorine contamination on the wafer surface. To examine the effects of airborne molecular contamination, the wafers are directly exposed to HF fume followed by SOD coating. It appears that the film thickness decreases by higher contact angle on the wafer surface due to fluorine contamination. The thickness of the SOD film decreased with increasing fluorine contamination on the wafer surface. It means that the wafer surface with more hydrophobic property generates less hydrogen bonding with the functional group of Si-NH in polysilazane(PSZ)-SOD film. Therefore, the wetting properties of silicon wafer surfaces can be degraded by inorganic contamination in SOD coating process.

  20. Preparation of CdS nanoparticels with spin-coating assisted successive ionic layer reaction and their photoelectrochemical properties

    Directory of Open Access Journals (Sweden)

    Bao SUN

    2017-10-01

    Full Text Available In order to settle the problems in the traditional SILAR method for CdS deposition, such as smaller particles and being difficult to enhance the sensitive layers, an improved spin-coating assisted successive ionic layer reaction method (S-SILR substituted for the traditional SILAR method is used to deposit the CdS nanocrystals. The comparison between the improved and traditional methods is studied after depositing the CdS nanocrystals onto the ZnO nanorod arrays with the two approaches. Different analysis methods, SEM, XRD, UV-vis and the transit photocurrent measurement are conducted to characterize the morphologies and structures of the samples, as well as investigating the light absorption properties, and the photoelectric conversion performance of the electrodes. The results indicate that the CdS nanocrystals photosensitive layers could be totally coated onto the ZnO nanorod arrays more easily by the improved S-SILR method; the light absorption properties and the photoelectric conversion performance of the electrodes prepared by the improved S-SILR method are more excellent compared with those electrodes prepared by the traditional SILAR method. The improvement of the CdS deposition method has certain guiding significance in enhancing the operability of the preparation technology and the photovoltaic performance of the solar cells.

  1. Analysis of the current-voltage characteristics of polymer-based organic light-emitting diodes (OLEDs deposited by spin coating

    Directory of Open Access Journals (Sweden)

    Ricardo Vera

    2010-04-01

    Full Text Available Polymer-based organic light-emitting diodes (OLEDs with the structure ITO / PEDOT:PSS / MDMO-PPV / Metal were prepared by spincoating. It is known that electroluminescence of these devices is strongly dependent on the material used as cathode and on the depositionparameters of the polymer electroluminescent layer MDMO-PPV. Objective. In this work the effect of i the frequency of the spin coater(1000-8000 rpm, ii the concentration of the MDMO-PPV: Toluene solution, and iii the material used as cathode (Aluminium or Silveron the electrical response of the devices, was evaluated through current-voltage (I-V measurements. Materials and methods. PEDOT:PPSand MDMO-PPV organic layers were deposited by spin coating on ITO substrates, and the OLED structure was completed with cathodesof aluminium and silver. The electric response of the devices was evaluated based on the I-V characteristics. Results. Diodes prepared withthinner organic films allow higher currents at lower voltages; this can be achieved either by increasing the frequency of the spin coater orby using concentrations of MDMO-PPV: Toluene lower than 2% weight. A fit of the experimental data showed that the diodes have twocontributions to the current. The first one is attributed to parasitic currents between anode and cathode, and the other one is a parallel currentthrough the organic layer, in which the carrier injection mechanism is mediated by thermionic emission. Conclusions. The results of thefitting and the energy level alignment through the whole structure show that PPV-based OLEDs are unipolar devices, with current mainlyattributed to hole transport.

  2. LaSrMnO{sub 3} thin films on YSZ/YSZ - NiO by the spin coating method: synthesis and microstructural characterization

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Laurenia Martins Pereira; Souza, Graziele Lopes de [Universidade Federal do Rio Grande do Norte (NUPEG/UFRN), Natal, RN (Brazil). Nucleo de Pesquisa em Petroleo e Gas], Email: lauengmat@hotmail.com; Macedo, Daniel Araujo de; Cela, Beatriz; Paskocimas, Carlos Alberto; Nascimento, Rubens Maribondo do [Universidade Federal do Rio Grande do Norte (PPGCEM/UFRN), Natal, RN (Brazil). Programa de Pos Graduacao em Ciencia e Engenharia de Materiais; Cesario, Moises Romolos [Universidade Federal do Rio Grande do Norte (PPGQ/UFRN), Natal, RN (Brazil). Programa de Pos Graduacao em Quimica

    2010-07-01

    Fuel cells are devices which work by electrochemical mechanism directly converting the chemical energy, by fuel the oxidizing, in electric energy. The Solid Oxide Fuel Cell - SOFC consist an anode, an electrolyte and one cathode made with ceramic materials. The most widely known functional materials used in SOFC are Yttria-stabilized zirconia electrolyte (YSZ), composite anode of YSZ-Ni O and strontium-doped lanthanum manganite cathode (La{sub 1-x}Sr{sub x}MnO{sub 3} - LGSM). In this work the thin films of cathode LSM were deposited by spin coating in a half cell YSZ/YSZ - Ni O. The polymeric resin of 22% strontium-doped lanthanum manganite (LSM 22) was attained by the polymeric precursor method. This resin was directly used for the deposition process. The deposition of 2 or 4 layers occurred by spin coating method with the following conditions: 500 rpm during 15 s and 300 rpm during 40 s. Each layer was thermally treated at 500 deg C for 2 h and heating rate equal to 1 deg C/min. The multi layers were sintered at 1000 deg C for 2 h, heating rate of 3 deg C/min and characterized by X-ray diffraction (XRD) and scanning electronic microscopy (SEM). The LSM 22 thin films presented microstructure with thin particles and thickness of 1 {mu}m. The surface cracks' quantity and size reduction tendency was observed with the increase of the layers deposition number. (author)

  3. Morphological and voltammetric characterization of different concentrations of spin coated Nafion-Ru(bpy)2+3 thin films

    International Nuclear Information System (INIS)

    Tuason, B S B; Tiong-Palisoc, S; Tiamzon-Natividad, M

    2015-01-01

    Different concentrations of Ru(bpy) 2+ 3 were successfully deposited on ITO coated glass substrates employing a simple method using a spin coater. The surface morphology was determined by scanning electron microscopy (SEM). The transport mechanism and the diffusion coefficient of the redox mediators within the films were characterized using cyclic voltammetry (CV). The concentrations were varied by dissolving different amounts of the redox mediator in methanol and 5% Nafion. SEM micrographs showed that the roughness of the surface increased with concentration of redox mediator. CV showed successful incorporation of Ru(bpy) 2+ 3 . The order of the magnitude of the diffusion coefficients confirmed that the redox mediators were immobilized within the Nafion thin film. The resulting amount of redox mediator immobilized can be manipulated by simply varying the concentration of the casting solution. (paper)

  4. Properties of ZnO:Al Films Prepared by Spin Coating of Aged Precursor Solution

    International Nuclear Information System (INIS)

    Shrestha, Shankar Prasad; Ghimire, Rishi; Nakarmi, Jeevan Jyoti; Kim, Young Sung; Shrestha, Sabita; Park, Chong Yun; Boo, Jin Hyo

    2010-01-01

    Transparent conducting undoped and Al impurity doped ZnO films were deposited on glass substrate by spin coat technique using 24 days aged ZnO precursor solution with solution of ethanol and diethanolamine. The films were characterized by UV-Visible spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), electrical resistivity (ρ), carrier concentration (n), and hall mobility (μ) measurements. XRD data show that the deposited film shows polycrystalline nature with hexagonal wurtzite structure with preferential orientation along (002) crystal plane. The SEM images show that surface morphology, porosity and grain sizes are affected by doping concentration. The Al doped samples show high transmittance and better resistivity. With increasing Al concentration only mild change in optical band gap is observed. Optical properties are not affected by aging of parent solution. A lowest resistivity (8.5 x 10 -2 ohm cm) is observed at 2 atomic percent (at.%) Al. With further increase in Al concentration, the resistivity started to increase significantly. The decrease resistivity with increasing Al concentration can be attributed to increase in both carrier concentration and hall mobility

  5. Nonvolatile memory thin film transistors using CdSe/ZnS quantum dot-poly(methyl methacrylate) composite layer formed by a two-step spin coating technique

    Science.gov (United States)

    Chen, Ying-Chih; Huang, Chun-Yuan; Yu, Hsin-Chieh; Su, Yan-Kuin

    2012-08-01

    The nonvolatile memory thin film transistors (TFTs) using a core/shell CdSe/ZnS quantum dot (QD)-poly(methyl methacrylate) (PMMA) composite layer as the floating gate have been demonstrated, with the device configuration of n+-Si gate/SiO2 insulator/QD-PMMA composite layer/pentacene channel/Au source-drain being proposed. To achieve the QD-PMMA composite layer, a two-step spin coating technique was used to successively deposit QD-PMMA composite and PMMA on the insulator. After the processes, the variation of crystal quality and surface morphology of the subsequent pentacene films characterized by x-ray diffraction spectra and atomic force microscopy was correlated to the two-step spin coating. The crystalline size of pentacene was improved from 147.9 to 165.2 Å, while the degree of structural disorder was decreased from 4.5% to 3.1% after the adoption of this technique. In pentacene-based TFTs, the improvement of the performance was also significant, besides the appearances of strong memory characteristics. The memory behaviors were attributed to the charge storage/discharge effect in QD-PMMA composite layer. Under the programming and erasing operations, programmable memory devices with the memory window (Δ Vth) = 23 V and long retention time were obtained.

  6. Ordered alternating binary polymer nanodroplet array by sequential spin dewetting.

    Science.gov (United States)

    Bhandaru, Nandini; Das, Anuja; Salunke, Namrata; Mukherjee, Rabibrata

    2014-12-10

    We report a facile technique for fabricating an ordered array of nearly equal-sized mesoscale polymer droplets of two constituent polymers (polystyrene, PS and poly(methyl methacrylate), PMMA) arranged in an alternating manner on a topographically patterned substrate. The self-organized array of binary polymers is realized by sequential spin dewetting. First, a dilute solution of PMMA is spin-dewetted on a patterned substrate, resulting in an array of isolated PMMA droplets arranged along the substrate grooves due to self-organization during spin coating itself. The sample is then silanized with octadecyltrichlorosilane (OTS), and subsequently, a dilute solution of PS is spin-coated on to it, which also undergoes spin dewetting. The spin-dewetted PS drops having a size nearly equal to the pre-existing PMMA droplets position themselves between two adjacent PMMA drops under appropriate conditions, forming an alternating binary polymer droplet array. The alternating array formation takes place for a narrow range of solution concentration for both the polymers and depends on the geometry of the substrate. The size of the droplets depends on the extent of confinement, and droplets as small as 100 nm can be obtained by this method, on a suitable template. The findings open up the possibility of creating novel surfaces having ordered multimaterial domains with a potential multifunctional capability.

  7. Polymeric Coatings for Combating Biocorrosion

    Science.gov (United States)

    Guo, Jing; Yuan, Shaojun; Jiang, Wei; Lv, Li; Liang, Bin; Pehkonen, Simo O.

    2018-03-01

    Biocorrosion has been considered as big trouble in many industries and marine environments due to causing great economic loss. The main disadvantages of present approaches to prevent corrosion include being limited by environmental factors, being expensive, inapplicable to field, and sometimes inefficient. Studies show that polymer coatings with anti-corrosion and anti-microbial properties have been widely accepted as a novel and effective approach to preventbiocorrosion. The main purpose of this review is to summarize up the progressive status of polymer coatings used for combating microbially-induced corrosion. Polymers used to synthesize protective coatings are generally divided into three categories: i) traditional polymers incorporated with biocides, ii) antibacterial polymers containing quaternary ammonium compounds, and iii) conductive polymers. The strategies to synthesize polymer coatings resort mainly to grafting anti-bacterial polymers from the metal substrate surface using novel surface-functionalization approaches, such as free radical polymerization, chemically oxidative polymerization and surface-initiated atom transfer radical polymerization, as opposed to the traditional approaches of dip coating or spin coating.

  8. Spin Speed and Duration Dependence of TiO2 Thin Films pH Sensing Behavior

    Directory of Open Access Journals (Sweden)

    Muhammad AlHadi Zulkefle

    2016-01-01

    Full Text Available Titanium dioxide (TiO2 thin films were applied as the sensing membrane of an extended-gate field-effect transistor (EGFET pH sensor. TiO2 thin films were deposited by spin coating method and the influences of the spin speed and spin duration on the pH sensing behavior of TiO2 thin films were investigated. The spin coated TiO2 thin films were connected to commercial metal-oxide-semiconductor field-effect transistor (MOSFET to form the extended gates and the MOSFET was integrated in a readout interfacing circuit to complete the EGFET pH sensor system. For the spin speed parameter investigation, the highest sensitivity was obtained for the sample spun at 3000 rpm at a fixed spinning time of 60 s, which was 60.3 mV/pH. The sensitivity was further improved to achieve 68 mV/pH with good linearity of 0.9943 when the spin time was 75 s at the speed of 3000 rpm.

  9. Structural characterization and dielectric properties of BaTiO3 thin films obtained by spin coating

    Directory of Open Access Journals (Sweden)

    Branimir Bajac

    2014-12-01

    Full Text Available Barium titanate thin films were prepared by spin coating deposition technique of an acetic precursor sol and sintered at 750, 900 and 1050 °C. Phase composition of the obtained thin films was characterized by X-ray diffraction and Raman spectroscopy. Their morphology was analysed by scanning electron microscopy and atomic force microscopy. Dielectric properties of thin films sintered at 750 and 900 °C were characterized by LCD device, where the influence of sintering temperature on dielectric permittivity and loss tangent was inspected. It was concluded that higher sintering temperature increases grain size and amount of tetragonal phase, hence higher relative permittivity was recorded. The almost constant relative permittivity in the measured frequency (800 Hz–0.5 MHz and temperature (25–200 °C ranges as well as low dielectric loss are very important for the application of BaTiO3 films in microelectronic devices.

  10. Dependence of electrical property on the applied magnetic fields in spin coated Fe(III)-Phorphyrin films

    International Nuclear Information System (INIS)

    Utari; Kusumandari; Purnama, B.; Mudasir; Abraha, K.

    2016-01-01

    We report here on the experimental results of the effect of external magnetic field on the current flow in plane surface of Fe(III)-porphyrin thin layer. The deposition of the Fe(III)- porphyrin thin layer was done by spin coating method. The I-V characteristics of film were measured by means of two point probes. The sample of layer number N = 4 was used to evaluate the magnetic effect on the electrical currents. The ohmic characteristics of the I-V film measurement were obtained. The current decreases when magnetic field is applied to the system and saturated current is obtained at a given magnetic field. Here, the decrease in the current can be attributed to the recombination of carrier charge under the magnetic field. In addition, the magnitude of the saturated current is found to increase with the increase in the voltage used. (paper)

  11. The adhesion of SiNx thin layers on silica-acrylate coated polymer substrates

    NARCIS (Netherlands)

    Abdallah, Amir; Lu, K.; Ovchinnikov, C.D.; Bulle-Lieuwma, C.W.T.; Bouten, P.C.P.; With, de G.

    2009-01-01

    Plasma Enhanced Chemical Vapor Deposition (PECVD) was used to grow 200, 300 and 400 nm thick silicon nitride layers (SiN x ) on a high temperature aromatic polyester substrate spin coated with a silica-acrylate hybrid coating (hard coat). Layers deposited without oxygen plasma treatment remained

  12. CdS/CdSe quantum dot shell decorated vertical ZnO nanowire arrays by spin-coating-based SILAR for photoelectrochemical cells and quantum-dot-sensitized solar cells.

    Science.gov (United States)

    Zhang, Ran; Luo, Qiu-Ping; Chen, Hong-Yan; Yu, Xiao-Yun; Kuang, Dai-Bin; Su, Cheng-Yong

    2012-04-23

    A CdS/CdSe composite shell is assembled onto the surface of ZnO nanowire arrays with a simple spin-coating-based successive ionic layer adsorption and reaction method. The as-prepared photoelectrode exhibit a high photocurrent density in photoelectrochemical cells and also generates good power conversion efficiency in quantum-dot-sensitized solar cells. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Roll coated large area ITO- and vacuum-free all organic solar cells from diketopyrrolopyrrole based non-fullerene acceptors with molecular geometry effects

    DEFF Research Database (Denmark)

    Brandt, Rasmus Guldbaek; Zhang, Fei; Andersen, Thomas Rieks

    2016-01-01

    morphology, and photovoltaic performance of both spin-coated ITO based and roll coated large area, ITO- and vacuum-free organic solar cells (OSCs). For spin-coated devices based on P3HT as the donor polymer the solar cells gave power conversion efficiencies (PCEs) in the following order for (P3HT:PhDMe(DPP)2...

  14. Preparation and characterization of enamel coating on pure titanium as a hydrogen penetration barrier

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Jie, E-mail: taojie@nuaa.edu.cn [College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu 210016 (China); Guo, Xunzhong [College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu 210016 (China); Huang, Zhendong [Graduate School of Human and Environmental Studies, Kyoto University, oshida-Nihonmatsu-Cho, Sakyo-Ku, Kyoto shi 606-8501 (Japan); Liu, Hongbing [Shanghai Aircraft Manufacturing Co,. Ltd, Shanghai 200436 (China); Wang, Tao [College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu 210016 (China)

    2013-06-15

    Highlights: ► The enamel coating was prepared by spin-coating and enameling method. ► The dense enamel coatings were chemically bonded with TA1 substrate. ► The coatings possessed better thermal shock resistance property. ► The coatings had excellent ball-dropping impact properties. ► The enamel coating exhibited a good barrier effect to hydrogen isotope penetration. -- Abstract: The enamel coating with a thickness of 90–110 × 10{sup −6} m was prepared on TA1 substrate by spin-coating and enameling to solve the problems of hydrogen isotope penetration for commercial pure titanium TA1. The microstructure and the interfacial morphology of the samples were characterized respectively by X-ray diffraction, optical and scanning electron microscopy. The profiles of main elements at the interface were analyzed by EDS line-scanning. The experimental results indicated that the dense enamel coatings were chemically bonded with TA1 substrate, and possessed better thermal shock resistance and ball-dropping impact properties. It was concluded from the results of hydrogen charging test with Vickers microhardness measurement and deuterium penetration experiments that the as-prepared dense enamel coating exhibited a good barrier effect to hydrogen isotope penetration.

  15. Optical characterization of antirelaxation coatings

    Science.gov (United States)

    Tsvetkov, S.; Gateva, S.; Cartaleva, S.; Mariotti, E.; Nasyrov, K.

    2018-03-01

    Antirelaxation coatings (ARC) are used in optical cells containing alkali metal vapor to reduce the depolarization of alkali atoms after collisions with the cell walls. The long-lived ground state polarization is a basis for development of atomic clocks, magnetometers, quantum memory, slow light experiments, precision measurements of fundamental symmetries etc. In this work, a simple method for measuring the number of collisions of the alkali atoms with the cell walls without atomic spin randomization (Nasyrov et al., Proc. SPIE (2015)) was applied to characterize the AR properties of two PDMS coatings prepared from different solutions in ether (PDMS 2% and PDMS 5%). We observed influence of the light-induced atomic desorption (LIAD) on the AR properties of coatings.

  16. Ordering of Polystyrene Nanoparticles on Substrates Pre-Coated with Different Polyelectrolyte Architectures

    Directory of Open Access Journals (Sweden)

    Matthias Karg

    2013-06-01

    Full Text Available Adjusting the inter-particle distances in ordered nanoparticle arrays can create new nano-devices and is of increasing importance to a number of applications such as nanoelectronics and optical devices. The assembly of negatively charged polystyrene (PS nanoparticles (NPs on Poly(2-(dimethylaminoethyl methacrylate (PDMAEMA brushes, quaternized PDMAEMA brushes and Si/PEI/(PSS/PAH2, was studied using dip- and spin-coating techniques. By dip-coating, two dimensional (2-D, randomly distributed non-close packed particle arrays were assembled on Si/PEI/(PSS/PAH2 and PDMAEMA brushes. The inter-particle repulsion leads to lateral mobility of the particles on these surfaces. The 200 nm diameter PS NPs tended to an inter-particle distance of 350 to 400 nm (center to center. On quaternized PDMAEMA brushes, the strong attractive interaction between the NPs and the brush dominated, leading to clustering of the particles on the brush surface. Particle deposition using spin-coating at low spin rates resulted in hexagonal close-packed multilayer structures on Si/PEI/(PSS/PAH2. Close-packed assemblies with more pronounced defects are also observed on PDMAEMA brushes and QPDMAEMA brushes. In contrast, randomly distributed monolayer NP arrays were achieved at higher spin rates on all polyelectrolyte architectures. The area fraction of the particles decreased with increasing spin rate.

  17. Annealing Heat Treatment of ZnO Nanoparticles Grown on Porous Si Substrate Using Spin-Coating Method

    Directory of Open Access Journals (Sweden)

    K. A. Eswar

    2014-01-01

    Full Text Available ZnO nanoparticles were successfully deposited on porous silicon (PSi substrate using spin-coating method. In order to prepare PSi, electrochemical etching was employed to modify the Si surface. Zinc acetate dihydrate was used as a starting material in ZnO sol-gel solution preparation. The postannealing treatments were investigated on morphologies and photoluminescence (PL properties of the ZnO thin films. Field emission scanning electron microscopy (FESEM results indicate that the thin films composed by ZnO nanoparticles were distributed uniformly on PSi. The average sizes of ZnO nanoparticle increase with increasing annealing temperature. Atomic force microscopic (AFM analysis reveals that ZnO thin films annealed at 500°C had the smoothest surface. PL spectra show two peaks that completely correspond to nanostructured ZnO and PSi. These findings indicate that the ZnO nanostructures grown on PSi are promising for application as light emitting devices.

  18. Low-cost growth of magnesium doped gallium nitride thin films by sol-gel spin coating method

    Science.gov (United States)

    Amin, N. Mohd; Ng, S. S.

    2018-01-01

    Low-cost sol-gel spin coating growth of magnesium (Mg) doped gallium nitride (GaN) thin films with different concentrations of Mg was reported. The effects of the Mg concentration on the structural, surface morphology, elemental compositions, lattice vibrational, and electrical properties of the deposited films were investigated. X-ray diffraction results show that the Mg-doped samples have wurtzite structure with preferred orientation of GaN(002). The crystallite size decreases and the surface of the films with pits/pores were formed, while the crystalline quality of the films degraded as the Mg concentration increases from 2% to 6. %. All the Raman active phonon modes of the wurtzite GaN were observed while a broad peak attributed to the Mg-related lattice vibrational mode was detected at 669 cm-1. Hall effect results show that the resistivity of the thin films decreases while the hole concentration and hall mobility of thin films increases as the concentration of the Mg increases.

  19. Torque calculation in the induction motor with the finite element method; Calculo del par en el motor de induccion con el metodo del elemento finito

    Energy Technology Data Exchange (ETDEWEB)

    Castillo Diaz, Ramon

    2002-06-15

    In this work the method of the finite element is applied to the bi-dimensional analysis of the induction motor in operation in steady state, excited by sine sources of laminar currents and sine sources of voltage. The analysis is focused mainly in the calculation of the electromagnetic torque. The topics of electromagnetic theory are covered and in an idealized model of the induction motor, analytically and numerically with the method of the finite element, in the variant method of Galerkin, the vectorial potential and the torque are calculated. The results obtained with the analytical and numerical methods are compared. Three formulations are developed to calculate the torque with the method of the finite element, using triangular elements of first order, based in the equation of force of Lorentz, the Maxwell tensor and the principle of the virtual work. Finally, a motor of induction of real characteristics is simulated, assuming it is connected to a three-phase voltage source. In this motor it is analyzed the convergence and the evolution in the results obtained of the torque with different discretions, and the torque-velocity performance curve is calculated. [Spanish] En este trabajo se aplica el metodo del elemento finito al analisis bidimensional del motor de induccion en operacion en estado estable, excitado por fuentes de corriente laminar senoidales y fuentes de voltaje senoidales. El analisis se enfoca principalmente en el calculo del par electromagnetico. Se tratan los topicos de teoria electromagnetica involucrados y en un modelo idealizado del motor de induccion, se calculan analitica y numericamente con el metodo del elemento finito, en la variante metodo de Galerkin, el potencial vectorial y el par. Se comparan resultados obtenidos con los metodos analiticos y numericos. Se desarrollan tres formulaciones para calcular el par con el metodo del elemento finito, utilizando elementos triangulares de primer orden, basadas en la ecuacion de fuerza de

  20. Synthesis of Colloidal ZnO Nanoparticles and Deposit of Thin Films by Spin Coating Technique

    Directory of Open Access Journals (Sweden)

    Jose Alberto Alvarado

    2013-01-01

    Full Text Available ZnO colloidal nanoparticles were synthesized, the average size of these nanoparticles is around 25 nm with hexagonal form. It was noted that stabilization depends directly on the purifying process; in this work we do not change the nature of the solution as a difference from Meulekamp's method, and we do not use any alkanes to remove the byproducts; only a centrifuge to remove those ones was used, thereby the stabilization increases up to 24 days. It is observed from the results that only three times of washing is enough to prevent the rapid aging process. The effect of annealing process on the composition, size, and geometrical shape of ZnO nanoparticles was studied in order to know whether the annealing process affects the crystallization and growth of the nanoparticles. After the synthesis, the colloidal nanoparticles were deposited by spin coating technique showing that the formed nanoparticles have no uniformly deposition pattern. But is possible to deposit those ones in glass substrates. A possible deposition process of the nanoparticles is proposed.

  1. Characterizations of multilayer ZnO thin films deposited by sol-gel spin coating technique

    Directory of Open Access Journals (Sweden)

    M.I. Khan

    Full Text Available In this work, zinc oxide (ZnO multilayer thin films are deposited on glass substrate using sol-gel spin coating technique and the effect of these multilayer films on optical, electrical and structural properties are investigated. It is observed that these multilayer films have great impact on the properties of ZnO. X-ray Diffraction (XRD confirms that ZnO has hexagonal wurtzite structure. Scanning Electron Microscopy (SEM showed the crack-free films which have uniformly distributed grains structures. Both micro and nano particles of ZnO are present on thin films. Four point probe measured the electrical properties showed the decreasing trend between the average resistivity and the number of layers. The optical absorption spectra measured using UV–Vis. showed the average transmittance in the visible region of all films is 80% which is good for solar spectra. The performance of the multilayer as transparent conducting material is better than the single layer of ZnO. This work provides a low cost, environment friendly and well abandoned material for solar cells applications. Keywords: Multilayer films, Semiconductor, ZnO, XRD, SEM, Optoelectronic properties

  2. Density-controllable nonvolatile memory devices having metal nanocrystals through chemical synthesis and assembled by spin-coating technique

    International Nuclear Information System (INIS)

    Wang Guangli; Chen Yubin; Shi Yi; Pu Lin; Pan Lijia; Zhang Rong; Zheng Youdou

    2010-01-01

    A novel two-step method is employed, for the first time, to fabricate nonvolatile memory devices that have metal nanocrystals. First, size-averaged Au nanocrystals are synthesized chemically; second, they are assembled into memory devices by a spin-coating technique at room temperature. This attractive approach makes it possible to tailor the diameter and control the density of nanocrystals individually. In addition, processes at room temperature prevent Au diffusion, which is a main concern for the application of metal nanocrystal-based memory. The experimental results, both the morphology characterization and the electrical measurements, reveal that there is an optimum density of nanocrystal monolayer to balance between long data retention and a large hysteresis memory window. At the same time, density-controllable devices could also feed the preferential emphasis on either memory window or retention time. All these facts confirm the advantages and novelty of our two-step method. (semiconductor devices)

  3. Correlacion entre metodos de analisis de Zn disponible en cuatro ordenes de suelos de Costa Rica

    Directory of Open Access Journals (Sweden)

    Eloy Molina

    2001-01-01

    Full Text Available Se realizo una comparación entre métodos analisis del Zn disponible en 4 ordenes de sue- Analytilos de Costa Rica (Ultisoles, Vertisoles, Andisoles Inceptisoles, 25 de c/u, utilizando las siguientes soluciones extractoras: Olsen Modificado, Meh- lich 3, Morgan Modificado, DTPA y HC1. Las cantidades de Zn extrafdas dependieron de la natu- raleza qufmica de la solucion extractora. El HCl presento los contenidos mas altos de Zn en los chasuelos, excepto en Vertisoles. Las soluciones que hicontienen el agente quelante EDTA (Olsen Modi- ficado y Mehlich`3, extrajeron niveles interme- Modidios de Zn, en tanto que los metodos que contie- Den el quelato DTPA (Morgan Modificado y DT - PA, obtuvieron los valores mas bajos. Las corre- laciones de Zn extrafble entre los 5 metodos fue- signifirOD significativas en la mayona de los casos, tanto nivel de orden de suelos como en el conjunto de indivilos 100 suelos analizados. Los coeficientes de co- rrelacion mas altos, se presentaron entre Mehlich Morgan Modificado y DTPA. Las correlaciones Modifueron consistentes en los 4 ordenes, 10 que indica que estas soluciones poseen un amplio margen de adaptacion a diferentes tipos de suelo, siendo una caractenstica ventajosa para la selección de un metodo de analisis. El Olsen Modificado fue mas slighteficiente para la extraccion de Zn en suelos de pH ligeramente acido 0 neutro (Vertisoles e Inceptiso- les, que en suelos acidos (Ultisoles y Andisoles. EI HCI extrajo cantidades muy aItas de Zn que Moraparentementestan relacionadas con formas no disponibles para lag plantas. Se concluye que lag soluciones Mehlich 3, Morgan Modificado y DT - PA son semejantes en la forma de extraer Zn dispo- Dible, y podrian seT una altemativa para sustituir el metoda tradicional de Olsen Modificado utilizado en Costa Rica. Sin embargo,la eficiencia de ellas no puede seT establecida sino a traves de log estudios de correlacion contra rendimiento en invernadero y campo.

  4. Spin-Dependent Transport through Chiral Molecules Studied by Spin-Dependent Electrochemistry

    Science.gov (United States)

    2016-01-01

    Conspectus Molecular spintronics (spin + electronics), which aims to exploit both the spin degree of freedom and the electron charge in molecular devices, has recently received massive attention. Our recent experiments on molecular spintronics employ chiral molecules which have the unexpected property of acting as spin filters, by way of an effect we call “chiral-induced spin selectivity” (CISS). In this Account, we discuss new types of spin-dependent electrochemistry measurements and their use to probe the spin-dependent charge transport properties of nonmagnetic chiral conductive polymers and biomolecules, such as oligopeptides, L/D cysteine, cytochrome c, bacteriorhodopsin (bR), and oligopeptide-CdSe nanoparticles (NPs) hybrid structures. Spin-dependent electrochemical measurements were carried out by employing ferromagnetic electrodes modified with chiral molecules used as the working electrode. Redox probes were used either in solution or when directly attached to the ferromagnetic electrodes. During the electrochemical measurements, the ferromagnetic electrode was magnetized either with its magnetic moment pointing “UP” or “DOWN” using a permanent magnet (H = 0.5 T), placed underneath the chemically modified ferromagnetic electrodes. The spin polarization of the current was found to be in the range of 5–30%, even in the case of small chiral molecules. Chiral films of the l- and d-cysteine tethered with a redox-active dye, toludin blue O, show spin polarizarion that depends on the chirality. Because the nickel electrodes are susceptible to corrosion, we explored the effect of coating them with a thin gold overlayer. The effect of the gold layer on the spin polarization of the electrons ejected from the electrode was investigated. In addition, the role of the structure of the protein on the spin selective transport was also studied as a function of bias voltage and the effect of protein denaturation was revealed. In addition to

  5. Optical and magneto-optical properties of spin coated films of novel trinuclear bis(oxamato) and bis(oxamidato) type complexes

    Energy Technology Data Exchange (ETDEWEB)

    Abdulmalic, Mohammad A. [Technische Universität Chemnitz, Fakultät für Naturwissenschaften, Institut für Chemie, Straße der Nationen 62, D-09111 Chemnitz (Germany); Fronk, Michael [Technische Universität Chemnitz, Fakultät für Naturwissenschaften, Institut für Physik, Reichenhainer Straße 70, D-09107 Chemnitz (Germany); Bräuer, Björn [Stanford Institute of Materials and Energy Science, Stanford University, Stanford, CA 94025 (United States); Zahn, Dietrich R.T. [Technische Universität Chemnitz, Fakultät für Naturwissenschaften, Institut für Physik, Reichenhainer Straße 70, D-09107 Chemnitz (Germany); Salvan, Georgeta, E-mail: salvan@physik.tu-chemnitz.de [Technische Universität Chemnitz, Fakultät für Naturwissenschaften, Institut für Physik, Reichenhainer Straße 70, D-09107 Chemnitz (Germany); Eya' ane Meva, Francois [Department of Pharmaceutical Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, BP 2701 (Cameroon); and others

    2016-12-01

    This work reports the first example of the spectroscopic measurements of the Magneto-Optical Kerr Effect (MOKE) of films being composed of trinuclear transition metal complexes on a non-transparent substrate at room temperature. The thin films of the tailor-made trinuclear bis(oxamidato) type complex 5 ([Cu{sub 3}(opbo{sup n}Pr{sub 2})(tmcd){sub 2}(NO{sub 3}){sub 2}], opbo{sup n}Pr{sub 2} = o-phenylenebis(N’-{sup n}propyloxamido, tmcd=trans-(1 R,2 R)-N,N,N′,N′-tetramethyl-cyclohexanediamine) and of the bis(oxamato) type complexes 11 ([Cu{sub 2}Ni(opbaCF{sub 3})(pmdta){sub 2}(NO{sub 3}){sub 2}], opbaCF{sub 3} = 4-trifluoromethyl-o-phenylenebis(oxamato), pmdta = N,N,N,′N″,N″-pentamethyldiethylenetriamine) and 12 ([Cu{sub 3}(opba)(bppe){sub 2}(NO{sub 3}){sub 2}] (opba = o-phenylenebis(oxamato), bppe = S-N,N-bis(2-picolyl)−1-phenylethylamine) were fabricated by spin-coating and their thicknesses in the range between 0.5 µm and 2 µm was determined by spectroscopic ellipsometry. Based on the spectroscopic ellipsometry results it was also possible to determine the optical constants of the film and compare them with the absorption of the complexes in solution in order to confirm the complex integrity after the film deposition. The fabrication of high-quality films which exhibit Kerr rotation up to 0.2 mrad (11.5 mdeg) was only possible due to tailor-made synthesis, which allows circumventing intermolecular interactions of the trinuclear complexes during the film formation. - Highlights: • Tailor-made trinuclear bis(oxamidato) and bis(oxamato) type complexes were synthesized. • Thin films (between 0.5 µm and 2 µm) were fabricated by spin-coating. • The film optical constants indicate the complex integrity after the deposition. • Film quality enabled first spectroscopic MOKE measurements of multi-nuclear complexes. • Magneto-optical Kerr rotation up to 11.5 mdeg was observed at RT (in 1.7 T).

  6. Influence of annealing conditions on the optical and structural properties of spin-coated As(2)S(3) chalcogenide glass thin films.

    Science.gov (United States)

    Song, Shanshan; Dua, Janesha; Arnold, Craig B

    2010-03-15

    Spin-coating of chalcogenide glass is a low-cost, scalable method to create optical grade thin films, which are ideal for visible and infrared applications. In this paper, we study the influence of annealing on optical parameters of As(2)S(3) films by examining UV-visible and infrared spectroscopy and correlating the results to changes in the physical properties associated with solvent removal. Evaporation of excess solvent results in a more highly coordinated, denser glass network with higher index and lower absorption. Depending on the annealing temperature and time, index values ranging from n = 2.1 to the bulk value (n = 2.4) can be obtained, enabling a pathway to materials optimization.

  7. Titanate nanotube coatings on biodegradable photopolymer scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Beke, S., E-mail: szabolcs.beke@iit.it [Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy); Kőrösi, L. [Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertváros u. 2, H-7632, Pécs (Hungary); Scarpellini, A. [Department of Nanochemistry, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy); Anjum, F.; Brandi, F. [Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy)

    2013-05-01

    Rigid, biodegradable photopolymer scaffolds were coated with titanate nanotubes (TNTs) by using a spin-coating method. TNTs were synthesized by a hydrothermal process at 150 °C under 4.7 bar ambient pressure. The biodegradable photopolymer scaffolds were produced by mask-assisted excimer laser photocuring at 308 nm. For scaffold coating, a stable ethanolic TNT sol was prepared by a simple colloid chemical route without the use of any binding compounds or additives. Scanning electron microscopy along with elemental analysis revealed that the scaffolds were homogenously coated by TNTs. The developed TNT coating can further improve the surface geometry of fabricated scaffolds, and therefore it can further increase the cell adhesion. Highlights: ► Biodegradable scaffolds were produced by mask-assisted UV laser photocuring. ► Titanate nanotube deposition was carried out without binding compounds or additives. ► The titanate nanotube coating can further improve the surface geometry of scaffolds. ► These reproducible platforms will be of high importance for biological applications.

  8. Ultra-high mobility transparent organic thin film transistors grown by an off-centre spin-coating method.

    Science.gov (United States)

    Yuan, Yongbo; Giri, Gaurav; Ayzner, Alexander L; Zoombelt, Arjan P; Mannsfeld, Stefan C B; Chen, Jihua; Nordlund, Dennis; Toney, Michael F; Huang, Jinsong; Bao, Zhenan

    2014-01-01

    Organic semiconductors with higher carrier mobility and better transparency have been actively pursued for numerous applications, such as flat-panel display backplane and sensor arrays. The carrier mobility is an important figure of merit and is sensitively influenced by the crystallinity and the molecular arrangement in a crystal lattice. Here we describe the growth of a highly aligned meta-stable structure of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) from a blended solution of C8-BTBT and polystyrene by using a novel off-centre spin-coating method. Combined with a vertical phase separation of the blend, the highly aligned, meta-stable C8-BTBT films provide a significantly increased thin film transistor hole mobility up to 43 cm(2) Vs(-1) (25 cm(2) Vs(-1) on average), which is the highest value reported to date for all organic molecules. The resulting transistors show high transparency of >90% over the visible spectrum, indicating their potential for transparent, high-performance organic electronics.

  9. Study on fabrication of TiO{sub 2} thin films by spincoating and their optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Zharvan, Vicran, E-mail: vicran.zharvan@gmail.com; Daniyati, Risqa; Nur Ichzan, A.S.; Yudoyono, Gatut; Darminto, E-mail: darminto@physics.its.ac.id [Department of Physics, Institut Teknologi Sepuluh Nopember (ITS), Kampus ITS Sukolilo, Surabaya 60111 (Indonesia)

    2016-03-11

    Study on fabrication of TiO{sub 2} thin films and their optical properties in UV-VIS spectrum has been conducted. TiO{sub 2} nanopowders were prepared by co-precipitation method with varying mixing duration for 5, 10 and 25 hours using TiCl{sub 3} as precursor. The as-synthesized TiO{sub 2} phase is anatase having crystalline size of 14.25 nm, 13.75 nm and 12.62, respectively for the corresponding mixing duration. Thin films of TiO{sub 2} were fabricated by spin coating method and then checked by XRD diffractometer and UV-Vis Spectrophotometer to examine their structure and band gap energy. The prepared films also contain anatase phase of TiO{sub 2} with respective band gap of 3.70 eV, 3.74 eV and 3.76 eV, depending on the powders and their treatment.

  10. Optically enhanced SnO{sub 2}/CdSe core/shell nanostructures grown by sol-gel spin coating method

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Vijay, E-mail: vijaynadda83@gmail.com; Goswami, Y. C. [School of Physical Sciences, ITM University, Turari, Gwalior, MP 474001 (India); Rajaram, P. [School of Studies in Physics, Jiwaji University, Gwalior MP 474011 (India)

    2015-08-28

    Synthesis of SnO{sub 2}/CdSe metal oxide/ chalcogenide nanostructures on glass micro slides using ultrasonic sol-gel process followed by spin coating has been reported. Stannous chloride, cadmium chloride and selenium dioxide compounds were used for Sn, Cd and Se precursors respectively. Ethylene glycol was used as complexing agent. The samples were characterized by XRD, SEM, AFM and UV-spectrophotometer. All the peaks shown in diffractograms are identified for SnO{sub 2}. Peak broadening observed in core shell due to stress behavior of CdSe lattice. Scanning electron microscope and AFM exhibits the conversion of cluster in to nanorods structures forms. Atomic force microscope shows the structures in nanorods form and a roughness reduced 1.5194 nm by the deposition of CdSe. Uv Visible spectra shows a new absorption edge in the visible region make them useful for optoelectronic applications.

  11. Method to allow the estimation of heat transfer coefficients in solar stills; Metodo para determinar coeficientes locales de transferencia de calor en destiladores solares

    Energy Technology Data Exchange (ETDEWEB)

    Rubio Cerda, Eduardo; Porta Gandara, Miguel A [CIBNOR, Mexico D.F (Mexico); Fernandez Zayas, Jose Luis [UNAM Mexico, D.F. (Mexico)

    2000-07-01

    This work reports an experimental method that allows to estimate the heat transfer coefficients in the neighborhood of walls or flat plates subject to convective transport phenomena. This method can be applied to a great variety of thermal systems since it is based on the knowledge of the border condition for the temperature at the surface of the plate, and the temperature profile that characterize the dimensionless coefficient of heat transfer in the fluid, according to its definition given by the Nusselt number. The approach of this work are the foundations of the method and the system that has been developed to apply it, that incorporates automatic acquisition equipment for continuos monitoring of the information and elements to control the parameters of interest. In addition, the experimental cavities on which the method will be evaluated are discussed, considering two different scales, as well as experiments in cavities filled with air, and with a mixture of air and steam water, as is the case for solar distillation. [Spanish] En este trabajo se presenta un metodo que permite determinar de manera experimental coeficientes de transferencia de calor por conveccion. Este metodo puede ser aplicado a una gran variedad de sistemas termicos ya que se fundamenta en el conocimiento de la condicion de frontera para la temperatura en la superficie de la placa, y del perfil de temperaturas que caracteriza el coeficiente adimensional de transferencia de calor en el fluido, de acuerdo a la definicion de este, dada por el numero de Nusselt. El trabajo que aqui se reporta esta enfocado a la fundamentacion del metodo y al equipamiento que se ha desarrollado para instrumentarlo, que incorpora equipos automaticos de adquisicion continua de informacion y elementos de control para los parametros de interes. Se presentan ademas, las cavidades experimentales sobre las que sera evaluado el metodo, que considera dos escalas diferentes, asi como experimentos en cavidades llenas de aire

  12. Synthesis of ZnO thin film by sol-gel spin coating technique for H2S gas sensing application

    Science.gov (United States)

    Nimbalkar, Amol R.; Patil, Maruti G.

    2017-12-01

    In this present work, zinc oxide (ZnO) thin film synthesized by a simple sol-gel spin coating technique. The structural, morphology, compositional, microstructural, optical, electrical and gas sensing properties of the film were studied by using XRD, FESEM, EDS, XPS, HRTEM, Raman, FTIR and UV-vis techniques. The ZnO thin film shows hexagonal wurtzite structure with a porous structured morphology. Gas sensing performance of synthesized ZnO thin film was tested initially for H2S gas at different operating temperatures as well as concentrations. The maximum gas response is achieved towards H2S gas at 300 °C operating temperature, at 100 ppm gas concentration as compared to other gases like CH3OH, Cl2, NH3, LPG, CH3COCH3, and C2H5OH with a good stability.

  13. Method of identifying the friction of rotors using the wavelet transform; Metodo para identificar el rozamiento de rotores utilizado la transformada wavelet

    Energy Technology Data Exchange (ETDEWEB)

    Jauregui Correa, Juan Carlos; Rubio Cerda, Eduardo; Gonzalez Brambila, Oscar [CIATEQ, A.C., Queretaro (Mexico)

    2007-11-15

    The modern processes of signal analysis that measure mechanical vibrations are based on the fast transform of Fourier (FFT), nevertheless, this method is not able to identify transient phenomena nor of nonlinear nature. Although many efforts have been made to try to identify these phenomena in the frequency spectra, it is not possible to correlate the spectra with the physical characteristics of this type of phenomena. Within these phenomena on the rubbing of a rotor against the housing or trunnion of a bearing, this phenomenon has a nonlinear behavior, as it is demonstrated in this paper. In the first part a method based on the of signal analysis type wavelets is presented and how this technique can be used to predict transient and nonlinear phenomena. Once defined the method, its application in the identification of the friction of rotors is demonstrated. With this, one demonstrates that the method presented in this paper allows to also identifying in real time the rubbing phenomenon and also that it can be used as an of analysis technique in the preventive maintenance systems. [Spanish] Los procesos modernos de analisis de senales que miden vibraciones mecanicas se basan en la transformada rapida de Fourier (FFT por sus siglas en ingles), sin embargo, este metodo no es capaz de identificar fenomenos transitorios ni de naturaleza no lineal. A pesar de que se han hecho muchos esfuerzos para tratar de identificar estos fenomenos en los espectros de frecuencia, no es posible correlacionar el espectro con las caracteristicas fisicas de este tipo de fenomenos. Dentro de estos fenomenos sobre el rozamiento de un rotor contra la carcasa o munon de una chumacera, este fenomeno tiene un comportamiento no lineal, como se demuestra en este trabajo. En la primera parte se presenta un metodo basado en el analisis de senales tipo wavelets y como esta tecnica puede utilizarse para predecir fenomenos transitorios y no lineales. Una vez definido el metodo, se demuestra su

  14. Construction of cost effective homebuilt spin coater for coating ...

    African Journals Online (AJOL)

    We report the construction of a cost effective and low power consumption spin coater from a direct current (DC) brushless motor. The DC mechanical component is widdely available in the central processing unit (CPU) cooler. This set up permits simple operation where the DC voltage can be controlled manually in order to ...

  15. Investigation of anti-Relaxation coatings for alkali-metal vapor cells using surface science techniques

    Energy Technology Data Exchange (ETDEWEB)

    Seltzer, S. J.; Michalak, D. J.; Donaldson, M. H.; Balabas, M. V.; Barber, S. K.; Bernasek, S. L.; Bouchiat, M.-A.; Hexemer, A.; Hibberd, A. M.; Jackson Kimball, D. F.; Jaye, C.; Karaulanov, T.; Narducci, F. A.; Rangwala, S. A.; Robinson, H. G.; Shmakov, A. K.; Voronov, D. L.; Yashchuk, V. V.; Pines, A.; Budker, D.

    2010-10-11

    Many technologies based on cells containing alkali-metal atomic vapor benefit from the use of antirelaxation surface coatings in order to preserve atomic spin polarization. In particular, paraffin has been used for this purpose for several decades and has been demonstrated to allow an atom to experience up to 10?000 collisions with the walls of its container without depolarizing, but the details of its operation remain poorly understood. We apply modern surface and bulk techniques to the study of paraffin coatings in order to characterize the properties that enable the effective preservation of alkali spin polarization. These methods include Fourier transform infrared spectroscopy, differential scanning calorimetry, atomic force microscopy, near-edge x-ray absorption fine structure spectroscopy, and x-ray photoelectron spectroscopy. We also compare the light-induced atomic desorption yields of several different paraffin materials. Experimental results include the determination that crystallinity of the coating material is unnecessary, and the detection of C=C double bonds present within a particular class of effective paraffin coatings. Further study should lead to the development of more robust paraffin antirelaxation coatings, as well as the design and synthesis of new classes of coating materials.

  16. Flow in potential cascades by means of the finite element method; Flujo en cascadas potenciales mediante el metodo del elemento finito

    Energy Technology Data Exchange (ETDEWEB)

    Sosa Cordero, Rodolfo; Fernandez Valencia, Gonzalo [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1987-12-31

    This article presents a mathematical model and its solution by means of the finite element method with approximate Garlekin formulation, for the flow analysis in a circular cascade, in a surface of revolution current of a turbo- machine, that can be axial, mixed or radial. To the revolution surface an agreed transformation is applied to obtain a plane, eliminating in this form one term in the equation succeeding in avoiding an iterative solution. Likewise, the finite element method allows to solve the equation in partial derivatives of the elliptical type in its quasi-harmonic form. Additionally, the method followed to introduce the contour conditions is presented; specially, the Kutta-Joukowsky conditions and the one of periodicity, which distinguishes this problem from the classical problems of ideal flows evaluated in the contour. [Espanol] En este articulo se presenta un modelo matematico y su solucion mediante el empleo del metodo del elemento finito con formulacion aproximada de Galerkin, para el analisis del flujo en una cascada circular, en una superficie de corriente de revolucion de una turbomaquina, que puede ser axial, mixta o radial. A la superficie de revolucion se le aplica una transformacion conforme para obtener un plano, eliminando de esta forma un termino en la ecuacion logrando evitar la solucion iterativa. Asimismo, el metodo del elemento finito permite resolver la ecuacion en derivadas parciales del tipo eliptico en su forma cuasiarmonica. Se presenta, ademas, el metodo seguido para introducir las condiciones de contorno; en especial, las condiciones de Kutta-Joukowsky y la de periodicidad, que distinguen a este problema de los problemas clasicos de flujos ideales valuados en el contorno.

  17. Flow in potential cascades by means of the finite element method; Flujo en cascadas potenciales mediante el metodo del elemento finito

    Energy Technology Data Exchange (ETDEWEB)

    Sosa Cordero, Rodolfo; Fernandez Valencia, Gonzalo [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1986-12-31

    This article presents a mathematical model and its solution by means of the finite element method with approximate Garlekin formulation, for the flow analysis in a circular cascade, in a surface of revolution current of a turbo- machine, that can be axial, mixed or radial. To the revolution surface an agreed transformation is applied to obtain a plane, eliminating in this form one term in the equation succeeding in avoiding an iterative solution. Likewise, the finite element method allows to solve the equation in partial derivatives of the elliptical type in its quasi-harmonic form. Additionally, the method followed to introduce the contour conditions is presented; specially, the Kutta-Joukowsky conditions and the one of periodicity, which distinguishes this problem from the classical problems of ideal flows evaluated in the contour. [Espanol] En este articulo se presenta un modelo matematico y su solucion mediante el empleo del metodo del elemento finito con formulacion aproximada de Galerkin, para el analisis del flujo en una cascada circular, en una superficie de corriente de revolucion de una turbomaquina, que puede ser axial, mixta o radial. A la superficie de revolucion se le aplica una transformacion conforme para obtener un plano, eliminando de esta forma un termino en la ecuacion logrando evitar la solucion iterativa. Asimismo, el metodo del elemento finito permite resolver la ecuacion en derivadas parciales del tipo eliptico en su forma cuasiarmonica. Se presenta, ademas, el metodo seguido para introducir las condiciones de contorno; en especial, las condiciones de Kutta-Joukowsky y la de periodicidad, que distinguen a este problema de los problemas clasicos de flujos ideales valuados en el contorno.

  18. Polymorphic regenerated silk fibers assembled through bioinspired spinning.

    Science.gov (United States)

    Ling, Shengjie; Qin, Zhao; Li, Chunmei; Huang, Wenwen; Kaplan, David L; Buehler, Markus J

    2017-11-09

    A variety of artificial spinning methods have been applied to produce regenerated silk fibers; however, how to spin regenerated silk fibers that retain the advantages of natural silks in terms of structural hierarchy and mechanical properties remains challenging. Here, we show a bioinspired approach to spin regenerated silk fibers. First, we develop a nematic silk microfibril solution, highly viscous and stable, by partially dissolving silk fibers into microfibrils. This solution maintains the hierarchical structures in natural silks and serves as spinning dope. It is then spun into regenerated silk fibers by direct extrusion in the air, offering a useful route to generate polymorphic and hierarchical regenerated silk fibers with physical properties beyond natural fiber construction. The materials maintain the structural hierarchy and mechanical properties of natural silks, including a modulus of 11 ± 4 GPa, even higher than natural spider silk. It can further be functionalized with a conductive silk/carbon nanotube coating, responsive to changes in humidity and temperature.

  19. Effect of aluminum addition on the optical, morphology and electrical behavior of spin coated zinc oxide thin films

    Directory of Open Access Journals (Sweden)

    Amit Kumar Srivastava

    2011-09-01

    Full Text Available Aluminum-doped ZnO thin films of high optical transmittance (∼ 84-100% and low resistivity (∼ 2.3x10-2 Ωcm have been prepared on glass substrate by the spin coating and subsequent annealing at 500°C for 1h in air or vacuum. Effect of aluminum doping and annealing environment on morphology, optical transmittance and electrical resistivity of ZnO thin films has been studied with possible application as a transparent electrode in photovoltaic. The changes occurring due to aluminum addition include reduction in grain size, root mean square roughness, peak-valley separation, and sheet resistance with improvement in the optical transmittance to 84-100% in the visible range. The origin of low electrical resistivity lies in increase in i electron concentration following aluminum doping (being trivalent, formation of oxygen vacancies due to vacuum annealing, filling of cation site with additional zinc at solution stage itself and ii carrier mobility.

  20. Constraints on long-range spin-gravity and monopole-dipole couplings of the proton

    Science.gov (United States)

    Jackson Kimball, Derek F.; Dudley, Jordan; Li, Yan; Patel, Dilan; Valdez, Julian

    2017-10-01

    Results of a search for a long-range monopole-dipole coupling between the mass of the Earth and rubidium (Rb) nuclear spins are reported. The experiment simultaneously measures the spin precession frequencies of overlapping ensembles of 85Rb and 87Rb atoms contained within an evacuated, antirelaxation-coated vapor cell. The nuclear structure of the Rb isotopes makes the experiment particularly sensitive to spin-dependent interactions of the proton. The spin-dependent component of the gravitational energy of the proton in the Earth's field is found to be smaller than 3 ×10-18 eV , improving laboratory constraints on long-range monopole-dipole interactions by over 3 orders of magnitude.

  1. Synchrotron radiation total reflection x-ray fluorescence analysis; of polymer coated silicon wafers

    International Nuclear Information System (INIS)

    Brehm, L.; Kregsamer, P.; Pianetta, P.

    2000-01-01

    It is well known that total reflection x-ray fluorescence (TXRF) provides an efficient method for analyzing trace metal contamination on silicon wafer surfaces. New polymeric materials used as interlayer dielectrics in microprocessors are applied to the surface of silicon wafers by a spin-coating process. Analysis of these polymer coated wafers present a new challenge for TXRF analysis. Polymer solutions are typically analyzed for bulk metal contamination prior to application on the wafer using inductively coupled plasma mass spectrometry (ICP-MS). Questions have arisen about how to relate results of surface contamination analysis (TXRF) of a polymer coated wafer to bulk trace analysis (ICP-MS) of the polymer solutions. Experiments were done to explore this issue using synchrotron radiation (SR) TXRF. Polymer solutions were spiked with several different concentrations of metals. These solutions were applied to silicon wafers using the normal spin-coating process. The polymer coated wafers were then measured using the SR-TXRF instrument set-up at the Stanford Synchrotron Radiation Laboratory (SSRL). Several methods of quantitation were evaluated. The best results were obtained by developing calibration curves (intensity versus ppb) using the spiked polymer coated wafers as standards. Conversion of SR-TXRF surface analysis results (atoms/cm 2 ) to a volume related concentration was also investigated. (author)

  2. Structure and optical properties of nanocrystalline NiO thin film synthesized by sol-gel spin-coating method

    Energy Technology Data Exchange (ETDEWEB)

    Al-Ghamdi, A.A. [King Abdulaziz University, Faculty of Science, Physics Department, Jeddah (Saudi Arabia); Mahmoud, Waleed E., E-mail: w_e_mahmoud@yahoo.co [King Abdulaziz University, Faculty of Science, Physics Department, Jeddah (Saudi Arabia); Suez Canal University, Faculty of Science, Physics Department, Ismailia (Egypt); Yaghmour, S.J.; Al-Marzouki, F.M. [King Abdulaziz University, Faculty of Science, Physics Department, Jeddah (Saudi Arabia)

    2009-11-03

    NiO thin film was prepared by sol-gel spin-coating method. This thin film annealed at T = 600 deg. C. The structure of NiO thin film was investigated by means of X-ray diffraction (XRD) technique and scanning electron microscopy (SEM). The optical properties of the deposited film were characterized from the analysis of the experimentally recorded transmittance and reflectance data in the spectral wavelength range of 300-800 nm. The values of some important parameters of the studied films are determined, such as refractive index (n), extinction coefficient (k), optical absorption coefficient (alpha) and band energy gap (E{sub g}). According to the analysis of dispersion curves, it has been found that the dispersion data obeyed the single oscillator of the Wemple-DiDomenico model, from which the dispersion parameters and high-frequency dielectric constant were determined. In such work, from the transmission spectra, the dielectric constant (epsilon{sub i}nfinity), the third-order optical nonlinear susceptibility chi{sup (3)}, volume energy loss function (VELF) and surface energy loss function (SELF) were determined.

  3. A novel simple one-step air jet spinning approach for deposition of poly(vinyl acetate)/hydroxyapatite composite nanofibers on Ti implants

    Energy Technology Data Exchange (ETDEWEB)

    Abdal-hay, Abdalla, E-mail: abda_55@jbnu.ac.kr [Dept. of Engineering Materials and Mechanical Design, Faculty of Engineering, South Valley of University, Qena 83523 (Egypt); Dept. of Computer Science, Faculty of Engineering, Universidad de Cuenca, Cuenca 01.01.168 (Ecuador); Dept. of Bionano System Engineering, College of Engineering, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Hamdy, Abdel Salam [Dept. of Manufacturing Engineering, College of Engineering and Computer Science, University of Texas Pan-American, 1201 West University Dr., Edinburg, TX 78541-2999 (United States); Khalil, Khalil Abdelrazek [Dept. of Mechanical Engineering, College of Engineering King Saud University, P.O. Box 800, Riyadh 11421 (Saudi Arabia); Department of Mechanical Engineering, Faculty of Energy Engineering, Aswan University, Aswan (Egypt); Lim, Ju Hyun, E-mail: jhlim@gnah.co.kr [Dept. of Urology, Gangneung Asan Hospital, University of Ulsan, College of Medicine, Gangneung (Korea, Republic of)

    2015-04-01

    A biocompatible coating consists of a poly(vinyl acetate)/hydroxyapatite (PVAc/HA) composite nanofiber mat was applied to NaOH-treated titanium metal by means of a novel, facile and efficient air jet spinning (AJS) approach. Results showed that HA nanoparticles (NPs) strongly embedded onto the AJS single fiber surface resulting in a strong chemical interfacial bonding between the two phases due to the difference in kinetic energies. It was proven that AJS membrane coatings can provide significant improvement in the corrosion resistance of titanium substrate. Interestingly, the biocompatibility using MC3T3-E1 osteoblast to the PVAc/HA fiber composite layer coated on Ti was significantly higher than pure titanium-substrates. - Highlights: • A novel PVAc/HA composite nanofiber mat layer has been fabricated. • PVAc/HA nanocomposites coated on Ti substrates by means of air jet spinning • AJS method enabled the formation of well-adherent and uniform coatings. • Coatings of PVAc/HA on Ti surfaces definitely favored cell proliferation.

  4. Moessbauer spectroscopy studies of spin reorientations in amorphous and crystalline (Co0.2Fe0.8)72.5Si12.5B15 glass coated micro-wires

    International Nuclear Information System (INIS)

    Nowik, I.; Felner, I.; Garcia-Miquel, H.

    2007-01-01

    Thermo-gravimetric, differential scanning calorimetry and comprehensive 57 Fe Moessbauer spectroscopy studies of amorphous and crystalline ferromagnetic glass coated (Co 0.2 Fe 0.8 ) 72.5 Si 12.5 B 15 micro-wires have been recorded. The Curie temperature of the amorphous phase is T C (amorp) ∼730 K. The analysis of the Moessbauer spectra reveals that below 623 K the easy axis of the magnetization is axial-along the wires, and that a tangential or/and radial orientation occurs at higher temperatures. At 770 K, in the first 4 hours the Moessbauer spectrum exhibits a pure paramagnetic doublet. Crystallization and decomposition to predominantly α-Fe(Si) and Fe 2 B occurs either by raising the temperature above 835 K or isothermally in time at lower temperatures. Annealing for a day at 770 K, leads to crystallization. In the crystalline material the magnetic moments have a complete random orientation. After cooling back to ambient temperature, both α-Fe(Si) and Fe 2 B in the glass coated wire show pure axial magnetic orientation like in the original amorphous state. The observed spin reorientations are associated with changes in the stress induced by the glass coating

  5. Annealing time dependence of the physical, electrical and pH response characteristics of spin coated TiO2 thin films

    International Nuclear Information System (INIS)

    Zulkefle, M A; Rahman, R A; Yusoff, K A; Herman, S H; Abdullah, W F H; Rusop, M

    2015-01-01

    Titanium dioxide (TiO 2 ) thin film was deposited on indium tin oxide (ITO) substrate and used as sensing membrane of EGFET pH sensor. The thin film was fabricated using sol- gel spin coating method. All samples were annealed at 400 °C but the annealing time was varied. This is done to study the effects of annealing time on physical and electrical properties of titanium dioxide thin film. The sensitivity of each sample towards H + ion was measured and result shows that sample annealed for 45 minutes has the highest sensitivity (52.6 mV/pH). It is found that increasing annealing duration will increase the pH sensitivity but a limit will be reached at certain point. Longer annealing processes done beyond this point will results in lower pH sensitivity. (paper)

  6. Corrosion behaviour and galvanic coupling with steel of Al-based coating alternatives to electroplated cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Fasuba, O.A.; Yerokhin, A., E-mail: A.Yerokhin@sheffield.ac.uk; Matthews, A.; Leyland, A.

    2013-08-15

    The galvanic corrosion behaviour of bare steel coupled to steel with an Al–Zn flake inorganic spin coating, an Al-based slurry sprayed coating, an arc sprayed Al coating and electroplated cadmium has been investigated. The sacrificial and galvanic behaviour of the coatings was studied in 3.5 wt. % NaCl solution using open-circuit potential, potentiodynamic polarisation and electrochemical noise measurements. The coatings were characterised by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. Experimental results showed that the Al-based slurry sprayed coating exhibited an open-circuit potential closer to the steel substrate than other coatings, as well as a low corrosion current density and a more positive corrosion potential. In terms of the galvanic suitability of the investigated coatings for the steel substrate, both the Al–Zn flake inorganic spin coating and the Al-based slurry sprayed coating show low galvanic current, in comparison with the arc sprayed Al coating and electroplated cadmium. This behaviour confirms their superior cathodic protection capability and galvanic compatibility over other coatings tested. Electrochemical noise measurements provide accurate information on the coatings' galvanic behaviour, which can be complimented by the data obtained from superposition of potentiodynamic corrosion scans of the coating and bare steel, provided that the corrosion potential difference between the two materials does not exceed 300 mV. - Highlights: • Al-based slurry coating has best galvanic compatibility with steel. • Mg, Cr, P in Al-based slurry coating reinforce its corrosion resistance. • Ennoblement of Al–Zn flake coating compromises its cathodic protection. • Poor corrosion behaviour of arc sprayed Al coating caused by rough morphology. • Electrochemical noise provides adequate estimates of galvanic behaviour.

  7. Spin-coating deposition of PbS and CdS thin films for solar cell application

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Jayesh; Mighri, Frej [Laval University, CREPEC, Department of Chemical Engineering, Quebec, QC (Canada); Ajji, Abdellah [Ecole Polytechnique, CREPEC, Chemical Engineering Department, Montreal, QC (Canada); Tiwari, Devendra; Chaudhuri, Tapas K. [Charotar University of Science and Technology (CHARUSAT), Dr. K.C. Patel Research and Development Centre, Anand District, Gujarat (India)

    2014-12-15

    In this work, we describe a simple spin-coating deposition technique for lead sulphide (PbS) and cadmium sulphide (CdS) films from a methanolic metal-thiourea complex. The characterization of the films by X-ray diffraction and X-ray photoelectron spectroscopy techniques revealed that pure cubic phase PbS and CdS layers were formed via this method. As shown by atomic force microscopy and scanning electron microscopy results, both films were homogeneous and presented a smooth surface. Optical properties showed that the energy band gap of PbS and CdS films were around 1.65 and 2.5 eV, respectively. The PbS film is p-type in nature with an electrical conductivity of around 0.8 S/cm. The hole concentration and mobility were 2.35 x 10{sup 18} cm{sup -3} and 2.16 x 10{sup -3} cm{sup 2}/V/s, respectively, as determined from Hall measurement. Both films were used to develop a thin film solar cell device of graphite/PbS/CdS/ITO/glass. Device characterization showed the power conversion efficiency of around 0.24 %. The corresponding open circuit voltage, short circuit current and fill factor were 0.570 V, 1.32 mA/cm{sup 2} and 0.32, respectively. (orig.)

  8. Polydimethylsiloxane microspheres with poly(methyl methacrylate) coating: Modelling, preparation, and characterization

    DEFF Research Database (Denmark)

    Ma, Baoguang; Hansen, Jens Henrik; Hvilsted, Søren

    2015-01-01

    functional PDMS microspheres were coated with poly(methyl methacrylate) (PMMA) by spin coating with different concentrations of PMMA solutions. The quality of the resulting PMMA shell is investigated using rheological measurements at 50 8C with a timesweep procedure. The results strongly suggest that PMMA-coated...... PDMS microspheres react around 20 times slower than the uncoated ones, and that the PMMA shell significantly hinders the reaction between the PDMS microsphere and cross-linker. Thus the thin PMMA shells are very efficient in protecting the reactive PDMS microspheres, since the PMMA shell forms...

  9. Preparation of Organic-Inorganic Multifunctional Nanocomposite Coating via Sol-Gel Routes

    International Nuclear Information System (INIS)

    Li Haoying; Chen Yunfa; Ruan Chengxiang; Gao Weimin; Xie Yusheng

    2001-01-01

    The inorganic-organic nanocomposite coatings are prepared on poly(methyl methacrylate) (PMMA) substrate by the spinning technique which involves incorporating homogeneously nanosized ZnO particle into the molecular inorganic-organic hybrid matrices. The hybrid matrices are derived from tetraethoxyasilane (TEOS) and 3-glycidoxypropyltrimethoxyailane (GLYMO). To avoid the destruction of the polymer structure caused by ZnO and modify the interface between nanoparticles and organic groups, ZnO was first surface-coated with SiO 2 from hydrolyzed TEOS using ammonia water as catalyst. The coatings thus obtained are dense, flexible, abrasion resistant and UV absorbent

  10. Dip-coating of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) anodes for efficient polymer solar cells

    International Nuclear Information System (INIS)

    Huang, Like; Hu, Ziyang; Zhang, Ke; Chen, Peipei; Zhu, Yuejin

    2015-01-01

    The fabrication of anodes and active layers by dip-coating in indium tin oxide (ITO)-free polymer solar cells (PSCs) is investigated. A highly conductive poly(3, 4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS) layer was used as an anode while a blend film of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) was employed as an active layer. The transmittance and sheet resistance of dip-coated PEDOT:PSS layers prepared with different thickness were studied. These layers were integrated into PSCs. The PSCs with the dip-coated PEDOT:PSS and P3HT:PCBM films exhibited power conversion efficiencies of 3.21% and 3.03% on glass and polyethylene terephthalate substrates, respectively, comparable to those of conventional ITO-based cells. Our research results suggest the feasibility of fabricating PSCs without a traditional spin-coating process and the possibility to substitute the ITO electrodes for conducting polymer films using the facile dip-coating method. - Highlights: • ITO-free polymer solar cells (PSCs) were fabricated by dip coating method. • Highly conductive PEDOT:PSS films used as anode were prepared. • The ITO-free PSCs performance was comparable with that of the spin coated devices. • Our results suggest the possibility of replacing ITO with dip coated PEDOT:PSS

  11. Dip-coating of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) anodes for efficient polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Like; Hu, Ziyang, E-mail: huziyang@nbu.edu.cn; Zhang, Ke; Chen, Peipei; Zhu, Yuejin, E-mail: zhuyuejin@nbu.edu.cn

    2015-03-02

    The fabrication of anodes and active layers by dip-coating in indium tin oxide (ITO)-free polymer solar cells (PSCs) is investigated. A highly conductive poly(3, 4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS) layer was used as an anode while a blend film of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) was employed as an active layer. The transmittance and sheet resistance of dip-coated PEDOT:PSS layers prepared with different thickness were studied. These layers were integrated into PSCs. The PSCs with the dip-coated PEDOT:PSS and P3HT:PCBM films exhibited power conversion efficiencies of 3.21% and 3.03% on glass and polyethylene terephthalate substrates, respectively, comparable to those of conventional ITO-based cells. Our research results suggest the feasibility of fabricating PSCs without a traditional spin-coating process and the possibility to substitute the ITO electrodes for conducting polymer films using the facile dip-coating method. - Highlights: • ITO-free polymer solar cells (PSCs) were fabricated by dip coating method. • Highly conductive PEDOT:PSS films used as anode were prepared. • The ITO-free PSCs performance was comparable with that of the spin coated devices. • Our results suggest the possibility of replacing ITO with dip coated PEDOT:PSS.

  12. Simulation of reflectance from white-anodised aluminium surfaces using polyurethane–TiO2 composite coatings

    DEFF Research Database (Denmark)

    Gudla, Visweswara Chakravarthy; Johansen, Villads Egede; Ambat, Rajan

    2015-01-01

    of anodised surfaces. PU matrix was selected for its matching refractive-index (n = 1.7) with anodic alumina layer. Three different TiO2 particle size distributions were dispersed in PU and spin coated onto bright high-gloss and matte caustic-etched aluminium substrates. The reflectance spectra of coated...

  13. Hybrid Perovskite Thin Film Formation: From Lab Scale Spin Coating to Large Area Blade Coating

    KAUST Repository

    Munir, Rahim

    2017-01-01

    in which an anti-solvent is used during the coating process through the solvent mixture of GBL and DMSO in different ratios. It has been shown that solvent engineering produce pin hole-free films, justifying its wide adoption across the field. We

  14. Low-Cost and Green Fabrication of Polymer Electronic Devices by Push-Coating of the Polymer Active Layers.

    Science.gov (United States)

    Vohra, Varun; Mróz, Wojciech; Inaba, Shusei; Porzio, William; Giovanella, Umberto; Galeotti, Francesco

    2017-08-02

    Because of both its easy processability and compatibility with roll-to-roll processes, polymer electronics is considered to be the most promising technology for the future generation of low-cost electronic devices such as light-emitting diodes and solar cells. However, the state-of-the-art deposition technique for polymer electronics (spin-coating) generates a high volume of chlorinated solution wastes during the active layer fabrication. Here, we demonstrate that devices with similar or higher performances can be manufactured using the push-coating technique in which a poly(dimethylsiloxane) (PDMS) layer is simply laid over a very small amount of solution (less than 1μL/covered cm 2 ), which is then left for drying. Using mm thick PDMS provides a means to control the solvent diffusion kinetics (sorption/retention) and removes the necessity for additional applied pressure to generate the desired active layer thickness. Unlike spin-coating, push-coating is a slow drying process that induces a higher degree of crystallinity in the polymer thin film without the necessity for a post-annealing step. The polymer light-emitting diodes and solar cells prepared by push-coating exhibit slightly higher performances with respect to the reference spin-coated devices, whereas at the same time reduce the amounts of active layer materials and chlorinated solvents by 50 and 20 times, respectively. These increased performances can be correlated to the higher polymer crystallinities obtained without applying a post-annealing treatment. As push-coating is a roll-to-roll compatible method, the results presented here open the path to low-cost and eco-friendly fabrication of a wide range of emerging devices based on conjugated polymer materials.

  15. Nanostructured antistatic and antireflective thin films made of indium tin oxide and silica over-coat layer

    Science.gov (United States)

    Cho, Young-Sang; Hong, Jeong-Jin; Yang, Seung-Man; Choi, Chul-Jin

    2010-08-01

    Stable dispersion of colloidal indium tin oxide nanoparticles was prepared by using indium tin oxide nanopowder, organic solvent, and suitable dispersants through attrition process. Various comminution parameters during the attrition step were studied to optimize the process for the stable dispersion of indium tin oxide sol. The transparent and conductive films were fabricated on glass substrate using the indium tin oxide sol by spin coating process. To obtain antireflective function, partially hydrolyzed alkyl silicate was deposited as over-coat layer on the pre-fabricated indium tin oxide film by spin coating technique. This double-layered structure of the nanostructured film was characterized by measuring the surface resistance and reflectance spectrum in the visible wavelength region. The final film structure was enough to satisfy the TCO regulations for EMI shielding purposes.

  16. Reduction of coating induced polarization aberrations by controlling the polarization state variation

    International Nuclear Information System (INIS)

    Li, Yanghui; Shen, Weidong; Zheng, Zhenrong; Zhang, Yueguang; Liu, Xu; Hao, Xiang

    2011-01-01

    The mechanism of coating induced polarization state variation is analysed by the Jones matrix. Pauli spin matrices are used to establish the relationship between coating induced polarization state variation and polarization aberrations. To reduce coating induced polarization aberrations, we propose that δ = 0 and T s = T p at arbitrary incident angle should be appended as two additional optimization goals of optical coating design when the requirements of transmittance are met. Two typical anti-reflection (AR) coatings are designed and the polarization state variation induced by them is simulated. The MTF (modulation transfer function) calculated by polarization ray tracing is applied to evaluate the polarization aberrations of the practical lithography objective system with the two AR coatings. All the obtained results show that the coating induced polarization aberrations can be reduced by optimizing the angle dependent properties of the optical coating without additional optical elements

  17. Laser-driven source of spin-polarized atomic hydrogen and deuterium

    International Nuclear Information System (INIS)

    Poelker, M.

    1995-01-01

    A laser-driven source of spin-polarized hydrogen (H) and deuterium (D) that relies on the technique of optical pumping spin exchange has been constructed. In this source, H or D atoms and potassium atoms flow continuously through a drifilm-coated spin-exchange cell where potassium atoms are optically pumped with circularly-polarized laser light in a high magnetic field. The H or D atoms become polarized through spin-exchange collisions with polarized potassium atoms. High electron polarization (∼80%) has been measured for H and D atoms at flow rates ∼2x10 17 atoms/s. Lower polarization values are measured for flow rates exceeding 1x10 18 atoms/s. In this paper, we describe the performance of the laser-driven source as a function of H and D atomic flow rate, magnetic field strength, alkali density and pump-laser power. Polarization measurements as a function of flow rate and magnetic field suggest that, despite a high magnetic field, atoms within the optical-pumping spin-exchange apparatus evolve to spin-temperature equilibrium which results in direct polarization of the H and D nuclei. (orig.)

  18. Electron-spin polarization in tunnel junctions with ferromagnetic EuS barriers

    International Nuclear Information System (INIS)

    Hao, X.; Moodera, J.S.; Meservey, R.

    1989-01-01

    The authors report here spin-polarized tunneling experiments using non-ferromagnetic electrodes and ferromagnetic EuS barriers. Because of the conduction band in EuS splits into spin-up and spin-down subbands when the temperature is below 16.7 K, the Curie temperature of EuS, the tunnel barrier for electrons with different spin directions is different, therefore giving rise to tunnel current polarization. The spin-filter effect, as it may be called, was observed earlier, directly or indirectly, by several groups: Esaki et al. made a tunneling study on junctions having EuS and EuSe barriers; Thompson et al. studied Schottky barrier tunneling between In and doped EuS; Muller et al. and Kisker et al. performed electron field emission experiments on EuS-coated tungsten tips. The field emission experiments gave a maximum polarization of (89 + 7)% for the emitted electrons. Although the previous tunneling studies did not directly show electron polarization, their results were explained by the same spin- filter effect. This work uses the spin-polarized tunneling technique to show directly that tunnel current is indeed polarized and polarization can be as high as 85%

  19. Fabrication of metal organic framework materials using a layer-by-layer spin coating approach

    KAUST Repository

    Eddaoudi, Mohamed; Shekhah, Osama

    2016-01-01

    Embodiments describe a method of depositing an MOF, including depositing a metal solution onto a substrate, spinning the substrate sufficient to spread the metal solution, depositing an organic ligand solution onto the substrate and spinning the substrate sufficient to spread the organic ligand solution and form a MOF layer.

  20. Fabrication of metal organic framework materials using a layer-by-layer spin coating approach

    KAUST Repository

    Eddaoudi, Mohamed

    2016-03-17

    Embodiments describe a method of depositing an MOF, including depositing a metal solution onto a substrate, spinning the substrate sufficient to spread the metal solution, depositing an organic ligand solution onto the substrate and spinning the substrate sufficient to spread the organic ligand solution and form a MOF layer.

  1. Formation of Nano scale Bio imprints of Muscle Cells Using UV-Cured Spin-Coated Polymers

    International Nuclear Information System (INIS)

    Samsuri, F.; Alkaisi, M.M.; Mitchell, J.S.; Evans, J.J.

    2009-01-01

    We report a nano scale replication method suitable for biological specimens that has potential in single cell studies and in formation of 3D biocompatible scaffolds. Earlier studies using a heat-curable polydimethylsiloxane (PDMS) or a UV-curable elastomer introduced Bio imprint replication to facilitate cell imaging. However, the replicating conditions for thermal polymerization are known to cause cell dehydration during curing. In this study, a UV-cured methacrylate copolymer was developed for use in creating replicas of living cells and was tested on rat muscle cells. Bio imprints of muscle cells were formed by spin coating under UV irradiation. The polymer replicas were then separated from the muscle cells and were analyzed under an Atomic Force Microscope (AFM), in tapping mode, because it has low tip-sample forces and thus will not destroy the fine structures of the imprint. The new polymer is biocompatible with higher replication resolution and has a faster curing process than other types of silicon-based organic polymers such as PDMS. High resolution images of the muscle cell imprints showed the micro-and nano structures of the muscle cells, including cellular fibers and structures within the cell membranes. The AFM is able to image features at nano scale resolution with the potential for recognizing abnormalities on cell membranes at early stages of disease progression.

  2. Self-organized morphological evolution and dewetting in solvent vapor annealing of spin coated polymer blend nanostructures.

    Science.gov (United States)

    Roy, Sudeshna; Sharma, Ashutosh

    2015-07-01

    Dewetting pathways, kinetics and morphologies of thin films of phase separating polymer blends are governed by the relative mobilities of the two components. We characterize the morphological transformations of the nanostructures of a PS/PMMA blend by annealing in toluene and chloroform vapors. Toluene leads to faster reorganization of PS, whereas chloroform engenders the opposite effect. Spin coating produces a very rough PMMA rich layer that completely wets the substrate and forms a plethora of slender columns protruding through the continuous PS rich layer on top. The nanostructures were stable under long thermal annealing but in the vapor annealing, phase separation and dewetting occurred readily to form the equilibrium structures of dewetted droplets of PS on top of PMMA which also climbed around the PS droplets to form rims. Toluene and chloroform annealing required around 50 h and 1 h respectively to attain the equilibrium. Substantial differences are observed in the intermediate morphologies (heights of nanostructures, roughness and size). PMMA columns remained embedded in the dewetted PS droplets, whereas a high mobility of PMMA in chloroform allowed its rapid evacuation during dewetting to produce an intermediate swiss-cheese like morphology of PS domains. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Structural, Optical Constants and Photoluminescence of ZnO Thin Films Grown by Sol-Gel Spin Coating

    Directory of Open Access Journals (Sweden)

    Abdel-Sattar Gadallah

    2013-01-01

    Full Text Available We report manufacturing and characterization of low cost ZnO thin films grown on glass substrates by sol-gel spin coating method. For structural properties, X-ray diffraction measurements have been utilized for evaluating the dominant orientation of the thin films. For optical properties, reflectance and transmittance spectrophotometric measurements have been done in the spectral range from 350 nm to 2000 nm. The transmittance of the prepared thin films is 92.4% and 88.4%. Determination of the optical constants such as refractive index, absorption coefficient, and dielectric constant in this wavelength range has been evaluated. Further, normal dispersion of the refractive index has been analyzed in terms of single oscillator model of free carrier absorption to estimate the dispersion and oscillation energy. The lattice dielectric constant and the ratio of free carrier concentration to free carrier effective mass have been determined. Moreover, photoluminescence measurements of the thin films in the spectral range from 350 nm to 900 nm have been presented. Electrical measurements for resistivity evaluation of the films have been done. An analysis in terms of order-disorder of the material has been presented to provide more consistency in the results.

  4. Characterization of multilayer anti-fog coatings.

    Science.gov (United States)

    Chevallier, Pascale; Turgeon, Stéphane; Sarra-Bournet, Christian; Turcotte, Raphaël; Laroche, Gaétan

    2011-03-01

    Fog formation on transparent substrates constitutes a major challenge in several optical applications requiring excellent light transmission characteristics. Anti-fog coatings are hydrophilic, enabling water to spread uniformly on the surface rather than form dispersed droplets. Despite the development of several anti-fog coating strategies, the long-term stability, adherence to the underlying substrate, and resistance to cleaning procedures are not yet optimal. We report on a polymer-based anti-fog coating covalently grafted onto glass surfaces by means of a multistep process. Glass substrates were first activated by plasma functionalization to provide amino groups on the surface, resulting in the subsequent covalent bonding of the polymeric layers. The anti-fog coating was then created by the successive spin coating of (poly(ethylene-maleic anhydride) (PEMA) and poly(vinyl alcohol) (PVA) layers. PEMA acted as an interface by covalently reacting with both the glass surface amino functionalities and the PVA hydroxyl groups, while PVA added the necessary surface hydrophilicity to provide anti-fog properties. Each step of the procedure was monitored by XPS, which confirmed the successful grafting of the coating. Coating thickness was evaluated by profilometry, nanoindentation, and UV visible light transmission. The hydrophilic nature of the anti-fog coating was assessed by water contact angle (CA), and its anti-fog efficiency was determined visually and tested quantitatively for the first time using an ASTM standard protocol. Results show that the PEMA/PVA coating not only delayed the initial period required for fog formation but also decreased the rate of light transmission decay. Finally, following a 24 hour immersion in water, these PEMA/PVA coatings remained stable and preserved their anti-fog properties.

  5. Gas sensors for ammonia detection based on polyaniline-coated multi-wall carbon nanotubes

    International Nuclear Information System (INIS)

    He Lifang; Jia Yong; Meng Fanli; Li Minqiang; Liu Jinhuai

    2009-01-01

    Polyaniline-coated multi-wall carbon nanotubes (PANI-coated MWNTs) were prepared by in situ polymerization method. Field emission scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and thermogravimetric analysis were used to characterize the as-prepared PANI-coated MWNTs. Obtained results indicated that PANI was uniformly coated on MWNTs, and the thickness of the coatings can be controlled by changing the weight ratios of aniline monomer and MWNTs in the polymerization process. Sensors were fabricated by spin-coating onto pre-patterned electrodes, and ammonia gas sensing properties of the as-prepared PANI-coated MWNTs were studied. The results showed a good response and reproducibility towards ammonia at room temperature. In addition, PANI-coated MWNTs exhibited a linear response to ammonia in the range of 0.2-15 ppm. The effects of the thickness of PANI coatings on the gas sensing properties were also investigated in detail. The results suggest a potential application of PANI-coated MWNTs in gas sensor for detecting ammonia.

  6. Comparison of silicone and spin-on glass packaging materials for light-emitting diode encapsulation

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Liann-Be; Pan, Ke-Wei; Yen, Chia-Yi [Department of Electronic Engineering and Green Technology Research Center, Chang Gung University, Taoyuan, Taiwan (China); Jeng, Ming-Jer, E-mail: mjjeng@mail.cgu.edu.tw [Department of Electronic Engineering and Green Technology Research Center, Chang Gung University, Taoyuan, Taiwan (China); Wu, Chun-Te; Hu, Sung-Cheng; Kuo, Yang-Kuao [Chemical Systems Research Division, Chung-Shan Institute of Science and Technology Armaments Bureau, MND, Taoyuan, Taiwan (China)

    2014-11-03

    Traditional white light light-emitting diode (LED) encapsulation is performed by mixed phosphors and silicone coating on LED die. However, this encapsulation with silicone coating incurs overheated temperatures and yellowing problem. Therefore, this work attempts to replace silicone paste by using spin-on-glass (SOG) materials. Experimental results indicate that although initial brightness of SOG-based packaging is lower than that of silicone packaging, its light attenuation is significantly lower than that of silicone for a long lighting time. After the LED power is turned on for 12 h, the brightness of LED with silicone and SOG material packaging decreases from 84 to 48 lm and 73 to 59 lm, respectively. Therefore, SOG material provides an alternative packaging solution for high power LED lighting applications. - Highlights: • Spin-on-glass (SOG) material was used to replace silicone coating for LED packaging. • Initial brightness of SOG packaging is lower than that of silicone packaging. • Over time, light attenuation in SOG is much lower than that in silicone. • Color rendering index and brightness of LED packaging was optimized by Taguchi method.

  7. An isoindigo containing donor-acceptor polymer: synthesis and photovoltaic properties of all-solution-processed ITO- and vacuum-free large area roll-coated single junction and tandem solar cells

    DEFF Research Database (Denmark)

    Brandt, Rasmus Guldbæk; Yue, Wei; Andersen, Thomas Rieks

    2015-01-01

    In this work, the design, synthesis, and characterization of a donor-acceptor polymer from dithieno[3,2-b:2',3'-d]pyrrole and isoindigo (i-ID) are presented. The synthesized polymer has been applied in large area ITO-free organic photovoltaics, both as spin coated and roll coated devices; the lat......In this work, the design, synthesis, and characterization of a donor-acceptor polymer from dithieno[3,2-b:2',3'-d]pyrrole and isoindigo (i-ID) are presented. The synthesized polymer has been applied in large area ITO-free organic photovoltaics, both as spin coated and roll coated devices...

  8. Biomimetic novel nanoporous niobium oxide coating for orthopaedic applications

    Science.gov (United States)

    Pauline, S. Anne; Rajendran, N.

    2014-01-01

    Niobium oxide was synthesized by sol-gel methodology and a crystalline, nanoporous and adherent coating of Nb2O5 was deposited on 316L SS using the spin coating technique and heat treatment. The synthesis conditions were optimized to obtain a nanoporous morphology. The coating was characterized using attenuated total reflectance-Infrared spectroscopy (ATR-IR), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX), atomic force microscopy (AFM) and transmission electron microscopy (TEM) and the formation of crystalline Nb2O5 coating with nanoporous morphology was confirmed. Mechanical studies confirmed that the coating has excellent adherence to the substrate and the hardness value of the coating was excellent. Contact angle analysis showed increased hydrophilicity for the coated substrate. In vitro bioactivity test confirmed that the Nb2O5 coating with nanoporous morphology facilitated the growth of hydroxyapatite (HAp). This was further confirmed by the solution analysis test where increased uptake of calcium and phosphorous ions from simulated body fluid (SBF) was observed. Electrochemical evaluation of the coating confirmed that the crystalline coating is insulative and protective in nature and offered excellent corrosion protection to 316L SS. Thus, this study confirmed that the nanoporous crystalline Nb2O5 coating conferred bioactivity and enhanced corrosion resistance on 316L SS.

  9. Biomimetic novel nanoporous niobium oxide coating for orthopaedic applications

    Energy Technology Data Exchange (ETDEWEB)

    Pauline, S. Anne; Rajendran, N., E-mail: nrajendran@annauniv.edu

    2014-01-30

    Niobium oxide was synthesized by sol–gel methodology and a crystalline, nanoporous and adherent coating of Nb{sub 2}O{sub 5} was deposited on 316L SS using the spin coating technique and heat treatment. The synthesis conditions were optimized to obtain a nanoporous morphology. The coating was characterized using attenuated total reflectance-Infrared spectroscopy (ATR-IR), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX), atomic force microscopy (AFM) and transmission electron microscopy (TEM) and the formation of crystalline Nb{sub 2}O{sub 5} coating with nanoporous morphology was confirmed. Mechanical studies confirmed that the coating has excellent adherence to the substrate and the hardness value of the coating was excellent. Contact angle analysis showed increased hydrophilicity for the coated substrate. In vitro bioactivity test confirmed that the Nb{sub 2}O{sub 5} coating with nanoporous morphology facilitated the growth of hydroxyapatite (HAp). This was further confirmed by the solution analysis test where increased uptake of calcium and phosphorous ions from simulated body fluid (SBF) was observed. Electrochemical evaluation of the coating confirmed that the crystalline coating is insulative and protective in nature and offered excellent corrosion protection to 316L SS. Thus, this study confirmed that the nanoporous crystalline Nb{sub 2}O{sub 5} coating conferred bioactivity and enhanced corrosion resistance on 316L SS.

  10. Hydrogen permeation through sol-gel-coated iron during galvanostatic charging

    International Nuclear Information System (INIS)

    Zakorchemna, I.; Carmona, N.; Zakroczymski, T.

    2008-01-01

    One-layer sol-gel silica-zirconia and two-layer silica-zirconia and zirconia coatings were deposited on one side of iron membranes by spin-coating, densified in air and annealed up to 800 deg. C in vacuum. Hydrogen permeation through the membranes, coated and uncoated, polarised cathodically under galvanostatic control in 0.1 M NaOH solution was studied using the electrochemical permeation technique. During the initial period, the effect of the sol-gel coatings was insignificant. However, the coatings quite efficiently prevented the iron surface become more active to hydrogen entry during a long-lasting cathodic polarisation. In addition, the electrochemical-corrosion behaviour of the coated iron and the effect of the sol-gel coatings on the effective diffusivity of hydrogen in the coated membranes were studied. On the basis of the polarisation curves and the hydrogen permeation data it was proved that the sol-gel coatings blocked the iron surface for the hydrogen evolution reaction and, consequently, for the hydrogen entry into iron. The effective coating coverage was determined by comparison of the hydrogen fluxes permeating the coated and uncoated membranes. Finally the real concentration of hydrogen beneath the uncoated iron sites and the amount of hydrogen stored in a membrane were evaluated

  11. Two-component spin-coated Ag/CNT composite films based on a silver heterogeneous nucleation mechanism adhesion-enhanced by mechanical interlocking and chemical grafting

    Science.gov (United States)

    Zhang, Yang; Kang, Zhixin; Bessho, Takeshi

    2017-03-01

    In this paper, a new method for the synthesis of silver carbon nanotube (Ag/CNT) composite films as conductive connection units for flexible electronic devices is presented. This method is about a two-component solution process by spin coating with an after-treatment annealing process. In this method, multi-walled carbon nanotubes (MWCNTs) act as the core of silver heterogeneous nucleation, which can be observed and analyzed by a field-emission scanning electron microscope. With the effects of mechanical interlocking, chemical grafting, and annealing, the interfacial adhesive strength between films and PET sheets was enhanced to 12 N cm-1. The tensile strength of the Ag/CNT composite films was observed to increase by 38% by adding 5 g l-1 MWCNTs. In the four-probe method, the resistivity of Ag/CNT-5 declined by 78.2% compared with pristine Ag films. The anti-fatigue performance of the Ag/CNT composite films was monitored by cyclic bending deformation and the results revealed that the growth rate of electrical resistance during the deformation was obviously retarded. As for industrial application, this method provides an efficient low-cost way to prepare Ag/CNT composite films and can be further applied to other coating systems.

  12. The hydrophobic and omnidirectional antireflection coating of SiO2 nanospheres with C18-TEOS

    Science.gov (United States)

    Hsu, Cheng-Chih; Lan, Wen-Lin; Chen, Nien-Po; Wu, Chyan-Chyi

    2014-06-01

    This paper demonstrates the antireflection coating of SiO2 nanospheres applied to cover glass by using the optimal spin-coating method. Because of the hydrolysis and condensation reactions between the SiO2 nanosphere antireflection (AR) coating and n-octadecyltriethoxysilane solution (C18-TEOS), the contact angle of the AR coating with hydrophobic treatment is improved approximately 38%, and the moisture-resistance remains unchanged, which preserved similar transmittance for six weeks. Furthermore, the AR coating with hydrophobic treatment exhibits approximately 3% and 7% improvement in the transmittance at normal and oblique incidence, respectively. The hydrophobic and omnidirectional AR coating with nanoscale SiO2 particles can be fabricated using the proposed simple and economical method.

  13. Synthesis and characterization of Ba_0_._5Pb_0_._5TiO_3 perovskite - type thin films deposited by spin coating at low temperatures

    International Nuclear Information System (INIS)

    Wermuth, T.B.; Wiederkehr, N.A.; Alves, A.K.; Bergmann, C.P.

    2014-01-01

    In this paper we present a non-aqueous sol-gel route for the obtention of solid compounds and thin films of oxide type- perovskite ABO_3, such as Ba_0_._5 Pb_0_._5 TiO_3, synthesized by sol - gel route with subsequent heat treatment. The solid compounds were characterized by X-ray diffraction (XRD) techniques and thermal analysis (TGA / DTA). The thin film was obtained by using spin-coating techniques at low temperatures onto commercial substrates of polymethylmethacrylate (PMMA) and characterized by contact angle, atomic force microscopy (AFM) and scanning electron microscopy (SEM). The results show that the films present microstructures and roughness directly related to annealing temperatures, characterized by the formation of crystalline nanostructures with surface regularity and transparency. (author)

  14. Temperature Dependent Electrical Transport in Al/Poly(4-vinyl phenol/p-GaAs Metal-Oxide-Semiconductor by Sol-Gel Spin Coating Method

    Directory of Open Access Journals (Sweden)

    Şadan Özden

    2016-01-01

    Full Text Available Deposition of poly(4-vinyl phenol insulator layer is carried out by applying the spin coating technique onto p-type GaAs substrate so as to create Al/poly(4-vinyl phenol/p-GaAs metal-oxide-semiconductor (MOS structure. Temperature was set to 80–320 K while the current-voltage (I-V characteristics of the structure were examined in the study. Ideality factor (n and barrier height (ϕb values found in the experiment ranged from 3.13 and 0.616 eV (320 K to 11.56 and 0.147 eV (80 K. Comparing the thermionic field emission theory and thermionic emission theory, the temperature dependent ideality factor behavior displayed that thermionic field emission theory is more valid than the latter. The calculated tunneling energy was 96 meV.

  15. Copper oxide thin films anchored on glass substrate by sol gel spin coating technique

    Science.gov (United States)

    Krishnaprabha, M.; Venu, M. Parvathy; Pattabi, Manjunatha

    2018-05-01

    Owing to the excellent optical, thermal, electrical and photocatalytic properties, copper oxide nanoparticles/films have found applications in optoelectronic devices like solar/photovoltaic cells, lithium ion batteries, gas sensors, catalysts, magnetic storage media etc. Copper oxide is a p-type semiconductor material having a band gap energy varying from 1.2 eV-2.1 eV. Syzygium Samarangense fruit extract was used as reducing agent to synthesize copper oxide nanostructures at room temperature from 10 mM copper sulphate pentahydrate solution. The synthesized nanostructures are deposited onto glass substrate by spin coating followed by annealing the film at 200 °C. Both the copper oxide colloid and films are characterized using UV-Vis spectroscopy, field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy (EDS) techniques. Presence of 2 peaks at 500 nm and a broad peak centered around 800 nm in the UV-Vis absorbance spectra of copper oxide colloid/films is indicative of the formation of anisotropic copper oxide nanostructures is confirmed by the FESEM images which showed the presence of triangular shaped and rod shaped particles. The rod shaped particles inside island like structures were found in unannealed films whereas the annealed films contained different shaped particles with reduced sizes. The elemental analysis using EDS spectra of copper oxide nanoparticles/films showed the presence of both copper and oxygen. Electrical properties of copper oxide nanoparticles are affected due to quantum size effect. The electrical studies carried out on both unannealed and annealed copper oxide films revealed an increase in resistivity with annealing of the films.

  16. Obtaining hydroxyapatite coatings on titanium by the biomimetic method; Obtencion de recubrimientos de hidroxiapatita sobre titanio mediante el metodo biomimetico

    Energy Technology Data Exchange (ETDEWEB)

    Paz, A.; Martin, Y.; Pazos, L. M.; Parodi, M. B.; Ybarra, G. O.; Gonzalez, J. E.

    2011-07-01

    In this work, a study about the deposition of hydroxyapatite on a titanium substrate employing the biomimetic method is presented. A solution with high content of calcium and phosphorus (SCS) was used. In addition, activation of titanium with hydrogen peroxide and hydrochloric acid and a subsequent heat treatment was performed. The characterization of materials used and the coating obtained was carried out by Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX). As a result of the activation processes a hydrated titanium oxide was formed. On the active surface, a coating of hydroxyapatite was obtained after a period of 24 h, which has a thickness of about 2-4 {mu}m. (Author) 21 refs.

  17. Entangled spins and ghost-spins

    Directory of Open Access Journals (Sweden)

    Dileep P. Jatkar

    2017-09-01

    Full Text Available We study patterns of quantum entanglement in systems of spins and ghost-spins regarding them as simple quantum mechanical toy models for theories containing negative norm states. We define a single ghost-spin as in [20] as a 2-state spin variable with an indefinite inner product in the state space. We find that whenever the spin sector is disentangled from the ghost-spin sector (both of which could be entangled within themselves, the reduced density matrix obtained by tracing over all the ghost-spins gives rise to positive entanglement entropy for positive norm states, while negative norm states have an entanglement entropy with a negative real part and a constant imaginary part. However when the spins are entangled with the ghost-spins, there are new entanglement patterns in general. For systems where the number of ghost-spins is even, it is possible to find subsectors of the Hilbert space where positive norm states always lead to positive entanglement entropy after tracing over the ghost-spins. With an odd number of ghost-spins however, we find that there always exist positive norm states with negative real part for entanglement entropy after tracing over the ghost-spins.

  18. Spin Current Noise of the Spin Seebeck Effect and Spin Pumping

    Science.gov (United States)

    Matsuo, M.; Ohnuma, Y.; Kato, T.; Maekawa, S.

    2018-01-01

    We theoretically investigate the fluctuation of a pure spin current induced by the spin Seebeck effect and spin pumping in a normal-metal-(NM-)ferromagnet(FM) bilayer system. Starting with a simple ferromagnet-insulator-(FI-)NM interface model with both spin-conserving and non-spin-conserving processes, we derive general expressions of the spin current and the spin-current noise at the interface within second-order perturbation of the FI-NM coupling strength, and estimate them for a yttrium-iron-garnet-platinum interface. We show that the spin-current noise can be used to determine the effective spin carried by a magnon modified by the non-spin-conserving process at the interface. In addition, we show that it provides information on the effective spin of a magnon, heating at the interface under spin pumping, and spin Hall angle of the NM.

  19. Thin Glass Coatings for the Corrosion Protection of Metals

    DEFF Research Database (Denmark)

    Lampert, Felix

    in corrosion sensitive applications. Since the deposition of SiOx thin films is a well-established technology, the SOG technology was directly benchmarked to PVD-based SiO2 coatings. The coating adhesion was assessed by cross cut testing and increasing load scratch testing and the efficiency of the sub...... with localized corrosion and do not impact the heat transfer or the component performance. The herein presented approach focuses primarily on the formation of SiOx-like thin films from Hydrogen Silsesquioxane (HSQ) –based “spin-on-glass” (SOG) precursor. The technology is well known for the deposition...

  20. Investigation of microwave transitions and nonlinear magneto-optical rotation in anti-relaxation-coated cells

    International Nuclear Information System (INIS)

    Budker, D.; Hollberg, L.; Kimball, D.F.; Kitching, J.; Pustclny, S.; Robinson, H.G.; Yashchuk, V.V.

    2004-01-01

    Using laser optical pumping, widths and frequency shifts are determined for microwave transitions between the components of the ground-state hyperfine structure for 85 Rb and 87 Rb atoms contained in vapor cells with alkane anti-relaxation coatings. The results are compared with data on Zeeman relaxation obtained in nonlinear magneto-optical rotation (NMOR) experiments, a comparison important for quantitative understanding of spin-relaxation mechanisms in coated cells. By comparing cells manufactured over a forty-year period we demonstrate the long-term stability of coated cells, which may be useful for atomic clocks and magnetometers

  1. Investigation of microwave transitions and nonlinear magneto-optical rotation in anti-relaxation-coated cells

    International Nuclear Information System (INIS)

    Budker, Dmitry; Hollberg, Leo; Kimball, Derek F.; Kitching, J.; Pustelny, Szymon; Yashchuk, Valeriy V.

    2004-01-01

    Using laser optical pumping, widths and frequency shifts are determined for microwave transitions between ground-state hyperfine components of 85 Rb and 87 Rb atoms contained in vapor cells with alkane anti-relaxation coatings. The results are compared with data on Zeeman relaxation obtained in nonlinear magneto-optical rotation (NMOR) experiments, a comparison important for quantitative understanding of spin-relaxation mechanisms in coated cells. By comparing cells manufactured over a forty-year period we demonstrate the long-term stability of coated cells, an important property for atomic clocks and magnetometers

  2. ESR accident dosimetry using medicine tablets coated with sugar

    International Nuclear Information System (INIS)

    Kai, A.; Miki, T.; Ikeya, M.

    1990-01-01

    Properties of radiation-induced radicals in medicine tablets were investigated using electron spin resonance (ESR). A sharp ESR signal sensitive to gamma ray irradiation was observed in the sugar coating part of the tablets. The signal has anisotropic g values of g 1 = 2.0009, g 2 = 2.0007 and g 3 = 2.0002. The signal grows linearly with dose at least up to about 20 Gy. No fading was observed at room temperature even when exposed to sunlight. The dose to artificially irradiated tablets was estimated using the signal intensity and a previously determined calibration curve. The signal in sugar coated tablets can be utilised for dose measurements. In particular, the wide distribution of sugar coated tablets allows the use of the tablets as accident dosemeters. (author)

  3. High-sensitivity green resist material with organic solvent-free spin-coating and tetramethylammonium hydroxide-free water-developable processes for EB and EUV lithography

    Science.gov (United States)

    Takei, Satoshi; Hanabata, Makoto; Oshima, Akihiro; Kashiwakura, Miki; Kozawa, Takahiro; Tagawa, Seiichi

    2015-03-01

    We investigated the eco-friendly electron beam (EB) and extreme-ultraviolet (EUV) lithography using a high-sensitive negative type of green resist material derived from biomass to take advantage of organic solvent-free water spin-coating and tetramethylammonium hydroxide(TMAH)-free water-developable techniques. A water developable, non-chemically amplified, high sensitive, and negative tone resist material in EB lithography was developed for environmental affair, safety, easiness of handling, and health of the working people, instead of the common developable process of TMAH. The material design concept to use the water-soluble resist material with acceptable properties such as pillar patterns with less than 100 nm in high EB sensitivity of 10 μC/cm2 and etch selectivity with a silicon-based middle layer in CF4 plasma treatment was demonstrated for EB and EUV lithography.

  4. Geometrical spin symmetry and spin

    International Nuclear Information System (INIS)

    Pestov, I. B.

    2011-01-01

    Unification of General Theory of Relativity and Quantum Mechanics leads to General Quantum Mechanics which includes into itself spindynamics as a theory of spin phenomena. The key concepts of spindynamics are geometrical spin symmetry and the spin field (space of defining representation of spin symmetry). The essence of spin is the bipolar structure of geometrical spin symmetry induced by the gravitational potential. The bipolar structure provides a natural derivation of the equations of spindynamics. Spindynamics involves all phenomena connected with spin and provides new understanding of the strong interaction.

  5. A numerical study of spin-dependent organization of alkali-metal atomic clusters using density-functional method

    International Nuclear Information System (INIS)

    Liu Xuan; Ito, Haruhiko; Torikai, Eiko

    2012-01-01

    We calculate the different geometric isomers of spin clusters composed of a small number of alkali-metal atoms using the UB3LYP density-functional method. The electron density distribution of clusters changes according to the value of total spin. Steric structures as well as planar structures arise when the number of atoms increases. The lowest spin state is the most stable and Li n , Na n , K n , Rb n , and Cs n with n = 2–8 can be formed in higher spin states. In the highest spin state, the preparation of clusters depends on the kind and the number of constituent atoms. The interaction energy between alkali-metal atoms and rare-gas atoms is smaller than the binding energy of spin clusters. Consequently, it is possible to self-organize the alkali-metal-atom clusters on a non-wetting substrate coated with rare-gas atoms.

  6. A numerical study of spin-dependent organization of alkali-metal atomic clusters using density-functional method

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xuan, E-mail: liu.x.ad@m.titech.ac.jp; Ito, Haruhiko [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology (Japan); Torikai, Eiko [Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi (Japan)

    2012-08-15

    We calculate the different geometric isomers of spin clusters composed of a small number of alkali-metal atoms using the UB3LYP density-functional method. The electron density distribution of clusters changes according to the value of total spin. Steric structures as well as planar structures arise when the number of atoms increases. The lowest spin state is the most stable and Li{sub n}, Na{sub n}, K{sub n}, Rb{sub n}, and Cs{sub n} with n = 2-8 can be formed in higher spin states. In the highest spin state, the preparation of clusters depends on the kind and the number of constituent atoms. The interaction energy between alkali-metal atoms and rare-gas atoms is smaller than the binding energy of spin clusters. Consequently, it is possible to self-organize the alkali-metal-atom clusters on a non-wetting substrate coated with rare-gas atoms.

  7. Coating, Degrading and Testing of Organic Polymer Devices - Reducing the route from Laboratory to Production scale devices

    DEFF Research Database (Denmark)

    Dam, Henrik Friis

    volume, which for spin coating allowed making a single 1 cm2 device, using the mini roll coater (MRC) enable the coating of a 100 cm2 area, resulting in 60 1cm2 devices with the present mask designs. With the relative expensive polymers, this translates into a large saving for performing the same amount...

  8. Subsurface microbial ecology. Epi fluorescence direct counts; Ecologia microbica del sottosuolo: metodo di conta diretta in epifluorescenza

    Energy Technology Data Exchange (ETDEWEB)

    Barra Caracciolo, A.; Silvestri, C.; Creo, C.; Izzo, G. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Ambiente

    1998-07-01

    To the aim of recognize the importance of microorganisms in affecting or even determining the fate of xenobiotics in the subsurface environment evaluating bacteria concentration in a subsurface ecosystem, the report discusses a soil sample treatment method which has been developed for epi fluorescence direct counting with DAPI. [Italian] Lo studio discute un metodo di trattamento del campione per la conta diretta in epifluorescenza con un marcatore selettivo per il DNA, il DAPI, al fine di quantificare la concentrazione batterica del sottosuolo e studiare il ruolo dei microrganismi nella biodegradazione delle molecole esogene, ancora poco indagato.

  9. Characteristics of TiO_2/ZnO bilayer film towards pH sensitivity prepared by different spin coating deposition process

    International Nuclear Information System (INIS)

    Rahman, Rohanieza Abdul; Zulkefle, Muhammad Al Hadi; Abdullah, Wan Fazlida Hanim; Rusop, M.; Herman, Sukreen Hana

    2016-01-01

    In this study, titanium dioxide (TiO_2) and zinc oxide (ZnO) bilayer film for pH sensing application will be presented. TiO_2/ZnO bilayer film with different speed of spin-coating process was deposited on Indium Tin Oxide (ITO), prepared by sol-gel method. This fabricated bilayer film was used as sensing membrane for Extended Gate Field-Effect Transistor (EGFET) for pH sensing application. Experimental results indicated that the sensor is able to detect the sensitivity towards pH buffer solution. In order to obtained the result, sensitivity measurement was done by using the EGFET setup equipment with constant-current (100 µA) and constant-voltage (0.3 V) biasing interfacing circuit. TiO_2/ZnO bilayer film which the working electrode, act as the pH-sensitive membrane was connected to a commercial metal-oxide semiconductor FET (MOSFET). This MOSFET then was connected to the interfacing circuit. The sensitivity of the TiO2 thin film towards pH buffer solution was measured by dipping the sensing membrane in pH4, pH7 and pH10 buffer solution. These thin films were characterized by using Field Emission Scanning Electron Microscope (FESEM) to obtain the surface morphology of the composite bilayer films. In addition, I-V measurement was done in order to determine the electrical properties of the bilayer films. According to the result obtained in this experiment, bilayer film that spin at 4000 rpm, gave highest sensitivity which is 52.1 mV/pH. Relating the I-V characteristic of the thin films and sensitivity, the sensing membrane with higher conductivity gave better sensitivity.

  10. Bidisperse silica nanoparticles close-packed monolayer on silicon substrate by three step spin method

    Science.gov (United States)

    Khanna, Sakshum; Marathey, Priyanka; Utsav, Chaliawala, Harsh; Mukhopadhyay, Indrajit

    2018-05-01

    We present the studies on the structural properties of monolayer Bidisperse silica (SiO2) nanoparticles (BDS) on Silicon (Si-100) substrate using spin coating technique. The Bidisperse silica nanoparticle was synthesised by the modified sol-gel process. Nanoparticles on the substrate are generally assembled in non-close/close-packed monolayer (CPM) form. The CPM form is obtained by depositing the colloidal suspension onto the silicon substrate using complex techniques. Here we report an effective method for forming a monolayer of bidisperse silica nanoparticle by three step spin coating technique. The samples were prepared by mixing the monodisperse solutions of different particles size 40 and 100 nm diameters. The bidisperse silica nanoparticles were self-assembled on the silicon substrate forming a close-packed monolayer film. The scanning electron microscope images of bidisperse films provided in-depth film structure of the film. The maximum surface coverage obtained was around 70-80%.

  11. Sol-gel derived antireflective coatings for silicon

    Energy Technology Data Exchange (ETDEWEB)

    Brinker, C J; Harrington, M S

    1981-08-01

    The preparation of TiO2-SiO2 AR coatings, containing from 30 to 95 mol % TiO2, from alkoxide precursor solutions (titanium tetraethoxide and silicon tetraethoxide) by a sol-gel process is presented. The preparation of the solutions is described, which involves the separate partial hydrolysis of one or both alkoxides prior to their mixing (Yoldas, 1980). The solutions are applied to polished, circular (1 and 2 in. diameter) silicon wafers by a spinning process. The coated wafers are successively heated in air at each of the following temperatures: 200, 300, 350, 400, and 450 C, and optical measurements are performed on them after each heat treatment. The durability of 90 and 95% TiO2 coatings is evaluated in both acidic and basic environments, and reflectivity, film thickness, and refractive index are measured as a function of exposure time. It is shown that sol-gel films applied at 400 C reveal broad regions of antireflectance compared to other titanium-based films.

  12. Analysis of Crystal Structure of Fe3O4 Thin Films Based on Iron Sand Growth by Spin Coating Method

    Science.gov (United States)

    Rianto, D.; Yulfriska, N.; Murti, F.; Hidayati, H.; Ramli, R.

    2018-04-01

    Recently, iron sand used as one of base materials in the steel industry. However, the content of iron sand can be used as starting materials in sensor technology in the form of thin films. In this paper, we report the analysis of crystal structure of magnetite thin film based on iron sand from Tiram’s Beach. The magnetic content of sand separated by a permanent magnet, then it was milled at 30 hours milling time. In order to increase the purity of magnetite, it washed after milling using aquades under magnetic separation by a magnet permanent. The thin film has been prepared using iron (III) nitrate by sol–gel technique. The precursor is resulted by dissolving magnetite in oxalic acid and nitric acid. Then, solution of iron (III) nitrate dissolved in ethylene glycol was applied on glass substrates by spin coating. The X-Ray Diffraction is operated thin film characterization. The structure of magnetite has been studied based on X-Ray Peaks that correspond to magnetite content of thin films.

  13. Spin Torques in Systems with Spin Filtering and Spin Orbit Interaction

    KAUST Repository

    Ortiz Pauyac, Christian

    2016-06-19

    In the present thesis we introduce the reader to the field of spintronics and explore new phenomena, such as spin transfer torques, spin filtering, and three types of spin-orbit torques, Rashba, spin Hall, and spin swapping, which have emerged very recently and are promising candidates for a new generation of memory devices in computer technology. A general overview of these phenomena is presented in Chap. 1. In Chap. 2 we study spin transfer torques in tunnel junctions in the presence of spin filtering. In Chap. 3 we discuss the Rashba torque in ferromagnetic films, and in Chap. 4 we study spin Hall effect and spin swapping in ferromagnetic films, exploring the nature of spin-orbit torques based on these mechanisms. Conclusions and perspectives are summarized in Chap. 5.

  14. Flow measurement in a 170-MW hydraulic turbine using the Gibson method; Medicion del flujo de una turbina hidraulica de 170 MW utilizando el metodo Gibson

    Energy Technology Data Exchange (ETDEWEB)

    Urquiza, Gustavo [Universidad Autonoma del Estado de Morelos (Mexico); Adamkowski, Adam [The Szewalski Institute of Fluid-Flow Machinery (Poland); Kubiak, Janusz; Sierra, Fernando [Universidad Autonoma del Estado de Morelos (Mexico); Janicki, Waldemar [The Szewalski Institute of Fluid-Flow Machinery (Poland); Fernandez, J. Manuel [Comision Federal de Electricidad (Mexico)

    2007-07-15

    This paper describes the methodology applied for measuring water flow through a 170-MW hydraulic turbine. The flow rate was measured using the pressure-time method, also known as the Gibson method. This method uses the well-known water hammer phenomenon in pipelines; in turbine penstocks, for instance. The version of this method used here is based on measuring, during total stop of the water stream, the time-history of pressure change in one section of the turbine penstock and relate it to the pressure in the upper reservoir to which the penstock is connected. The volumetric flow rate is determined from the relevant integration of the measured temporary pressure rise. Flow measurement was possible this way because the influence of the penstock inlet was negligible as far as an error of the measurement is concerned. The length of the penstock was 300 m. Previous experience and a standard IEC-41-1991 were the criteria adopted and applied. A fast and efficient acquisition system, including a 16 bit card, was used. The flow rate was calculated using a computer program developed and tested on several cases. The results obtained with the Gibson method were used for calibration of the on-line flow measuring system based on the Winter-Kennedy method as one of the index methods. This method is very often used for continuous monitoring of the flow rate through hydraulic turbines, when the calibration has been done on site by using the results of measurements obtained by the absolute method. Having measured the flow rate and output power, the efficiency was calculated for any operating conditions. A curve showing the best operating conditions based on the highest efficiency is presented and discussed. The details of the instrumentation, its installation, and the results obtained are discussed in the paper. [Spanish] Este articulo describe la metodologia aplicada para la medicion del flujo en una turbina hidraulica de 170 MW. El flujo se midio utilizando el metodo de presion

  15. Study of β-phase development in spin-coated PVDF thick films

    Indian Academy of Sciences (India)

    2017-06-09

    Jun 9, 2017 ... C and increase in spin speed increases the β-phase ... extensively used in the field of sensors and actuators [1–8]. ... some methods to achieve these polar phases in PVDF such as ... ites with materials, such as, gold nanoparticles [14], carbon ..... change in degree of crystallinity of the films subject to the ...

  16. Effects of Doping Concentration on the Structural and Optical Properties of Spin-Coated In-doped ZnO Thin Films Grown on Thermally Oxidized ZnO Film/ZnO Buffer Layer/Mica Substrate

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Byunggu; Leem, Jae-Young [Inje University, Gimhae (Korea, Republic of)

    2017-01-15

    ZnO buffer layers were deposited on mica substrates using a sol-gel spin coating method. Then, a thin film of metallic Zn was deposited onto the ZnO buffer layer/mica substrate using a thermal evaporator, and the deposited Zn thin films were then thermally oxidized in a furnace at 500 ℃ for 2 h in air. Finally, In-doped ZnO (IZO) thin films with different In concentrations were grown on the oxidized ZnO film/ZnO buffer layer/mica substrates using the sol-gel spin-coating method. All the IZO films showed ZnO peaks with similar intensities. The full width at half maximum values of the ZnO (002) peak for the IZO thin films decreased with an increase in the In concentration to 1 at%, because the crystallinity of the films was enhanced. However, a further increase in the In concentration caused the crystal quality to degrade. This might be attributed to the fact that the higher In doping resulted in an increase in the number of ionized impurities. The Urbach energy (EU) values of the IZO thin film decreased with an increase in the In concentration to 1 at % because of the enhanced crystal quality of the films. The EU values for the IZO thin films increased with the In concentration from 1 at%to 3 at%, reflecting the broadening of localized band tail state near the conduction band edge of the films.

  17. Effects of Doping Concentration on the Structural and Optical Properties of Spin-Coated In-doped ZnO Thin Films Grown on Thermally Oxidized ZnO Film/ZnO Buffer Layer/Mica Substrate

    International Nuclear Information System (INIS)

    Kim, Byunggu; Leem, Jae-Young

    2017-01-01

    ZnO buffer layers were deposited on mica substrates using a sol-gel spin coating method. Then, a thin film of metallic Zn was deposited onto the ZnO buffer layer/mica substrate using a thermal evaporator, and the deposited Zn thin films were then thermally oxidized in a furnace at 500 ℃ for 2 h in air. Finally, In-doped ZnO (IZO) thin films with different In concentrations were grown on the oxidized ZnO film/ZnO buffer layer/mica substrates using the sol-gel spin-coating method. All the IZO films showed ZnO peaks with similar intensities. The full width at half maximum values of the ZnO (002) peak for the IZO thin films decreased with an increase in the In concentration to 1 at%, because the crystallinity of the films was enhanced. However, a further increase in the In concentration caused the crystal quality to degrade. This might be attributed to the fact that the higher In doping resulted in an increase in the number of ionized impurities. The Urbach energy (EU) values of the IZO thin film decreased with an increase in the In concentration to 1 at % because of the enhanced crystal quality of the films. The EU values for the IZO thin films increased with the In concentration from 1 at%to 3 at%, reflecting the broadening of localized band tail state near the conduction band edge of the films.

  18. Simple roll coater with variable coating and temperature control for printed polymer solar cells

    DEFF Research Database (Denmark)

    Dam, Henrik Friis; Krebs, Frederik C

    2012-01-01

    of solution, enabling roll coating testing of new polymers where only small amounts are often available. We demonstrate the formation of >50 solar cells (each with an active area of 1 cm2) with printed metal back electrodes using as little as 0.1 mL of active layer solution. This approach outperforms spin...... coating with respect to temperature control, ink usage, speed and is directly compatible with industrial processing and upscaling....

  19. Spin-polarized spin excitation spectroscopy

    International Nuclear Information System (INIS)

    Loth, Sebastian; Lutz, Christopher P; Heinrich, Andreas J

    2010-01-01

    We report on the spin dependence of elastic and inelastic electron tunneling through transition metal atoms. Mn, Fe and Cu atoms were deposited onto a monolayer of Cu 2 N on Cu(100) and individually addressed with the probe tip of a scanning tunneling microscope. Electrons tunneling between the tip and the substrate exchange energy and spin angular momentum with the surface-bound magnetic atoms. The conservation of energy during the tunneling process results in a distinct onset threshold voltage above which the tunneling electrons create spin excitations in the Mn and Fe atoms. Here we show that the additional conservation of spin angular momentum leads to different cross-sections for spin excitations depending on the relative alignment of the surface spin and the spin of the tunneling electron. For this purpose, we developed a technique for measuring the same local spin with a spin-polarized and a non-spin-polarized tip by exchanging the last apex atom of the probe tip between different transition metal atoms. We derive a quantitative model describing the observed excitation cross-sections on the basis of an exchange scattering process.

  20. Research Update: Large-area deposition, coating, printing, and processing techniques for the upscaling of perovskite solar cell technology

    Directory of Open Access Journals (Sweden)

    Stefano Razza

    2016-09-01

    Full Text Available To bring perovskite solar cells to the industrial world, performance must be maintained at the photovoltaic module scale. Here we present large-area manufacturing and processing options applicable to large-area cells and modules. Printing and coating techniques, such as blade coating, slot-die coating, spray coating, screen printing, inkjet printing, and gravure printing (as alternatives to spin coating, as well as vacuum or vapor based deposition and laser patterning techniques are being developed for an effective scale-up of the technology. The latter also enables the manufacture of solar modules on flexible substrates, an option beneficial for many applications and for roll-to-roll production.

  1. Spin current and spin transfer torque in ferromagnet/superconductor spin valves

    Science.gov (United States)

    Moen, Evan; Valls, Oriol T.

    2018-05-01

    Using fully self-consistent methods, we study spin transport in fabricable spin valve systems consisting of two magnetic layers, a superconducting layer, and a spacer normal layer between the ferromagnets. Our methods ensure that the proper relations between spin current gradients and spin transfer torques are satisfied. We present results as a function of geometrical parameters, interfacial barrier values, misalignment angle between the ferromagnets, and bias voltage. Our main results are for the spin current and spin accumulation as functions of position within the spin valve structure. We see precession of the spin current about the exchange fields within the ferromagnets, and penetration of the spin current into the superconductor for biases greater than the critical bias, defined in the text. The spin accumulation exhibits oscillating behavior in the normal metal, with a strong dependence on the physical parameters both as to the structure and formation of the peaks. We also study the bias dependence of the spatially averaged spin transfer torque and spin accumulation. We examine the critical-bias effect of these quantities, and their dependence on the physical parameters. Our results are predictive of the outcome of future experiments, as they take into account imperfect interfaces and a realistic geometry.

  2. Biocorrosion of TiO2 nanoparticle coating of Ti–6Al–4V in DMEM under specific in vitro conditions

    International Nuclear Information System (INIS)

    Höhn, Sarah; Virtanen, Sannakaisa

    2015-01-01

    Highlights: • Possibility to fabricate a TiO 2 NP-coating on Ti–6Al–4V by a simple spin-coating method. • The NP-coating enhances biomimetic apatite formation on the surface immersed in DMEM. • The TiO 2 coating can efficiently reduce Al release from the alloy during immersion in DMEM. • TiO 2 NP-coating makes the surface more bioactive. - Abstract: A TiO 2 nanoparticle coating was prepared on a biomedical Ti–6Al–4V alloy using “spin-coating” technique with a colloidal suspension of TiO 2 nanopowders with the aim to optimize the surface morphology (e.g., roughness) for improved biocompatibility. The influence of a TiO 2 nanoparticle (NP) coating on the corrosion behavior, metal ion release, and biomimetic apatite formation was studied in DMEM, at 37.5 °C with a continuous supply of 5% CO 2 . Electrochemical impedance spectroscopy measurements indicate a formation of a new layer on the surface of the NP-coated sample upon 28 days immersion in DMEM. Scanning electron microscopy (SEM) and X-ray spectroscopy confirm that the surface of the NP-coated Ti–6Al–4V shows a complete coverage by a Ca–phosphate layer in contrast to the non-coated Ti–6Al–4V alloy. Hence, the TiO 2 -NP coating strongly enhances biomimetic apatite formation on the alloy surface. In addition, the TiO 2 -NP coating can efficiently reduce Al-release from the alloy, for which the bare Ti–6Al–4V alloy is significant for at least 28 days of immersion in DMEM

  3. Improved cell activity on biodegradable photopolymer scaffolds using titanate nanotube coatings

    Energy Technology Data Exchange (ETDEWEB)

    Beke, S., E-mail: szabolcs.beke@iit.it [Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova (Italy); Barenghi, R. [IEIIT, National Research Council (CNR), Via De Marini 6, 16149 Genova (Italy); Farkas, B.; Romano, I. [Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova (Italy); Kőrösi, L. [Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertváros u. 2, H-7632 Pécs (Hungary); Scaglione, S. [IEIIT, National Research Council (CNR), Via De Marini 6, 16149 Genova (Italy); Brandi, F. [Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova (Italy); Istituto Nazionale di Ottica, CNR, Via G. Moruzzi 1, 56124-Pisa (Italy)

    2014-11-01

    The development of bioactive materials is in the premise of tissue engineering. For several years, surface functionalization of scaffolds has been one of the most promising approaches to stimulate cellular activity and finally improve implant success. Herein, we describe the development of a bioactive composite scaffold composed of a biodegradable photopolymer scaffold and titanate nanotubes (TNTs). The biodegradable photopolymer scaffolds were fabricated by applying mask-projection excimer laser photocuring at 308 nm. TNTs were synthesized and then spin-coated on the porous scaffolds. Upon culturing fibroblast cells on scaffolds, we found that nanotubes coating affects cell viability and proliferation demonstrating that TNT coatings enhance cell growth on the scaffolds by further improving their surface topography. - Highlights: • Biodegradable scaffolds were produced by mask-assisted UV laser photocuring. • Titanate nanotube deposition was carried out without binding compounds or additives. • Titanate nanotube coatings enhanced cell viability and proliferation.

  4. Characteristics of TiO{sub 2}/ZnO bilayer film towards pH sensitivity prepared by different spin coating deposition process

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Rohanieza Abdul, E-mail: rohanieza.abdrahman@gmail.com; Zulkefle, Muhammad Al Hadi, E-mail: alhadizulkefle@gmail.com [NANO-Electronic Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Abdullah, Wan Fazlida Hanim, E-mail: wanfaz@salam.uitm.edu.my [Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM) Shah Alam, 40450 Shah Alam, Selangor (Malaysia); Rusop, M., E-mail: rusop@salam.uitm.com [NANO-Electronic Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); NANO-Science Technology Centre (NST), Institute of Science (IOS), Faculty of Applied Science, Universiti Teknologi MARA - UiTM, 40450 Shah Alam, Selangor (Malaysia); Herman, Sukreen Hana, E-mail: hana1617@salam.uitm.edu.my [NANO-Electronic Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); CoRe of Frontier Materials & Industry Applications, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia)

    2016-07-06

    In this study, titanium dioxide (TiO{sub 2}) and zinc oxide (ZnO) bilayer film for pH sensing application will be presented. TiO{sub 2}/ZnO bilayer film with different speed of spin-coating process was deposited on Indium Tin Oxide (ITO), prepared by sol-gel method. This fabricated bilayer film was used as sensing membrane for Extended Gate Field-Effect Transistor (EGFET) for pH sensing application. Experimental results indicated that the sensor is able to detect the sensitivity towards pH buffer solution. In order to obtained the result, sensitivity measurement was done by using the EGFET setup equipment with constant-current (100 µA) and constant-voltage (0.3 V) biasing interfacing circuit. TiO{sub 2}/ZnO bilayer film which the working electrode, act as the pH-sensitive membrane was connected to a commercial metal-oxide semiconductor FET (MOSFET). This MOSFET then was connected to the interfacing circuit. The sensitivity of the TiO2 thin film towards pH buffer solution was measured by dipping the sensing membrane in pH4, pH7 and pH10 buffer solution. These thin films were characterized by using Field Emission Scanning Electron Microscope (FESEM) to obtain the surface morphology of the composite bilayer films. In addition, I-V measurement was done in order to determine the electrical properties of the bilayer films. According to the result obtained in this experiment, bilayer film that spin at 4000 rpm, gave highest sensitivity which is 52.1 mV/pH. Relating the I-V characteristic of the thin films and sensitivity, the sensing membrane with higher conductivity gave better sensitivity.

  5. The Comparative Accuracy of the 4 {pi} Liquid Scintillation Counting Method of Radioisotope Standardization; L'exactitude comparee de la methode de comptage 4 {pi} a scintillateurs liquides pour l'etalonnage des radioisotopes; Sravnitel'naya tochnost' 4 {pi} zhidkogo stsintillatsionnogo metoda podscheta standartiziruemykh radioizotopov; Exactitud del metodo de recuento con centelleador liquido 4 {pi} para normalizar radioisotopos, comparada con la de otros metodos

    Energy Technology Data Exchange (ETDEWEB)

    Steyn, J [National Physical Research Laboratory, Pretoria (South Africa)

    1960-06-15

    The accuracy of the 4 {pi} liquid scintillation counting method of standardizing {beta} emitters was compared to 4 l{pi} {beta}-{gamma} coincidence counting for the nuclides Co{sup 60}, I{sup 131} and Au{sup 198}. For P{sup 32} the liquid counting results were compared to 4 {pi} proportional counting. The efficiency of the liquid scintillation counting method was found to be energy dependent, dropping to about 97.5% for Co{sup 60} which was the lowest energy {beta} emitter investigated. (author) [French] La precision de la methode de comptage 4 {pi} a scintillateurs liquides pour l'etalonnage des emetteurs {beta} a ete comparee au comptage par coincidences 4 {pi} {beta}-{gamma} pour le So{sup 60}, le I{sup 131} et le Au{sup 198}. Dans le cas du P{sup 32}, les resultats du comptage au liquide ont ete compares a ceux du comptage 4 {pi} proportionnel. On a constate que le rendement de la methode de comptage a scintillateurs liquides variait en fonction de l'energie emise et qu'il descendait a environ 97.5% pour le Co{sup 60} qui, de tous les emetteurs {beta} etudies, emet l'energie la plus faible. (author) [Spanish] El autor compara la precision del metodo de recuento con centelleador iquido 4 {pi} para normalizar emisores {beta} con la del metodo de coincidencias {beta}-{gamma} 4 {pi}, para los siguientes nuclidos: So{sup 60}, I{sup 131} y Au{sup 198}. En el caso del P{sup 32}, confronta los resultados del primer metodo con los obtenidos mediante el recuento proporcional 4 {pi}. Comprueba que la eficacia del metodo de recuento con centelleador liquido depende de la energia y desciende al 97.5%, aproximadamente, para el Co{sup 60}, que fue el emisor {beta} mas debil que se investigo. (author) [Russian] Tochnost' 4 {pi} zhidkogo stsintillyatsionnog o metoda podscheta standartiziruemogo {beta}-izluchatelya sravnivalas' s 4 {pi} {beta}-{gamma} metodom podscheta na sovpadeniyakh dlya izotopov So{sup 60}, I{sup 131} i Au{sup 198}. Dlya R{sup 32} rezultaty zhidkogo

  6. Photolithography of thick photoresist coating for electrically controlled liquid crystal photonic bandgap fibre devices

    DEFF Research Database (Denmark)

    Wei, Lei; Khomtchenko, Elena; Alkeskjold, Thomas Tanggaard

    2009-01-01

    Thick photoresist coating for electrode patterning in an anisotropically etched V-groove is investigated for electrically controlled liquid crystal photonic bandgap fibre devices. The photoresist step coverage at the convex corners is compared with and without soft baking after photoresist spin...

  7. Photocatalytic Graphene-TiO2 Thin Films Fabricated by Low-Temperature Ultrasonic Vibration-Assisted Spin and Spray Coating in a Sol-Gel Process

    Directory of Open Access Journals (Sweden)

    Fatemeh Zabihi

    2017-05-01

    Full Text Available In this work, we communicate a facile and low temperature synthesis process for the fabrication of graphene-TiO2 photocatalytic composite thin films. A sol-gel chemical route is used to synthesize TiO2 from the precursor solutions and spin and spray coating are used to deposit the films. Excitation of the wet films during the casting process by ultrasonic vibration favorably influences both the sol-gel route and the deposition process, through the following mechanisms. The ultrasound energy imparted to the wet film breaks down the physical bonds of the gel phase. As a result, only a low-temperature post annealing process is required to eliminate the residues to complete the conversion of precursors to TiO2. In addition, ultrasonic vibration creates a nanoscale agitating motion or microstreaming in the liquid film that facilitates mixing of TiO2 and graphene nanosheets. The films made based on the above-mentioned ultrasonic vibration-assisted method and annealed at 150 °C contain both rutile and anatase phases of TiO2, which is the most favorable configuration for photocatalytic applications. The photoinduced and photocatalytic experiments demonstrate effective photocurrent generation and elimination of pollutants by graphene-TiO2 composite thin films fabricated via scalable spray coating and mild temperature processing, the results of which are comparable with those made using lab-scale and energy-intensive processes.

  8. Effect of different coating layer on the topography and optical properties of ZnO nanostructured

    Science.gov (United States)

    Mohamed, R.; Mamat, M. H.; Malek, M. F.; Ismail, A. S.; Yusoff, M. M.; Asiah, M. N.; Khusaimi, Z.; Rusop, M.

    2018-05-01

    Magnesium (Mg) and aluminum (Al) co-doped zinc oxide (MAZO) thin films were synthesized on glass substrate by sol-gel spin coating method. MAZO thin films were prepared at different coating layers range from 1 to 9. Atomic Force Microscopy (AFM) was used to investigate the topography of the thin films. According to the AFM results, Root Means Square (RMS) of MAZO thin films was increased from 0.747 to 6.545 nm, with increase of number coating layer from 1 to 9, respectively. The results shown the variation on structural and topography properties of MAZO seed film when it's deposited at different coating layers on glass substrate. The optical properties was analyzed using UV-Vis spectroscopy. The obtained results show that the transmittance spectra was increased as thin films coating layer increases.

  9. Effect of Illumination on the Photovoltaic Parameters of Al/p-Si Diode with an Organic Interlayer Prepared by Spin Coating Method

    Directory of Open Access Journals (Sweden)

    Arife GENCER IMER

    2016-12-01

    Full Text Available In this study, the photovoltaic device application of bromothymol blue (BTB as an organic interlayer has been reported. After Al back contact fabrication on the surface of the chemically cleaned substrate by thermal evaporation method, the organic interlayer has been grown on p-Si substrate via spin coating technique. Al top contacts have been formed on this organic thin film to finalize the device constructions. The different illumination intensities were exposed to the prepared sample for the enhancement in the photovoltaic properties of device. The fundamental photovoltaic parameters such as open circuit voltage (Voc, short circuit current (Isc and output power (P were determined for the device under different illuminations. The photocurrent and the photo voltage have been increased with the increasing in illumination intensity. The dependence of the capacitance on the voltage at high and low frequency has been also reported for the studied device. Consequently, it has been confirmed that the illumination intensity has an important influence on the photovoltaic parameters of the device.

  10. Biocorrosion of TiO{sub 2} nanoparticle coating of Ti–6Al–4V in DMEM under specific in vitro conditions

    Energy Technology Data Exchange (ETDEWEB)

    Höhn, Sarah, E-mail: sarah.hoehn@fau.de; Virtanen, Sannakaisa, E-mail: virtanen@ww.uni-erlangen.de

    2015-02-28

    Highlights: • Possibility to fabricate a TiO{sub 2} NP-coating on Ti–6Al–4V by a simple spin-coating method. • The NP-coating enhances biomimetic apatite formation on the surface immersed in DMEM. • The TiO{sub 2} coating can efficiently reduce Al release from the alloy during immersion in DMEM. • TiO{sub 2} NP-coating makes the surface more bioactive. - Abstract: A TiO{sub 2} nanoparticle coating was prepared on a biomedical Ti–6Al–4V alloy using “spin-coating” technique with a colloidal suspension of TiO{sub 2} nanopowders with the aim to optimize the surface morphology (e.g., roughness) for improved biocompatibility. The influence of a TiO{sub 2} nanoparticle (NP) coating on the corrosion behavior, metal ion release, and biomimetic apatite formation was studied in DMEM, at 37.5 °C with a continuous supply of 5% CO{sub 2}. Electrochemical impedance spectroscopy measurements indicate a formation of a new layer on the surface of the NP-coated sample upon 28 days immersion in DMEM. Scanning electron microscopy (SEM) and X-ray spectroscopy confirm that the surface of the NP-coated Ti–6Al–4V shows a complete coverage by a Ca–phosphate layer in contrast to the non-coated Ti–6Al–4V alloy. Hence, the TiO{sub 2}-NP coating strongly enhances biomimetic apatite formation on the alloy surface. In addition, the TiO{sub 2}-NP coating can efficiently reduce Al-release from the alloy, for which the bare Ti–6Al–4V alloy is significant for at least 28 days of immersion in DMEM.

  11. Spin current evolution in the separated spin-up and spin-down quantum hydrodynamics

    International Nuclear Information System (INIS)

    Trukhanova, Mariya Iv.

    2015-01-01

    We have developed a method of quantum hydrodynamics (QHD) that describes particles with spin-up and with spin-down in separate. We have derived the equation of the spin current evolution as a part of the set of the quantum hydrodynamics equations that treat particles with different projection of spin on the preferable direction as two different species. We have studied orthogonal propagation of waves in the external magnetic field and determined the contribution of quantum corrections due to the Bohm potential and to magnetization energy of particles with different projections of spin in the spin-current wave dispersion. We have analyzed the limits of weak and strong magnetic fields. - Highlights: • We derive the spin current equation for particles with different projection of spin. • We predict the contribution of Bohm potential to the dynamics of spin current. • We derive the spin-current wave in the system of spin-polarized particles. • We study the propagation of spin-acoustic wave in magnetized dielectrics.

  12. Muonium spin exchange in spin-polarized media: Spin-flip and -nonflip collisions

    International Nuclear Information System (INIS)

    Senba, M.

    1994-01-01

    The transverse relaxation of the muon spin in muonium due to electron spin exchange with a polarized spin-1/2 medium is investigated. Stochastic calculations, which assume that spin exchange is a Poisson process, are carried out for the case where the electron spin polarization of the medium is on the same axis as the applied field. Two precession signals of muonium observed in intermediate fields (B>30 G) are shown to have different relaxation rates which depend on the polarization of the medium. Furthermore, the precession frequencies are shifted by an amount which depends on the spin-nonflip rate. From the two relaxation rates and the frequency shift in intermediate fields, one can determine (i) the encounter rate of muonium and the paramagnetic species, (ii) the polarization of the medium, and most importantly (iii) the quantum-mechanical phase shift (and its sign) associated with the potential energy difference between electron singlet and triplet encounters. Effects of spin-nonflip collisions on spin dynamics are discussed for non-Poisson as well as Poisson processes. In unpolarized media, the time evolution of the muon spin in muonium is not influenced by spin-nonflip collisions, if the collision process is Poissonian. This seemingly obvious statement is not true anymore in non-Poissonian processes, i.e., it is necessary to specify both spin-flip and spin-nonflip rates to fully characterize spin dynamics

  13. Neutron spin quantum precession using multilayer spin splitters and a phase-spin echo interferometer

    International Nuclear Information System (INIS)

    Ebisawa, Toru; Tasaki, Seiji; Kawai, Takeshi; Hino, Masahiro; Akiyoshi, Tsunekazu; Achiwa, Norio; Otake, Yoshie; Funahashi, Haruhiko.

    1996-01-01

    Neutron spin quantum precession by multilayer spin splitter has been demonstrated using a new spin interferometer. The multilayer spin splitter consists of a magnetic multilayer mirror on top, followed by a gap layer and a non magnetic multilayer mirror which are evaporated on a silicon substrate. Using the multilayer spin splitter, a polarized neutron wave in a magnetic field perpendicular to the polarization is split into two spin eigenstates with a phase shift in the direction of the magnetic field. The spin quantum precession is equal to the phase shift, which depends on the effective thickness of the gap layer. The demonstration experiments verify the multilayer spin splitter as a neutron spin precession device as well as the coherent superposition principle of the two spin eigenstates. We have developed a new phase-spin echo interferometer using the multilayer spin splitters. We present successful performance tests of the multilayer spin splitter and the phase-spin echo interferometer. (author)

  14. Self-cleaning glass coating containing titanium oxide and silicon

    International Nuclear Information System (INIS)

    Araujo, A.O. de; Alves, A.K.; Berutti, F.A.; Bergmann, C.P.

    2009-01-01

    Using the electro spinning technique nano fibers of titanium oxide doped with silicon were synthesized. As precursor materials, titanium propoxide, silicon tetra propoxide and a solution of polyvinylpyrrolidone were used. The non-tissue material obtained was characterized by X-ray diffraction to determine the phase and crystallite size, BET method to determine the surface and SEM to analyze the microstructure of the fibers. After ultrasound dispersion of this material in ethanol, the glass coatings were made by dip-coating methodology. The influence of the removal velocity, the solution composition and the glass surface preparation were evaluated. The film was characterized by the contact angle of a water droplet in its surface. (author)

  15. Polymer thin film as coating layer to prevent corrosion of metal/metal oxide film

    Science.gov (United States)

    Sarkar, Suman; Kundu, Sarathi

    2018-04-01

    Thin film of polymer is used as coating layer and the corrosion of metal/metal oxide layer is studied with the variation of the thickness of the coating layer. The thin layer of polystyrene is fabricated using spin coating method on copper oxide (CuO) film which is deposited on glass substrate using DC magnetron sputtering technique. Thickness of the polystyrene and the CuO layers are determined using X-ray reflectivity (XRR) technique. CuO thin films coated with the polystyrene layer are exposed to acetic acid (2.5 v/v% aqueous CH3COOH solution) environments and are subsequently analyzed using UV-Vis spectroscopy and atomic force microscopy (AFM). Surface morphology of the film before and after interaction with the acidic environment is determined using AFM. Results obtained from the XRR and UV-Vis spectroscopy confirm that the thin film of polystyrene acts as an anticorrosion coating layer and the strength of the coating depends upon the polymer layer thickness at a constant acid concentration.

  16. High mobility and low operating voltage ZnGaO and ZnGaLiO transistors with spin-coated Al2O3 as gate dielectric

    International Nuclear Information System (INIS)

    Xia, D X; Xu, J B

    2010-01-01

    Spin-coated alumina serving as a gate dielectric in thin film transistors shows interesting dielectric properties for low-voltage applications, despite a moderate capacitance. With Ga singly doped and Ga, Li co-doped ZnO as the active channel layers, typical mobilities of 4.7 cm 2 V -1 s -1 and 2.1 cm 2 V -1 s -1 are achieved, respectively. At a given gate bias, the operation current is much smaller than the previously reported values in low-voltage thin film transistors, primarily relying on the giant-capacitive dielectric. The reported devices combine advantages of high mobility, low power consumption, low cost and ease of fabrication. In addition to the transparent nature of both the dielectric and semiconducting active channels, the superior electrical properties of the devices may provide a new avenue for future transparent electronics. (fast track communication)

  17. Morphology control in thin films of PS:PLA homopolymer blends by dip-coating deposition

    Energy Technology Data Exchange (ETDEWEB)

    Vital, Alexane [Interfaces, Confinement, Matériaux et Nanostructures (ICMN), CNRS-Université d’Orléans, UMR 7374, 1B Rue de la Férollerie, C.S. 40059, 45071 Orléans Cedex 2 (France); Groupe de recherches sur l’énergétique des milieux ionisés (GREMI), CNRS-Université d’Orléans, UMR 7344, 14 rue d' Issoudun, B.P. 6744, F45067 Orléans Cedex 2 (France); Vayer, Marylène [Interfaces, Confinement, Matériaux et Nanostructures (ICMN), CNRS-Université d’Orléans, UMR 7374, 1B Rue de la Férollerie, C.S. 40059, 45071 Orléans Cedex 2 (France); Tillocher, Thomas; Dussart, Rémi [Groupe de recherches sur l’énergétique des milieux ionisés (GREMI), CNRS-Université d’Orléans, UMR 7344, 14 rue d' Issoudun, B.P. 6744, F45067 Orléans Cedex 2 (France); Boufnichel, Mohamed [STMicroelectronics, 16, rue Pierre et Marie Curie, B.P. 7155, 37071 Tours Cedex 2 (France); and others

    2017-01-30

    Highlights: • A process to control the morphology of polymer blends thin film is described. • It is based on the use of dip-coating at various withdrawal speeds. • The process is examined within the capillary and the draining regimes. • The final dried morphology is controlled by the regime of deposition. • This study is of high interest for the preparation of advanced functional surfaces. - Abstract: In this work, smooth polymer films of PS, PLA and their blends, with thicknesses ranging from 20 nm up to 400 nm and very few defects on the surface were obtained by dip-coating. In contrast to the process of spin-coating which is conventionally used to prepare thin films of polymer blends, we showed that depending on the deposition parameters (withdrawal speed and geometry of the reservoir), various morphologies such as layered films and laterally phase-separated domains could be formed for a given blend/solvent pair, offering much more opportunities compared to the spin-coating process. This diversity of morphologies was explained by considering the superposition of different phenomena such as phase separation process, dewetting and vitrification in which parameters such as the drying time, the compatibility of the polymer/solvent pairs and the affinity of the polymer towards the interfaces were suspected to play a significant role. For that purpose, the process of dip-coating was examined within the capillary and the draining regimes (for low and high withdrawal speed respectively) in order to get a full description of the thickness variation and evaporation rate as a function of the deposition parameters.

  18. Tribological behavior of dual-layer electroless-plated Ag–carbon nanotube coatings

    International Nuclear Information System (INIS)

    Lee, Hyun-Dai; Penkov, Oleksiy V.; Kim, Dae-Eun

    2013-01-01

    The tribological behavior of electroless Ag-plated carbon nanotube (CNT) dual-layer coatings was assessed and compared to that of the pure CNT coating. The motivation was to protect the surface of CNT coatings from wear by depositing a thin, soft Ag coating. The methods used for coating CNTs and Ag were spin coating and electroless plating, respectively. These coating methods were selected based on their simplicity and cost effectiveness. Wear tests were conducted by sliding the coatings against a stainless steel ball under a 10–30 mN applied load. Results showed that the wear rate of the dual-layer coating was strongly dependent on the thickness of the Ag layer as well as the applied load. At a 10 mN load and an Ag thickness of 65 nm, the wear rate of the dual-layer coating was about 10 times less than that of the pure CNT coating. However, when the thickness of the Ag was decreased to 11.5 nm, the wear rate was significantly higher. Also, the steady-state friction coefficients of the CNT and the dual-layer Ag–CNT coatings were in the range of 0.65–0.73 for all loads. A model of the wear reduction mechanism of the dual-layer Ag–CNT coating was proposed. - Highlights: ► Dual-layer Ag–carbon nanotube (CNT) coatings were deposited on silicon wafer. ► Friction coefficient of the Ag–CNT coatings was about 0.65. ► Wear of Ag–CNT coatings depended on the thickness of Ag layer and the applied load. ► Wear rate of the Ag–CNT coating was 10-fold less than that of the pure CNT coating

  19. Through-plane uniformity of optical anisotropy in spin-coated biphenyl dianhydride-p-phenylenediamine films

    International Nuclear Information System (INIS)

    Diao Jie; Hess, Dennis W.

    2005-01-01

    The uniformity of the average refractive index and birefringence of poly-(biphenyl dianhydride-p-phenylenediamine) (BPDA-PDA) films has been investigated experimentally as a function of film thickness. Spin-cast and cured BPDA-PDA films were thinned sequentially by reactive ion etching and the dependence of average refractive index and birefringence on the post-thinned film thickness was determined using a prism wave-guide coupler. Negligible changes in the average refractive index and the birefringence were observed as a result of the thinning process. These results confirm previous assumptions that assert uniform optical anisotropy in the through-plane direction for spin-cast BPDA-PDA films

  20. Spin drift and spin diffusion currents in semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Idrish Miah, M [Nanoscale Science and Technology Centre and School of Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)], E-mail: m.miah@griffith.edu.au

    2008-09-15

    On the basis of a spin drift-diffusion model, we show how the spin current is composed and find that spin drift and spin diffusion contribute additively to the spin current, where the spin diffusion current decreases with electric field while the spin drift current increases, demonstrating that the extension of the spin diffusion length by a strong field does not result in a significant increase in spin current in semiconductors owing to the competing effect of the electric field on diffusion. We also find that there is a spin drift-diffusion crossover field for a process in which the drift and diffusion contribute equally to the spin current, which suggests a possible method of identifying whether the process for a given electric field is in the spin drift or spin diffusion regime. Spin drift-diffusion crossover fields for GaAs are calculated and are found to be quite small. We derive the relations between intrinsic spin diffusion length and the spin drift-diffusion crossover field of a semiconductor for different electron statistical regimes. The findings resulting from this investigation might be important for semiconductor spintronics.

  1. Spin drift and spin diffusion currents in semiconductors

    Directory of Open Access Journals (Sweden)

    M Idrish Miah

    2008-01-01

    Full Text Available On the basis of a spin drift-diffusion model, we show how the spin current is composed and find that spin drift and spin diffusion contribute additively to the spin current, where the spin diffusion current decreases with electric field while the spin drift current increases, demonstrating that the extension of the spin diffusion length by a strong field does not result in a significant increase in spin current in semiconductors owing to the competing effect of the electric field on diffusion. We also find that there is a spin drift-diffusion crossover field for a process in which the drift and diffusion contribute equally to the spin current, which suggests a possible method of identifying whether the process for a given electric field is in the spin drift or spin diffusion regime. Spin drift-diffusion crossover fields for GaAs are calculated and are found to be quite small. We derive the relations between intrinsic spin diffusion length and the spin drift-diffusion crossover field of a semiconductor for different electron statistical regimes. The findings resulting from this investigation might be important for semiconductor spintronics.

  2. Spin drift and spin diffusion currents in semiconductors

    International Nuclear Information System (INIS)

    Idrish Miah, M

    2008-01-01

    On the basis of a spin drift-diffusion model, we show how the spin current is composed and find that spin drift and spin diffusion contribute additively to the spin current, where the spin diffusion current decreases with electric field while the spin drift current increases, demonstrating that the extension of the spin diffusion length by a strong field does not result in a significant increase in spin current in semiconductors owing to the competing effect of the electric field on diffusion. We also find that there is a spin drift-diffusion crossover field for a process in which the drift and diffusion contribute equally to the spin current, which suggests a possible method of identifying whether the process for a given electric field is in the spin drift or spin diffusion regime. Spin drift-diffusion crossover fields for GaAs are calculated and are found to be quite small. We derive the relations between intrinsic spin diffusion length and the spin drift-diffusion crossover field of a semiconductor for different electron statistical regimes. The findings resulting from this investigation might be important for semiconductor spintronics.

  3. Low Band Gap Polymers for Roll-to-Roll Coated Organic Photovoltaics – Design, Synthesis and Characterization

    DEFF Research Database (Denmark)

    Bundgaard, Eva; Hagemann, Ole; Jørgensen, Mikkel

    2011-01-01

    In this paper we present the design and synthesis of 25 new low band gap polymers. The polymers were characterized by UV-vis spectroscopy which showed optical band gaps of 2.0–0.9 eV. The polymers which were soluble enough were applied in organic photovoltaics, both small area devices with a spin...... coated active layer and in large area modules where all layers including the active layer were either roll-to-roll coated or printed. These experiments showed that the design of polymers compatible with roll-toroll coating is not straightforward and that there are various issues such as donor...

  4. Polylactic acid coating on a biodegradable magnesium alloy: An in vitro degradation study by electrochemical impedance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Alabbasi, Alyaa; Liyanaarachchi, S.; Kannan, M. Bobby, E-mail: bobby.mathan@jcu.edu.au

    2012-09-30

    Polylactic acid (PLA) was coated on a biodegradable magnesium alloy, AZ91, using spin coating technique for temporary implant applications. The degradation behaviour of the coated alloy samples was evaluated using electrochemical impedance spectroscopy (EIS) method in simulated body fluid (SBF). EIS results suggested that the PLA coating enhanced the degradation resistance of the alloy significantly. Increase in the PLA coating thickness was found to increase the degradation resistance, but resulted in poor adhesion. Long-term EIS experiments of the PLA coated samples suggested that their degradation resistance gradually decreased with increase in SBF exposure time. However, the degradation resistance of the PLA coated samples was significantly higher than that of the bare metal even after a 48 h exposure to SBF. - Highlights: Black-Right-Pointing-Pointer Polylactic acid (PLA) was coated on a magnesium-based alloy. Black-Right-Pointing-Pointer PLA coating enhanced the in vitro degradation resistance of the alloy. Black-Right-Pointing-Pointer Increase in the PLA coating thickness improved the alloy degradation resistance. Black-Right-Pointing-Pointer Thin film PLA coating exhibited both good degradation resistance and adhesion.

  5. Polylactic acid coating on a biodegradable magnesium alloy: An in vitro degradation study by electrochemical impedance spectroscopy

    International Nuclear Information System (INIS)

    Alabbasi, Alyaa; Liyanaarachchi, S.; Kannan, M. Bobby

    2012-01-01

    Polylactic acid (PLA) was coated on a biodegradable magnesium alloy, AZ91, using spin coating technique for temporary implant applications. The degradation behaviour of the coated alloy samples was evaluated using electrochemical impedance spectroscopy (EIS) method in simulated body fluid (SBF). EIS results suggested that the PLA coating enhanced the degradation resistance of the alloy significantly. Increase in the PLA coating thickness was found to increase the degradation resistance, but resulted in poor adhesion. Long-term EIS experiments of the PLA coated samples suggested that their degradation resistance gradually decreased with increase in SBF exposure time. However, the degradation resistance of the PLA coated samples was significantly higher than that of the bare metal even after a 48 h exposure to SBF. - Highlights: ► Polylactic acid (PLA) was coated on a magnesium-based alloy. ► PLA coating enhanced the in vitro degradation resistance of the alloy. ► Increase in the PLA coating thickness improved the alloy degradation resistance. ► Thin film PLA coating exhibited both good degradation resistance and adhesion.

  6. Spin Polarization Oscillations without Spin Precession: Spin-Orbit Entangled Resonances in Quasi-One-Dimensional Spin Transport

    Directory of Open Access Journals (Sweden)

    D. H. Berman

    2014-03-01

    Full Text Available Resonant behavior involving spin-orbit entangled states occurs for spin transport along a narrow channel defined in a two-dimensional electron gas, including an apparent rapid relaxation of the spin polarization for special values of the channel width and applied magnetic field (so-called ballistic spin resonance. A fully quantum-mechanical theory for transport using multiple subbands of the one-dimensional system provides the dependence of the spin density on the applied magnetic field and channel width and position along the channel. We show how the spatially nonoscillating part of the spin density vanishes when the Zeeman energy matches the subband energy splittings. The resonance phenomenon persists in the presence of disorder.

  7. Effect of spin rotation coupling on spin transport

    International Nuclear Information System (INIS)

    Chowdhury, Debashree; Basu, B.

    2013-01-01

    We have studied the spin rotation coupling (SRC) as an ingredient to explain different spin-related issues. This special kind of coupling can play the role of a Dresselhaus like coupling in certain conditions. Consequently, one can control the spin splitting, induced by the Dresselhaus like term, which is unusual in a semiconductor heterostructure. Within this framework, we also study the renormalization of the spin-dependent electric field and spin current due to the k → ⋅p → perturbation, by taking into account the interband mixing in the rotating system. In this paper we predict the enhancement of the spin-dependent electric field resulting from the renormalized spin rotation coupling. The renormalization factor of the spin electric field is different from that of the SRC or Zeeman coupling. The effect of renormalized SRC on spin current and Berry curvature is also studied. Interestingly, in the presence of this SRC-induced SOC it is possible to describe spin splitting as well as spin galvanic effect in semiconductors. -- Highlights: •Studied effect of spin rotation coupling on the spin electric field, spin current and Berry curvature. •In the k → ⋅p → framework we study the renormalization of spin electric field and spin current. •For an inertial system we have discussed the spin splitting. •Expression for the Berry phase in the inertial system is discussed. •The inertial spin galvanic effect is studied

  8. Effect of spin rotation coupling on spin transport

    Energy Technology Data Exchange (ETDEWEB)

    Chowdhury, Debashree, E-mail: debashreephys@gmail.com; Basu, B., E-mail: sribbasu@gmail.com

    2013-12-15

    We have studied the spin rotation coupling (SRC) as an ingredient to explain different spin-related issues. This special kind of coupling can play the role of a Dresselhaus like coupling in certain conditions. Consequently, one can control the spin splitting, induced by the Dresselhaus like term, which is unusual in a semiconductor heterostructure. Within this framework, we also study the renormalization of the spin-dependent electric field and spin current due to the k{sup →}⋅p{sup →} perturbation, by taking into account the interband mixing in the rotating system. In this paper we predict the enhancement of the spin-dependent electric field resulting from the renormalized spin rotation coupling. The renormalization factor of the spin electric field is different from that of the SRC or Zeeman coupling. The effect of renormalized SRC on spin current and Berry curvature is also studied. Interestingly, in the presence of this SRC-induced SOC it is possible to describe spin splitting as well as spin galvanic effect in semiconductors. -- Highlights: •Studied effect of spin rotation coupling on the spin electric field, spin current and Berry curvature. •In the k{sup →}⋅p{sup →} framework we study the renormalization of spin electric field and spin current. •For an inertial system we have discussed the spin splitting. •Expression for the Berry phase in the inertial system is discussed. •The inertial spin galvanic effect is studied.

  9. Optical and Structural Characterization of ZnO/TiO2 Bilayer Thin Films Grown by Sol-Gel Spin Coating

    Science.gov (United States)

    Gareso, P. L.; Musfitasari; Juarlin, Eko

    2018-03-01

    Structural and optical properties of ZnO/TiO2 bilayers thin films have been investigated using x-ray diffraction (X-RD), scanning electron microscopy (SEM), and optical transmittance UV-Vis measurements. ZnO thin films were prepared by dissolving zinc acetate dehydrated into a solvent of ethanol and then added triethanolamin. In the case of TiO2 layers, tetraisoproxide was dissolved into ethanol and then added an acetate acid. The layer of ZnO was deposited first followed by TiO2 layer on a glass substrate using a spin coating technique. The ZnO/TiO2 bilayers were annealed at various temperatures from 300°C until 600°C for 60 minutes. The X-ray diffraction results show that there was an enhancement of the x-ray spectra as annealed temperature increased to 600°C in comparison to the samples that were annealed at 300°C. Based on the optical measurement of UV-Vis, the band gap energy of ZnO/TiO2 bilayer is around 3.2 eV at temperature of 300°C. This value is similar to the band gap energy of ZnO. SEM results show that there is no cluster in the surface of ZnO/TiO2 bilayer.

  10. Spin coating and plasma process for 2.5D and hybrid 3D micro-resonators on multilayer polymers

    Science.gov (United States)

    Bêche, B.; Gaviot, E.; Godet, C.; Zebda, A.; Potel, A.; Barbe, J.; Camberlein, L.; Vié, V.; Panizza, P.; Loas, G.; Hamel, C.; Zyss, J.; Huby, N.

    2009-05-01

    We have designed and realized three integrated photonic families of micro-resonators (MR) on multilayer organic materials. Such so-called 2.5D-MR and 3D-MR structures show off radius values ranging from 40 to 200μm. Both first and second families are especially designed on organic multilayer materials and shaped as ring- and disk-MR organics structures arranged upon (and coupled with) a pair of SU8-organic waveguides. The third family is related to hybrid 3D-MR structures composed of spherical glass-MR coupled to organic waveguides by a Langmuir-Blodgett lipid film about three nanometers in thickness. At first, polymer spin coating, surface plasma treatment and selective UV-lithography processes have been developed to realize 2.5D photonic micro-resonators. Secondly, we have designed and characterized photonic-quadripoles made of 3D-glass-MR arranged upon a pair of SU8 waveguides. Such structures are defined by a 4-ports or 4-waveguides coupled by the spherical glass-MR. We have achieved an evanescent photonic coupling between the 3D-MR and the 4-ports structure. Spectral resonances have been measured for 4-whispering gallery-modes (WGM) into such 3D-structures respectively characterized by a 0.97 nm free spectral range (FSR) and a high quality Q-factor up to 4.104.

  11. Removing seed coat fragments with a lint cleaner grid bar air knife

    Science.gov (United States)

    Seed coat fragments (SCF) in ginned lint cause spinning problems at the textile mill and undesirable defects in finished goods. Work continued on developing an air knife that may help remove SCF from ginned lint. The air knife is mounted on the 1st lint cleaner grid bar of a saw-type lint cleaner,...

  12. Hydrogen Silsesquioxane based silica glass coatings for the corrosion protection of austenitic stainless steel

    DEFF Research Database (Denmark)

    Lampert, Felix; Jensen, Annemette Hindhede; Din, Rameez Ud

    2016-01-01

    -film barrier coatings were deposited on AISI 316L grade austenitic stainless steel with 2B surface finish from Hydrogen Silsesquioxane (HSQ) spin-on-glass precursor and thermally cured to tailor the film properties. Results showed that curing at 500 °C resulted in a film-structure with a polymerized siloxane...... backbone and a reduced amount of Si-H moieties. The coatings showed good substrate coverage and the average thickness was between 200 and 400 nm on the rough substrate surface, however, film thicknesses of > 1400 nm were observed at substrate defects. Deposition of these films significantly improved...... the barrier-properties by showing a 1000 times higher modulus while an ionic transport over the coating was also observed....

  13. Improved Morphology of Poly(3,4-ethylenedioxythiophene:Poly(styrenesulfonate Thin Films for All-Electrospray-Coated Organic Photovoltaic Cells

    Directory of Open Access Journals (Sweden)

    Yingjie Liao

    2016-01-01

    Full Text Available Spray coating technique has been established as a promising substitute for the traditional coating methods in the fabrication of organic devices in many reports recently. Control of film morphology at the microscopic scale is critical if spray-coated devices are to achieve high performance. Here we investigate electrospray deposition protocols for the fabrication of poly(3,4-ethylenedioxythiophene:poly(styrenesulfonate (PEDOT:PSS thin films with a single additive system under ambient conditions at room temperature. Critical deposition parameters including solution composition, applied voltage, and relative humidity are discussed systematically. Optimized process for preparing homogenous PEDOT:PSS thin films is applied to all-electrospray-coated organic photovoltaic cells and contributes to a power conversion efficiency comparable to that of the corresponding all-spin-coated device.

  14. Spin-polarized scanning tunneling spectroscopy of self-organized nanoscale Co islands on Au(111) surfaces.

    Science.gov (United States)

    Schouteden, K; Muzychenko, D A; Van Haesendonck, C

    2008-07-01

    Magnetic monolayer and bilayer Co islands of only a few nanometer in size were grown by atomic deposition on atomically flat Au(111) films. The islands were studied in situ by scanning tunneling microscopy (STM) and spectroscopy at low temperatures. Spin-resolved tunneling spectroscopy, using an STM tip with a magnetic coating, revealed that the Co islands exhibit a net magnetization perpendicular to the substrate surface due to the presence of spin-polarized d-states. A random distribution of islands with either upward or downward pointing magnetization was observed, without any specific correlation of magnetization orientation with island size or island height.

  15. Synthesis and characterization of Cerium-doped hydroxyapatite/polylactic acid composite coatings on metal substrates

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Qiuhua, E-mail: yuanqiuh@szu.edu.cn; Qin, Caoping; Wu, Jianbo; Xu, Anping; Zhang, Ziqiang; Liao, Junquan; Lin, Songxin; Ren, Xiangzhong; Zhang, Peixin

    2016-10-01

    Ce-doped hydroxyapatite/polylactic acid (HA/PLA) composites serving as implant coatings have rarely been studied by other researchers in recent years. This paper was focused to study the existence of Ce ions in structure, chemical composition and surface morphology of HA and its composite coatings. Ce-doped HA powders were synthesized by chemical precipitation method with different Ce molar fractions (0(pure HA), 0.5 mol%, 1 mol% and 2 mol%). And Ce-doped HA/PLA composite coatings were fabricated for the first time on stainless steel substrates by spin coating technique. The obtained samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) coupled with energy dispersive X-ray detector (EDX), thermo gravimetric-differential thermal analysis (TG-DTA) and X-ray photoelectron spectroscopy (XPS). The results showed that Ce ions were doped into the crystal lattice of apatite successfully. The (Ce + Ca)/P atomic ratios in the doped HA/PLA samples ranged from 1.614 to 1.673, which were very close to the theoretical value of 1.67 for the stoichiometric HA. The addition of PLA could keep metal substrates from catalyzing the decomposition of HA. TG-DTA analysis indicated that Ce-doped HA powder had high thermal stability, and the SEM micrographs revealed that the surface topography of Ce-doped HA/PLA composite coatings was uniform and dense when the Ce molar fraction was 2 mol%. XPS results indicated that the Ce ions doped in HA showed mixed valences of Ce{sup 3+} and Ce{sup 4+}. - Highlights: • Ce-doped HA composite coatings were synthesized by spin-coating technique for the first time. • Ce ions were demonstrated to dope into HA crystal lattice successfully. • The addition of PLA could keep metal substrates from catalyzing the decomposition of HA. • XPS results showed that Ce ions doped in HA have mixed valences of Ce{sup 3+} and Ce{sup 4+}.

  16. Spin Hall and spin swapping torques in diffusive ferromagnets

    KAUST Repository

    Pauyac, C. O.

    2017-12-08

    A complete set of the generalized drift-diffusion equations for a coupled charge and spin dynamics in ferromagnets in the presence of extrinsic spin-orbit coupling is derived from the quantum kinetic approach, covering major transport phenomena, such as the spin and anomalous Hall effects, spin swapping, spin precession and relaxation processes. We argue that the spin swapping effect in ferromagnets is enhanced due to spin polarization, while the overall spin texture induced by the interplay of spin-orbital and spin precessional effects displays a complex spatial dependence that can be exploited to generate torques and nucleate/propagate domain walls in centrosymmetric geometries without use of external polarizers, as opposed to the conventional understanding of spin-orbit mediated torques.

  17. Spin Hall and spin swapping torques in diffusive ferromagnets

    KAUST Repository

    Pauyac, C. O.; Chshiev, M.; Manchon, Aurelien; Nikolaev, S. A.

    2017-01-01

    A complete set of the generalized drift-diffusion equations for a coupled charge and spin dynamics in ferromagnets in the presence of extrinsic spin-orbit coupling is derived from the quantum kinetic approach, covering major transport phenomena, such as the spin and anomalous Hall effects, spin swapping, spin precession and relaxation processes. We argue that the spin swapping effect in ferromagnets is enhanced due to spin polarization, while the overall spin texture induced by the interplay of spin-orbital and spin precessional effects displays a complex spatial dependence that can be exploited to generate torques and nucleate/propagate domain walls in centrosymmetric geometries without use of external polarizers, as opposed to the conventional understanding of spin-orbit mediated torques.

  18. Spin-orbit and spin-lattice coupling

    International Nuclear Information System (INIS)

    Bauer, Gerrit E.W.; Ziman, Timothy; Mori, Michiyasu

    2014-01-01

    We pursued theoretical research on the coupling of electron spins in the condensed matter to the lattice as mediated by the spin-orbit interaction with special focus on the spin and anomalous Hall effects. (author)

  19. Spin rotation after a spin-independent scattering. Spin properties of an electron gas in a solid

    International Nuclear Information System (INIS)

    Zayets, V.

    2014-01-01

    It is shown that spin direction of an electron may not be conserved after a spin-independent scattering. The spin rotations occur due to a quantum-mechanical fact that when a quantum state is occupied by two electrons of opposite spins, the total spin of the state is zero and the spin direction of each electron cannot be determined. It is shown that it is possible to divide all conduction electrons into two group distinguished by their time-reversal symmetry. In the first group the electron spins are all directed in one direction. In the second group there are electrons of all spin directions. The number of electrons in each group is conserved after a spin-independent scattering. This makes it convenient to use these groups for the description of the magnetic properties of conduction electrons. The energy distribution of spins, the Pauli paramagnetism and the spin distribution in the ferromagnetic metals are described within the presented model. The effects of spin torque and spin-torque current are described. The origin of spin-transfer torque is explained within the presented model

  20. Sheet resistance, transmittance, and chromatic property of CNTs coated with PEDOT:PSS films for transparent electrodes of touch screen panels

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bu-Jong; Han, Sang-Hoon; Park, Jin-Seok

    2014-12-01

    This study demonstrates hybrid-type transparent electrodes based on carbon nanotubes (CNTs) that possess characteristics desirable for touch screen panels. This has been accomplished by depositing CNTs via spray-coating and then depositing thin conductive polymer (such as PEDOT:PSS) films on the CNTs via spin-coating. For all of the samples such as CNTs, PEDOT:PSS, and hybrid (i.e., PEDOT:PSS-coated CNTs), their surface morphologies, sheet resistances, visible transmittances, and chromatic properties are characterized as functions of their preparation conditions. In the PEDOT:PSS-coated CNTs, the PEDOT:PSS particles fill up the voids between tubes in CNTs, forming a conduction bridge for electron transfer and eventually decreasing the sheet resistance of the hybrid electrode. Also, the hybrid electrode reveals a superior color property compared with that of CNTs or the PEDOT:PSS single electrode due to the complementary color relation between CNTs and PEDOT:PSS. Experimental results show that the fabricated hybrid-type electrodes can simultaneously satisfy the requirements necessary for transparent electrodes of touch screen panels such as the sheet resistance requiring to be lower than 100 Ω/sq, visible transmittance higher than 80%, and yellowness approaching to zero. - Highlights: • Hybrid-type (PEDOT:PSS-coated CNTs) electrodes for touch panels are fabricated. • PEDOT:PSS films are coated via spin-coating on spray-deposited CNTs. • Hybrid electrodes are fabricated by varying the thickness of CNTs and PEDOT:PSS. • The resistance, transmittance, and color properties have been analyzed. • Hybrid electrodes satisfy electrical and optical properties for touch panels.

  1. Sheet resistance, transmittance, and chromatic property of CNTs coated with PEDOT:PSS films for transparent electrodes of touch screen panels

    International Nuclear Information System (INIS)

    Kim, Bu-Jong; Han, Sang-Hoon; Park, Jin-Seok

    2014-01-01

    This study demonstrates hybrid-type transparent electrodes based on carbon nanotubes (CNTs) that possess characteristics desirable for touch screen panels. This has been accomplished by depositing CNTs via spray-coating and then depositing thin conductive polymer (such as PEDOT:PSS) films on the CNTs via spin-coating. For all of the samples such as CNTs, PEDOT:PSS, and hybrid (i.e., PEDOT:PSS-coated CNTs), their surface morphologies, sheet resistances, visible transmittances, and chromatic properties are characterized as functions of their preparation conditions. In the PEDOT:PSS-coated CNTs, the PEDOT:PSS particles fill up the voids between tubes in CNTs, forming a conduction bridge for electron transfer and eventually decreasing the sheet resistance of the hybrid electrode. Also, the hybrid electrode reveals a superior color property compared with that of CNTs or the PEDOT:PSS single electrode due to the complementary color relation between CNTs and PEDOT:PSS. Experimental results show that the fabricated hybrid-type electrodes can simultaneously satisfy the requirements necessary for transparent electrodes of touch screen panels such as the sheet resistance requiring to be lower than 100 Ω/sq, visible transmittance higher than 80%, and yellowness approaching to zero. - Highlights: • Hybrid-type (PEDOT:PSS-coated CNTs) electrodes for touch panels are fabricated. • PEDOT:PSS films are coated via spin-coating on spray-deposited CNTs. • Hybrid electrodes are fabricated by varying the thickness of CNTs and PEDOT:PSS. • The resistance, transmittance, and color properties have been analyzed. • Hybrid electrodes satisfy electrical and optical properties for touch panels

  2. Spin injection and spin accumulation in all-metal mesoscopic spin valves

    NARCIS (Netherlands)

    Jedema, FJ; Nijboer, MS; Filip, AT; van Wees, BJ

    2003-01-01

    We study the electrical injection and detection of spin accumulation in lateral ferromagnetic-metal-nonmagnetic-metal-ferromagnetic-metal (F/N/F) spin valve devices with transparent interfaces. Different ferromagnetic metals, Permalloy (Py), cobalt (Co), and nickel (Ni), are used as electrical spin

  3. The susceptibilities in the spin-S Ising model

    International Nuclear Information System (INIS)

    Ainane, A.; Saber, M.

    1995-08-01

    The susceptibilities of the spin-S Ising model are evaluated using the effective field theory introduced by Tucker et al. for studying general spin-S Ising model. The susceptibilities are studied for all spin values from S = 1/2 to S = 5/2. (author). 12 refs, 4 figs

  4. Control of electron spin decoherence in nuclear spin baths

    Science.gov (United States)

    Liu, Ren-Bao

    2011-03-01

    Nuclear spin baths are a main mechanism of decoherence of spin qubits in solid-state systems, such as quantum dots and nitrogen-vacancy (NV) centers of diamond. The decoherence results from entanglement between the electron and nuclear spins, established by quantum evolution of the bath conditioned on the electron spin state. When the electron spin is flipped, the conditional bath evolution is manipulated. Such manipulation of bath through control of the electron spin not only leads to preservation of the center spin coherence but also demonstrates quantum nature of the bath. In an NV center system, the electron spin effectively interacts with hundreds of 13 C nuclear spins. Under repeated flip control (dynamical decoupling), the electron spin coherence can be preserved for a long time (> 1 ms) . Thereforesomecharacteristicoscillations , duetocouplingtoabonded 13 C nuclear spin pair (a dimer), are imprinted on the electron spin coherence profile, which are very sensitive to the position and orientation of the dimer. With such finger-print oscillations, a dimer can be uniquely identified. Thus, we propose magnetometry with single-nucleus sensitivity and atomic resolution, using NV center spin coherence to identify single molecules. Through the center spin coherence, we could also explore the many-body physics in an interacting spin bath. The information of elementary excitations and many-body correlations can be extracted from the center spin coherence under many-pulse dynamical decoupling control. Another application of the preserved spin coherence is identifying quantumness of a spin bath through the back-action of the electron spin to the bath. We show that the multiple transition of an NV center in a nuclear spin bath can have longer coherence time than the single transition does, when the classical noises due to inhomogeneous broadening is removed by spin echo. This counter-intuitive result unambiguously demonstrates the quantumness of the nuclear spin bath

  5. Magnetocaloric effect in quantum spin-s chains

    Directory of Open Access Journals (Sweden)

    A. Honecker

    2009-01-01

    Full Text Available We compute the entropy of antiferromagnetic quantum spin-s chains in an external magnetic field using exact diagonalization and Quantum Monte Carlo simulations. The magnetocaloric effect, i. e., temperature variations during adiabatic field changes, can be derived from the isentropes. First, we focus on the example of the spin-s=1 chain and show that one can cool by closing the Haldane gap with a magnetic field. We then move to quantum spin-s chains and demonstrate linear scaling with s close to the saturation field. In passing, we propose a new method to compute many low-lying excited states using the Lanczos recursion.

  6. Graphene spin diode: Strain-modulated spin rectification

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yunhua; Wang, B., E-mail: stslyl@mail.sysu.edu.cn, E-mail: wangbiao@mail.sysu.edu.cn [Sino-French Institute of Nuclear Engineering and Technology, School of Physics and Engineering, State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275 (China); Liu, Yulan, E-mail: stslyl@mail.sysu.edu.cn, E-mail: wangbiao@mail.sysu.edu.cn [School of Engineering, Sun Yat-sen University, Guangzhou 510275 (China)

    2014-08-04

    Strain effects on spin transport in a ferromagnetic/strained/normal graphene junction are explored theoretically. It is shown that the spin-resolved Fermi energy range can be controlled by the armchair direction strain because the strain-induced pseudomagnetic field suppresses the current. The spin rectification effect for the bias reversal occurs because of a combination of ferromagnetic exchange splitting and the broken spatial symmetry of the junction. In addition, the spin rectification performance can be tuned remarkably by manipulation of the strains. In view of this strain-modulated spin rectification effect, we propose that the graphene-based ferromagnetic/strained/normal junction can be used as a tunable spin diode.

  7. Spin Torques in Systems with Spin Filtering and Spin Orbit Interaction

    KAUST Repository

    Ortiz Pauyac, Christian

    2016-01-01

    filtering. In Chap. 3 we discuss the Rashba torque in ferromagnetic films, and in Chap. 4 we study spin Hall effect and spin swapping in ferromagnetic films, exploring the nature of spin-orbit torques based on these mechanisms. Conclusions and perspectives

  8. Drones, quasi-spin or iso-spin. A comparison of many-body techniques for general spin

    International Nuclear Information System (INIS)

    McKenzie, B.J.; Stedman, G.E.

    1976-01-01

    For an effective-spin system with 2S + 1 levels there are a number of possible mappings of spin onto pseudo-fermion operators. The relative merits of three of these methods are investigated by calculating to second order the dispersion relation for coupled spin-phonon modes in crystals containing S = 1 effective spin impurities. It is found that the drone formalism quickly becomes intractable at higher spin values, as does the related quasi-spin formalism developed in contrast with the iso-spin (or Abrinkosov projection) formalism. (author)

  9. Spin-current emission governed by nonlinear spin dynamics.

    Science.gov (United States)

    Tashiro, Takaharu; Matsuura, Saki; Nomura, Akiyo; Watanabe, Shun; Kang, Keehoon; Sirringhaus, Henning; Ando, Kazuya

    2015-10-16

    Coupling between conduction electrons and localized magnetization is responsible for a variety of phenomena in spintronic devices. This coupling enables to generate spin currents from dynamical magnetization. Due to the nonlinearity of magnetization dynamics, the spin-current emission through the dynamical spin-exchange coupling offers a route for nonlinear generation of spin currents. Here, we demonstrate spin-current emission governed by nonlinear magnetization dynamics in a metal/magnetic insulator bilayer. The spin-current emission from the magnetic insulator is probed by the inverse spin Hall effect, which demonstrates nontrivial temperature and excitation power dependences of the voltage generation. The experimental results reveal that nonlinear magnetization dynamics and enhanced spin-current emission due to magnon scatterings are triggered by decreasing temperature. This result illustrates the crucial role of the nonlinear magnon interactions in the spin-current emission driven by dynamical magnetization, or nonequilibrium magnons, from magnetic insulators.

  10. Spin Funneling for Enhanced Spin Injection into Ferromagnets

    Science.gov (United States)

    Sayed, Shehrin; Diep, Vinh Q.; Camsari, Kerem Yunus; Datta, Supriyo

    2016-07-01

    It is well-established that high spin-orbit coupling (SOC) materials convert a charge current density into a spin current density which can be used to switch a magnet efficiently and there is increasing interest in identifying materials with large spin Hall angle for lower switching current. Using experimentally benchmarked models, we show that composite structures can be designed using existing spin Hall materials such that the effective spin Hall angle is larger by an order of magnitude. The basic idea is to funnel spins from a large area of spin Hall material into a small area of ferromagnet using a normal metal with large spin diffusion length and low resistivity like Cu or Al. We show that this approach is increasingly effective as magnets get smaller. We avoid unwanted charge current shunting by the low resistive NM layer utilizing the newly discovered phenomenon of pure spin conduction in ferromagnetic insulators via magnon diffusion. We provide a spin circuit model for magnon diffusion in FMI that is benchmarked against recent experiments and theory.

  11. Spin nematics next to spin singlets

    Science.gov (United States)

    Yokoyama, Yuto; Hotta, Chisa

    2018-05-01

    We provide a route to generate nematic order in a spin-1/2 system. Unlike the well-known magnon-binding mechanism, our spin nematics requires neither the frustration effect nor spin polarization in a high field or in the vicinity of a ferromagnet, but instead appears next to the spin singlet phase. We start from a state consisting of a quantum spin-1/2 singlet dimer placed on each site of a triangular lattice, and show that interdimer ring exchange interactions efficiently dope the SU(2) triplets that itinerate and interact, easily driving a stable singlet state to either Bose-Einstein condensates or a triplet crystal, some hosting a spin nematic order. A variety of roles the ring exchange serves includes the generation of a bilinear-biquadratic interaction between nearby triplets, which is responsible for the emergent nematic order separated from the singlet phase by a first-order transition.

  12. Preparation of Ag/SiO{sub 2} near-infrared absorbers using the combination of sputtering and spin-coating depositions

    Energy Technology Data Exchange (ETDEWEB)

    Liau, Leo Chau-Kuang, E-mail: lckliau@saturn.yzu.edu.tw [Department of Chemical Engineering and Materials Science, Yuan Ze University, Chung-Li 320, Taiwan (China); Lai, Guo-Bin [Department of Chemical Engineering and Materials Science, Yuan Ze University, Chung-Li 320, Taiwan (China); Juang, Rei-Cheng; Chang, Bing-Hung [Green Energy and Environmental Laboratories, Industrial Technology Research Institute, Hsinchu 300, Taiwan (China); Yang, Thomas Chun-Kuang [Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei 106, Taiwan (China)

    2015-03-02

    This study presents the design and fabrication of near-infrared (NIR) absorbers constructed in multilayer structures using Ag and SiO{sub 2} materials. The absorbers, consisting of Ag and SiO{sub 2} films, were fabricated using sputtering and spin-coating approaches, respectively. The fabricated absorbing devices were evaluated using ultraviolet–visible-NIR spectra. Results revealed that the structure of the Ag/SiO{sub 2}/Ag films exhibited an NIR absorbing effect. The absorbing properties were substantially influenced by the fabrication parameters and the thickness of the multilayer films. Furthermore, the NIR absorbing performance improved significantly when the SiO{sub 2} layer was annealed at 300 °C before the deposition of the top Ag film. Additionally, the absorptance of the absorbers was affected by the thickness of the top Ag layer. The long-term stability of the multilayer absorber was tested and verified based on absorptance data analysis. The NIR absorbing performance can be further improved using the optimal device design of the film thickness and by fabricating additional Ag/SiO{sub 2} layers. - Highlights: • Ag/SiO{sub 2} near-infrared absorbers were designed and fabricated. • The absorbing performance was greatly influenced by the fabrication schemes. • The optimal fabrication process of the absorber was obtained. • The long-term stability of the absorber was verified.

  13. Non magnetic neutron spin quantum precession using multilayer spin splitter and a phase-spin echo interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Ebisawa, T.; Tasaki, S.; Kawai, T.; Akiyoshi, T. [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst.; Achiwa, N.; Hino, M.; Otake, Y.; Funahashi, H.

    1996-08-01

    The authors have developed cold neutron optics and interferometry using multilayer mirrors. The advantages of the multilayer mirrors are their applicability to long wavelength neutrons and a great variety of the mirror performance. The idea of the present spin interferometry is based on nonmagnetic neutron spin quantum precession using multilayer spin splitters. The equation for polarized neutrons means that the polarized neutrons are equivalent to the coherent superposition of two parallel spin eigenstates. The structure and principle of a multilayer spin splitter are explained, and the nonmagnetic gap layer of the multilayer spin splitter gives rise to neutron spin quantum precession. The performance test of the multilayer spin splitter were made with a new spin interferometer, which is analogous optically to a spin echo system with vertical precession field. The spin interferometers were installed at Kyoto University research reactor and the JRR-3. The testing method and the results are reported. The performance tests on a new phase-spin echo interferometer are described, and its applications to the development of a high resolution spin echo system and a Jamin type cold neutron interferometer are proposed. (K.I.)

  14. Super-Hydrophobic/Icephobic Coatings Based on Silica Nanoparticles Modified by Self-Assembled Monolayers

    Directory of Open Access Journals (Sweden)

    Junpeng Liu

    2016-12-01

    Full Text Available A super-hydrophobic surface has been obtained from nanocomposite materials based on silica nanoparticles and self-assembled monolayers of 1H,1H,2H,2H-perfluorooctyltriethoxysilane (POTS using spin coating and chemical vapor deposition methods. Scanning electron microscope images reveal the porous structure of the silica nanoparticles, which can trap small-scale air pockets. An average water contact angle of 163° and bouncing off of incoming water droplets suggest that a super-hydrophobic surface has been obtained based on the silica nanoparticles and POTS coating. The monitored water droplet icing test results show that icing is significantly delayed by silica-based nano-coatings compared with bare substrates and commercial icephobic products. Ice adhesion test results show that the ice adhesion strength is reduced remarkably by silica-based nano-coatings. The bouncing phenomenon of water droplets, the icing delay performance and the lower ice adhesion strength suggest that the super-hydrophobic coatings based on a combination of silica and POTS also show icephobicity. An erosion test rig based on pressurized pneumatic water impinging impact was used to evaluate the durability of the super-hydrophobic/icephobic coatings. The results show that durable coatings have been obtained, although improvement will be needed in future work aiming for applications in aerospace.

  15. Using Spin-Coated Silver Nanoparticles/Zinc Oxide Thin Films to Improve the Efficiency of GaInP/(InGaAs/Ge Solar Cells

    Directory of Open Access Journals (Sweden)

    Po-Hsun Lei

    2018-06-01

    Full Text Available We synthesized a silver nanoparticle/zinc oxide (Ag NP/ZnO thin film by using spin-coating technology. The treatment solution for Ag NP/ZnO thin film deposition contained zinc acetate (Zn(CH3COO2, sodium hydroxide (NaOH, and silver nitrate (AgNO3 aqueous solutions. The crystalline characteristics, surface morphology, content of elements, and reflectivity of the Ag NPs/ZnO thin film at various concentrations of the AgNO3 aqueous solution were investigated using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, atomic force microscopy, and ultraviolet–visible–near infrared spectrophotometry. The results indicated that the crystalline structure, Ag content, and reflectance of Ag NP/ZnO thin films depended on the AgNO3 concentration. Hybrid antireflection coatings (ARCs composed of SiNx and Ag NPs/ZnO thin films with various AgNO3 concentrations were deposited on GaInP/(InGaAs/Ge solar cells. We propose that the optimal ARC consists of SiNx and Ag NP/ZnO thin films prepared using a treatment solution of 0.0008 M AgNO3, 0.007 M Zn(CH3COO2, and 1 M NaOH, followed by post-annealing at 200 °C. GaInP/(AlGaAs/Ge solar cells with the optimal hybrid ARC and SiNx ARC exhibit a conversion efficiency of 34.1% and 30.2% with Voc = 2.39 and 2.4 V, Jsc = 16.63 and 15.37 mA/cm2, and fill factor = 86.1% and 78.8%.

  16. Spin current through quantum-dot spin valves

    International Nuclear Information System (INIS)

    Wang, J; Xing, D Y

    2006-01-01

    We report a theoretical study of the influence of the Coulomb interaction on the equilibrium spin current in a quantum-dot spin valve, in which the quantum dot described by the Anderson impurity model is coupled to two ferromagnetic leads with noncollinear magnetizations. In the Kondo regime, electrons transmit through the quantum dot via higher-order virtual processes, in which the spin of either lead electrons or a localized electron on the quantum dot may reverse. It is found that the magnitude of the spin current decreases with increasing Coulomb interactions due to spin flip effects on the dot. However, the spatial direction of the spin current remains unchanged; it is determined only by the exchange coupling between two noncollinear magnetizations

  17. Back interface effect on the topography and magnetism relationship studied from Ni nano-coatings: role of ITO and Cu substrates

    International Nuclear Information System (INIS)

    Ebothé, Jean; Nzoghe-Mendome, Lény; Khamis Aloufy, Affaf

    2015-01-01

    A comparative study is here reported on the role of ITO and Cu substrates in the surface growth, topography and the magnetism of mesoscopic scale thick nanocrystallized Ni electrocoatings in the thickness interval 60 < d < 1200 nm. The cathodic voltammetry (C-V) technique used for the coating formation engenders conglomerated grain patterns with ITO and spaced needle-like features with Cu. These surface configurations are particularly marked with the thinnest samples. They undergo a noticeable smoothing with the coating thickness increase. The magnetic reversal (MR) of the Ni samples on Cu is ruled by the spin rotation mechanism. A transition from the domain wall (DW) motion mechanism to the spin rotation one occurs with ITO while the d value increases. The study of the topography-magnetism relationship reveals that the spin rotation mechanism of the Ni samples is incoherent with both substrates. The co-existence of the Bloch magnetic domains (MD) B and the Néel domain wall (DW) N types is identified for ITO in the thinner (rougher) Ni samples associated with the DW motion MR. The same sequence occurs for Cu for the thicker (smoother) samples linked to the spin rotation MR, as long as their normalized roughness values are confined below σ o ′ ≈ 0.15. (paper)

  18. Compound nucleus effects in spin-spin cross sections

    International Nuclear Information System (INIS)

    Thompson, W.J.

    1976-01-01

    By comparison with recent data, it is shown that spin-spin cross sections for low-energy neutrons may be dominated by a simple compound-elastic level-density effect, independent of spin-spin terms in the nucleon-nucleus optical-model potential. (Auth.)

  19. Ultra-low fouling and high antibody loading zwitterionic hydrogel coatings for sensing and detection in complex media.

    Science.gov (United States)

    Chou, Ying-Nien; Sun, Fang; Hung, Hsiang-Chieh; Jain, Priyesh; Sinclair, Andrew; Zhang, Peng; Bai, Tao; Chang, Yung; Wen, Ten-Chin; Yu, Qiuming; Jiang, Shaoyi

    2016-08-01

    For surface-based diagnostic devices to achieve reliable biomarker detection in complex media such as blood, preventing nonspecific protein adsorption and incorporating high loading of biorecognition elements are paramount. In this work, a novel method to produce nonfouling zwitterionic hydrogel coatings was developed to achieve these goals. Poly(carboxybetaine acrylamide) (pCBAA) hydrogel thin films (CBHTFs) prepared with a carboxybetaine diacrylamide crosslinker (CBAAX) were coated on gold and silicon dioxide surfaces via a simple spin coating process. The thickness of CBHTFs could be precisely controlled between 15 and 150nm by varying the crosslinker concentration, and the films demonstrated excellent long-term stability. Protein adsorption from undiluted human blood serum onto the CBHTFs was measured with surface plasmon resonance (SPR). Hydrogel thin films greater than 20nm exhibited ultra-low fouling (crosslinked, purely zwitterionic, carboxybetaine thin film hydrogel (CBHTF) coating platform. The CBHTF on a hydrophilic surface demonstrated long-term stability. By varying the crosslinker content in the spin-coated hydrogel solution, the thickness of CBHTFs could be precisely controlled. Optimized CBHTFs exhibited ultra-low nonspecific protein adsorption below 5ng/cm(2) measured by a surface plasmon resonance (SPR) sensor, and their 3D architecture allowed antibody loading to reach 693ng/cm(2). This strategy provides a facile method to modify SPR biosensor chips with an advanced nonfouling material, and can be potentially expanded to a variety of implantable medical devices and diagnostic biosensors. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  20. Atlas de aves: Un metodo para documentar distribucion y seguir poblaciones

    Science.gov (United States)

    Robbins, C.S.; Dowell, B.A.; Dawson, D.K.; Alvarez-Lopez, Humberto; Kattan, Gustavo; Murcia, Carolina

    1988-01-01

    Los Atlas de Aves son proyectos nacionales o regionalies para trazar en mapas la distribucion en reproduccion de cada especie de ave. Ese procedimiento se esta usando en Europa, Australia, Nueva Zelanda, Norteamerica, y partes de Africa. El tama?o de los cuadrados varia de medio grado de latitud y Iongitud hasta 5 x 5 km. El trabajo de campo de cada proyecto exige aproxlmadamente cinco a?os, pero los aficionados pueden llevar a cabo la mayor parte del trabajo. Es posible almacenar los resultados en un computador personal. Hay muchos beneficios: (I) se presenta la distribucion corriente de las aves de la nacion, del estado, o de la Iocalidad; (2) se desarrolla nueva informacion especialmente sobre especies raras o en peligro; (3) se descubren areas que tienen una avlfauna sobresaliente o habitats raros y ayuda a su proteccion, (4) se documentan cambios de dlstribucion; (5) se pueden usar para documentar cambios de poblacion, especialmente en los tropicos donde otros metodos son mas dificiles de usar porque hay muchas especies y no hay muchos observadores calificados en la identificacion de sonidos de las aves; (6) son proyectos buenos de investigacion para estudiantes graduados; (7) los turistas y los jefes de excursiones de historia natural pueden contribuir con muchas informaciones

  1. Optical spin generation/detection and spin transport lifetimes

    International Nuclear Information System (INIS)

    Miah, M. Idrish

    2011-01-01

    We generate electron spins in semiconductors by optical pumping. The detection of them is also performed by optical technique using time-resolved pump-probe photoluminescence polarization measurements in the presence of an external magnetic field perpendicular to the generated spin. The spin polarization in dependences of the pulse length, pump-probe delay and external magnetic field is studied. From the dependence of spin-polarization on the delay of the probe, the electronic spin transport lifetimes and the spin relaxation frequencies as a function of the strength of the magnetic field are estimated. The results are discussed based on hyperfine effects for interacting electrons.

  2. Optical spin generation/detection and spin transport lifetimes

    Energy Technology Data Exchange (ETDEWEB)

    Miah, M. Idrish, E-mail: m.miah@griffith.edu.au [Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh)

    2011-02-25

    We generate electron spins in semiconductors by optical pumping. The detection of them is also performed by optical technique using time-resolved pump-probe photoluminescence polarization measurements in the presence of an external magnetic field perpendicular to the generated spin. The spin polarization in dependences of the pulse length, pump-probe delay and external magnetic field is studied. From the dependence of spin-polarization on the delay of the probe, the electronic spin transport lifetimes and the spin relaxation frequencies as a function of the strength of the magnetic field are estimated. The results are discussed based on hyperfine effects for interacting electrons.

  3. The Optical Properties of Thin Film Reduced Graphene Oxide/Poly (3,4 Ethylenedioxtriophene):Poly (Styrene Sulfonate)(PEDOT:PSS) Fabricated by Spin Coating

    Science.gov (United States)

    Rokmana, Arinta W.; Asriani, A.; Suhendar, H.; Triyana, K.; Kusumaatmaja, A.; Santoso, I.

    2018-04-01

    Reduced Graphene Oxide (rGO) has been successfully synthesized from Graphite powder through chemical process using modified Hummers method by removing NaNO3 from reaction formula. Hydrazine hydrate 80 wt% has been chosen as reductor to eliminate the epoxy group in GO. FTIR and Uv-Vis spectroscopy result showed that Graphene Oxide (GO) and rGO were formed. Our produced rGO then used to fabricated the composite thin film rGO/PEDOT:PSS by spin coating at room temperature. The optical constant of thin film rGO/PEDOT:PSS were calculated from the absorbance spectrum of Uv-Visible spectra. The result showed that the value of coefficient absorbance of rGO dropped from 4.7×106 m-1 to 1.3×106 m-1 after doped with 0.02 mL PEDOT:PSS, then increase with the addition volume concentration of PEDOT:PSS. The value of extinction coefficient decrease from 0.31 to 0.08 after rGO doped with 0.02 ml PEDOT:PSS and then increase with the addition concentration of PEDOT:PSS. Our result show that thin film rGO/PEDOT:PSS was more transparent than that of thin film rGO.

  4. Angular dependence of spin-orbit spin-transfer torques

    KAUST Repository

    Lee, Ki-Seung

    2015-04-06

    In ferromagnet/heavy-metal bilayers, an in-plane current gives rise to spin-orbit spin-transfer torque, which is usually decomposed into fieldlike and dampinglike torques. For two-dimensional free-electron and tight-binding models with Rashba spin-orbit coupling, the fieldlike torque acquires nontrivial dependence on the magnetization direction when the Rashba spin-orbit coupling becomes comparable to the exchange interaction. This nontrivial angular dependence of the fieldlike torque is related to the Fermi surface distortion, determined by the ratio of the Rashba spin-orbit coupling to the exchange interaction. On the other hand, the dampinglike torque acquires nontrivial angular dependence when the Rashba spin-orbit coupling is comparable to or stronger than the exchange interaction. It is related to the combined effects of the Fermi surface distortion and the Fermi sea contribution. The angular dependence is consistent with experimental observations and can be important to understand magnetization dynamics induced by spin-orbit spin-transfer torques.

  5. Angular dependence of spin-orbit spin-transfer torques

    KAUST Repository

    Lee, Ki-Seung; Go, Dongwook; Manchon, Aurelien; Haney, Paul M.; Stiles, M. D.; Lee, Hyun-Woo; Lee, Kyung-Jin

    2015-01-01

    In ferromagnet/heavy-metal bilayers, an in-plane current gives rise to spin-orbit spin-transfer torque, which is usually decomposed into fieldlike and dampinglike torques. For two-dimensional free-electron and tight-binding models with Rashba spin-orbit coupling, the fieldlike torque acquires nontrivial dependence on the magnetization direction when the Rashba spin-orbit coupling becomes comparable to the exchange interaction. This nontrivial angular dependence of the fieldlike torque is related to the Fermi surface distortion, determined by the ratio of the Rashba spin-orbit coupling to the exchange interaction. On the other hand, the dampinglike torque acquires nontrivial angular dependence when the Rashba spin-orbit coupling is comparable to or stronger than the exchange interaction. It is related to the combined effects of the Fermi surface distortion and the Fermi sea contribution. The angular dependence is consistent with experimental observations and can be important to understand magnetization dynamics induced by spin-orbit spin-transfer torques.

  6. Tribological behavior of polytetrafluoroethylene coating reinforced with black phosphorus nanoparticles

    Science.gov (United States)

    Peng, Shiguang; Guo, Yue; Xie, Guoxin; Luo, Jianbin

    2018-05-01

    This study compares the tribological performance of polytetrafluoroethylene (PTFE) thin film coating reinforced with black phosphorus (BP) or ball-milled graphite (BMG) nanoparticles, so as to elucidate their mechanism of action under reciprocating sliding test conditions. PTFE coatings with 0.5 wt.% BMG (BMG/PTFE) and 0.5 wt.% BP (BP/PTFE) were prepared on GCr15 bearing steel disk by using a spin coater. The friction and wear tests were carried out by using the ball-on-disk tribometer under a normal load of 1 N (contact pressure: 780 MPa), a frequency of 2 Hz, and 4.2 mm sliding displacement amplitude. The surface roughness, wear volume and surface morphology of the coatings were characterized by the three-dimensional white light, and Energy Dispersive X-ray Detector (EDX) analysis coupled with environmental scanning electron microscope (ESEM). It is found that BP/PTFE coating has better anti-wear and anti-friction performances than those of pure PTFE or BMG/PTFE coating. The coating with BP nanoparticles shows excellent tribological properties with the wear volume decreased from 3.52 × 106 μm3 to 1.64 × 106 μm3 and the coefficient of friction (COF) decreased from 0.117 to 0.046. More importantly, the BP layer probably expands and absorbs much energy due to its negative Poisson's ratio phenomenon under reciprocating sliding, and effectively reducing furrow and adhesive wear.

  7. Microscopic studies of nonlocal spin dynamics and spin transport (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Adur, Rohan; Du, Chunhui; Cardellino, Jeremy; Scozzaro, Nicolas; Wolfe, Christopher S.; Wang, Hailong; Herman, Michael; Bhallamudi, Vidya P.; Pelekhov, Denis V.; Yang, Fengyuan; Hammel, P. Chris, E-mail: hammel@physics.osu.edu [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States)

    2015-05-07

    Understanding the behavior of spins coupling across interfaces in the study of spin current generation and transport is a fundamental challenge that is important for spintronics applications. The transfer of spin angular momentum from a ferromagnet into an adjacent normal material as a consequence of the precession of the magnetization of the ferromagnet is a process known as spin pumping. We find that, in certain circumstances, the insertion of an intervening normal metal can enhance spin pumping between an excited ferromagnetic magnetization and a normal metal layer as a consequence of improved spin conductance matching. We have studied this using inverse spin Hall effect and enhanced damping measurements. Scanned probe magnetic resonance techniques are a complementary tool in this context offering high resolution magnetic resonance imaging, localized spin excitation, and direct measurement of spin lifetimes or damping. Localized magnetic resonance studies of size-dependent spin dynamics in the absence of lithographic confinement in both ferromagnets and paramagnets reveal the close relationship between spin transport and spin lifetime at microscopic length scales. Finally, detection of ferromagnetic resonance of a ferromagnetic film using the photoluminescence of nitrogen vacancy spins in neighboring nanodiamonds demonstrates long-range spin transport between insulating materials, indicating the complexity and generality of spin transport in diverse, spatially separated, material systems.

  8. Microscopic studies of nonlocal spin dynamics and spin transport (invited)

    Science.gov (United States)

    Adur, Rohan; Du, Chunhui; Cardellino, Jeremy; Scozzaro, Nicolas; Wolfe, Christopher S.; Wang, Hailong; Herman, Michael; Bhallamudi, Vidya P.; Pelekhov, Denis V.; Yang, Fengyuan; Hammel, P. Chris

    2015-05-01

    Understanding the behavior of spins coupling across interfaces in the study of spin current generation and transport is a fundamental challenge that is important for spintronics applications. The transfer of spin angular momentum from a ferromagnet into an adjacent normal material as a consequence of the precession of the magnetization of the ferromagnet is a process known as spin pumping. We find that, in certain circumstances, the insertion of an intervening normal metal can enhance spin pumping between an excited ferromagnetic magnetization and a normal metal layer as a consequence of improved spin conductance matching. We have studied this using inverse spin Hall effect and enhanced damping measurements. Scanned probe magnetic resonance techniques are a complementary tool in this context offering high resolution magnetic resonance imaging, localized spin excitation, and direct measurement of spin lifetimes or damping. Localized magnetic resonance studies of size-dependent spin dynamics in the absence of lithographic confinement in both ferromagnets and paramagnets reveal the close relationship between spin transport and spin lifetime at microscopic length scales. Finally, detection of ferromagnetic resonance of a ferromagnetic film using the photoluminescence of nitrogen vacancy spins in neighboring nanodiamonds demonstrates long-range spin transport between insulating materials, indicating the complexity and generality of spin transport in diverse, spatially separated, material systems.

  9. Microscopic studies of nonlocal spin dynamics and spin transport (invited)

    International Nuclear Information System (INIS)

    Adur, Rohan; Du, Chunhui; Cardellino, Jeremy; Scozzaro, Nicolas; Wolfe, Christopher S.; Wang, Hailong; Herman, Michael; Bhallamudi, Vidya P.; Pelekhov, Denis V.; Yang, Fengyuan; Hammel, P. Chris

    2015-01-01

    Understanding the behavior of spins coupling across interfaces in the study of spin current generation and transport is a fundamental challenge that is important for spintronics applications. The transfer of spin angular momentum from a ferromagnet into an adjacent normal material as a consequence of the precession of the magnetization of the ferromagnet is a process known as spin pumping. We find that, in certain circumstances, the insertion of an intervening normal metal can enhance spin pumping between an excited ferromagnetic magnetization and a normal metal layer as a consequence of improved spin conductance matching. We have studied this using inverse spin Hall effect and enhanced damping measurements. Scanned probe magnetic resonance techniques are a complementary tool in this context offering high resolution magnetic resonance imaging, localized spin excitation, and direct measurement of spin lifetimes or damping. Localized magnetic resonance studies of size-dependent spin dynamics in the absence of lithographic confinement in both ferromagnets and paramagnets reveal the close relationship between spin transport and spin lifetime at microscopic length scales. Finally, detection of ferromagnetic resonance of a ferromagnetic film using the photoluminescence of nitrogen vacancy spins in neighboring nanodiamonds demonstrates long-range spin transport between insulating materials, indicating the complexity and generality of spin transport in diverse, spatially separated, material systems

  10. Roll-coating fabrication of flexible large area small molecule solar cells with power conversion efficiency exceeding 1%

    DEFF Research Database (Denmark)

    Liu, Wenqing; Liu, Shiyong; Zawacka, Natalia Klaudia

    2014-01-01

    All solution-processed flexible large area small molecule bulk heterojunction solar cells were fabricated via roll-coating technology. Our devices were produced from slot-die coating on a lab-scale mini roll-coater under ambient conditions without the use of spin-coating or vacuum evaporation.......01%, combined with an open circuit voltage of 0.73 V, a short-circuit current density of 3.13 mA cm (2) and a fill factor of 44% were obtained for the device with SM1, which was the first example reported for efficient roll-coating fabrication of flexible large area small molecule solar cells with PCE exceeding...... methods. Four diketopyrrolopyrrole based small molecules (SMs 1-4) were utilized as electron donors with (6,6)phenyl- C61-butyric acid methyl ester as an acceptor and their photovoltaic performances based on roll-coated devices were investigated. The best power conversion efficiency (PCE) of 1...

  11. Noise in tunneling spin current across coupled quantum spin chains

    Science.gov (United States)

    Aftergood, Joshua; Takei, So

    2018-01-01

    We theoretically study the spin current and its dc noise generated between two spin-1 /2 spin chains weakly coupled at a single site in the presence of an over-population of spin excitations and a temperature elevation in one subsystem relative to the other, and we compare the corresponding transport quantities across two weakly coupled magnetic insulators hosting magnons. In the spin chain scenario, we find that applying a temperature bias exclusively leads to a vanishing spin current and a concomitant divergence in the spin Fano factor, defined as the spin current noise-to-signal ratio. This divergence is shown to have an exact analogy to the physics of electron scattering between fractional quantum Hall edge states and not to arise in the magnon scenario. We also reveal a suppression in the spin current noise that exclusively arises in the spin chain scenario due to the fermion nature of the spin-1/2 operators. We discuss how the spin Fano factor may be extracted experimentally via the inverse spin Hall effect used extensively in spintronics.

  12. Optical and environmentally protective coatings for potassium dihydrogen phosphate (KDP) harmonic converter crystals

    International Nuclear Information System (INIS)

    Thomas, I.M.

    1991-01-01

    Potassium dihydrogen phosphate (KDP) crystals have been used as harmonic converters on the Nova laser at LLNL for over six years. All crystals were coated with a single layer, quarterwave AR coating of porous silica with a refractive index of 1.22. This was prepared by a sol-gel process and was applied from a colloidal suspension by spin coating at room temperature. A few crystals were also coated with a methyl silicone coating prior to the application of the AR coating for environmental protection. The initial optical performance of all crystals was very good but there has been some deterioration over the years because of environmental and laser damage degradation. The deterioration in the silicone samples was, however, much less than the others. We are now in the process of replacing all ten KDP arrays with new crystals and will apply the silicone undercoat to all samples. Recently we have been evaluating a new perfluorinated organic polymer coating which has a refractive index of 1.29. This material is soluble in fluorinated solvents and can be applied by dip coating from solution at room temperature. We hope that this can provide environmental protection when applied to KDP and also act as an AR coating at the same time. The optical performance is not as good as our porous silica because of the higher index; about 0.3% reflection per surface is obtained. 4 refs., 10 figs., 1 tab

  13. When measured spin polarization is not spin polarization

    International Nuclear Information System (INIS)

    Dowben, P A; Wu Ning; Binek, Christian

    2011-01-01

    Spin polarization is an unusually ambiguous scientific idiom and, as such, is rarely well defined. A given experimental methodology may allow one to quantify a spin polarization but only in its particular context. As one might expect, these ambiguities sometimes give rise to inappropriate interpretations when comparing the spin polarizations determined through different methods. The spin polarization of CrO 2 and Cr 2 O 3 illustrate some of the complications which hinders comparisons of spin polarization values. (viewpoint)

  14. Magnetic Nanostructures Spin Dynamics and Spin Transport

    CERN Document Server

    Farle, Michael

    2013-01-01

    Nanomagnetism and spintronics is a rapidly expanding and increasingly important field of research with many applications already on the market and many more to be expected in the near future. This field started in the mid-1980s with the discovery of the GMR effect, recently awarded with the Nobel prize to Albert Fert and Peter Grünberg. The present volume covers the most important and most timely aspects of magnetic heterostructures, including spin torque effects, spin injection, spin transport, spin fluctuations, proximity effects, and electrical control of spin valves. The chapters are written by internationally recognized experts in their respective fields and provide an overview of the latest status.

  15. Spin Relaxation and Manipulation in Spin-orbit Qubits

    Science.gov (United States)

    Borhani, Massoud; Hu, Xuedong

    2012-02-01

    We derive a generalized form of the Electric Dipole Spin Resonance (EDSR) Hamiltonian in the presence of the spin-orbit interaction for single spins in an elliptic quantum dot (QD) subject to an arbitrary (in both direction and magnitude) applied magnetic field. We predict a nonlinear behavior of the Rabi frequency as a function of the magnetic field for sufficiently large Zeeman energies, and present a microscopic expression for the anisotropic electron g-tensor. Similarly, an EDSR Hamiltonian is devised for two spins confined in a double quantum dot (DQD). Finally, we calculate two-electron-spin relaxation rates due to phonon emission, for both in-plane and perpendicular magnetic fields. Our results have immediate applications to current EDSR experiments on nanowire QDs, g-factor optimization of confined carriers, and spin decay measurements in DQD spin-orbit qubits.

  16. Nonlinear spin current generation in noncentrosymmetric spin-orbit coupled systems

    Science.gov (United States)

    Hamamoto, Keita; Ezawa, Motohiko; Kim, Kun Woo; Morimoto, Takahiro; Nagaosa, Naoto

    2017-06-01

    Spin current plays a central role in spintronics. In particular, finding more efficient ways to generate spin current has been an important issue and has been studied actively. For example, representative methods of spin-current generation include spin-polarized current injections from ferromagnetic metals, the spin Hall effect, and the spin battery. Here, we theoretically propose a mechanism of spin-current generation based on nonlinear phenomena. By using Boltzmann transport theory, we show that a simple application of the electric field E induces spin current proportional to E2 in noncentrosymmetric spin-orbit coupled systems. We demonstrate that the nonlinear spin current of the proposed mechanism is supported in the surface state of three-dimensional topological insulators and two-dimensional semiconductors with the Rashba and/or Dresselhaus interaction. In the latter case, the angular dependence of the nonlinear spin current can be manipulated by the direction of the electric field and by the ratio of the Rashba and Dresselhaus interactions. We find that the magnitude of the spin current largely exceeds those in the previous methods for a reasonable magnitude of the electric field. Furthermore, we show that application of ac electric fields (e.g., terahertz light) leads to the rectifying effect of the spin current, where dc spin current is generated. These findings will pave a route to manipulate the spin current in noncentrosymmetric crystals.

  17. Application of sol gel spin coated yttria-stabilized zirconia layers for the improvement of solid oxide fuel cell electrolytes produced by atmospheric plasma spraying

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Lars [University of British Columbia, Department of Materials Engineering, 309-6350 Stores Road, Vancouver, British Columbia, V6T 1Z4 (Canada); National Research Council, Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, British Columbia, V6T 1W5 (Canada); Kesler, Olivera [National Research Council, Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, British Columbia, V6T 1W5 (Canada); University of British Columbia, Department of Mechanical Engineering, 2054-6250 Applied Science Lane, Vancouver, British Columbia, V6T 1Z4 (Canada); Tang, Zhaolin; Burgess, Alan [Northwest Mettech Corp., 467 Mountain Hwy, North Vancouver, British Columbia, V7J 2L3 (Canada)

    2007-05-15

    Due to its high thermal stability and purely oxide ionic conductivity, yttria-stabilized zirconia (YSZ) is the most commonly used electrolyte material for solid oxide fuel cells (SOFCs). Standard electrolyte fabrication techniques for planar SOFCs involve wet ceramic techniques such as tape-casting or screen printing, requiring sintering steps at temperatures above 1300 C. Plasma spraying (PS) may provide a more rapid and cost efficient method to produce SOFCs without sintering. High-temperature sintering requires long processing times and can lead to oxidation of metal alloys used as mechanical supports, or to detrimental interreactions between the electrolyte and adjacent electrode layers. This study investigates the use of spin coated sol gel derived YSZ precursor solutions to fill the pores present in plasma sprayed YSZ layers, and to enhance the surface area for reaction at the electrolyte-cathode interface, without the use of high-temperature firing steps. The effects of different plasma conditions and sol concentrations and solid loadings on the gas permeability and fuel cell performance have been investigated. (author)

  18. Spin temperature concept verified by optical magnetometry of nuclear spins

    Science.gov (United States)

    Vladimirova, M.; Cronenberger, S.; Scalbert, D.; Ryzhov, I. I.; Zapasskii, V. S.; Kozlov, G. G.; Lemaître, A.; Kavokin, K. V.

    2018-01-01

    We develop a method of nonperturbative optical control over adiabatic remagnetization of the nuclear spin system and apply it to verify the spin temperature concept in GaAs microcavities. The nuclear spin system is shown to exactly follow the predictions of the spin temperature theory, despite the quadrupole interaction that was earlier reported to disrupt nuclear spin thermalization. These findings open a way for the deep cooling of nuclear spins in semiconductor structures, with the prospect of realizing nuclear spin-ordered states for high-fidelity spin-photon interfaces.

  19. Spin-Mechatronics

    Science.gov (United States)

    Matsuo, Mamoru; Saitoh, Eiji; Maekawa, Sadamichi

    2017-01-01

    We investigate the interconversion phenomena between spin and mechanical angular momentum in moving objects. In particular, the recent results on spin manipulation and spin-current generation by mechanical motion are examined. In accelerating systems, spin-dependent gauge fields emerge, which enable the conversion from mechanical angular momentum into spins. Such a spin-mechanical effect is predicted by quantum theory in a non-inertial frame. Experiments which confirm the effect, i.e., the resonance frequency shift in nuclear magnetic resonance, the stray field measurement of rotating metals, and electric voltage generation in liquid metals, are discussed.

  20. Electron spin and nuclear spin manipulation in semiconductor nanosystems

    International Nuclear Information System (INIS)

    Hirayama, Yoshiro; Yusa, Go; Sasaki, Satoshi

    2006-01-01

    Manipulations of electron spin and nuclear spin have been studied in AlGaAs/GaAs semiconductor nanosystems. Non-local manipulation of electron spins has been realized by using the correlation effect between localized and mobile electron spins in a quantum dot- quantum wire coupled system. Interaction between electron and nuclear spins was exploited to achieve a coherent control of nuclear spins in a semiconductor point contact device. Using this device, we have demonstrated a fully coherent manipulation of any two states among the four spin levels of Ga and As nuclei. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Bulk electron spin polarization generated by the spin Hall current

    OpenAIRE

    Korenev, V. L.

    2005-01-01

    It is shown that the spin Hall current generates a non-equilibrium spin polarization in the interior of crystals with reduced symmetry in a way that is drastically different from the previously well-known equilibrium polarization during the spin relaxation process. The steady state spin polarization value does not depend on the strength of spin-orbit interaction offering possibility to generate relatively high spin polarization even in the case of weak spin-orbit coupling.

  2. Bulk electron spin polarization generated by the spin Hall current

    Science.gov (United States)

    Korenev, V. L.

    2006-07-01

    It is shown that the spin Hall current generates a nonequilibrium spin polarization in the interior of crystals with reduced symmetry in a way that is drastically different from the previously well-known “equilibrium” polarization during the spin relaxation process. The steady state spin polarization value does not depend on the strength of spin-orbit interaction offering possibility to generate relatively high spin polarization even in the case of weak spin-orbit coupling.

  3. A poly(dimethylsiloxane)-coated flexible mold for nanoimprint lithography

    International Nuclear Information System (INIS)

    Lee, Nae Yoon; Kim, Youn Sang

    2007-01-01

    In this paper, we introduce an anti-adhesion poly(dimethylsiloxane) (PDMS)-coated flexible mold and its applications for room-temperature imprint lithography. The flexible mold is fabricated using an ultraviolet-curable prepolymer on a flexible substrate, and its surface is passivated with a thin layer of PDMS to impart an anti-adhesion property. The highly flexible mold enables conformal contact with a substrate on which a low-viscosity polymer resist is spin-cast in a thin layer. Large-area imprinting is then realized at room temperature under significantly reduced pressure. The mold was durable even after repetitive imprinting of over 200 times. Also, we show a double imprinting on the substrate with a PDMS-coated replica polymeric mold having 500 nm line patterns. This enables the formation of matrix patterns with varying feature heights in less than 7 min

  4. Determination of the Pt spin diffusion length by spin-pumping and spin Hall effect

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wei; Pearson, John E.; Hoffmann, Axel [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Vlaminck, Vincent [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Colegio de Ciencias e Ingenería, Universidad San Fransciso de Quito, Quito (Ecuador); Divan, Ralu [Center for Nanoscale Materials, Argonne National Laboratory, Illinois 60439 (United States); Bader, Samuel D. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Center for Nanoscale Materials, Argonne National Laboratory, Illinois 60439 (United States)

    2013-12-09

    The spin diffusion length of Pt at room temperature and at 8 K is experimentally determined via spin pumping and spin Hall effect in permalloy/Pt bilayers. Voltages generated during excitation of ferromagnetic resonance from the inverse spin Hall effect and anisotropic magnetoresistance effect were investigated with a broadband approach. Varying the Pt layer thickness gives rise to an evolution of the voltage line shape due to the superposition of the above two effects. By studying the ratio of the two voltage components with the Pt layer thickness, the spin diffusion length of Pt can be directly extracted. We obtain a spin diffusion length of ∼1.2 nm at room temperature and ∼1.6 nm at 8 K.

  5. Homogeneous PCBM layers fabricated by horizontal-dip coating for efficient bilayer heterojunction organic photovoltaic cells.

    Science.gov (United States)

    Huh, Yoon Ho; Bae, In-Gon; Jeon, Hong Goo; Park, Byoungchoo

    2016-10-31

    We herein report a homogeneous [6,6]-phenyl C61 butyric acid methyl ester (PCBM) layer, produced by a solution process of horizontal-dipping (H-dipping) to improve the photovoltaic (PV) effects of bilayer heterojunction organic photovoltaic cells (OPVs) based on a bi-stacked poly(3-hexylthiophene) (P3HT) electron donor layer and a PCBM electron acceptor layer (P3HT/PCBM). It was shown that a homogeneous and uniform coating of PCBM layers in the P3HT/PCBM bilayer OPVs resulted in reliable and reproducible device performance. We recorded a power conversion efficiency (PCE) of 2.89%, which is higher than that (2.00%) of bilayer OPVs with a spin-coated PCBM layer. Moreover, introducing surfactant additives of poly(oxyethylene tridecyl ether) (PTE) into the homogeneous P3HT/PCBM PV layers resulted in the bilayer OPVs showing a PCE value of 3.95%, which is comparable to those of conventional bulk-heterojunction (BHJ) OPVs (3.57-4.13%) fabricated by conventional spin-coating. This improved device performance may be attributed to the selective collection of charge carriers at the interfaces among the active layers and electrodes due to the PTE additives as well as the homogeneous formation of the functional PCBM layer on the P3HT layer. Furthermore, H-dip-coated PCBM layers were deposited onto aligned P3HT layers by a rubbing technique, and the rubbed bilayer OPV exhibited improved in-plane anisotropic PV effects with PCE anisotropy as high as 1.81, which is also higher than that (1.54) of conventional rubbed BHJ OPVs. Our results suggest that the use of the H-dip-coating process in the fabrication of PCBM layers with the PTE interface-engineering additive could be of considerable interest to those seeking to improve PCBM-based opto-electrical organic thin-film devices.

  6. Structural, magnetic and optical properties of Y bFe2O4 films deposited by spin coating

    Directory of Open Access Journals (Sweden)

    Tatsuo Fujii

    2016-08-01

    Full Text Available Rare-earth iron oxides (RFe2O4 have attracting attention as new electronic device materials because of their numerous functionalities, such as electronic ferroelectricity, ferrimagnetism, and high infrared absorption. In this paper, nearly monophasic Y bFe2O4 films were prepared on α-Al2O3(001 substrates by the spin coating method using an aqueous-based Y bFe2O4 solution. The solution was composed of a stoichiometric ratio of Y b(CH3COO3 and Fe(NO33 with excess chelating agents. After heat treatment above 800 °C, well-crystallized and highly (001-oriented Y bFe2O4 started to epitaxially form on the substrate under controlled oxygen partial pressure with H2/CO2 gas mixtures. X-ray pole figure analysis confirmed the following epitaxial relationship: Y bFe2O4[100](001//α-Al2O3[100](001. Moreover formation of an Fe3O4 interracial layer between Y bFe2O4 and α-Al2O3 was detected by high-resolution transmission electron microscopy. Presence of the Fe3O4 interracial layer seemed to release the lattice misfit with the substrate. The Fe2+/Fe3+ ratio in the obtained Y bFe2O4 films was nearly stoichiometric and the indirect bandgap assigned to Fe2+ → Fe3+ charge transfer excitation was found to be ∼0.4 eV by optical spectroscopy. A clear magnetic transition from the paramagnetic state to the ferrimagnetic state occurred at ∼230 K.

  7. Photovoltaic performance of dye-sensitized solar cells with various MWCNT counter electrode structures produced by different coating methods

    International Nuclear Information System (INIS)

    Munkhbayar, B.; Hwang, Seunghwa; Kim, Junhyo; Bae, Kangyoul; Ji, Myoungkuk; Chung, Hanshik; Jeong, Hyomin

    2012-01-01

    Highlights: ► Catalyst on tube surface was removed and the tube caps were opened by purification. ► Highest peak of UV-light absorption was achieved in the purified and ground MWCNTs solution. ► The particles uniformly distributed on glass substrate by spin coating method. ► Highest photoelectric efficiency of DSSCs with MWCNTs counter electrode was achieved 4.94%. - Abstract: We report the successful application of multi-walled carbon nanotubes (MWCNTs) as electrocatalysts for triiodide reduction in dye-sensitized solar cells (DSSCs). To improve the photovoltaic performance of DSSCs, upgrade the quality of MWCNT structure and obtain an optimum deposition approach regarding a counter electrode, the present study was investigated. Three different MWCNT structures, raw, purified and purified and ground, were investigated as platinum (Pt) alternatives for counter electrodes in DSSCs. The counter electrodes were prepared on fluorine-doped tin oxide (FTO) glass substrates by two different techniques: spin coating from fluid-type MWCNTs and screen printing from paste-type MWCNTs. By utilizing a spin-coating technique, a DSSC that was fabricated with a purified and ground MWCNT counter electrode achieved an overall photovoltaic efficiency of 4.94%. This photovoltaic performance is comparable to that of a DSSC using a conventional “Pt” counter electrode fabricated under the same conditions. We found that the grinding method is powerful for increasing specific surface area and porosity. With this technique, macropores can be transformed into mesopores, thereby reducing the agglomeration of the MWCNTs, and with an additional modification, an increased DSSC photovoltaic efficiency results.

  8. Enhanced protective properties and UV stability of epoxy/graphene nanocomposite coating on stainless steel

    Directory of Open Access Journals (Sweden)

    H. Alhumade

    2016-12-01

    Full Text Available Epoxy-Graphene (E/G nanocomposites with different loading of graphene were prepared via in situ prepolymerization and evaluated as protective coating for Stainless Steel 304 (SS304. The prepolymer composites were spin coated on SS304 substrates and thermally cured. Transmission Electron Microscopy (TEM and Scanning Electron Microscopy (SEM were utilized to examine the dispersion of graphene in the epoxy matrix. Epoxy and E/G nanocomposites were characterized using X-ray diffraction (XRD and Fourier Transform Infrared (FTIR techniques and the thermal behavior of the prepared coatings is analyzed using Thermogravimetric analysis (TGA and Differential scanning calorimetry (DSC. The corrosion protection properties of the prepared coatings were evaluated using Electrochemical Impedance Spectroscopy (EIS and Cyclic Voltammetry (CV measurements. In addition to corrosion mitigation properties, the long-term adhesion performance of the coatings was evaluated by measuring the adhesion of the coatings to the SS304 substrate after 60 days of exposure to 3.5 wt% NaCl medium. The effects of graphene loading on the impact resistance, flexibility, and UV stability of the coating are analyzed and discussed. SEM was utilized to evaluate post adhesion and UV stability results. The results indicate that very low graphene loading up to 0.5 wt % significantly enhances the corrosion protection, UV stability, and impact resistance of epoxy coatings.

  9. Muon spin relaxation measurements of spin-correlation decay in spin-glass AgMn

    Energy Technology Data Exchange (ETDEWEB)

    Heffner, R.H.; Cooke, D.W.; Leon, M.; Schillaci, M.E. (Los Alamos National Lab., NM (USA)); MacLaughlin, D.E.; Gupta, L.C. (California Univ., Riverside (USA))

    1984-01-01

    The field (H) dependence of the muon longitudinal spin-lattice relaxation rate well below the spin glass temperature in AgMn is found to obey an algebraic form given by (H)sup(..gamma..-1), with ..gamma.. = 0.54 +- 0.05. This suggests that Mn spin correlations decay with time as tsup(-..gamma..), in agreement with mean field theories of spin-glass dynamics which yield ..gamma..

  10. Hybrid coating on a magnesium alloy for minimizing the localized degradation for load-bearing biodegradable mini-implant applications

    Energy Technology Data Exchange (ETDEWEB)

    Kannan, M. Bobby, E-mail: bobby.mathan@jcu.edu.au; Liyanaarachchi, S.

    2013-10-01

    The effect of a hybrid coating, calcium phosphate (CaP) + polylactic acid (PLA), on a magnesium alloy on its in vitro degradation (general and localized) behaviour was studied for potential load-bearing biodegradable mini-implant applications. CaP was coated on a magnesium alloy, AZ91, using an electrochemical deposition method. A spin coating method was used to coat PLA on the CaP coated alloy. In vitro degradation performance of the alloy with hybrid coating was evaluated using electrochemical impedance spectroscopy (EIS) in simulated body fluid (SBF). The EIS results showed that the hybrid coating enhanced the degradation resistance of the alloy by more than two-order of magnitude as compared to the bare alloy and one-order of magnitude higher than that of the CaP coated alloy, after 1 h exposure in simulated body fluid (SBF). Long-term (48 h) EIS results also confirmed that the hybrid coating performed better than the bare alloy and the CaP coated alloy. Importantly, the hybrid coating improved the localized degradation resistance of the alloy significantly, which is critical for better in service mechanical integrity. - Highlights: • A hybrid coating (CaP + PLA) was applied on a magnesium-based alloy. • The hybrid coating enhanced the in vitro degradation resistance of the alloy. • Localized degradation resistance was also improved by the hybrid coating.

  11. Hybrid coating on a magnesium alloy for minimizing the localized degradation for load-bearing biodegradable mini-implant applications

    International Nuclear Information System (INIS)

    Kannan, M. Bobby; Liyanaarachchi, S.

    2013-01-01

    The effect of a hybrid coating, calcium phosphate (CaP) + polylactic acid (PLA), on a magnesium alloy on its in vitro degradation (general and localized) behaviour was studied for potential load-bearing biodegradable mini-implant applications. CaP was coated on a magnesium alloy, AZ91, using an electrochemical deposition method. A spin coating method was used to coat PLA on the CaP coated alloy. In vitro degradation performance of the alloy with hybrid coating was evaluated using electrochemical impedance spectroscopy (EIS) in simulated body fluid (SBF). The EIS results showed that the hybrid coating enhanced the degradation resistance of the alloy by more than two-order of magnitude as compared to the bare alloy and one-order of magnitude higher than that of the CaP coated alloy, after 1 h exposure in simulated body fluid (SBF). Long-term (48 h) EIS results also confirmed that the hybrid coating performed better than the bare alloy and the CaP coated alloy. Importantly, the hybrid coating improved the localized degradation resistance of the alloy significantly, which is critical for better in service mechanical integrity. - Highlights: • A hybrid coating (CaP + PLA) was applied on a magnesium-based alloy. • The hybrid coating enhanced the in vitro degradation resistance of the alloy. • Localized degradation resistance was also improved by the hybrid coating

  12. Spin manipulation and relaxation in spin-orbit qubits

    Science.gov (United States)

    Borhani, Massoud; Hu, Xuedong

    2012-03-01

    We derive a generalized form of the electric dipole spin resonance (EDSR) Hamiltonian in the presence of the spin-orbit interaction for single spins in an elliptic quantum dot (QD) subject to an arbitrary (in both direction and magnitude) applied magnetic field. We predict a nonlinear behavior of the Rabi frequency as a function of the magnetic field for sufficiently large Zeeman energies, and present a microscopic expression for the anisotropic electron g tensor. Similarly, an EDSR Hamiltonian is devised for two spins confined in a double quantum dot (DQD), where coherent Rabi oscillations between the singlet and triplet states are induced by jittering the inter-dot distance at the resonance frequency. Finally, we calculate two-electron-spin relaxation rates due to phonon emission, for both in-plane and perpendicular magnetic fields. Our results have immediate applications to current EDSR experiments on nanowire QDs, g-factor optimization of confined carriers, and spin decay measurements in DQD spin-orbit qubits.

  13. A reverse method to estimate initial temperatures in geothermal reservoirs; Un metodo inverso para estimacion de la temperatura inicial de yacimientos geotermicos

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Gutierrez, Alfonso [Instituto de Investigaciones Electricas, Gerencia de Geotermia, Cuernavaca, Morelos (Mexico)]. E-mail: aggarcia@iie.org.mx; Ramos Alcantara, Jose R. [Centro Nacional de Investigacion y Desarrollo Tecnologico, Departamento de Ingenieria Mecanica, Cuernavaca, Morelos (Mexico); Arellano Gomez, Victor M. [Instituto de Investigaciones Electricas, Gerencia de Geotermia, Cuernavaca, Morelos (Mexico)

    2010-01-15

    A method is presented for estimating the initial temperature in geothermal-reservoir formations. The method is based on control theory where the measured temperatures or temperature logs are compared with corresponding simulated temperatures for different times with the well closed. The comparison is made using a control algorithm that makes changes to the originally assumed reservoir temperatures and performs iterations until the best fit between the temperature logs and the simulated temperatures is obtained. The simulation of fluid transport and heat in the well includes the processes of circulation and stop in the presence of circulation losses, modeled on macroscopic balances of momentum and energy. The transport processes in the formation regard the reservoir as an isotropic porous medium and fluid flow is described by Darcy's law. This model generates the fields of temperatures, pressures and speeds as a function of time and space. The method was tested with data from well LV-3 in Las Tres Virgenes geothermal field, Baja California Sur, Mexico. The estimated temperatures of the undisturbed formation-or initial temperatures-are compared within {+-}15 degrees Celsius with the measured temperatures, which is an acceptable outcome from an engineering point of view. [Spanish] Se presenta un metodo para la estimacion de la temperatura inicial en las formaciones de yacimientos geotermicos. El metodo se basa en la teoria de control donde las temperaturas medidas o registros de temperatura se comparan con las correspondientes temperaturas simuladas a diferentes tiempos con el pozo cerrado. La comparacion se hace usando un algoritmo de control el cual hace cambios a las temperaturas de yacimiento originalmente supuestas y realiza iteraciones hasta que se obtiene el mejor ajuste entre los registros de temperatura y las temperaturas simuladas. La simulacion del transporte de fluidos y calor en el pozo incluye los procesos de circulacion y paro en presencia de

  14. Spin transfer torque with spin diffusion in magnetic tunnel junctions

    KAUST Repository

    Manchon, Aurelien

    2012-08-09

    Spin transport in magnetic tunnel junctions in the presence of spin diffusion is considered theoretically. Combining ballistic tunneling across the barrier and diffusive transport in the electrodes, we solve the spin dynamics equation in the metallic layers. We show that spin diffusion mixes the transverse spin current components and dramatically modifies the bias dependence of the effective spin transfer torque. This leads to a significant linear bias dependence of the out-of-plane torque, as well as a nonconventional thickness dependence of both spin torque components.

  15. Muon spin relaxation measurements of spin-correlation decay in spin-glass AgMn

    International Nuclear Information System (INIS)

    Heffner, R.H.; Cooke, D.W.; Leon, M.; Schillaci, M.E.; MacLaughlin, D.E.; Gupta, L.C.

    1984-01-01

    The field (H) dependence of the muon longitudinal spin-lattice relaxation rate well below the spin glass temperature in AgMn is found to obey an algebraic form given by (H)sup(γ-1), with γ = 0.54 +- 0.05. This suggests that Mn spin correlations decay with time as tsup(-γ), in agreement with mean field theories of spin-glass dynamics which yield γ < approx. 0.5. Near the glass temperature the agreement between the data and theory is not as good. (Auth.)

  16. Engineered Protein Coatings to Improve the Osseointegration of Dental and Orthopaedic Implants

    Science.gov (United States)

    Raphel, Jordan; Karlsson, Johan; Galli, Silvia; Wennerberg, Ann; Lindsay, Christopher; Haugh, Matthew; Pajarinen, Jukka; Goodman, Stuart B.; Jimbo, Ryo; Andersson, Martin; Heilshorn, Sarah C.

    2016-01-01

    Here we present the design of an engineered, elastin-like protein (ELP) that is chemically modified to enable stable coatings on the surfaces of titanium-based dental and orthopaedic implants by novel photocrosslinking and solution processing steps. The ELP includes an extended RGD sequence to confer bio-signaling and an elastin-like sequence for mechanical stability. ELP thin films were fabricated on cp-Ti and Ti6Al4V surfaces using scalable spin and dip coating processes with photoactive covalent crosslinking through a carbene insertion mechanism. The coatings withstood procedures mimicking dental screw and hip replacement stem implantations, a key metric for clinical translation. They promoted rapid adhesion of MG63 osteoblast-like cells, with over 80% adhesion after 24 hours, compared to 38% adhesion on uncoated Ti6Al4V. MG63 cells produced significantly more mineralization on ELP coatings compared to uncoated Ti6Al4V. Human bone marrow mesenchymal stem cells (hMSCs) had an earlier increase in alkaline phosphatase activity, indicating more rapid osteogenic differentiation and mineral deposition on adhesive ELP coatings. Rat tibia and femur in vivo studies demonstrated that cell-adhesive ELP-coated implants increased bone-implant contact area and interfacial strength after one week. These results suggest that ELP coatings withstand surgical implantation and promote rapid osseointegration, enabling earlier implant loading and potentially preventing micromotion that leads to aseptic loosening and premature implant failure. PMID:26790146

  17. Spin-orbit mediated control of spin qubits

    DEFF Research Database (Denmark)

    Flindt, Christian; Sørensen, A.S; Flensberg, Karsten

    2006-01-01

    We propose to use the spin-orbit interaction as a means to control electron spins in quantum dots, enabling both single-qubit and two-qubit operations. Very fast single-qubit operations may be achieved by temporarily displacing the electrons. For two-qubit operations the coupling mechanism is bas...... on a combination of the spin-orbit coupling and the mutual long-ranged Coulomb interaction. Compared to existing schemes using the exchange coupling, the spin-orbit induced coupling is less sensitive to random electrical fluctuations in the electrodes defining the quantum dots....

  18. Spinning particle approach to higher spin field theory

    International Nuclear Information System (INIS)

    Corradini, Olindo

    2011-01-01

    We shortly review on the connection between higher-spin gauge field theories and supersymmetric spinning particle models. In such approach the higher spin equations of motion are linked to the first-class constraint algebra associated with the quantization of particle models. Here we consider a class of spinning particle models characterized by local O(N)-extended supersymmetry since these models are known to provide an alternative approach to the geometric formulation of higher spin field theory. We describe the canonical quantization of the models in curved target space and discuss the obstructions that appear in presence of an arbitrarily curved background. We then point out the special role that conformally flat spaces appear to have in such models and present a derivation of the higher-spin curvatures for maximally symmetric spaces.

  19. Shot noise of spin current and spin transfer torque

    Science.gov (United States)

    Yu, Yunjin; Zhan, Hongxin; Wan, Langhui; Wang, Bin; Wei, Yadong; Sun, Qingfeng; Wang, Jian

    2013-04-01

    We report the theoretical investigation of the shot noise of the spin current (Sσ) and the spin transfer torque (Sτ) for non-collinear spin polarized transport in a spin-valve device which consists of a normal scattering region connected by two ferromagnetic electrodes (MNM system). Our theory was developed using the non-equilibrium Green’s function method, and general nonlinear Sσ - V and Sτ - V relations were derived as a function of the angle θ between the magnetizations of two leads. We have applied our theory to a quantum dot system with a resonant level coupled with two ferromagnetic electrodes. It was found that, for the MNM system, the auto-correlation of the spin current is enough to characterize the fluctuation of the spin current. For a system with three ferromagnetic layers, however, both auto-correlation and cross-correlation of the spin current are needed to characterize the noise of the spin current. For a quantum dot with a resonant level, the derivative of spin torque with respect to bias voltage is proportional to sinθ when the system is far away from resonance. When the system is near resonance, the spin transfer torque becomes a non-sinusoidal function of θ. The derivative of the noise of the spin transfer torque with respect to the bias voltage Nτ behaves differently when the system is near or far away from resonance. Specifically, the differential shot noise of the spin transfer torque Nτ is a concave function of θ near resonance while it becomes a convex function of θ far away from resonance. For certain bias voltages, the period Nτ(θ) becomes π instead of 2π. For small θ, it was found that the differential shot noise of the spin transfer torque is very sensitive to the bias voltage and the other system parameters.

  20. Controlled protein adsorption on PMOXA/PAA based coatings by thermally induced immobilization

    Science.gov (United States)

    Mumtaz, Fatima; Chen, Chaoshi; Zhu, Haikun; Pan, Chao; Wang, Yanmei

    2018-05-01

    In this work, poly(2-methyl-2-oxazoline-random-glycidyl methacrylate) (PMOXA-r-GMA) and poly(acrylic acid)-block-poly(glycidyl methacrylate) (PAA-b-PGMA) copolymers were synthesized via cationic ring-opening polymerization (CROP) of 2-methyl-2-oxazoline (MOXA) and reversible addition-fragmentation chain transfer (RAFT) polymerization of acrylic acid (AA) followed by their random and block copolymerization with glycidyl methacrylate (GMA), respectively, and then characterized carefully. PMOXA/PAA based coatings were then prepared by simply spin coating the mixture of PMOXA-r-GMA and PAA-b-PGMA copolymer solutions onto silicon/glass substrates followed by annealing at 110 °C. The coatings were rigorously characterized by using X-ray photoelectron spectroscopy (XPS), the static water contact angle (WCA) test, ellipsometry and atomic force microscopy (AFM). The results demonstrated that the coating based mixed PMOXA/PAA brushes with desired surface composition could be attained by simply maintaining their percentage in the mixture of PMOXA-r-GMA and PAA-b-PGMA copolymer solutions. Finally, the switchable behavior of PMOXA/PAA based coatings toward bovine serum albumin (BSA) adsorption was investigated by fluorescein isothiocyanate-labelled BSA (FITC-BSA) assay and quartz crystal microbalance with dissipation monitoring (QCM-D), which indicated that the coating based mixed PMOXA/PAA brushes could control BSA adsorption/desorption from very low to high amount (>90% desorption) through adjusting the composition of PMOXA-r-GMA and PAA-b-PGMA solution used in preparing PMOXA/PAA based coatings upon pH and ionic strength change. Furthermore, PMOXA/PAA based coatings displayed efficient repeatability of reversible BSA adsorption/desorption cycles.

  1. Spin precession and spin Hall effect in monolayer graphene/Pt nanostructures

    Science.gov (United States)

    Savero Torres, W.; Sierra, J. F.; Benítez, L. A.; Bonell, F.; Costache, M. V.; Valenzuela, S. O.

    2017-12-01

    Spin Hall effects have surged as promising phenomena for spin logics operations without ferromagnets. However, the magnitude of the detected electric signals at room temperature in metallic systems has been so far underwhelming. Here, we demonstrate a two-order of magnitude enhancement of the signal in monolayer graphene/Pt devices when compared to their fully metallic counterparts. The enhancement stems in part from efficient spin injection and the large spin resistance of graphene but we also observe 100% spin absorption in Pt and find an unusually large effective spin Hall angle of up to 0.15. The large spin-to-charge conversion allows us to characterise spin precession in graphene under the presence of a magnetic field. Furthermore, by developing an analytical model based on the 1D diffusive spin-transport, we demonstrate that the effective spin-relaxation time in graphene can be accurately determined using the (inverse) spin Hall effect as a means of detection. This is a necessary step to gather full understanding of the consequences of spin absorption in spin Hall devices, which is known to suppress effective spin lifetimes in both metallic and graphene systems.

  2. Muon spin-relaxation measurements of spin-correlation decay in spin-glass AgMn

    International Nuclear Information System (INIS)

    Heffner, R.H.; Cooke, D.W.; Leon, M.; Schillaci, M.E.; MacLaughlin, D.E.; Gupta, L.C.

    1983-01-01

    The field (H) dependence of the muon longitudinal spin-lattice relaxation rate well below the spin-glass temperature in AgMn is found to obey an algebraic form given by (H)/sup nu-1/, with nu = 0.54 +- 0.05. This suggests that Mn spin correlations decay with time as t - /sup nu/, in agreement with mean field theories of spin-glass dynamics which yield nu less than or equal to 0.5. Near the glass temperature the agreement between the data and theory is not as good

  3. Spin-chirality decoupling in Heisenberg spin glasses and related systems

    OpenAIRE

    Kawamura, Hikaru

    2006-01-01

    Recent studies on the spin and the chirality orderings of the three-dimensional Heisenberg spin glass and related systems are reviewed with particular emphasis on the possible spin-chirality decoupling phenomena. Chirality scenario of real spin-glass transition and its experimental consequence on the ordering of Heisenberg-like spin glasses are discussed.

  4. Spin current

    CERN Document Server

    Valenzuela, Sergio O; Saitoh, Eiji; Kimura, Takashi

    2012-01-01

    In a new branch of physics and technology called spin-electronics or spintronics, the flow of electrical charge (usual current) as well as the flow of electron spin, the so-called 'spin current', are manipulated and controlled together. This book provides an introduction and guide to the new physics and application of spin current.

  5. Performance and durability tests of smart icephobic coatings to reduce ice adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Janjua, Zaid A.; Turnbull, Barbara [Faculty of Engineering, University of Nottingham (United Kingdom); Choy, Kwang-Leong; Pandis, Christos [Institute for Materials Discovery, University College London (UCL) (United Kingdom); Liu, Junpeng; Hou, Xianghui; Choi, Kwing-So [Faculty of Engineering, University of Nottingham (United Kingdom)

    2017-06-15

    Highlights: • Repeated ice adhesion and removal occurs on nanocoatings. • Icephobicity of nanocoatings reduces with each test cycle. • Adhesion strength linked to contact angle hysteresis in Gaussian fit. • Icephobicity not linked to hydrophobicity. - Abstract: The accretion of ice can cause damage in applications ranging from power lines and shipping decks, to wind turbines and rail infrastructure. In particular on aircraft, it can change aerodynamic characteristics, greatly affecting the flight safety. Commercial aircraft are therefore required to be equipped with de-icing devices, such as heating mats over the wings. The application of icephobic coatings near the leading edge of a wing can in theory reduce the high power requirements of heating mats, which melt ice that forms there. Such coatings are effective in preventing the accretion of runback ice, formed from airborne supercooled droplets, or the water that the heating mats generate as it is sheared back over the wing's upper surface. However, the durability and the practicality of applying them over a large wing surface have been prohibitive factors in deploying this technology so far. Here, we evaluated the ice adhesion strength of four non-conductive coatings and seven thermally conductive coatings by shearing ice samples from coated plates by spinning them in a centrifuge device. The durability of the coating performance was also assessed by repeating the tests, each time regrowing ice samples on the previously-used coatings. Contact angle parameters of each coating were tested for each test to determine influence on ice adhesion strength. The results indicate that contact angle hysteresis is a crucial parameter in determining icephobicity of a coating and hydrophobicity is not necessarily linked to icephobicity.

  6. Spin current

    CERN Document Server

    Valenzuela, Sergio O; Saitoh, Eiji; Kimura, Takashi

    2017-01-01

    Since the discovery of the giant magnetoresistance effect in magnetic multilayers in 1988, a new branch of physics and technology, called spin-electronics or spintronics, has emerged, where the flow of electrical charge as well as the flow of electron spin, the so-called “spin current,” are manipulated and controlled together. The physics of magnetism and the application of spin current have progressed in tandem with the nanofabrication technology of magnets and the engineering of interfaces and thin films. This book aims to provide an introduction and guide to the new physics and applications of spin current, with an emphasis on the interaction between spin and charge currents in magnetic nanostructures.

  7. Nuclear spin noise in the central spin model

    Science.gov (United States)

    Fröhling, Nina; Anders, Frithjof B.; Glazov, Mikhail

    2018-05-01

    We study theoretically the fluctuations of the nuclear spins in quantum dots employing the central spin model which accounts for the hyperfine interaction of the nuclei with the electron spin. These fluctuations are calculated both with an analytical approach using homogeneous hyperfine couplings (box model) and with a numerical simulation using a distribution of hyperfine coupling constants. The approaches are in good agreement. The box model serves as a benchmark with low computational cost that explains the basic features of the nuclear spin noise well. We also demonstrate that the nuclear spin noise spectra comprise a two-peak structure centered at the nuclear Zeeman frequency in high magnetic fields with the shape of the spectrum controlled by the distribution of the hyperfine constants. This allows for direct access to this distribution function through nuclear spin noise spectroscopy.

  8. Entanglement entropy in random quantum spin-S chains

    International Nuclear Information System (INIS)

    Saguia, A.; Boechat, B.; Continentino, M. A.; Sarandy, M. S.

    2007-01-01

    We discuss the scaling of entanglement entropy in the random singlet phase (RSP) of disordered quantum magnetic chains of general spin S. Through an analysis of the general structure of the RSP, we show that the entanglement entropy scales logarithmically with the size of a block, and we provide a closed expression for this scaling. This result is applicable for arbitrary quantum spin chains in the RSP, being dependent only on the magnitude S of the spin. Remarkably, the logarithmic scaling holds for the disordered chain even if the pure chain with no disorder does not exhibit conformal invariance, as is the case for Heisenberg integer-spin chains. Our conclusions are supported by explicit evaluations of the entanglement entropy for random spin-1 and spin-3/2 chains using an asymptotically exact real-space renormalization group approach

  9. Competing Spin Liquids and Hidden Spin-Nematic Order in Spin Ice with Frustrated Transverse Exchange

    Directory of Open Access Journals (Sweden)

    Mathieu Taillefumier

    2017-12-01

    Full Text Available Frustration in magnetic interactions can give rise to disordered ground states with subtle and beautiful properties. The spin ices Ho_{2}Ti_{2}O_{7} and Dy_{2}Ti_{2}O_{7} exemplify this phenomenon, displaying a classical spin-liquid state, with fractionalized magnetic-monopole excitations. Recently, there has been great interest in closely related “quantum spin-ice” materials, following the realization that anisotropic exchange interactions could convert spin ice into a massively entangled, quantum spin liquid, where magnetic monopoles become the charges of an emergent quantum electrodynamics. Here we show that even the simplest model of a quantum spin ice, the XXZ model on the pyrochlore lattice, can realize a still-richer scenario. Using a combination of classical Monte Carlo simulation, semiclassical molecular-dynamics simulation, and analytic field theory, we explore the properties of this model for frustrated transverse exchange. We find not one, but three competing forms of spin liquid, as well as a phase with hidden, spin-nematic order. We explore the experimental signatures of each of these different states, making explicit predictions for inelastic neutron scattering. These results show an intriguing similarity to experiments on a range of pyrochlore oxides.

  10. Validation of Hiriart equation to compute steam production by the lip pressure method; Validacion de la ecuacion de Hiriart para calculo de gasto de vapor por el metodo de presion de labio

    Energy Technology Data Exchange (ETDEWEB)

    Flores Armenta, Magaly [Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad, Morelia (Mexico)

    1996-09-01

    Mainly in new geothermal wells, it is necessary to evaluate the production in a very fast, simple and not expensive way, to know the convenience to install surface equipment, such as silencers and separators, to drive the steam to the commercial gathering system. In practice, one of the most known methods is the lip pressure one, which requires a simple set of installations. The objective of this paper is to validate the steam flow rate calculated by the lip pressure method, with respect to the ASME method. The ASME method is known for its accuracy, and is done by measuring the steam and liquid after a high pressure separator, by an orifice plate of known diameter and a triangular weir. Results of the validation show up the feasibility of application of the lip pressure method by using a simple adjustment equation. Percentage of mistake results less than 1%, without any notable influence of the production enthalpy. That equation to be applied in a general case, is as follows: Q{nu} =(20642)(F*P*D{sup 2}/{radical}h-2000). For the particular case of the Los Azufres geothermal field, the equation is: Q{nu}= 810*P*D{sup 2} [Espanol] En los pozos geotermicos, principalmente en los nuevos, es necesario evaluar su produccion de manera rapida, sencilla y economica, para determinar la conveniencia de instalar equipo superficial, como separadores, silenciadores, etc., que permita la integracion del vapor al sistema comercial de generacion electrica. Para fines practicos uno de los metodos mas conocidos es el de presion de labio, que solo requiere un arreglo sencillo de instalaciones superficiales. En este documento se validan y ajustan los calculos de produccion de vapor por ese metodo de presion de labio, con respecto a las mediciones exactas efectuadas con el metodo ASME. Este ultimo es reconocido internacionalmente por su precision, y se lleva a cabo separando la mezcla obtenida en superficie en un recipiente a presion para medir el vapor a traves de una placa de orificio

  11. Separating inverse spin Hall voltage and spin rectification voltage by inverting spin injection direction

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wenxu, E-mail: xwzhang@uestc.edu.cn; Peng, Bin; Han, Fangbin; Wang, Qiuru; Zhang, Wanli [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Soh, Wee Tee; Ong, Chong Kim [Center for Superconducting and Magnetic Materials, Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117551 (Singapore)

    2016-03-07

    We develop a method for universally resolving the important issue of separating the inverse spin Hall effect (ISHE) from the spin rectification effect (SRE) signal. This method is based on the consideration that the two effects depend on the spin injection direction: The ISHE is an odd function of the spin injection direction while the SRE is independent on it. Thus, the inversion of the spin injection direction changes the ISHE voltage signal, while the SRE voltage remains. It applies generally to analyzing the different voltage contributions without fitting them to special line shapes. This fast and simple method can be used in a wide frequency range and has the flexibility of sample preparation.

  12. Growth of uniform thin-walled carbon nanotubes with spin-coated Fe catalyst and the correlation between the pre-growth catalyst size and the nanotube diameter

    International Nuclear Information System (INIS)

    Seah, Choon-Ming; Chai, Siang-Piao; Ichikawa, Satoshi; Mohamed, Abdul Rahman

    2013-01-01

    Single-walled carbon nanotubes (CNTs) and double-walled CNTs with a selectivity of 93 % were obtained by means of the novel homemade iron catalysts which were spin coated on silicon wafer. The average diameters of the iron particles prepared from the colloidal solutions containing 30, 40, 50, 60, and 70 mmol/L of iron nitrate were 8.2, 5.1, 20.8, 32.2, and 34.7 nm, respectively, and growing thin-walled CNTs with the average diameters of 4.1, 2.2, 9.2, 11.1, and 18.1 nm, respectively. The diameters of the CNTs were correlated with the geometric sizes of the pre-growth catalyst particles. Thin-walled CNTs were found to have a catalyst mean diameter-to-CNT average diameter ratio of 2.31. Iron carbide was formed after the growth of CNTs, and it is believed that during the growth of CNTs, carbon source decomposed and deposited on the surface of catalyst, followed by the diffusion of surface carbon into the iron catalyst particles, resulting in carbon supersaturation state before the growth of CNTs.

  13. Quantum dynamics of nuclear spins and spin relaxation in organic semiconductors

    Science.gov (United States)

    Mkhitaryan, V. V.; Dobrovitski, V. V.

    2017-06-01

    We investigate the role of the nuclear-spin quantum dynamics in hyperfine-induced spin relaxation of hopping carriers in organic semiconductors. The fast-hopping regime, when the carrier spin does not rotate much between subsequent hops, is typical for organic semiconductors possessing long spin coherence times. We consider this regime and focus on a carrier random-walk diffusion in one dimension, where the effect of the nuclear-spin dynamics is expected to be the strongest. Exact numerical simulations of spin systems with up to 25 nuclear spins are performed using the Suzuki-Trotter decomposition of the evolution operator. Larger nuclear-spin systems are modeled utilizing the spin-coherent state P -representation approach developed earlier. We find that the nuclear-spin dynamics strongly influences the carrier spin relaxation at long times. If the random walk is restricted to a small area, it leads to the quenching of carrier spin polarization at a nonzero value at long times. If the random walk is unrestricted, the carrier spin polarization acquires a long-time tail, decaying as 1 /√{t } . Based on the numerical results, we devise a simple formula describing the effect quantitatively.

  14. Chaotic spin exchange: is the spin non-flip rate observable?

    International Nuclear Information System (INIS)

    Senba, Masayoshi

    1994-01-01

    If spin exchange is of the Poisson nature, that is, if the time distribution of collisions obeys an exponential distribution function and the collision process is random, the muon spin depolarization is determined only by the spin flip rate regardless of the spin non-flip rate. In this work, spin exchange is discussed in the case of chaotic spin exchange, where the distribution of collision time sequences, generated by a deterministic equation, is exponential but not random (deterministic chaos). Even though this process has the same time distribution as a Poisson process, the muon polarization is affected by the spin non-flip rate. Having an exponential time distribution function is not a sufficient condition for the non-observation of the spin non-flip rate and it is essential that the process is also random. (orig.)

  15. Vibration dependence of the tensor spin-spin and scalar spin-spin hyperfine interactions by precision measurement of hyperfine structures of 127I2 near 532 nm

    International Nuclear Information System (INIS)

    Hong Fenglei; Zhang Yun; Ishikawa, Jun; Onae, Atsushi; Matsumoto, Hirokazu

    2002-01-01

    Hyperfine structures of the R(87)33-0, R(145)37-0, and P(132)36-0 transitions of molecular iodine near 532 nm are measured by observing the heterodyne beat-note signal of two I 2 -stabilized lasers, whose frequencies are bridged by an optical frequency comb generator. The measured hyperfine splittings are fit to a four-term Hamiltonian, which includes the electric quadrupole, spin-rotation, tensor spin-spin, and scalar spin-spin interactions, with an accuracy of ∼720 Hz. High-accurate hyperfine constants are obtained from this fit. Vibration dependences of the tensor spin-spin and scalar spin-spin hyperfine constants are determined for molecular iodine, for the first time to our knowledge. The observed hyperfine transitions are good optical frequency references in the 532-nm region

  16. Shot noise of spin current and spin transfer torque

    International Nuclear Information System (INIS)

    Yu Yunjin; Zhan Hongxin; Wan Langhui; Wang Bin; Wei Yadong; Sun Qingfeng; Wang Jian

    2013-01-01

    We report the theoretical investigation of the shot noise of the spin current (S σ ) and the spin transfer torque (S τ ) for non-collinear spin polarized transport in a spin-valve device which consists of a normal scattering region connected by two ferromagnetic electrodes (MNM system). Our theory was developed using the non-equilibrium Green’s function method, and general nonlinear S σ − V and S τ − V relations were derived as a function of the angle θ between the magnetizations of two leads. We have applied our theory to a quantum dot system with a resonant level coupled with two ferromagnetic electrodes. It was found that, for the MNM system, the auto-correlation of the spin current is enough to characterize the fluctuation of the spin current. For a system with three ferromagnetic layers, however, both auto-correlation and cross-correlation of the spin current are needed to characterize the noise of the spin current. For a quantum dot with a resonant level, the derivative of spin torque with respect to bias voltage is proportional to sinθ when the system is far away from resonance. When the system is near resonance, the spin transfer torque becomes a non-sinusoidal function of θ. The derivative of the noise of the spin transfer torque with respect to the bias voltage N τ behaves differently when the system is near or far away from resonance. Specifically, the differential shot noise of the spin transfer torque N τ is a concave function of θ near resonance while it becomes a convex function of θ far away from resonance. For certain bias voltages, the period N τ (θ) becomes π instead of 2π. For small θ, it was found that the differential shot noise of the spin transfer torque is very sensitive to the bias voltage and the other system parameters. (paper)

  17. Effect of iron doping on structural and optical properties of TiO2 thin film by sol–gel routed spin coating technique

    Directory of Open Access Journals (Sweden)

    Stephen Lourduraj

    2017-08-01

    Full Text Available Thin films of iron (Fe-doped titanium dioxide (Fe:TiO2 were prepared by sol–gel spin coating technique and further calcined at 450∘C. The structural and optical properties of Fe-doped TiO2 thin films were investigated by X-ray diffraction (XRD, scanning electron microscopy (SEM, ultraviolet–visible spectroscopy (UV–vis and atomic force microscopic (AFM techniques. The XRD results confirm the nanostructured TiO2 thin films having crystalline nature with anatase phase. The characterization results show that the calcined thin films having high crystallinity and the effect of iron substitution lead to decreased crystallinity. The SEM investigations of Fe-doped TiO2 films also gave evidence that the films were continuous spherical shaped particles with a nanometric range of grain size and film was porous in nature. AFM analysis establishes that the uniformity of the TiO2 thin film with average roughness values. The optical measurements show that the films having high transparency in the visible region and the optical band gap energy of Fe-doped TiO2 film with iron (Fe decrease with increase in iron content. These important requirements for the Fe:TiO2 films are to be used as window layers in solar cells.

  18. Depolarization of neutron spin echo by magnetic fluid

    International Nuclear Information System (INIS)

    Achiwa, N.; Sirozu, G.; Nishioka, T.; Ebisawa, T.; Hino, M.; Tasaki, S.; Kawai, T.; Yamazaki, D.

    2001-01-01

    A new method to study the fluctuations of magnetization in magnetic fluids by measuring relations between the phase shift of Larmor precession and the visibility of the neutron spin echo caused by the change of flight path length is studied. Magnetic fluid in which fine particles of magnetite of about 10 nm diameters coated with oleic acid and suspended in water was used. Thickness of the sample was 2 mm. In the dynamics of magnetic fluids, Brownian motions of colloids and the thermal fluctuations of magnetization known as the superparamagnetism are dominant. Isolated ferromagnetic particles of the present size are superparamagnetic but they aggregate to form clusters in a weak magnetic field in the sample of 40% weight density. When neutrons pass the sample, spins process in the magnetic flux density of the clusters fluctuating in time and space. Consequently the Larmor precession phases become distributed and the quantization axes are fluctuated. The result is observed as a decrease of the visibility of the spin echo signals. The change of magnetic flux density in the magnetic fluid is measured from the change of echo visibility of the neutrons, vice versa. In the present experiment, echo was measured at q=0. It is observed that the phase shift changes as a quadratic function of the sample angle reflecting the change of the path length through the sample. Since the number of Larmor precession is proportional to the product of the magnetic field and the length of the flight path, mean flux density in the magnetic fluid is calculated from the phase shift. On the other hand, the decrease of the spin echo amplitude as the function of the sample angle reflects the time and space fluctuations of the flux density in the sample. If the direction of the magnetic flux density vector (quantization axis) changes slowly enough compared to the Larmor precession period while a neutron passes one magnetic domain, the neutron spin rotation in the domain is given by the spin

  19. Biocompatibility of sol-gel hydroxyapatite-titania composite and bilayer coatings

    Energy Technology Data Exchange (ETDEWEB)

    Sidane, D., E-mail: dj.sidane@yahoo.fr [Laboratoire de Génie de l' Environnement (LGE), Faculté de Technologie, Université de Bejaia, 06000, Bejaia (Algeria); Rammal, H. [Equipe d' Accueil 4691 Biomatériaux et Inflammation en Site Osseux, SFR-CAP Santé (FED 4231), Université de Reims Champagne Ardenne, 1 Avenue du Maréchal Juin, 51100 Reims (France); Beljebbar, A. [UMR CNRS 7369, Equipe MéDIAN Biophotonique et Technologies pour la Santé, UFR de Pharmacie, SFR-CAP Santé (FED 4231), Université de Reims Champagne Ardenne, 51 rue Cognacq-Jay, 51096 Reims (France); Gangloff, S.C. [Equipe d' Accueil 4691 Biomatériaux et Inflammation en Site Osseux, SFR-CAP Santé (FED 4231), Université de Reims Champagne Ardenne, 1 Avenue du Maréchal Juin, 51100 Reims (France); Chicot, D. [FRE 3723 - LML - Laboratoire de Mécanique de Lille, Univ. Lille, 59000 Lille (France); Velard, F. [Equipe d' Accueil 4691 Biomatériaux et Inflammation en Site Osseux, SFR-CAP Santé (FED 4231), Université de Reims Champagne Ardenne, 1 Avenue du Maréchal Juin, 51100 Reims (France); Khireddine, H. [Laboratoire de Génie de l' Environnement (LGE), Faculté de Technologie, Université de Bejaia, 06000, Bejaia (Algeria); and others

    2017-03-01

    Titania-Hydroxyapatite (TiO{sub 2}/HAP) reinforced coatings are proposed to enhance the bioactivity and corrosion resistance of 316L stainless steel (316L SS). Herein, spin- and dip-coating sol-gel processes were investigated to construct two kinds of coatings: TiO{sub 2}/HAP composite and TiO{sub 2}/HAP bilayer. Physicochemical characterization highlighted the bioactivity response of the TiO{sub 2}/HAP composite once incubated in physiological conditions for 7 days whereas the TiO{sub 2}/HAP bilayer showed instability and dissolution. Biological analysis revealed a failure in human stem cells adhesion on TiO{sub 2}/HAP bilayer whereas on TiO{sub 2}/HAP composite the presence of polygonal shaped cells, possessing good behaviour attested a good biocompatibility of the composite coating. Finally, TiO{sub 2}/HAP composite with hardness up to 0.6 GPa and elastic modulus up to 18 GPa, showed an increased corrosion resistance of 316L SS. In conclusion, the user-friendly sol-gel processes led to bioactive TiO{sub 2}/HAP composite buildup suitable for biomedical applications. - Highlights: • 316L SS implant TiO{sub 2} reinforced HAP coatings were investigated and compared. • TiO{sub 2}/HAP composite had better structural features and biocompatible properties. • Improvement of 316L SS implants corrosion resistance. • TiO{sub 2}/HAP composite mechanical properties close to bone tissue • Low cost and desired material for hard tissue applications.

  20. Biocompatibility of sol-gel hydroxyapatite-titania composite and bilayer coatings

    International Nuclear Information System (INIS)

    Sidane, D.; Rammal, H.; Beljebbar, A.; Gangloff, S.C.; Chicot, D.; Velard, F.; Khireddine, H.

    2017-01-01

    Titania-Hydroxyapatite (TiO 2 /HAP) reinforced coatings are proposed to enhance the bioactivity and corrosion resistance of 316L stainless steel (316L SS). Herein, spin- and dip-coating sol-gel processes were investigated to construct two kinds of coatings: TiO 2 /HAP composite and TiO 2 /HAP bilayer. Physicochemical characterization highlighted the bioactivity response of the TiO 2 /HAP composite once incubated in physiological conditions for 7 days whereas the TiO 2 /HAP bilayer showed instability and dissolution. Biological analysis revealed a failure in human stem cells adhesion on TiO 2 /HAP bilayer whereas on TiO 2 /HAP composite the presence of polygonal shaped cells, possessing good behaviour attested a good biocompatibility of the composite coating. Finally, TiO 2 /HAP composite with hardness up to 0.6 GPa and elastic modulus up to 18 GPa, showed an increased corrosion resistance of 316L SS. In conclusion, the user-friendly sol-gel processes led to bioactive TiO 2 /HAP composite buildup suitable for biomedical applications. - Highlights: • 316L SS implant TiO 2 reinforced HAP coatings were investigated and compared. • TiO 2 /HAP composite had better structural features and biocompatible properties. • Improvement of 316L SS implants corrosion resistance. • TiO 2 /HAP composite mechanical properties close to bone tissue • Low cost and desired material for hard tissue applications

  1. SU (N ) spin-wave theory: Application to spin-orbital Mott insulators

    Science.gov (United States)

    Dong, Zhao-Yang; Wang, Wei; Li, Jian-Xin

    2018-05-01

    We present the application of the SU (N ) spin-wave theory to spin-orbital Mott insulators whose ground states exhibit magnetic orders. When taking both spin and orbital degrees of freedom into account rather than projecting Hilbert space onto the Kramers doublet, which is the lowest spin-orbital locked energy levels, the SU (N ) spin-wave theory should take the place of the SU (2 ) one due to the inevitable spin-orbital multipole exchange interactions. To implement the application, we introduce an efficient general local mean-field method, which involves all local fluctuations, and develop the SU (N ) linear spin-wave theory. Our approach is tested firstly by calculating the multipolar spin-wave spectra of the SU (4 ) antiferromagnetic model. Then, we apply it to spin-orbital Mott insulators. It is revealed that the Hund's coupling would influence the effectiveness of the isospin-1 /2 picture when the spin-orbital coupling is not large enough. We further carry out the SU (N ) spin-wave calculations of two materials, α -RuCl3 and Sr2IrO4 , and find that the magnonic and spin-orbital excitations are consistent with experiments.

  2. Spin-inversion in nanoscale graphene sheets with a Rashba spin-orbit barrier

    Directory of Open Access Journals (Sweden)

    Somaieh Ahmadi

    2012-03-01

    Full Text Available Spin-inversion properties of an electron in nanoscale graphene sheets with a Rashba spin-orbit barrier is studied using transfer matrix method. It is found that for proper values of Rashba spin-orbit strength, perfect spin-inversion can occur in a wide range of electron incident angle near the normal incident. In this case, the graphene sheet with Rashba spin-orbit barrier can be considered as an electron spin-inverter. The efficiency of spin-inverter can increase up to a very high value by increasing the length of Rashba spin-orbit barrier. The effect of intrinsic spin-orbit interaction on electron spin inversion is then studied. It is shown that the efficiency of spin-inverter decreases slightly in the presence of intrinsic spin-orbit interaction. The present study can be used to design graphene-based spintronic devices.

  3. Spin-pump-induced spin transport in a thermally evaporated pentacene film

    Energy Technology Data Exchange (ETDEWEB)

    Tani, Yasuo; Shikoh, Eiji, E-mail: shikoh@elec.eng.osaka-cu.ac.jp [Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); Teki, Yoshio [Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan)

    2015-12-14

    We report the spin-pump-induced spin transport properties of a pentacene film prepared by thermal evaporation. In a palladium(Pd)/pentacene/Ni{sub 80}Fe{sub 20} tri-layer sample, a pure spin-current is generated in the pentacene layer by the spin-pumping of Ni{sub 80}Fe{sub 20}, which is independent of the conductance mismatch problem in spin injection. The spin current is absorbed into the Pd layer, converted into a charge current with the inverse spin-Hall effect in Pd, and detected as an electromotive force. This is clear evidence for the pure spin current at room temperature in pentacene films prepared by thermal evaporation.

  4. Spin-Triplet Pairing Induced by Spin-Singlet Interactions in Noncentrosymmetric Superconductors

    Science.gov (United States)

    Matsuzaki, Tomoaki; Shimahara, Hiroshi

    2017-02-01

    In noncentrosymmetric superconductors, we examine the effect of the difference between the intraband and interband interactions, which becomes more important when the band splitting increases. We define the difference ΔVμ between their coupling constants, i.e., that between the intraband and interband hopping energies of intraband Cooper pairs. Here, the subscript μ of ΔVμ indicates that the interactions scatter the spin-singlet and spin-triplet pairs when μ = 0 and μ = 1,2,3, respectively. It is shown that the strong antisymmetric spin-orbit interaction reverses the target spin parity of the interaction: it converts the spin-singlet and spin-triplet interactions represented by ΔV0 and ΔVμ>0 into effective spin-triplet and spin-singlet pairing interactions, respectively. Hence, for example, triplet pairing can be induced solely by the singlet interaction ΔV0. We name the pairing symmetry of the system after that of the intraband Cooper pair wave function, but with an odd-parity phase factor excluded. The pairing symmetry must then be even, even for the triplet component, and the following results are obtained. When ΔVμ is small, the spin-triplet p-wave interactions induce spin-triplet s-wave and spin-triplet d-wave pairings in the regions where the repulsive singlet s-wave interaction is weak and strong, respectively. When ΔV0 is large, a repulsive interband spin-singlet interaction can stabilize spin-triplet pairing. When the Rashba interaction is adopted for the spin-orbit interaction, the spin-triplet pairing interactions mediated by transverse magnetic fluctuations do not contribute to triplet pairing.

  5. Dynamical spin accumulation in large-spin magnetic molecules

    Science.gov (United States)

    Płomińska, Anna; Weymann, Ireneusz; Misiorny, Maciej

    2018-01-01

    The frequency-dependent transport through a nanodevice containing a large-spin magnetic molecule is studied theoretically in the Kondo regime. Specifically, the effect of magnetic anisotropy on dynamical spin accumulation is of primary interest. Such accumulation arises due to finite components of frequency-dependent conductance that are off diagonal in spin. Here, employing the Kubo formalism and the numerical renormalization group method, we demonstrate that the dynamical transport properties strongly depend on the relative orientation of spin moments in electrodes of the device, as well as on intrinsic parameters of the molecule. In particular, the effect of dynamical spin accumulation is found to be greatly affected by the type of magnetic anisotropy exhibited by the molecule, and it develops for frequencies corresponding to the Kondo temperature. For the parallel magnetic configuration of the device, the presence of dynamical spin accumulation is conditioned by the interplay of ferromagnetic-lead-induced exchange field and the Kondo correlations.

  6. Hardy's argument and successive spin-s measurements

    International Nuclear Information System (INIS)

    Ahanj, Ali

    2010-01-01

    We consider a hidden-variable theoretic description of successive measurements of noncommuting spin observables on an input spin-s state. In this scenario, the hidden-variable theory leads to a Hardy-type argument that quantum predictions violate it. We show that the maximum probability of success of Hardy's argument in quantum theory is ((1/2)) 4s , which is more than in the spatial case.

  7. Large spin current injection in nano-pillar-based lateral spin valve

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, Tatsuya [Department of Physics, Kyushu University, 744 Motooka, Fukuoka, 819-0395 (Japan); Ohnishi, Kohei; Kimura, Takashi, E-mail: t-kimu@phys.kyushu-u.ac.jp [Department of Physics, Kyushu University, 744 Motooka, Fukuoka, 819-0395 (Japan); Research Center for Quantum Nano-Spin Sciences, Kyushu University, 744 Motooka, Fukuoka, 819-0395 (Japan)

    2016-08-26

    We have investigated the influence of the injection of a large pure spin current on a magnetization process of a non-locally located ferromagnetic dot in nano-pillar-based lateral spin valves. Here, we prepared two kinds of the nano-pillar-type lateral spin valve based on Py nanodots and CoFeAl nanodots fabricated on a Cu film. In the Py/Cu lateral spin valve, although any significant change of the magnetization process of the Py nanodot has not been observed at room temperature. The magnetization reversal process is found to be modified by injecting a large pure spin current at 77 K. Switching the magnetization by the nonlocal spin injection has also been demonstrated at 77 K. In the CoFeAl/Cu lateral spin valve, a room temperature spin valve signal was strongly enhanced from the Py/Cu lateral spin valve because of the highly spin-polarized CoFeAl electrodes. The room temperature nonlocal switching has been demonstrated in the CoFeAl/Cu lateral spin valve.

  8. Facile approach in the development of icephobic hierarchically textured coatings as corrosion barrier

    Energy Technology Data Exchange (ETDEWEB)

    Momen, G., E-mail: gmomen@uqac.ca; Farzaneh, M.

    2014-04-01

    Highlights: • A superhydrophobic coating is developed via a simple environmental-friendly method. • This coating can be used on the surface of various metals such as copper, magnesium. • The superhydrophobic aluminum surface showed the excellent corrosion resistance. • The fabricated surface revealed a drastically reduction of ice adhesion strength. • Such surfaces can advantageously be used in cold climate regions. - Abstract: An anti-corrosion superhydrophobic film with water contact angle greater than 160° on aluminum alloy 6061 substrate was fabricated simply through the spin-coating method applied to Al{sub 2}O{sub 3} nanoparticles doped in silicone rubber solution. The as-obtained sample was characterized by scanning electron microscopy (SEM) and water contact angle/surface energy measurement. The corrosion behaviour of such coating in the NaCl solutions was investigated using the potentiodynamic polarization. The results show that the corrosion resistance of the developed superhydrophobic surface is improved greatly due to the composite wetting states or interfaces with numerous air pockets between its surface and the NaCl solution. This superhydrophobic coating could serve as an effective barrier against aggressive medium. Ice adhesion strength of the as-prepared superhydrophobic coating was also evaluated by measuring its ice adhesion force which was found to have reduced by 4.8 times compared to that of aluminum substrate as reference test.

  9. Spin Hall effects

    Science.gov (United States)

    Sinova, Jairo; Valenzuela, Sergio O.; Wunderlich, J.; Back, C. H.; Jungwirth, T.

    2015-10-01

    Spin Hall effects are a collection of relativistic spin-orbit coupling phenomena in which electrical currents can generate transverse spin currents and vice versa. Despite being observed only a decade ago, these effects are already ubiquitous within spintronics, as standard spin-current generators and detectors. Here the theoretical and experimental results that have established this subfield of spintronics are reviewed. The focus is on the results that have converged to give us the current understanding of the phenomena, which has evolved from a qualitative to a more quantitative measurement of spin currents and their associated spin accumulation. Within the experimental framework, optical-, transport-, and magnetization-dynamics-based measurements are reviewed and linked to both phenomenological and microscopic theories of the effect. Within the theoretical framework, the basic mechanisms in both the extrinsic and intrinsic regimes are reviewed, which are linked to the mechanisms present in their closely related phenomenon in ferromagnets, the anomalous Hall effect. Also reviewed is the connection to the phenomenological treatment based on spin-diffusion equations applicable to certain regimes, as well as the spin-pumping theory of spin generation used in many measurements of the spin Hall angle. A further connection to the spin-current-generating spin Hall effect to the inverse spin galvanic effect is given, in which an electrical current induces a nonequilibrium spin polarization. This effect often accompanies the spin Hall effect since they share common microscopic origins. Both can exhibit the same symmetries when present in structures comprising ferromagnetic and nonmagnetic layers through their induced current-driven spin torques or induced voltages. Although a short chronological overview of the evolution of the spin Hall effect field and the resolution of some early controversies is given, the main body of this review is structured from a pedagogical

  10. Preparation of Impervious Pyrolytic Carbon Coatings and Application to Dispersed Fuels; Preparation de revetements de carbone pyrolytique etanches - applications aux combustibles disperses; Prigotovlenie nepronitsaemogo uglerodnogo piroliticheskogo pokrytiya dlya dispergirovannogo topliva; Preparacion de revestimientos estancos de carbono piroutico: aplicacion a los combustibles nucleares dispersos

    Energy Technology Data Exchange (ETDEWEB)

    Auriol, A.; David, C. [Battelle Memorial Institute, Geneve (Switzerland); Fillatre, A.; Kurka, G.; Le Boulbin, E.; Rappeneau, J. [Commissariat a l' Energie Atomique (France)

    1963-11-15

    A method of depositing pyrolytic carbon, which adheres well to a graphite support and is gas-tight, was developed and the physical properties of the deposit were evaluated. The fluidized bed technique was used in applying this method of coating to fissile granules of uranium oxide and uranium carbide. After explaining the conditions for coating the granules, the authors examined their macrostructure, microstructure and permeability. Their behaviour at high temperature was investigated with a view to using them in a reactor. (author) [French] Une methode de deposition de carbone pyrolydque adherant bien au graphite support et etanche aux gaz a ete mise au point. Les proprietes physiques du depot ont ete evaluees. Cette methode de revetement a ete transposee a des granules fissiles d'oxyde et de carbure d'uranium en utilisant la technique du lit fluidise. Apres avoir precise les conditions de revetement de ces granules, on etudie leur macrostructure, leur microstructure, ainsi que leur permeabilite. Le comportement de ces granules a haute temperature a ete examine en vue de leur utilisation eventuelle dans un reacteur. (author) [Spanish] Los autores han elaborado un metodo para depositar carbono pirolitico que se adhiere fuertemente al soporte de grafito y es estanco a los gases. Han determinado las propiedades de dicho deposito. Este metodo de revestimiento fue aplicado a granulos fisionables de oxido y de carburo de uranio, utilizando la tecnica del lecho fluidificado. Despues de determinar las condiciones en que se efectua el revestimiento de esos granulos, los autores estudiaron su macroestructura y su microestructura, asi como su permeabilidad. Examinaron tambien su comportamiento a temperatura elevada, con miras a utilizarlos oportunamente en los reactores. (author) [Russian] Razrabotan metod osazhdeniya piroliticheskogo ugleroda, khorosho pokryvayushchego grafitovuyu osnovu s polucheniem nepronitsaemogo dlya gazov pokrytiya. Otseneny fizicheskie svojstva

  11. Spin-orbit induced electronic spin separation in semiconductor nanostructures.

    Science.gov (United States)

    Kohda, Makoto; Nakamura, Shuji; Nishihara, Yoshitaka; Kobayashi, Kensuke; Ono, Teruo; Ohe, Jun-ichiro; Tokura, Yasuhiro; Mineno, Taiki; Nitta, Junsaku

    2012-01-01

    The demonstration of quantized spin splitting by Stern and Gerlach is one of the most important experiments in modern physics. Their discovery was the precursor of recent developments in spin-based technologies. Although electrical spin separation of charged particles is fundamental in spintronics, in non-uniform magnetic fields it has been difficult to separate the spin states of charged particles due to the Lorentz force, as well as to the insufficient and uncontrollable field gradients. Here we demonstrate electronic spin separation in a semiconductor nanostructure. To avoid the Lorentz force, which is inevitably induced when an external magnetic field is applied, we utilized the effective non-uniform magnetic field which originates from the Rashba spin-orbit interaction in an InGaAs-based heterostructure. Using a Stern-Gerlach-inspired mechanism, together with a quantum point contact, we obtained field gradients of 10(8) T m(-1) resulting in a highly polarized spin current.

  12. Spin-dependent transport properties of oleic acid molecule self-assembled La0.7Sr0.3MnO3 nanoparticles

    International Nuclear Information System (INIS)

    Xi, L.; Du, J.H.; Ma, J.H.; Wang, Z.; Zuo, Y.L.; Xue, D.S.

    2013-01-01

    Highlights: ► Spin-dependent transport property of LSMO/oleic acid nanoparticles is investigated. ► Transport properties and MR measured by Cu/nanoparticle assembly/elargol device. ► Non-linear I–V curve indicates a tunneling type transport properties. ► Tunnel barrier height around 1.3 ± 0.15 eV was obtained by fitting I–V curves. ► LFMR of LSMO/oleic acid molecules value reaches −18% with current of 0.1 μA at 10 K. - Abstract: Spin-dependent transport property through molecules is investigated using a monolayer of oleic acid molecule self-assembled half metallic La 0.7 Sr 0.3 MnO 3 (LSMO) nanoparticles, which was synthesized using a coprecipitation method. Fourier transform infrared spectroscopy was used to confirm that one-monolayer oleic acid molecules chemically bond to the LSMO nanoparticles. The transport properties and magnetoresistance (MR) effect of the oleic acid molecule coated LSMO nanoparticles were measured by a direct current four probes method using a Cu/nanoparticle assembly/elargol electrode sandwich device with various temperatures and bias voltages. The non-linear I–V curve indicates a tunneling type transport properties. The tunnel barrier height around 1.3 ± 0.15 eV was obtained by fitting the I–V curve according to the Simmons equation. The magnetoresistance curves can be divided to high-field MR and low-field MR (LFMR) parts. The former is ascribed to the influence of spin disorder or canting within the LSMO nanoparticle surface and the latter one with strong bias dependence is attributed to the spin-dependent tunneling effect through the insulating surface layer of LSMO and oleic acid molecules. The enhanced LFMR effect for oleic acid coated LSMO with respect to the bare LSMO was attributed to the enhanced tunneling transport and weak spin scattering in oleic acid molecule barrier.

  13. Canted spin structure and the first order magnetic transition in CoFe{sub 2}O{sub 4} nanoparticles coated by amorphous silica

    Energy Technology Data Exchange (ETDEWEB)

    Lyubutin, I.S. [Shubnikov Institute of Crystallography, Russian Academy of Sciences, Moscow 119333 (Russian Federation); Starchikov, S.S., E-mail: sergey.s.starchikov@gmail.com [Shubnikov Institute of Crystallography, Russian Academy of Sciences, Moscow 119333 (Russian Federation); Gervits, N.E.; Korotkov, N.Yu.; Dmitrieva, T.V. [Shubnikov Institute of Crystallography, Russian Academy of Sciences, Moscow 119333 (Russian Federation); Lin, Chun-Rong, E-mail: crlinspin@gmail.com [Department of Applied Physics, National Pingtung University, Pingtung County 90003, Taiwan (China); Tseng, Yaw-Teng [Department of Applied Physics, National Pingtung University, Pingtung County 90003, Taiwan (China); Shih, Kun-Yauh [Department of Applied Chemistry, National Pingtung University, Pingtung County 90003, Taiwan (China); Lee, Jiann-Shing [Department of Applied Physics, National Pingtung University, Pingtung County 90003, Taiwan (China); Wang, Cheng-Chien [Department of Chemical and Materials Engineering, Southern Taiwan University of Science and Technology, Tainan 710, Taiwan (China)

    2016-10-01

    The functional polymer (PMA-co-MAA) latex microspheres were used as a core template to prepare magnetic hollow spheres consisting of CoFe{sub 2}O{sub 4}/SiO{sub 2} composites. The spinel type crystal structure of CoFe{sub 2}O{sub 4} ferrite is formed under annealing, whereas the polymer cores are completely removed after annealing at 450 °C. Magnetic and Mössbauer spectroscopy measurements reveal very interesting magnetic properties of the CoFe{sub 2}O{sub 4}/SiO{sub 2} hollow spheres strongly dependent on the particle size which can be tuned by the annealing temperature. In the ground state of low temperatures, the CoFe{sub 2}O{sub 4} nanoparticles are in antiferromagnetic state due to the canted magnetic structure. Under heating in the applied field, the magnetic structure gradually transforms from canted to collinear, which increases the magnetization. The Mössbauer data revealed that the small size CoFe{sub 2}O{sub 4}/SiO{sub 2} particles (2.2–4.3 nm) do not show superparamagnetic behavior but transit from the magnetic to the paramagnetic state by a jump-like magnetic transition of the first order This effect is a specific property of the magnetic nanoparticles isolated by inert material, and can be initiated by internal pressure creating at the particle surface. The suggested method of synthesis can be modified with various bio-ligands on the silane surface, and such materials can find many applications in diagnostics and bio-separation. - Highlights: • CoFe{sub 2}O{sub 4}/SiO{sub 2} nanocomposites in shell of hollow microcapsules designed for biomedical applications • The CoFe{sub 2}O{sub 4} particle size and magnetic properties can be tuned by thermal treatment • Canted spin structure in the CoFe{sub 2}O{sub 4} nanoparticles coated by SiO{sub 2} • The first order magnetic transition in the CoFe{sub 2}O{sub 4} nanoparticles coated by silica.

  14. Mean-Field Studies of a Mixed Spin-3/2 and Spin-2 and a Mixed Spin-3/2 and Spin-5/2 Ising System with Different Anisotropies

    International Nuclear Information System (INIS)

    Wei Guozhu; Miao Hailing

    2009-01-01

    The magnetic properties of a mixed spin-3/2 and spin-2 and a mixed spin-3/2 and spin-5/2 Ising ferromagnetic system with different anisotropies are studied by means of mean-field theory (MFT). The dependence of the phase diagram on single-ion anisotropy strengths is studied too. In the mixed spin-3/2 and spin-2 Ising model, besides the second-order phase transition, the first order-disorder phase transition and the tricritical line are found. In the mixed spin-3/2 and spin-5/2 Ising model, there is no first-order transition and tricritical line. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  15. Comparative Aspects of Spin-Dependent Interaction Potentials for Spin-1/2 and Spin-1 Matter Fields

    Directory of Open Access Journals (Sweden)

    P. C. Malta

    2016-01-01

    Full Text Available This paper sets out to establish a comparative study between classes of spin- and velocity-dependent potentials for spin-1/2 and spin-1 matter currents/sources in the nonrelativistic regime. Both (neutral massive scalar and vector particles are considered to mediate the interactions between (pseudo-scalar sources or (pseudo-vector currents. Though our discussion is more general, we contemplate specific cases in which our results may describe the electromagnetic interaction with a massive (Proca-type photon exchanged between two spin-1/2 or two spin-1 carriers. We highlight the similarities and peculiarities of the potentials for the two different types of charged matter and also focus our attention on the comparison between the particular aspects of two different field representations for spin-1 matter particles. We believe that our results may contribute to a further discussion of the relation between charge, spin, and extensibility of elementary particles.

  16. Heat and spin interconversion

    International Nuclear Information System (INIS)

    Ohnuma, Yuichi; Matsuo, Mamoru; Maekawa, Sadamichi; Saitoh, Eeiji

    2017-01-01

    Spin Seebeck and spin Peltier effects, which are mutual conversion phenomena of heat and spin, are discussed on the basis of the microscopic theory. First, the spin Seebeck effect, which is the spin-current generation due to heat current, is discussed. The recent progress in research on the spin Seebeck effect are introduced. We explain the origin of the observed sign changes of the spin Seebeck effect in compensated ferromagnets. Next, the spin Peltier effect, which is the heat-current generation due to spin current, is discussed. Finally, we show that the spin Seebeck and spin Peltier effects are summarized by Onsager's reciprocal relation and derive Kelvin's relation for the spin and heat transports. (author)

  17. Rotational Invariance of the 2d Spin - Spin Correlation Function

    Science.gov (United States)

    Pinson, Haru

    2012-09-01

    At the critical temperature in the 2d Ising model on the square lattice, we establish the rotational invariance of the spin-spin correlation function using the asymptotics of the spin-spin correlation function along special directions (McCoy and Wu in the two dimensional Ising model. Harvard University Press, Cambridge, 1973) and the finite difference Hirota equation for which the spin-spin correlation function is shown to satisfy (Perk in Phys Lett A 79:3-5, 1980; Perk in Proceedings of III international symposium on selected topics in statistical mechanics, Dubna, August 22-26, 1984, JINR, vol II, pp 138-151, 1985).

  18. Optimized plasma-deposited fluorocarbon coating for dry release and passivation of thin SU-8 cantilevers

    DEFF Research Database (Denmark)

    Keller, Stephan Urs; Häfliger, Daniel; Boisen, Anja

    2008-01-01

    during fluorocarbon deposition, the surface free energy of the coating can be tuned to allow for uniform wetting during spin coating of arbitrary thin SU-8 films. Further, they define an optimal pressure regime for the release of thin polymer structures at high yield. They demonstrate the successful......Plasma-deposited fluorocarbon coatings are introduced as a convenient method for the dry release of polymer structures. In this method, the passivation process in a deep reactive ion etch reactor was used to deposit hydrophobic fluorocarbon films. Standard photolithography with the negative epoxy......-based photoresist SU-8 was used to fabricate polymer structures such as cantilevers and membranes on top of the nonadhesive release layer. The authors identify the plasma density as the main parameter determining the surface properties of the deposited fluorocarbon films. They show that by modifying the pressure...

  19. Spin-independent transparency of pure spin current at normal/ferromagnetic metal interface

    Science.gov (United States)

    Hao, Runrun; Zhong, Hai; Kang, Yun; Tian, Yufei; Yan, Shishen; Liu, Guolei; Han, Guangbing; Yu, Shuyun; Mei, Liangmo; Kang, Shishou

    2018-03-01

    The spin transparency at the normal/ferromagnetic metal (NM/FM) interface was studied in Pt/YIG/Cu/FM multilayers. The spin current generated by the spin Hall effect (SHE) in Pt flows into Cu/FM due to magnetic insulator YIG blocking charge current and transmitting spin current via the magnon current. Therefore, the nonlocal voltage induced by an inverse spin Hall effect (ISHE) in FM can be detected. With the magnetization of FM parallel or antiparallel to the spin polarization of pure spin currents ({{\\boldsymbol{σ }}}sc}), the spin-independent nonlocal voltage is induced. This indicates that the spin transparency at the Cu/FM interface is spin-independent, which demonstrates that the influence of spin-dependent electrochemical potential due to spin accumulation on the interfacial spin transparency is negligible. Furthermore, a larger spin Hall angle of Fe20Ni80 (Py) than that of Ni is obtained from the nonlocal voltage measurements. Project supported by the National Basic Research Program of China (Grant No. 2015CB921502), the National Natural Science Foundation of China (Grant Nos. 11474184 and 11627805), the 111 Project, China (Grant No. B13029), and the Fundamental Research Funds of Shandong University, China.

  20. Application of the identification methods from Hilbert and Prony to the study of oscillatory phenomena in electrical power systems; Aplicacion de los metodos de identificacion de Hilbert y Prony al estudio de fenomenos oscilatorios en sistemas electricos de potencia

    Energy Technology Data Exchange (ETDEWEB)

    Andrade Soto, Manuel Antonio

    2002-10-15

    In the present thesis work the application of identification techniques is investigated based on methods of spectral analysis to the study of the instantaneous characteristics of signals obtained by means of digital simulation of the dynamic behavior of the power system. The study focuses on the perspectives developed from two different approaches of analysis: the use of lineal methods of spectral analysis and the use of methods of non-lineal analysis, based on the concept of an analytical signal. The developed tools are applied to the study of two phenomena of electromechanical origin of different characteristics in complex power systems. A comparison between the results obtained is performed for these techniques and the possibility of its application is discussed for the problem of on-line identification in power systems. [Spanish] En el presente trabajo de tesis se investiga la aplicacion de tecnicas de identificacion basadas en metodos de analisis espectral al estudio de las caracteristicas instantaneas de senales obtenidas mediante simulacion digital del comportamiento dinamico del sistema de potencia. El estudio se centra en las aproximaciones desarrolladas desde dos enfoques distintos de analisis: la utilizacion de metodos lineales de analisis espectral y la utilizacion de metodos de analisis no lineal, basados en el concepto de una senal analitica. Las herramientas desarrolladas se aplican al estudio de dos fenomenos de origen electromecanico de caracteristicas distintas en sistemas complejos de potencia. Se hace una comparacion entre los resultados obtenidos por estas tecnicas y se discute la posibilidad de su aplicacion al problema de identificacion en linea en sistemas de potencia.

  1. Effect of thermal treatment on solid–solid interface of hematite thin film synthesized by spin-coating deposition solution

    International Nuclear Information System (INIS)

    Bellido-Aguilar, Daniel Angel; Tofanello, Aryane; Souza, Flavio L.; Furini, Leonardo Negri; Constantino, Carlos José Leopoldo

    2016-01-01

    This work describes hematite films prepared by a spin-coating deposition solution (SCDS) method that is a sol–gel method derived technique. Hematite films were prepared at two heat treatment temperatures (500 °C and 800 °C) and the influence of thermal treatment on the photoelectrochemical performance was studied. In addition, since the SCDS method allows an optimal control of stoichiometry and impurity incorporation, hematite films modified with Zn 2+ and Sn 4+ were also prepared. The 800 °C-treated hematite films had a higher wettability and roughness that enabled them to have a better photocatalytic response in comparison with that of 500 °C-treated hematite films. Moreover, modified hematite films demonstrated to have a performance slightly better than that of undoped hematite film as shown in linear sweep voltammetry and chronoamperometry results. Although an improvement in the performance of hematite films was achieved by annealing at higher temperatures and incorporating Zn 2+ or Sn 4+ , the general photocatalytic response of the films was poor. Two plausible hypotheses were discussed related to the (i) dopant segregation at grain boundary, and (ii) poor contact between the hematite and fluorine doped tin oxide layer (from the glass substrate), which was experimentally confirmed by a cross-sectional analysis conducted using scanning electron microscopy (SEM). In fact, additional experiments need to be done in order to improve the hematite deposition and make the SCDS a promise method for industrial application. - Highlights: • High temperature of annealing decreases the hematite adherence and performance. • Zn 2+ and Sn 4+ dopants affected differently the photocurrent onset potentials. • Dopants affected the grain size due to their segregation at grain boundaries.

  2. Spin-lattice relaxation of individual solid-state spins

    Science.gov (United States)

    Norambuena, A.; Muñoz, E.; Dinani, H. T.; Jarmola, A.; Maletinsky, P.; Budker, D.; Maze, J. R.

    2018-03-01

    Understanding the effect of vibrations on the relaxation process of individual spins is crucial for implementing nanosystems for quantum information and quantum metrology applications. In this work, we present a theoretical microscopic model to describe the spin-lattice relaxation of individual electronic spins associated to negatively charged nitrogen-vacancy centers in diamond, although our results can be extended to other spin-boson systems. Starting from a general spin-lattice interaction Hamiltonian, we provide a detailed description and solution of the quantum master equation of an electronic spin-one system coupled to a phononic bath in thermal equilibrium. Special attention is given to the dynamics of one-phonon processes below 1 K where our results agree with recent experimental findings and analytically describe the temperature and magnetic-field scaling. At higher temperatures, linear and second-order terms in the interaction Hamiltonian are considered and the temperature scaling is discussed for acoustic and quasilocalized phonons when appropriate. Our results, in addition to confirming a T5 temperature dependence of the longitudinal relaxation rate at higher temperatures, in agreement with experimental observations, provide a theoretical background for modeling the spin-lattice relaxation at a wide range of temperatures where different temperature scalings might be expected.

  3. Muon spin rotation and other microscopic probes of spin-glass dynamics

    International Nuclear Information System (INIS)

    MacLaughlin, D.E.

    1980-01-01

    A number of different microscopic probe techniques have been employed to investigate the onset of the spin-glass state in dilute magnetic alloys. Among these are Moessbauer-effect spectroscopy, neutron scattering, ESR of the impurity spins, host NMR and, most recently, muon spin rotation and depolarization. Spin probes yield information on the microscopic static and dynamic behavior of the impurity spins, and give insight into both the spin freezing process and the nature of low-lying excitations in the ordered state. Microscopic probe experiments in spin glasses are surveyed, and the unique advantages of muon studies are emphasized

  4. Quantifying Spin Hall Angles from Spin Pumping : Experiments and Theory

    NARCIS (Netherlands)

    Mosendz, O.; Pearson, J.E.; Fradin, F.Y.; Bauer, G.E.W.; Bader, S.D.; Hoffmann, A.

    2010-01-01

    Spin Hall effects intermix spin and charge currents even in nonmagnetic materials and, therefore, ultimately may allow the use of spin transport without the need for ferromagnets. We show how spin Hall effects can be quantified by integrating Ni80Fe20|normal metal (N) bilayers into a coplanar

  5. Proposal to measure spin-structure functions and semi-exclusive asymmetries for the proton and neutron at HERA

    International Nuclear Information System (INIS)

    Jackson, H.E.; Hansen, J.O.; Jones, C.E.

    1995-01-01

    Nucleon spin physics will be studied in the HERMES experiment, that will use polarized internal targets of essentially pure atomic H, D, and 3 He in the HERA electron storage ring at DESY. A series of measurements of spin-dependent properties of the nucleon and few-body nuclei will be made; the spin structure function g 1 (x) of the proton and neutron will be measured to test the Bjorken sum rule and study the fraction of the nucleon spin carried by quarks; the spin structure function g 2 W, sensitive to quark-gluon correlations, and the structure functions b 1 (x), and Δ(x), sensitive to nuclear binding effects, will be measured; and, using the particle identification capability of the HERMES detector, pions will be detected in coincidence with the scattered electrons. The coincident hadron measurements represent the most important extension that can be made at this time to the existing measurements on the nucleon spin structure functions because they provide information about the flavor-dependence of the quark spin distribution in the nucleon. Argonne is providing the Cerenkov counter to be used for particle identification and developing the drifilm coating technique for the ultrathin target cell required for this experiment. The HERMES collaboration intends to use polarized targets with the highest available figures of merit, and the Argonne laser-driven source offers the most promise for a significant advance in present-day targets

  6. Spin-orbit-coupled transport and spin torque in a ferromagnetic heterostructure

    KAUST Repository

    Wang, Xuhui; Ortiz Pauyac, Christian; Manchon, Aurelien

    2014-01-01

    Ferromagnetic heterostructures provide an ideal platform to explore the nature of spin-orbit torques arising from the interplay mediated by itinerant electrons between a Rashba-type spin-orbit coupling and a ferromagnetic exchange interaction. For such a prototypic system, we develop a set of coupled diffusion equations to describe the diffusive spin dynamics and spin-orbit torques. We characterize the spin torque and its two prominent—out-of-plane and in-plane—components for a wide range of relative strength between the Rashba coupling and ferromagnetic exchange. The symmetry and angular dependence of the spin torque emerging from our simple Rashba model is in an agreement with experiments. The spin diffusion equation can be generalized to incorporate dynamic effects such as spin pumping and magnetic damping.

  7. Spin-orbit-coupled transport and spin torque in a ferromagnetic heterostructure

    KAUST Repository

    Wang, Xuhui

    2014-02-07

    Ferromagnetic heterostructures provide an ideal platform to explore the nature of spin-orbit torques arising from the interplay mediated by itinerant electrons between a Rashba-type spin-orbit coupling and a ferromagnetic exchange interaction. For such a prototypic system, we develop a set of coupled diffusion equations to describe the diffusive spin dynamics and spin-orbit torques. We characterize the spin torque and its two prominent—out-of-plane and in-plane—components for a wide range of relative strength between the Rashba coupling and ferromagnetic exchange. The symmetry and angular dependence of the spin torque emerging from our simple Rashba model is in an agreement with experiments. The spin diffusion equation can be generalized to incorporate dynamic effects such as spin pumping and magnetic damping.

  8. Influence of biodegradable polymer coatings on corrosion, cytocompatibility and cell functionality of Mg-2.0Zn-0.98Mn magnesium alloy.

    Science.gov (United States)

    Witecka, Agnieszka; Yamamoto, Akiko; Idaszek, Joanna; Chlanda, Adrian; Święszkowski, Wojciech

    2016-08-01

    Four kinds of biodegradable polymers were employed to prepare bioresorbable coatings on Mg-2.0Zn-0.98Mn (ZM21) alloy to understand the relationship between polymer characteristics, protective effects on substrate corrosion, cytocompatibility and cell functionality. Poly-l-lactide (PLLA), poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) or poly(lactic-co-glycolic) acid (PLGA) was spin-coated on ZM21, obtaining a smooth, non-porous coating less than 0.5μm in thickness. Polymer coating characterization, a degradation study, and biocompatibility evaluations were performed. After 4 w of immersion into cell culture medium, degradation of PLGA and PLLA coatings were confirmed by ATR-FTIR observation. The coatings of PLLA, PHB and PHBV, which have lower water permeability and slower degradation than PLGA, provide better suppression of initial ZM21 degradation and faster promotion of human osteosarcoma cell growth and differentiation. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Effect of Sr on the bioactivity and corrosion resistance of nanoporous niobium oxide coating for orthopaedic applications

    International Nuclear Information System (INIS)

    Pauline, S. Anne; Rajendran, N.

    2014-01-01

    In this study, strontium incorporated Nb 2 O 5 was synthesized in two different proportions by sol–gel methodology and was deposited on 316L SS by spin coating method. The synthesis conditions were optimized to obtain a nanoporous morphology. The prepared Sr-incorporated Nb 2 O 5 coatings were uniform, smooth and well adherent on to the substrate 316L SS. The coatings were characterized by attenuated total reflectance-infrared spectroscopy (ATR-IR), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), atomic force microscopy (AFM) and transmission electron microscopy (TEM) and the formation of Sr-incorporated Nb 2 O 5 coatings with nanoporous morphology was confirmed. Static water contact angle measurements showed an enhancement in the wettability of the obtained coatings. In vitro bioactivity test of the coated substrates showed that 0.05 M Sr-incorporated Nb 2 O 5 coating had better bioactivity compared to 0.1 M Sr-incorporated coating. Solution analysis studies confirmed the controlled release of Sr ions from the coating, which aid and enhance hydroxyapatite (HAp) growth. Electrochemical studies confirmed that the coatings provided excellent corrosion protection to the base material as increased charge transfer resistance and decreased double layer capacitance was observed for the coated substrates. - Highlights: • Nanoporous Sr-incorporated Nb 2 O 5 coatings were deposited on 316L SS. • The coatings have excellent bond strength and high Vickers micro hardness value. • Nanoporous 0.05 M Sr-incorporated Nb 2 O 5 coating showed hydroxyapatite growth. • Slow release of strontium from the coating accelerated hydroxyapatite growth. • The nanoporous coatings offered excellent corrosion protection to 316L SS

  10. Electron-Spin Filters Would Offer Spin Polarization Greater than 1

    Science.gov (United States)

    Ting, David Z.

    2009-01-01

    A proposal has been made to develop devices that would generate spin-polarized electron currents characterized by polarization ratios having magnitudes in excess of 1. Heretofore, such devices (denoted, variously, as spin injectors, spin polarizers, and spin filters) have typically offered polarization ratios having magnitudes in the approximate range of 0.01 to 0.1. The proposed devices could be useful as efficient sources of spin-polarized electron currents for research on spintronics and development of practical spintronic devices.

  11. Preliminary evaluation of an aqueous wax emulsion for controlled-release coating.

    Science.gov (United States)

    Walia, P S; Stout, P J; Turton, R

    1998-02-01

    The purpose of this work was to evaluate the use of an aqueous carnauba wax emulsion (Primafresh HS, Johnson Wax) in a spray-coating process. This involved assessing the effectiveness of the wax in sustaining the release of the drug, theophylline. Second, the process by which the drug was released from the wax-coated pellets was modeled. Finally, a method to determine the optimum blend of pellets with different wax thicknesses, in order to yield a zero-order release profile of the drug, was addressed. Nonpareil pellets were loaded with theophylline using a novel powder coating technique. These drug-loaded pellets were then coated with different levels of carnauba wax in a 6-in. diameter Plexiglas fluid bed with a 3.5-in. diameter Wurster partition. Drug release was measured using a spin-filter dissolution device. The study resulted in continuous carnauba wax coatings which showed sustained drug release profile characteristics typical of a barrier-type, diffusion-controlled system. The effect of varying wax thickness on the release profiles was investigated. It was observed that very high wax loadings would be required to achieve long sustained-release times. The diffusion model, developed to predict the release of the drug, showed good agreement with the experimental data. However, the data exhibited an initial lag-time for drug release which could not be predicted a priori based on the wax coating thickness. A method of mixing pellets with different wax thicknesses was proposed as a way to approximate zero-order release.

  12. Efficient micromagnetic modelling of spin-transfer torque and spin-orbit torque

    Science.gov (United States)

    Abert, Claas; Bruckner, Florian; Vogler, Christoph; Suess, Dieter

    2018-05-01

    While the spin-diffusion model is considered one of the most complete and accurate tools for the description of spin transport and spin torque, its solution in the context of dynamical micromagnetic simulations is numerically expensive. We propose a procedure to retrieve the free parameters of a simple macro-spin like spin-torque model through the spin-diffusion model. In case of spin-transfer torque the simplified model complies with the model of Slonczewski. A similar model can be established for the description of spin-orbit torque. In both cases the spin-diffusion model enables the retrieval of free model parameters from the geometry and the material parameters of the system. Since these parameters usually have to be determined phenomenologically through experiments, the proposed method combines the strength of the diffusion model to resolve material parameters and geometry with the high performance of simple torque models.

  13. Spin Drag and Spin-Charge Separation in Cold Fermi Gases

    International Nuclear Information System (INIS)

    Polini, Marco; Vignale, Giovanni

    2007-01-01

    Low-energy spin and charge excitations of one-dimensional interacting fermions are completely decoupled and propagate with different velocities. These modes, however, can decay due to several possible mechanisms. In this Letter we expose a new facet of spin-charge separation: not only the speeds but also the damping rates of spin and charge excitations are different. While the propagation of long-wavelength charge excitations is essentially ballistic, spin propagation is intrinsically damped and diffusive. We suggest that cold Fermi gases trapped inside a tight atomic waveguide offer the opportunity to measure the spin-drag relaxation rate that controls the broadening of a spin packet

  14. Biocorrosion behavior of biodegradable nanocomposite fibers coated layer-by-layer on AM50 magnesium implant.

    Science.gov (United States)

    Abdal-Hay, Abdalla; Hasan, Anwarul; Kim, Yu-Kyoung; Yu-Kyoung; Lee, Min-Ho; Hamdy, Abdel Salam; Khalil, Khalil Abdelrazek

    2016-01-01

    This article demonstrates the use of hybrid nanofibers to improve the biodegradation rate and biocompatibility of AM50 magnesium alloy. Biodegradable hybrid membrane fiber layers containing nano-hydroxyapatite (nHA) particles and poly(lactide)(PLA) nanofibers were coated layer-by-layer (LbL) on AM50 coupons using a facile single-step air jet spinning (AJS) approach. The corrosion performance of coated and uncoated coupon samples was investigated by means of electrochemical measurements. The results showed that the AJS 3D membrane fiber layers, particularly the hybrid membrane layers containing a small amount of nHA (3 wt.%), induce a higher biocorrosion resistance and effectively decrease the initial degradation rate compared with the neat AM50 coupon samples. The adhesion strength improved highly due to the presence of nHA particles in the AJS layer. Furthermore, the long biodegradation rates of AM50 alloy in Hank's balanced salt solution (HBSS) were significantly controlled by the AJS-coatings. The results showed a higher cytocompatibility for AJS-coatings compared to that for neat Mg alloys. The nanostructured nHA embedded hybrid PLA nanofiber coating can therefore be a suitable coating material for Mg alloy as a potential material for biodegradable metallic orthopedic implants. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Thermally joining and/or coating or thermally separating the workpieces having heat-sensitive coating, comprises restoring coating by thermally coating the coating material after thermally joining and/or coating or thermally separating

    OpenAIRE

    Riedel, Frank; Winkelmann, Ralf; Puschmann, Markus

    2011-01-01

    The method for thermally joining and/or coating or thermally separating the workpieces (1), which have a heat-sensitive coating (2), comprises restoring the coating by thermally coating a coating material (3) after thermally joining and/or coating or thermally separating the workpieces. A part of the thermal energy introduced in the workpiece for joining and/or coating or separating or in the workpieces is used for thermally coating the coating material. Two workpieces are welded or soldered ...

  16. Influences of the iron ion (Fe3+)-doping on structural and optical properties of nanocrystalline TiO2 thin films prepared by sol-gel spin coating

    International Nuclear Information System (INIS)

    Ben Naceur, J.; Mechiakh, R.; Bousbih, F.; Chtourou, R.

    2011-01-01

    Titanium dioxide (TiO 2 ) thin films doping of various iron ion (Fe 3+ ) concentrations were deposited on silicon (Si) (100) and quartz substrates by sol-gel Spin Coating technique followed by a thermal treatment at 600 deg. C. The structure, surface morphology and optical properties, as a function of the doping, have been studied by X-ray diffractometer (XRD), Raman, ultraviolet-visible (UV-vis) and Spectroscopic Ellipsometry (SE). XRD and Raman analyzes of our thin films show that the crystalline phase of TiO 2 thin films comprised only the anatase TiO 2 , but the crystallinity decreased when the Fe 3+ content increased from 0% to 20%. During the Fe 3+ addition to 20%, the phase of TiO 2 thin film still maintained the amorphous state. The grain size calculated from XRD patterns varies from 29.3 to 22.6 nm. The complex index and the optical band gap (E g ) of the films were determined by the spectroscopic ellipsometry analysis. We have found that the optical band gap decreased with an increasing Fe 3+ content.

  17. Spinning Them Off: Entrepreneuring Practices in Corporate Spin-Offs

    Directory of Open Access Journals (Sweden)

    Katja Maria Hydle

    2016-01-01

    Full Text Available This paper focuses on the practices between parent and child firms in corporate spinoffs. We uncover the enacted aspects of knowledge, called knowing, through theories from seven cases of incumbent-backed spin-offs and find that the management of the parent firms are highly involved in the spin-offs. The practices associated with spinning off are solving problems, involving multidisciplinary expertise and entrepreneuring management at the parent firm. We contribute to the spin-off literature by discussing the knowledge required for successfully spinning off child firms and to practice theory by empirically uncovering the practical understanding involved in the origin and perpetuation of an organization.

  18. Spin and tunneling dynamics in an asymmetrical double quantum dot with spin-orbit coupling: Selective spin transport device

    Science.gov (United States)

    Singh, Madhav K.; Jha, Pradeep K.; Bhattacherjee, Aranya B.

    2017-09-01

    In this article, we study the spin and tunneling dynamics as a function of magnetic field in a one-dimensional GaAs double quantum dot with both the Dresselhaus and Rashba spin-orbit coupling. In particular, we consider different spatial widths for the spin-up and spin-down electronic states. We find that the spin dynamics is a superposition of slow as well as fast Rabi oscillations. It is found that the Rashba interaction strength as well as the external magnetic field strongly modifies the slow Rabi oscillations which is particularly useful for implementing solid state selective spin transport device.

  19. Enhanced Spin-Orbit Torque via Modulation of Spin Current Absorption

    KAUST Repository

    Qiu, Xuepeng

    2016-11-18

    The magnitude of spin-orbit torque (SOT), exerted to a ferromagnet (FM) from an adjacent heavy metal (HM), strongly depends on the amount of spin current absorbed in the FM. We exploit the large spin absorption at the Ru interface to manipulate the SOTs in HM/FM/Ru multilayers. While the FM thickness is smaller than its spin dephasing length of 1.2 nm, the top Ru layer largely boosts the absorption of spin currents into the FM layer and substantially enhances the strength of SOT acting on the FM. Spin-pumping experiments induced by ferromagnetic resonance support our conclusions that the observed increase in the SOT efficiency can be attributed to an enhancement of the spin-current absorption. A theoretical model that considers both reflected and transmitted mixing conductances at the two interfaces of FM is developed to explain the results.

  20. Excitation of coherent propagating spin waves by pure spin currents.

    Science.gov (United States)

    Demidov, Vladislav E; Urazhdin, Sergei; Liu, Ronghua; Divinskiy, Boris; Telegin, Andrey; Demokritov, Sergej O

    2016-01-28

    Utilization of pure spin currents not accompanied by the flow of electrical charge provides unprecedented opportunities for the emerging technologies based on the electron's spin degree of freedom, such as spintronics and magnonics. It was recently shown that pure spin currents can be used to excite coherent magnetization dynamics in magnetic nanostructures. However, because of the intrinsic nonlinear self-localization effects, magnetic auto-oscillations in the demonstrated devices were spatially confined, preventing their applications as sources of propagating spin waves in magnonic circuits using these waves as signal carriers. Here, we experimentally demonstrate efficient excitation and directional propagation of coherent spin waves generated by pure spin current. We show that this can be achieved by using the nonlocal spin injection mechanism, which enables flexible design of magnetic nanosystems and allows one to efficiently control their dynamic characteristics.

  1. Electrical detection of spin current and spin relaxation in nonmagnetic semiconductors

    International Nuclear Information System (INIS)

    Miah, M Idrish

    2008-01-01

    We report an electrical method for the detection of spin current and spin relaxation in nonmagnetic semiconductors. Optically polarized spins are dragged by an electric field in GaAs. We use the anomalous Hall effect for the detection of spin current and spin relaxation. It is found that the effect depends on the electric field and doping density as well as on temperature, but not on the excitation power. A calculation for the effect is performed using the measured spin polarization by a pump-probe experiment. The results are also discussed in comparison with a quantitative evaluation of the spin lifetimes of the photogenerated electrons under drift in GaAs

  2. Electrical detection of spin current and spin relaxation in nonmagnetic semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Miah, M Idrish [Nanoscale Science and Technology Centre and School of Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111 (Australia); Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh)], E-mail: m.miah@griffith.edu.au

    2008-09-21

    We report an electrical method for the detection of spin current and spin relaxation in nonmagnetic semiconductors. Optically polarized spins are dragged by an electric field in GaAs. We use the anomalous Hall effect for the detection of spin current and spin relaxation. It is found that the effect depends on the electric field and doping density as well as on temperature, but not on the excitation power. A calculation for the effect is performed using the measured spin polarization by a pump-probe experiment. The results are also discussed in comparison with a quantitative evaluation of the spin lifetimes of the photogenerated electrons under drift in GaAs.

  3. Spin Transport in Nondegenerate Si with a Spin MOSFET Structure at Room Temperature

    Science.gov (United States)

    Sasaki, Tomoyuki; Ando, Yuichiro; Kameno, Makoto; Tahara, Takayuki; Koike, Hayato; Oikawa, Tohru; Suzuki, Toshio; Shiraishi, Masashi

    2014-09-01

    Spin transport in nondegenerate semiconductors is expected to pave the way to the creation of spin transistors, spin logic devices, and reconfigurable logic circuits, because room-temperature (RT) spin transport in Si has already been achieved. However, RT spin transport has been limited to degenerate Si, which makes it difficult to produce spin-based signals because a gate electric field cannot be used to manipulate such signals. Here, we report the experimental demonstration of spin transport in nondegenerate Si with a spin metal-oxide-semiconductor field-effect transistor (MOSFET) structure. We successfully observe the modulation of the Hanle-type spin-precession signals, which is a characteristic spin dynamics in nondegenerate semiconductors. We obtain long spin transport of more than 20 μm and spin rotation greater than 4π at RT. We also observe gate-induced modulation of spin-transport signals at RT. The modulation of the spin diffusion length as a function of a gate voltage is successfully observed, which we attribute to the Elliott-Yafet spin relaxation mechanism. These achievements are expected to lead to the creation of practical Si-based spin MOSFETs.

  4. Current-induced spin polarization in a spin-polarized two-dimensional electron gas with spin-orbit coupling

    International Nuclear Information System (INIS)

    Wang, C.M.; Pang, M.Q.; Liu, S.Y.; Lei, X.L.

    2010-01-01

    The current-induced spin polarization (CISP) is investigated in a combined Rashba-Dresselhaus spin-orbit-coupled two-dimensional electron gas, subjected to a homogeneous out-of-plane magnetization. It is found that, in addition to the usual collision-related in-plane parts of CISP, there are two impurity-density-free contributions, arising from intrinsic and disorder-mediated mechanisms. The intrinsic parts of spin polarization are related to the Berry curvature, analogous with the anomalous and spin Hall effects. For short-range collision, the disorder-mediated spin polarizations completely cancel the intrinsic ones and the total in-plane components of CISP equal those for systems without magnetization. However, for remote disorders, this cancellation does not occur and the total in-plane components of CISP strongly depend on the spin-orbit interaction coefficients and magnetization for both pure Rashba and combined Rashba-Dresselhaus models.

  5. Anisotropic interactions of a single spin and dark-spin spectroscopy in diamond

    Science.gov (United States)

    Epstein, R. J.; Mendoza, F. M.; Kato, Y. K.; Awschalom, D. D.

    2005-11-01

    Experiments on single nitrogen-vacancy (N-V) centres in diamond, which include electron spin resonance, Rabi oscillations, single-shot spin readout and two-qubit operations with a nearby13C nuclear spin, show the potential of this spin system for solid-state quantum information processing. Moreover, N-V centre ensembles can have spin-coherence times exceeding 50 μs at room temperature. We have developed an angle-resolved magneto-photoluminescence microscope apparatus to investigate the anisotropic electron-spin interactions of single N-V centres at room temperature. We observe negative peaks in the photoluminescence as a function of both magnetic-field magnitude and angle that are explained by coherent spin precession and anisotropic relaxation at spin-level anti-crossings. In addition, precise field alignment unmasks the resonant coupling to neighbouring `dark' nitrogen spins, otherwise undetected by photoluminescence. These results demonstrate the capability of our spectroscopic technique for measuring small numbers of dark spins by means of a single bright spin under ambient conditions.

  6. Spin-resolved electron waiting times in a quantum-dot spin valve

    Science.gov (United States)

    Tang, Gaomin; Xu, Fuming; Mi, Shuo; Wang, Jian

    2018-04-01

    We study the electronic waiting-time distributions (WTDs) in a noninteracting quantum-dot spin valve by varying spin polarization and the noncollinear angle between the magnetizations of the leads using the scattering matrix approach. Since the quantum-dot spin valve involves two channels (spin up and down) in both the incoming and outgoing channels, we study three different kinds of WTDs, which are two-channel WTD, spin-resolved single-channel WTD, and cross-channel WTD. We analyze the behaviors of WTDs in short times, correlated with the current behaviors for different spin polarizations and noncollinear angles. Cross-channel WTD reflects the correlation between two spin channels and can be used to characterize the spin-transfer torque process. We study the influence of the earlier detection on the subsequent detection from the perspective of cross-channel WTD, and define the influence degree quantity as the cumulative absolute difference between cross-channel WTDs and first-passage time distributions to quantitatively characterize the spin-flip process. We observe that influence degree versus spin-transfer torque for different noncollinear angles as well as different polarizations collapse into a single curve showing universal behaviors. This demonstrates that cross-channel WTDs can be a pathway to characterize spin correlation in spintronics system.

  7. Novel hybrid coatings with controlled wettability by composite nanoparticle aggregation

    Energy Technology Data Exchange (ETDEWEB)

    Hritcu, Doina, E-mail: dhritcu@ch.tuiasi.ro; Dodi, Gianina; Iordache, Mirabela L.; Draganescu, Dan; Sava, Elena; Popa, Marcel I.

    2016-11-30

    Highlights: • Magnetite-grafted chitosan composite nanoparticles were synthesized. • The particles are able to assemble under the influence of a silane derivative. • Thin films containing composites, chitosan and hydrolyzed silane were optimized. • The novel hybrid coatings show hierarchical roughness and high wetting angle. - Abstract: The aim of this study is to evaluate novel hybrid materials as potential candidates for producing coatings with hierarchical roughness and controlled wetting behaviour. Magnetite (Fe{sub 3}O{sub 4}) nanoparticles obtained by co-precipitation were embedded in matrices synthesized by radical graft co-polymerization of butyl acrylate (BA), butyl methacrylate (BMA), hexyl acrylate (HA) or styrene (ST) with ethylene glycol di-methacrylate (EGDMA) onto previously modified chitosan bearing surface vinyl groups. The resulting composite particles were characterized regarding their average size, composition and magnetic properties. Hybrid thin films containing suspension of composite particles in ethanol and pre-hydrolysed hexadecyltrimethoxysilane (HDTS) as a coupling/crosslinking agent were deposited by spin coating or spraying. The films were cured by heating and subsequently characterized regarding their morphology (scanning electron microscopy), contact angle with water and adhesion to substrate (scratch test). The structure-property relationship is discussed.

  8. Spin Filters as High-Performance Spin Polarimeters

    International Nuclear Information System (INIS)

    Rougemaille, N.; Lampel, G.; Peretti, J.; Drouhin, H.-J.; Lassailly, Y.; Filipe, A.; Wirth, T.; Schuhl, A.

    2003-01-01

    A spin-dependent transport experiment in which hot electrons pass through a ferromagnetic metal / semiconductor Schottky diode has been performed. A spin-polarized free-electron beam, emitted in vacuum from a GaAs photocathode, is injected into the thin metal layer with an energy between 5 and 1000 eV above to the Fermi level. The transmitted current collected in the semiconductor substrate increases with injection energy because of secondary - electron multiplication. The spin-dependent part of the transmitted current is first constant up to about 100 eV and then increases by 4 orders of magnitude. As an immediate application, the solid-state hybrid structure studied here leads to a very efficient and compact device for spin polarization detection

  9. Spin transport in spin filtering magnetic tunneling junctions.

    Science.gov (United States)

    Li, Yun; Lee, Eok Kyun

    2007-11-01

    Taking into account spin-orbit coupling and s-d interaction, we investigate spin transport properties of the magnetic tunneling junctions with spin filtering barrier using Landauer-Büttiker formalism implemented with the recursive algorithm to calculate the real-space Green function. We predict completely different bias dependence of negative tunnel magnetoresistance (TMR) between the systems composed of nonmagnetic electrode (NM)/ferromagnetic barrier (FB)/ferromagnet (FM) and NM/FB/FM/NM spin filtering tunnel junctions (SFTJs). Analyses of the results provide us possible ways of designing the systems which modulate the TMR in the negative magnetoresistance regime.

  10. Silica Nanoparticles Functionalized with Zwitterionic Sulfobetaine Siloxane for Application as a Versatile Antifouling Coating System.

    Science.gov (United States)

    Knowles, Brianna R; Wagner, Pawel; Maclaughlin, Shane; Higgins, Michael J; Molino, Paul J

    2017-06-07

    The growing need to develop surfaces able to effectively resist biological fouling has resulted in the widespread investigation of nanomaterials with potential antifouling properties. However, the preparation of effective antifouling coatings is limited by the availability of reactive surface functional groups and our ability to carefully control and organize chemistries at a materials' interface. Here, we present two methods of preparing hydrophilic low-fouling surface coatings through reaction of silica-nanoparticle suspensions and predeposited silica-nanoparticle films with zwitterionic sulfobetaine (SB). Silica-nanoparticle suspensions were functionalized with SB across three pH conditions and deposited as thin films via a simple spin-coating process to generate hydrophilic antifouling coatings. In addition, coatings of predeposited silica nanoparticles were surface functionalized via exposure to zwitterionic solutions. Quartz crystal microgravimetry with dissipation monitoring was employed as a high throughput technique for monitoring and optimizing reaction to the silica-nanoparticle surfaces. Functionalization of nanoparticle films was rapid and could be achieved over a wide pH range and at low zwitterion concentrations. All functionalized particle surfaces presented a high degree of wettability and resulted in large reductions in adsorption of bovine serum albumin protein. Particle coatings also showed a reduction in adhesion of fungal spores (Epicoccum nigrum) and bacteria (Escherichia coli) by up to 87 and 96%, respectively. These results indicate the potential for functionalized nanosilicas to be further developed as versatile fouling-resistant coatings for widespread coating applications.

  11. Fabrication of indium tin oxide (ITO) thin film with pre-treated sol coating

    International Nuclear Information System (INIS)

    Hong, Sung-Jei; Han, Jeong-In

    2004-01-01

    A new pre-treated sol-coating method to fabricate an indium tin oxide (ITO) thin film is introduced in this paper. The pre-treatment sol-coating method is to form a seed layer on the substrate before spin coating of ITO sol. The pre-treatment was carried out at room temperature in order not to damage the substrate during the pre-treatment. It is effective to enhance the formation of the ITO sol film on the substrate, owing to the seed layer. The seed layer consists of ultrafine grains, which are observed at the pre-treated substrate. For the optimal pre-treatment condition, we used pre-treatment times of 24, 48, 72, and 96 hours to observe the effect on the characteristics of ITO sol film. As a result, the lowest resistance could be achieved with a pre-treatment time of 72 hours. The optical transmittance of the ITO sol film with the pre-treatment time of 72 hours exceeded 80 % at a wavelength of 400 nm. So, an ITO sol film with good electrical and optical properties could be fabricated by using the pretreatment sol coating.

  12. Spin relaxation through Kondo scattering in Cu/Py lateral spin valves

    Science.gov (United States)

    Batley, J. T.; Rosaond, M. C.; Ali, M.; Linfield, E. H.; Burnell, G.; Hickey, B. J.

    Within non-magnetic metals it is reasonable to expect the Elliot-Yafet mechanism to govern spin-relaxation and thus the temperature dependence of the spin diffusion length might be inversely proportional to resistivity. However, in lateral spin valves, measurements have found that at low temperatures the spin diffusion length unexpectedly decreases. We have fabricated lateral spin valves from Cu with different concentrations of magnetic impurities. Through temperature dependent charge and spin transport measurements we present clear evidence linking the presence of the Kondo effect within Cu to the suppression of the spin diffusion length below 30 K. We have calculated the spin-relaxation rate and isolated the contribution from magnetic impurities. At very low temperatures electron-electron interactions play a more prominent role in the Kondo effect. Well below the Kondo temperature a strong-coupling regime exists, where the moments become screened and the magnetic dephasing rate is reduced. We also investigate the effect of this low temperature regime (>1 K) on a pure spin current. This work shows the dominant role of Kondo scattering, even in low concentrations of order 1 ppm, within pure spin transport.

  13. Spin polarization of tunneling current in barriers with spin-orbit coupling

    International Nuclear Information System (INIS)

    Fujita, T; Jalil, M B A; Tan, S G

    2008-01-01

    We present a general method for evaluating the maximum transmitted spin polarization and optimal spin axis for an arbitrary spin-orbit coupling (SOC) barrier system, in which the spins lie in the azimuthal plane and finite spin polarization is achieved by wavevector filtering of electrons. Besides momentum filtering, another prerequisite for finite spin polarization is asymmetric occupation or transmission probabilities of the eigenstates of the SOC Hamiltonian. This is achieved most efficiently by resonant tunneling through multiple SOC barriers. We apply our analysis to common SOC mechanisms in semiconductors: pure bulk Dresselhaus SOC, heterostructures with mixed Dresselhaus and Rashba SOC and strain-induced SOC. In particular, we find that the interplay between Dresselhaus and Rashba SOC effects can yield several advantageous features for spin filter and spin injector functions, such as increased robustness to wavevector spread of electrons

  14. Spin polarization of tunneling current in barriers with spin-orbit coupling.

    Science.gov (United States)

    Fujita, T; Jalil, M B A; Tan, S G

    2008-03-19

    We present a general method for evaluating the maximum transmitted spin polarization and optimal spin axis for an arbitrary spin-orbit coupling (SOC) barrier system, in which the spins lie in the azimuthal plane and finite spin polarization is achieved by wavevector filtering of electrons. Besides momentum filtering, another prerequisite for finite spin polarization is asymmetric occupation or transmission probabilities of the eigenstates of the SOC Hamiltonian. This is achieved most efficiently by resonant tunneling through multiple SOC barriers. We apply our analysis to common SOC mechanisms in semiconductors: pure bulk Dresselhaus SOC, heterostructures with mixed Dresselhaus and Rashba SOC and strain-induced SOC. In particular, we find that the interplay between Dresselhaus and Rashba SOC effects can yield several advantageous features for spin filter and spin injector functions, such as increased robustness to wavevector spread of electrons.

  15. Spin pumping and inverse spin Hall effects in heavy metal/antiferromagnet/Permalloy trilayers

    Science.gov (United States)

    Saglam, Hilal; Zhang, Wei; Jungfleisch, M. Benjamin; Jiang, Wanjun; Pearson, John E.; Hoffmann, Axel

    Recent work shows efficient spin transfer via spin waves in insulating antiferromagnets (AFMs), suggesting that AFMs can play a more active role in the manipulation of ferromagnets. We use spin pumping and inverse spin Hall effect experiments on heavy metal (Pt and W)/AFMs/Py (Ni80Fe20) trilayer structures, to examine the possible spin transfer phenomenon in metallic AFMs, i . e . , FeMn and PdMn. Previous work has studied electronic effects of the spin transport in these materials, yielding short spin diffusion length on the order of 1 nm. However, the work did not examine whether besides diffusive spin transport by the conduction electrons, there are additional spin transport contributions from spin wave excitations. We clearly observe spin transport from the Py spin reservoir to the heavy metal layer through the sandwiched AFMs with thicknesses well above the previously measured spin diffusion lengths, indicating that spin transport by spin waves may lead to non-negligible contributions This work was supported by US DOE, OS, Materials Sciences and Engineering Division. Lithographic patterning was carried out at the CNM, which is supported by DOE, OS under Contract No. DE-AC02-06CH11357.

  16. Development of hybrid organic-inorganic optical coatings to prevent laser damage

    International Nuclear Information System (INIS)

    Compoint, Francois

    2015-01-01

    The optical devices (lents, mirrors, portholes...) that are set on the chains of the Laser Megajoule (LMJ) may be damaged by the high energy laser beam especially around the UV wavelength of 351 nm. The damages are micronic craters on the rear of the optics that grows exponentially after each laser shots. The study aims at developing some optical thin coatings on the rear of the optical substrates to prevent the growth of the damage by amortizing the laser shock wave, self-healing the craters that has appeared, or repairing the laser hole after the damage occurs. The thin coatings have been prepared by a sol-gel method by using silica precursor and a polydimethylsiloxane (PDMS) elastomer. The two species reacted together to get a hybrid organic-inorganic Ormosil (organically modified silica) material, by creating a silica network linked to the PDMS species with covalent and hydrogen bounds. The thin layers are obtained from the sol-gel solution by using a dip and spin coating method. The coatings have an excellent optical transmission around the UV (351 nm) wavelength. They also have some self-healing properties by using mechanical (viscoelastic) mechanism and chemical reversible hydrogen bounds action in the materials. The silica-PDMS coatings prove to be resistant to the laser beam at 351 nm, despite some optimizations that still need to be done to reach the sought laser damage threshold. (author) [fr

  17. Effect of different sol concentrations on the properties of nanocrystalline ZnO thin films grown on FTO substrates by sol-gel spin-coating

    International Nuclear Information System (INIS)

    Kim, Ikhyun; Kim, Younggyu; Nam, Giwoong; Kim, Dongwan; Park, Minju; Kim, Haeun; Lee, Wookbin; Leem, Jaeyoung; Kim, Jongsu; Kim, Jin Soo

    2014-01-01

    Nanocrystalline ZnO thin films grown on fluorine-doped tinoxide (FTO) substrates were fabricated using the spin-coating method. The structural and the optical properties of the ZnO thin films prepared using different sol concentrations were investigated by using field-emission scanning electron microscopy (FE-SEM), X-ray diffractometry (XRD), photoluminescence (PL) measurements, and ultraviolet-visible (UV-vis) spectrometry. The surface morphology of the ZnO thin films, as observed in the SEM images, exhibited a mountain-chain structure. XRD results indicated that the thin films were preferentially orientated along the direction of the c-axis and that the grain size of the ZnO thin films increased with increasing sol concentration. The PL spectra showed a strong ultraviolet emission peak at 3.22 eV and a broad orange emission peak at 2.0 eV. The intensities of deep-level emission (DLE) gradually increased with increasing sol concentration from 0.4 to 1.0 M. The transmittance spectra of the ZnO thin films showed that the ZnO thin films were transparent (∼85%) in the visible region and exhibited sharp absorption edges at 375 nm. Thus, The Urbach energy of ZnO thin films decreased with increasing sol concentration.

  18. Spin-photon interface and spin-controlled photon switching in a nanobeam waveguide

    DEFF Research Database (Denmark)

    Javadi, Alisa; Ding, Dapeng; Appel, Martin Hayhurst

    2018-01-01

    Access to the electron spin is at the heart of many protocols for integrated and distributed quantum-information processing [1-4]. For instance, interfacing the spin-state of an electron and a photon can be utilized to perform quantum gates between photons [2,5] or to entangle remote spin states [6......-9]. Ultimately, a quantum network of entangled spins constitutes a new paradigm in quantum optics [1]. Towards this goal, an integrated spin-photon interface would be a major leap forward. Here we demonstrate an efficient and optically programmable interface between the spin of an electron in a quantum dot...... and photons in a nanophotonic waveguide. The spin can be deterministically prepared with a fidelity of 96\\%. Subsequently the system is used to implement a "single-spin photonic switch", where the spin state of the electron directs the flow of photons through the waveguide. The spin-photon interface may...

  19. Spin symposium

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1989-01-15

    The recent 8th International Symposium on High Energy Spin Physics at the University of Minnesota in Minneapolis, Minnesota, opened with a bang when L. Pondrom (Wisconsin), donning a hard hat borrowed from construction workers, ventured that 'spin, the notorious inessential complication of hadronic physics, is finally telling us what real QCD (quantum chromodynamics, the field theory of quarks and gluons) looks like.' He was referring to an animated discussion on the meaning of the recent spin oriented (polarized) scattering results from the European Muon Collaboration (EMC) at CERN and reported at the Symposium by R. Garnet (Liverpool) and P. Schuler (Yale) which show that the proton spin is not simply a reflection of the spins of its constituent quarks.

  20. Inverse spin Hall effect by spin injection

    Science.gov (United States)

    Liu, S. Y.; Horing, Norman J. M.; Lei, X. L.

    2007-09-01

    Motivated by a recent experiment [S. O. Valenzuela and M. Tinkham, Nature (London) 442, 176 (2006)], the authors present a quantitative microscopic theory to investigate the inverse spin-Hall effect with spin injection into aluminum considering both intrinsic and extrinsic spin-orbit couplings using the orthogonalized-plane-wave method. Their theoretical results are in good agreement with the experimental data. It is also clear that the magnitude of the anomalous Hall resistivity is mainly due to contributions from extrinsic skew scattering.

  1. The kinematic differences between off-spin and leg-spin bowling in cricket.

    Science.gov (United States)

    Beach, Aaron J; Ferdinands, René E D; Sinclair, Peter J

    2016-09-01

    Spin bowling is generally coached using a standard technical framework, but this practice has not been based upon a comparative biomechanical analysis of leg-spin and off-spin bowling. This study analysed the three-dimensional (3D) kinematics of 23 off-spin and 20 leg-spin bowlers using a Cortex motion analysis system to identify how aspects of the respective techniques differed. A multivariate ANOVA found that certain data tended to validate some of the stated differences in the coaching literature. Off-spin bowlers had a significantly shorter stride length (p = 0.006) and spin rate (p = 0.001), but a greater release height than leg-spinners (p = 0.007). In addition, a number of other kinematic differences were identified that were not previously documented in coaching literature. These included a larger rear knee flexion (p = 0.007), faster approach speed (p < 0.001), and flexing elbow action during the arm acceleration compared with an extension action used by most of the off-spin bowlers. Off-spin and leg-spin bowlers also deviated from the standard coaching model for the shoulder alignment, front knee angle at release, and forearm mechanics. This study suggests that off-spin and leg-spin are distinct bowling techniques, supporting the development of two different coaching models in spin bowling.

  2. Field-controlled spin current in frustrated spin chains

    Directory of Open Access Journals (Sweden)

    A.K. Kolezhuk

    2009-01-01

    Full Text Available We study states with spontaneous spin current, emerging in frustrated antiferromagnetic spin-S chains subject to a strong external magnetic field. As a numerical tool, we use a non-Abelian symmetry realization of the density matrix renormalization group. The field dependence of the order parameter and the critical exponents are presented for zigzag chains with S=1/2, 1, 3/2, and 2.

  3. Nuclear spin content and constraints on exotic spin-dependent couplings

    International Nuclear Information System (INIS)

    Kimball, D F Jackson

    2015-01-01

    There are numerous recent and ongoing experiments employing a variety of atomic species to search for couplings of atomic spins to exotic fields. In order to meaningfully compare these experimental results, the coupling of the exotic field to the atomic spin must be interpreted in terms of the coupling to electron, proton, and neutron spins. Traditionally, constraints from atomic experiments on exotic couplings to neutron and proton spins have been derived using the single-particle Schmidt model for nuclear spin. In this model, particular atomic species are sensitive to either neutron or proton spin couplings, but not both. More recently, semi-empirical models employing nuclear magnetic moment data have been used to derive new constraints for non-valence nucleons. However, comparison of such semi-empirical models to detailed large-scale nuclear shell model calculations and analysis of known physical effects in nuclei show that existing semi-empirical models cannot reliably be used to predict the spin polarization of non-valence nucleons. The results of our re-analysis of nuclear spin content are applied to searches for exotic long-range monopole–dipole and dipole–dipole couplings of nuclei leading to significant revisions of some published constraints. (paper)

  4. Spin injection into Pt-polymers with large spin-orbit coupling

    Science.gov (United States)

    Sun, Dali; McLaughlin, Ryan; Siegel, Gene; Tiwari, Ashutosh; Vardeny, Z. Valy

    2014-03-01

    Organic spintronics has entered a new era of devices that integrate organic light-emitting diodes (OLED) in organic spin valve (OSV) geometry (dubbed bipolar organic spin valve, or spin-OLED), for actively manipulating the device electroluminescence via the spin alignment of two ferromagnetic electrodes (Science 337, 204-209, 2012; Appl. Phys. Lett. 103, 042411, 2013). Organic semiconductors that contain heavy metal elements have been widely used as phosphorescent dopants in white-OLEDs. However such active materials are detrimental for OSV operation due to their large spin-orbit coupling (SOC) that may limit the spin diffusion length and thus spin-OLED based on organics with large SOC is a challenge. We report the successful fabrication of OSVs based on pi-conjugated polymers which contain intrachain Platinum atoms (dubbed Pt-polymers). Spin injection into the Pt-polymers is investigated by the giant magnetoresistance (GMR) effect as a function of bias voltage, temperature and polymer layer thickness. From the GMR bias voltage dependence we infer that the ``impendence mismatch'' between ferromagnetic electrodes and Pt-polymer may be suppressed due to the large SOC. Research sponsored by the NSF (Grant No. DMR-1104495) and NSF-MRSEC (DMR 1121252) at the University of Utah.

  5. Spin-polarized light-emitting diodes based on organic bipolar spin valves

    Science.gov (United States)

    Vardeny, Zeev Valentine; Nguyen, Tho Duc; Ehrenfreund, Eitan Avraham

    2017-10-25

    Spin-polarized organic light-emitting diodes are provided. Such spin-polarized organic light-emitting diodes incorporate ferromagnetic electrodes and show considerable spin-valve magneto-electroluminescence and magneto-conductivity responses, with voltage and temperature dependencies that originate from the bipolar spin-polarized space charge limited current.

  6. QED approach to the nuclear spin-spin coupling tensor

    International Nuclear Information System (INIS)

    Romero, Rodolfo H.; Aucar, Gustavo A.

    2002-01-01

    A quantum electrodynamical approach for the calculation of the nuclear spin-spin coupling tensor of nuclear-magnetic-resonance spectroscopy is given. Quantization of radiation fields within the molecule is considered and expressions for the magnetic field in the neighborhood of a nucleus are calculated. Using a generalization of time-dependent response theory, an effective spin-spin interaction is obtained from the coupling of nuclear magnetic moments to a virtual quantized magnetic field. The energy-dependent operators obtained reduce to usual classical-field expressions at suitable limits

  7. Realization of tunable spin-dependent splitting in intrinsic photonic spin Hall effect

    Energy Technology Data Exchange (ETDEWEB)

    Ling, Xiaohui [SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, and Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Laboratory for spin photonics, College of Physics and Microelectronic Science, Hunan University, Changsha 410082 (China); Department of Physics and Electronic Information Science, Hengyang Normal University, Hengyang 421002 (China); Yi, Xunong [SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, and Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Zhou, Xinxing; Liu, Yachao; Shu, Weixing; Wen, Shuangchun [Laboratory for spin photonics, College of Physics and Microelectronic Science, Hunan University, Changsha 410082 (China); Luo, Hailu, E-mail: hailuluo@hnu.edu.cn [SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, and Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Laboratory for spin photonics, College of Physics and Microelectronic Science, Hunan University, Changsha 410082 (China)

    2014-10-13

    We report the realization of tunable spin-dependent splitting in intrinsic photonic spin Hall effect. By breaking the rotational symmetry of a cylindrical vector beam, the intrinsic vortex phases that the two spin components of the vector beam carries, which is similar to the geometric Pancharatnam-Berry phase, are no longer continuous in the azimuthal direction, and leads to observation of spin accumulation at the opposite edge of the beam. Due to the inherent nature of the phase and independency of light-matter interaction, the observed photonic spin Hall effect is intrinsic. Modulating the topological charge of the vector beam, the spin-dependent splitting can be enhanced and the direction of spin accumulation is switchable. Our findings may provide a possible route for generation and manipulation of spin-polarized photons, and enables spin-based photonics applications.

  8. Spin-flip and spin orbit interactions in heavy ion systems

    International Nuclear Information System (INIS)

    Bybell, D.P.

    1983-01-01

    The role of spin orbit forces in heavy ion reactions is not completely understood. Experimental data is scarce for these systems but the data that does exist indicates a stronger spin orbit force than predicted by the folding models. The spin-flip probability of non-spin zero projectiles is one technique used for these measurements and is often taken as a direct indicator of a spin orbit interaction. This work measures the projectile spin-flip probability for three inelastic reactions; 13 C + 24 Mg, E/sub cm/ = 22.7 MeV; 13 C + 12 C, E/sub cm/ = 17.3 MeV; and 6 Li + 12 C, E/sub cm/ = 15.2 MeV, all leading to the first J/sup π/ = 2 + state of the target. The technique of particle-γ angular correlations was used for measuring the final state density matrix elements, of which the absolute value M = 1 magnetic substate population is equivalent to the spin-flip probability. The method was explored in detail and found to be sensitive to spin-flip probabilities smaller than 1%. The technique was also found to be a good indicator of the reaction mechanism involved. Nonzero and occasionally large spin-flip probabilities were observed in all systems, much larger than the folding model predictions. Information was obtained on the non-spin-flip density matrix elements. In the 13 C + 24 Mg reaction, these were found to agree with calculations when the finite size of the particle detector is included

  9. Effect of Sr on the bioactivity and corrosion resistance of nanoporous niobium oxide coating for orthopaedic applications

    Energy Technology Data Exchange (ETDEWEB)

    Pauline, S. Anne; Rajendran, N., E-mail: nrajendran@annauniv.edu

    2014-03-01

    In this study, strontium incorporated Nb{sub 2}O{sub 5} was synthesized in two different proportions by sol–gel methodology and was deposited on 316L SS by spin coating method. The synthesis conditions were optimized to obtain a nanoporous morphology. The prepared Sr-incorporated Nb{sub 2}O{sub 5} coatings were uniform, smooth and well adherent on to the substrate 316L SS. The coatings were characterized by attenuated total reflectance-infrared spectroscopy (ATR-IR), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), atomic force microscopy (AFM) and transmission electron microscopy (TEM) and the formation of Sr-incorporated Nb{sub 2}O{sub 5} coatings with nanoporous morphology was confirmed. Static water contact angle measurements showed an enhancement in the wettability of the obtained coatings. In vitro bioactivity test of the coated substrates showed that 0.05 M Sr-incorporated Nb{sub 2}O{sub 5} coating had better bioactivity compared to 0.1 M Sr-incorporated coating. Solution analysis studies confirmed the controlled release of Sr ions from the coating, which aid and enhance hydroxyapatite (HAp) growth. Electrochemical studies confirmed that the coatings provided excellent corrosion protection to the base material as increased charge transfer resistance and decreased double layer capacitance was observed for the coated substrates. - Highlights: • Nanoporous Sr-incorporated Nb{sub 2}O{sub 5} coatings were deposited on 316L SS. • The coatings have excellent bond strength and high Vickers micro hardness value. • Nanoporous 0.05 M Sr-incorporated Nb{sub 2}O{sub 5} coating showed hydroxyapatite growth. • Slow release of strontium from the coating accelerated hydroxyapatite growth. • The nanoporous coatings offered excellent corrosion protection to 316L SS.

  10. Magnetic proximity control of spin currents and giant spin accumulation in graphene

    Science.gov (United States)

    Singh, Simranjeet

    Two dimensional (2D) materials provide a unique platform to explore the full potential of magnetic proximity driven phenomena. We will present the experimental study showing the strong modulation of spin currents in graphene layers by controlling the direction of the exchange field due to the ferromagnetic-insulator (FMI) magnetization in graphene/FMI heterostructures. Owing to clean interfaces, a strong magnetic exchange coupling leads to the experimental observation of complete spin modulation at low externally applied magnetic fields in short graphene channels. We also discover that the graphene spin current can be fully dephased by randomly fluctuating exchange fields. This is manifested as an unusually strong temperature dependence of the non-local spin signals in graphene, which is due to spin relaxation by thermally-induced transverse fluctuations of the FMI magnetization. Additionally, it has been a challenge to grow a smooth, robust and pin-hole free tunnel barriers on graphene, which can withstand large current densities for efficient electrical spin injection. We have experimentally demonstrated giant spin accumulation in graphene lateral spin valves employing SrO tunnel barriers. Nonlocal spin signals, as large as 2 mV, are observed in graphene lateral spin valves at room temperature. This high spin accumulations observed using SrO tunnel barriers puts graphene on the roadmap for exploring the possibility of achieving a non-local magnetization switching due to the spin torque from electrically injected spins. Financial support from ONR (No. N00014-14-1-0350), NSF (No. DMR-1310661), and C-SPIN, one of the six SRC STARnet Centers, sponsored by MARCO and DARPA.

  11. The effect of different annealing temperatures on the structure and luminescence properties of Y{sub 2}O{sub 3}:Bi{sup 3+} thin films fabricated by spin coating

    Energy Technology Data Exchange (ETDEWEB)

    Yousif, A.; Jafer, R.M.; Som, S. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Department of Physics, Faculty of Education, University of Khartoum, P.O. Box 321, 11115 Omdurman (Sudan); Duvenhage, M.M.; Coetsee, E. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Swart, H.C., E-mail: swarthc@ufs.ac.za [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa)

    2016-03-01

    Graphical abstract: - Highlights: • Y{sub 2−x}O{sub 3}:Bi{sub x=0.005} thin films were successfully fabricated by the spin coating method. • The Y{sub 2−x}O{sub 3}:Bi{sub x=0.005} thin films were converted into Y{sub 2}Si{sub 2}O{sub 7}:Bi films after annealing. • The conversion affected the PL properties of the Bi{sup +} ion in the newly formed host. • A blue shift in emission colour was observed. - Abstract: This paper reports on the structural, morphology and optical properties of Y{sub 2−x}O{sub 3}:Bi{sub x=0.005} micro-and nanophosphors synthesized via the spin coating method. The influence of different annealing temperatures (900–1200 °C) on the morphology, crystal structure and the photoluminescence (PL) properties of the synthesized films were studied in detail. The crystal structure of the films was investigated with X-ray diffraction. The presence of the three major diffraction peaks with Miller indexes (2 1 1), (2 2 2) and (4 0 0) indicated that the Y{sub 2−x}O{sub 3}:Bi{sub x=0.005} thin films were well-crystallized at 900 °C, 1000 °C, 1100 °C and 1200 °C. Additionally, extra diffraction peaks were observed for the sample that was annealed at 1200 °C. Those extra peaks were due to the formation of the Y{sub 2}Si{sub 2}O{sub 7} phase owing to the annealing induced changes in the crystal structure and chemical composition of the Y{sub 2−x}O{sub 3}:Bi{sub x=0.005} thin film. This may also be attributed to inter diffusion of atomic species between the Si substrate and the Y{sub 2−x}O{sub 3}:Bi{sub x=0.005} thin film at the high annealing temperature. Due to structure-sensitive properties of the Bi{sup 3+} ions, a blue shift of the centre PL emission band from 495 nm to 410 nm was clearly observed and explained in detail. The time-of-flight secondary ion mass spectroscopy results show the Si diffusion from the Si substrate, whereas, the scanning electron microscopy and the atomic force microscopy were used for the morphology

  12. Characteristics and optical properties of iron ion (Fe{sup 3+})-doped titanium oxide thin films prepared by a sol-gel spin coating

    Energy Technology Data Exchange (ETDEWEB)

    Wang, M.C. [Faculty of Fragrance and Cosmetics, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Lin, H.J. [Department of Materials Science and Engineering, National United University, 1 Lein-Da, Kung-Ching Li, Miao-Li 36003, Taiwan (China)], E-mail: hjlin@nuu.edu.tw; Yang, T.S. [Department of Materials Science and Engineering, National United University, 1 Lein-Da, Kung-Ching Li, Miao-Li 36003, Taiwan (China)

    2009-04-03

    Titanium dioxide (TiO{sub 2}) thin films doping of various iron ion (Fe{sup 3+}) concentrations have been prepared on a glass substrate by the sol-gel spin coating process. Characteristics and optical properties of TiO{sub 2} thin films doping of various Fe content were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible spectroscopy (UV-vis) and spectroscopic ellipsometry. The crystalline phase of TiO{sub 2} thin films comprised only the anatase TiO{sub 2}, but the crystallinity decreased when the Fe{sup 3+} content increased from 0 to 25.0 wt%. During the Fe{sup 3+} addition to 25.0 wt%, the phase of TiO{sub 2} thin film still maintained the amorphous state. The absorption edge of TiO{sub 2} thin films shifted towards longer wavelengths (i.e. red shifted) from 355 to 415 nm when the Fe{sup 3+}-doped concentration increased from 0 to 25.0 wt%. The values of the refractive index (n), and extinction coefficient (k), decreased with an increasing Fe{sup 3+} content. Moreover, the band-gap energy of TiO{sub 2} thin films also decreased from 3.29 to 2.83 eV with an increase in the Fe{sup 3+} content from 0 to 25.0 wt%.

  13. Possible evidence for spin-transfer torque induced by spin-triplet supercurrent

    KAUST Repository

    Li, Lailai

    2017-10-04

    Cooper pairs in superconductors are normally spin singlet. Nevertheless, recent studies suggest that spin-triplet Cooper pairs can be created at carefully engineered superconductor-ferromagnet interfaces. If Cooper pairs are spin-polarized they would transport not only charge but also a net spin component, but without dissipation, and therefore minimize the heating effects associated with spintronic devices. Although it is now established that triplet supercurrents exist, their most interesting property - spin - is only inferred indirectly from transport measurements. In conventional spintronics, it is well known that spin currents generate spin-transfer torques that alter magnetization dynamics and switch magnetic moments. The observation of similar effects due to spin-triplet supercurrents would not only confirm the net spin of triplet pairs but also pave the way for applications of superconducting spintronics. Here, we present a possible evidence for spin-transfer torques induced by triplet supercurrents in superconductor/ferromagnet/superconductor (S/F/S) Josephson junctions. Below the superconducting transition temperature T_c, the ferromagnetic resonance (FMR) field at X-band (~ 9.0 GHz) shifts rapidly to a lower field with decreasing temperature due to the spin-transfer torques induced by triplet supercurrents. In contrast, this phenomenon is absent in ferromagnet/superconductor (F/S) bilayers and superconductor/insulator/ferromagnet/superconductor (S/I/F/S) multilayers where no supercurrents pass through the ferromagnetic layer. These experimental observations are discussed with theoretical predictions for ferromagnetic Josephson junctions with precessing magnetization.

  14. Spin Currents and Spin Orbit Torques in Ferromagnets and Antiferromagnets

    Science.gov (United States)

    Hung, Yu-Ming

    This thesis focuses on the interactions of spin currents and materials with magnetic order, e.g., ferromagnetic and antiferromagnetic thin films. The spin current is generated in two ways. First by spin-polarized conduction-electrons associated with the spin Hall effect in heavy metals (HMs) and, second, by exciting spin-waves in ferrimagnetic insulators using a microwave frequency magnetic field. A conduction-electron spin current can be generated by spin-orbit coupling in a heavy non-magnetic metal and transfer its spin angular momentum to a ferromagnet, providing a means of reversing the magnetization of perpendicularly magnetized ultrathin films with currents that flow in the plane of the layers. The torques on the magnetization are known as spin-orbit torques (SOT). In the first part of my thesis project I investigated and contrasted the quasistatic (slowly swept current) and pulsed current-induced switching characteristics of micrometer scale Hall crosses consisting of very thin (magnetized CoFeB layers on beta-Ta. While complete magnetization reversal occurs at a threshold current density in the quasistatic case, pulses with short duration (≤10 ns) and larger amplitude (≃10 times the quasistatic threshold current) lead to only partial magnetization reversal and domain formation. The partial reversal is associated with the limited time for reversed domain expansion during the pulse. The second part of my thesis project studies and considers applications of SOT-driven domain wall (DW) motion in a perpendicularly magnetized ultrathin ferromagnet sandwiched between a heavy metal and an oxide. My experiment results demonstrate that the DW motion can be explained by a combination of the spin Hall effect, which generates a SOT, and Dzyaloshinskii-Moriya interaction, which stabilizes chiral Neel-type DW. Based on SOT-driven DW motion and magnetic coupling between electrically isolated ferromagnetic elements, I proposed a new type of spin logic devices. I then

  15. Inverse spin Hall effect induced by spin pumping into semiconducting ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung-Chuan [Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Huang, Leng-Wei [Graduate Institute of Applied Physics, National Chengchi University, Taipei 11605, Taiwan (China); Hung, Dung-Shing, E-mail: dshung@mail.mcu.edu.tw [Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Department of Information and Telecommunications Engineering, Ming Chuan University, Taipei 111, Taiwan (China); Chiang, Tung-Han [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China); Huang, J. C. A., E-mail: jcahuang@mail.ncku.edu.tw [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China); Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Liang, Jun-Zhi [Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Department of Physics, Fu Jen Catholic University, Taipei 242, Taiwan (China); Lee, Shang-Fan, E-mail: leesf@phys.sinica.edu.tw [Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Graduate Institute of Applied Physics, National Chengchi University, Taipei 11605, Taiwan (China)

    2014-02-03

    The inverse spin Hall effect (ISHE) of n-type semiconductor ZnO thin films with weak spin-orbit coupling has been observed by utilizing the spin pumping method. In the ferromagnetic resonance condition, the spin pumping driven by the dynamical exchange interaction of a permalloy film injects a pure spin current into the adjacent ZnO layer. This spin current gives rise to a DC voltage through the ISHE in the ZnO layer, and the DC voltage is proportional to the microwave excitation power. The effect is sizeable even when the spin backflow is considered.

  16. Inverse spin Hall effect induced by spin pumping into semiconducting ZnO

    International Nuclear Information System (INIS)

    Lee, Jung-Chuan; Huang, Leng-Wei; Hung, Dung-Shing; Chiang, Tung-Han; Huang, J. C. A.; Liang, Jun-Zhi; Lee, Shang-Fan

    2014-01-01

    The inverse spin Hall effect (ISHE) of n-type semiconductor ZnO thin films with weak spin-orbit coupling has been observed by utilizing the spin pumping method. In the ferromagnetic resonance condition, the spin pumping driven by the dynamical exchange interaction of a permalloy film injects a pure spin current into the adjacent ZnO layer. This spin current gives rise to a DC voltage through the ISHE in the ZnO layer, and the DC voltage is proportional to the microwave excitation power. The effect is sizeable even when the spin backflow is considered

  17. Induction-detection electron spin resonance with spin sensitivity of a few tens of spins

    Energy Technology Data Exchange (ETDEWEB)

    Artzi, Yaron; Twig, Ygal; Blank, Aharon [Schulich Faculty of Chemistry Technion—Israel Institute of Technology, Haifa 32000 (Israel)

    2015-02-23

    Electron spin resonance (ESR) is a spectroscopic method that addresses electrons in paramagnetic materials directly through their spin properties. ESR has many applications, ranging from semiconductor characterization to structural biology and even quantum computing. Although it is very powerful and informative, ESR traditionally suffers from low sensitivity, requiring many millions of spins to get a measureable signal with commercial systems using the Faraday induction-detection principle. In view of this disadvantage, significant efforts were made recently to develop alternative detection schemes based, for example, on force, optical, or electrical detection of spins, all of which can reach single electron spin sensitivity. This sensitivity, however, comes at the price of limited applicability and usefulness with regard to real scientific and technological issues facing modern ESR which are currently dealt with conventional induction-detection ESR on a daily basis. Here, we present the most sensitive experimental induction-detection ESR setup and results ever recorded that can detect the signal from just a few tens of spins. They were achieved thanks to the development of an ultra-miniature micrometer-sized microwave resonator that was operated at ∼34 GHz at cryogenic temperatures in conjunction with a unique cryogenically cooled low noise amplifier. The test sample used was isotopically enriched phosphorus-doped silicon, which is of significant relevance to spin-based quantum computing. The sensitivity was experimentally verified with the aid of a unique high-resolution ESR imaging approach. These results represent a paradigm shift with respect to the capabilities and possible applications of induction-detection-based ESR spectroscopy and imaging.

  18. Nuclear spin-lattice relaxation in nitroxide spin-label EPR.

    Science.gov (United States)

    Marsh, Derek

    2016-11-01

    Nuclear relaxation is a sensitive monitor of rotational dynamics in spin-label EPR. It also contributes competing saturation transfer pathways in T 1 -exchange spectroscopy, and the determination of paramagnetic relaxation enhancement in site-directed spin labelling. A survey shows that the definition of nitrogen nuclear relaxation rate W n commonly used in the CW-EPR literature for 14 N-nitroxyl spin labels is inconsistent with that currently adopted in time-resolved EPR measurements of saturation recovery. Redefinition of the normalised 14 N spin-lattice relaxation rate, b=W n /(2W e ), preserves the expressions used for CW-EPR, whilst rendering them consistent with expressions for saturation recovery rates in pulsed EPR. Furthermore, values routinely quoted for nuclear relaxation times that are deduced from EPR spectral diffusion rates in 14 N-nitroxyl spin labels do not accord with conventional analysis of spin-lattice relaxation in this three-level system. Expressions for CW-saturation EPR with the revised definitions are summarised. Data on nitrogen nuclear spin-lattice relaxation times are compiled according to the three-level scheme for 14 N-relaxation: T 1 n =1/W n . Results are compared and contrasted with those for the two-level 15 N-nitroxide system. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Effect of thermal treatment on solid–solid interface of hematite thin film synthesized by spin-coating deposition solution

    Energy Technology Data Exchange (ETDEWEB)

    Bellido-Aguilar, Daniel Angel; Tofanello, Aryane [Centro de Ciências Naturais e Humanas (CCNH), Universidade Federal do ABC, Av. dos Estados N°5001, Bangu, Santo André, São Paulo CEP 09210-580 (Brazil); Souza, Flavio L., E-mail: flavio.souza@ufabc.edu.br [Centro de Ciências Naturais e Humanas (CCNH), Universidade Federal do ABC, Av. dos Estados N°5001, Bangu, Santo André, São Paulo CEP 09210-580 (Brazil); Furini, Leonardo Negri; Constantino, Carlos José Leopoldo [Faculdade de Ciências e Tecnologia (FCT), UNESP Univ Estadual Paulista, Presidente Prudente, São Paulo, 19060-900 (Brazil)

    2016-04-01

    This work describes hematite films prepared by a spin-coating deposition solution (SCDS) method that is a sol–gel method derived technique. Hematite films were prepared at two heat treatment temperatures (500 °C and 800 °C) and the influence of thermal treatment on the photoelectrochemical performance was studied. In addition, since the SCDS method allows an optimal control of stoichiometry and impurity incorporation, hematite films modified with Zn{sup 2+} and Sn{sup 4+} were also prepared. The 800 °C-treated hematite films had a higher wettability and roughness that enabled them to have a better photocatalytic response in comparison with that of 500 °C-treated hematite films. Moreover, modified hematite films demonstrated to have a performance slightly better than that of undoped hematite film as shown in linear sweep voltammetry and chronoamperometry results. Although an improvement in the performance of hematite films was achieved by annealing at higher temperatures and incorporating Zn{sup 2+} or Sn{sup 4+}, the general photocatalytic response of the films was poor. Two plausible hypotheses were discussed related to the (i) dopant segregation at grain boundary, and (ii) poor contact between the hematite and fluorine doped tin oxide layer (from the glass substrate), which was experimentally confirmed by a cross-sectional analysis conducted using scanning electron microscopy (SEM). In fact, additional experiments need to be done in order to improve the hematite deposition and make the SCDS a promise method for industrial application. - Highlights: • High temperature of annealing decreases the hematite adherence and performance. • Zn{sup 2+} and Sn{sup 4+} dopants affected differently the photocurrent onset potentials. • Dopants affected the grain size due to their segregation at grain boundaries.

  20. Spin injection and detection in lateral spin valves with hybrid interfaces

    Science.gov (United States)

    Wang, Le; Liu, Wenyu; Ying, Hao; Chen, Luchen; Lu, Zhanjie; Han, Shuo; Chen, Shanshan; Zhao, Bing; Xu, Xiaoguang; Jiang, Yong

    2018-06-01

    Spin injection and detection in lateral spin valves with hybrid interfaces comprising a Co/Ag transparent contact and a Co/MgO/Ag junction (III) are investigated at room temperature in comparison with pure Co/Ag transparent contacts (I) and Co/MgO/Ag junctions (II). The measured spin-accumulation signals of a type III device are five times higher than those for type I. The extracted spin diffusion length in Ag is 180 nm for all three types of devices. The enhancement of the spin signal of the hybrid structure is mainly attributed to the increase of the interfacial spin polarization from the Co/MgO/Ag junction.

  1. Spin Seebeck effect and ballistic transport of quasi-acoustic magnons in room-temperature yttrium iron garnet films

    Science.gov (United States)

    Noack, Timo B.; Musiienko-Shmarova, Halyna Yu; Langner, Thomas; Heussner, Frank; Lauer, Viktor; Heinz, Björn; Bozhko, Dmytro A.; Vasyuchka, Vitaliy I.; Pomyalov, Anna; L’vov, Victor S.; Hillebrands, Burkard; Serga, Alexander A.

    2018-06-01

    We studied the transient behavior of the spin current generated by the longitudinal spin Seebeck effect (LSSE) in a set of platinum-coated yttrium iron garnet (YIG) films of different thicknesses. The LSSE was induced by means of pulsed microwave heating of the Pt layer and the spin currents were measured electrically using the inverse spin Hall effect in the same layer. We demonstrate that the time evolution of the LSSE is determined by the evolution of the thermal gradient triggering the flux of thermal magnons in the vicinity of the YIG/Pt interface. These magnons move ballistically within the YIG film with a constant group velocity, while their number decays exponentially within an effective propagation length. The ballistic flight of the magnons with energies above 20 K is a result of their almost linear dispersion law, similar to that of acoustic phonons. By fitting the time-dependent LSSE signal for different film thicknesses varying by almost an order of magnitude, we found that the effective propagation length is practically independent of the YIG film thickness. We consider this fact as strong support of a ballistic transport scenario—the ballistic propagation of quasi-acoustic magnons in room temperature YIG.

  2. Large spin accumulation due to spin-charge coupling across a break-junction

    Science.gov (United States)

    Chen, Shuhan; Zou, Han; Chui, Siu-Tat; Ji, Yi

    2013-03-01

    We investigate large spin signals in break-junction nonlocal spin valves (NLSV). The break-junction is a nanometer-sized vacuum tunneling gap between the spin detector and the nonmagnetic channel, formed by electro-static discharge. The spin signals can be either inverted or non-inverted and the magnitudes are much larger than those of standard NLSV. Spin signals with high percentage values (10% - 0%) have been observed. When the frequency of the a.c. modulation is varied, the absolute magnitudes of signals remain the same although the percentage values change. These observations affirm the nonlocal nature of the measurements and rule out local magnetoresistive effects. Owing to the spin-charge coupling across the break-junction, the spin accumulation in a ferromagnet splits into two terms. One term decays on the charge screening length (0.1 nm) and the other decays on the spin diffusion length (10 nm nm). The magnitude of the former is proportional to the resistance of the junction. Therefore a highly resistive break-junction leads to a large spin accumulation and thereby a large spin signal. The signs of the spin signal are determined by the relationship between spin-dependent conductivities, diffusion constants, and density of states of the ferromagnet. This work was supported by US DOE grant No. DE-FG02-07ER46374.

  3. Spin dynamics under local gauge fields in chiral spin-orbit coupling systems

    International Nuclear Information System (INIS)

    Tan, S.G.; Jalil, M.B.A.; Fujita, T.; Liu, X.J.

    2011-01-01

    Research highlights: → We derive a modified LLG equation in magnetic systems with spin-orbit coupling (SOC). → Our results are applied to magnetic multilayers, and DMS and magnetic Rashba systems. → SOC mediated magnetization switching is predicted in rare earth metals (large SOC). → The magnetization trajectory and frequency can be modulated by applied voltage. → This facilitates potential application as tunable microwave oscillators. - Abstract: We present a theoretical description of local spin dynamics in magnetic systems with a chiral spin texture and finite spin-orbit coupling (SOC). Spin precession about the relativistic effective magnetic field in a SOC system gives rise to a non-Abelian SU(2) gauge field reminiscent of the Yang-Mills field. In addition, the adiabatic relaxation of electron spin along the local spin yields an U(1) x U(1) topological gauge (Berry) field. We derive the corresponding equation of motion i.e. modified Landau-Lifshitz-Gilbert (LLG) equation, for the local spin under the influence of these effects. Focusing on the SU(2) gauge, we obtain the spin torque magnitude, and the amplitude and frequency of spin oscillations in this system. Our theoretical estimates indicate significant spin torque and oscillations in systems with large spin-orbit coupling, which may be utilized in technological applications such as current-induced magnetization-switching and tunable microwave oscillators.

  4. Spin correlations and spin-wave excitations in Dirac-Weyl semimetals

    Science.gov (United States)

    Araki, Yasufumi; Nomura, Kentaro

    We study correlations among magnetic dopants in three-dimensional Dirac and Weyl semimetals. Effective field theory for localized magnetic moments is derived by integrating out the itinerant electron degrees of freedom. We find that spin correlation in the spatial direction parallel to local magnetization is more rigid than that in the perpendicular direction, reflecting spin-momentum locking nature of the Dirac Hamiltonian. Such an anisotropy becomes stronger for Fermi level close to the Dirac points, due to Van Vleck paramagnetism triggered by spin-orbit coupling. One can expect topologically nontrivial spin textures under this anisotropy, such as a hedgehog around a single point, or a radial vortex around an axis, as well as a uniform ferromagnetic order. We further investigate the characteristics of spin waves in the ferromagnetic state. Spin-wave dispersion also shows a spatial anisotropy, which is less dispersed in the direction transverse to the magnetization than that in the longitudinal direction. The spin-wave dispersion anisotropy can be traced back to the rigidity and flexibility of spin correlations discussed above. This work was supported by Grant-in-Aid for Scientific Research (Grants No.15H05854, No.26107505, and No.26400308) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.

  5. Spin-spin cross relaxation and spin-Hamiltonian spectroscopy by optical pumping of Pr/sup 3+/:LaF3

    International Nuclear Information System (INIS)

    Lukac, M.; Otto, F.W.; Hahn, E.L.

    1989-01-01

    We report the observation of an anticrossing in solid-state laser spectroscopy produced by cross relaxation. Spin-spin cross relaxation between the /sup 141/Pr- and /sup 19/F-spin reservoirs in Pr/sup 3+/:LaF 3 and its influence on the /sup 141/Pr NMR spectrum is detected by means of optical pumping. The technique employed combines optical pumping and hole burning with either external magnetic field sweep or rf resonance saturation in order to produce slow transient changes in resonant laser transmission. At a certain value of the external Zeeman field, where the energy-level splittings of Pr and F spins match, a level repulsion and discontinuity of the Pr/sup 3+/ NMR lines is observed. This effect is interpreted as the ''anticrossing'' of the combined Pr-F spin-spin reservoir energy states. The Zeeman-quadrupole-Hamiltonian spectrum of the hyperfine optical ground states of Pr/sup 3+/:LaF 3 is mapped out over a wide range of Zeeman magnetic fields. A new scheme is proposed for dynamic polarization of nuclei by means of optical pumping, based on resonant cross relaxation between rare spins and spin reservoirs

  6. Bipolar spintronics: from spin injection to spin-controlled logic

    International Nuclear Information System (INIS)

    Zutic, Igor; Fabian, Jaroslav; Erwin, Steven C

    2007-01-01

    An impressive success of spintronic applications has been typically realized in metal-based structures which utilize magnetoresistive effects for substantial improvements in the performance of computer hard drives and magnetic random access memories. Correspondingly, the theoretical understanding of spin-polarized transport is usually limited to a metallic regime in a linear response, which, while providing a good description for data storage and magnetic memory devices, is not sufficient for signal processing and digital logic. In contrast, much less is known about possible applications of semiconductor-based spintronics and spin-polarized transport in related structures which could utilize strong intrinsic nonlinearities in current-voltage characteristics to implement spin-based logic. Here we discuss the challenges for realizing a particular class of structures in semiconductor spintronics: our proposal for bipolar spintronic devices in which carriers of both polarities (electrons and holes) contribute to spin-charge coupling. We formulate the theoretical framework for bipolar spin-polarized transport, and describe several novel effects in two- and three-terminal structures which arise from the interplay between nonequilibrium spin and equilibrium magnetization

  7. Inverse spin-valve effect in nanoscale Si-based spin-valve devices

    Science.gov (United States)

    Hiep, Duong Dinh; Tanaka, Masaaki; Hai, Pham Nam

    2017-12-01

    We investigated the spin-valve effect in nano-scale silicon (Si)-based spin-valve devices using a Fe/MgO/Ge spin injector/detector deposited on Si by molecular beam epitaxy. For a device with a 20 nm Si channel, we observed clear magnetoresistance up to 3% at low temperature when a magnetic field was applied in the film plane along the Si channel transport direction. A large spin-dependent output voltage of 20 mV was observed at a bias voltage of 0.9 V at 15 K, which is among the highest values in lateral spin-valve devices reported so far. Furthermore, we observed that the sign of the spin-valve effect is reversed at low temperatures, suggesting the possibility of a spin-blockade effect of defect states in the MgO/Ge tunneling barrier.

  8. Spin waves and spin instabilities in quantum plasmas

    OpenAIRE

    Andreev, P. A.; Kuz'menkov, L. S.

    2014-01-01

    We describe main ideas of method of many-particle quantum hydrodynamics allows to derive equations for description of quantum plasma evolution. We also present definitions of collective quantum variables suitable for quantum plasmas. We show that evolution of magnetic moments (spins) in quantum plasmas leads to several new branches of wave dispersion: spin-electromagnetic plasma waves and self-consistent spin waves. Propagation of neutron beams through quantum plasmas is also considered. Inst...

  9. Spin transfer torque with spin diffusion in magnetic tunnel junctions

    KAUST Repository

    Manchon, Aurelien; Matsumoto, R.; Jaffres, H.; Grollier, J.

    2012-01-01

    in the metallic layers. We show that spin diffusion mixes the transverse spin current components and dramatically modifies the bias dependence of the effective spin transfer torque. This leads to a significant linear bias dependence of the out-of-plane torque

  10. Spin transport in nanowires

    OpenAIRE

    Pramanik, S.; bandyopadhyay, S.; Cahay, M.

    2003-01-01

    We study high-field spin transport of electrons in a quasi one-dimensional channel of a $GaAs$ gate controlled spin interferometer (SPINFET) using a semiclassical formalism (spin density matrix evolution coupled with Boltzmann transport equation). Spin dephasing (or depolarization) is predominantly caused by D'yakonov-Perel' relaxation associated with momentum dependent spin orbit coupling effects that arise due to bulk inversion asymmetry (Dresselhaus spin orbit coupling) and structural inve...

  11. Nuclear spin-lattice relaxation in nitroxide spin-label EPR

    DEFF Research Database (Denmark)

    Marsh, Derek

    2016-01-01

    that the definition of nitrogen nuclear relaxation rate Wn commonly used in the CW-EPR literature for 14N-nitroxyl spin labels is inconsistent with that currently adopted in time-resolved EPR measurements of saturation recovery. Redefinition of the normalised 14N spin-lattice relaxation rate, b = Wn/(2We), preserves...... of spin-lattice relaxation in this three-level system. Expressions for CW-saturation EPR with the revised definitions are summarised. Data on nitrogen nuclear spin-lattice relaxation times are compiled according to the three-level scheme for 14N-relaxation: T1 n = 1/Wn. Results are compared and contrasted...

  12. Spin squeezing of atomic ensembles via nuclear-electronic spin entanglement

    DEFF Research Database (Denmark)

    Fernholz, Thomas; Krauter, Hanna; Jensen, Kasper

    2008-01-01

    quantum limit for quantum memory experiments and applications in quantum metrology and is thus a complementary alternative to spin squeezing obtained via inter-atom entanglement. Squeezing of the collective spin is verified by quantum state tomography.......We demonstrate spin squeezing in a room temperature ensemble of 1012 Cesium atoms using their internal structure, where the necessary entanglement is created between nuclear and electronic spins of each individual atom. This state provides improvement in measurement sensitivity beyond the standard...

  13. Phase transitions and thermal entanglement of the distorted Ising-Heisenberg spin chain: topology of multiple-spin exchange interactions in spin ladders

    Science.gov (United States)

    Arian Zad, Hamid; Ananikian, Nerses

    2017-11-01

    We consider a symmetric spin-1/2 Ising-XXZ double sawtooth spin ladder obtained from distorting a spin chain, with the XXZ interaction between the interstitial Heisenberg dimers (which are connected to the spins based on the legs via an Ising-type interaction), the Ising coupling between nearest-neighbor spins of the legs and rungs spins, respectively, and additional cyclic four-spin exchange (ring exchange) in the square plaquette of each block. The presented analysis supplemented by results of the exact solution of the model with infinite periodic boundary implies a rich ground state phase diagram. As well as the quantum phase transitions, the characteristics of some of the thermodynamic parameters such as heat capacity, magnetization and magnetic susceptibility are investigated. We prove here that among the considered thermodynamic and thermal parameters, solely heat capacity is sensitive versus the changes of the cyclic four-spin exchange interaction. By using the heat capacity function, we obtain a singularity relation between the cyclic four-spin exchange interaction and the exchange coupling between pair spins on each rung of the spin ladder. All thermal and thermodynamic quantities under consideration should be investigated by regarding those points which satisfy the singularity relation. The thermal entanglement within the Heisenberg spin dimers is investigated by using the concurrence, which is calculated from a relevant reduced density operator in the thermodynamic limit.

  14. Evidence for power-law spin-correlation decay from muon spin relaxation in AgMn spin-glass

    International Nuclear Information System (INIS)

    MacLaughlin, D.E.; Gupta, L.C.; Cooke, D.W.; Heffner, R.H.; Leon, M.; Schillaci, M.E.

    1983-01-01

    Muon spin relaxation measurements have been carried out below the ''glass'' temperature T/sub g/ in AgMn spin-glasses. The muon spin-lattice relaxation rate varies with field H as H/sup -0.46plus-or-minus0.05/ for 0.30< or =T/T/sub g/< or =0.66. This suggests that impurity-spin correlations decay with time as t/sup -nu/, νapprox. =0.54 +- 0.05, in contrast to the more usual exponential decay. The present data therefore agree quantitatively with the prediction νapprox. =(1/2) of mean-field dynamic theories

  15. Spin-transfer torque in spin filter tunnel junctions

    KAUST Repository

    Ortiz Pauyac, Christian

    2014-12-08

    Spin-transfer torque in a class of magnetic tunnel junctions with noncollinear magnetizations, referred to as spin filter tunnel junctions, is studied within the tight-binding model using the nonequilibrium Green\\'s function technique within Keldysh formalism. These junctions consist of one ferromagnet (FM) adjacent to a magnetic insulator (MI) or two FM separated by a MI. We find that the presence of the magnetic insulator dramatically enhances the magnitude of the spin-torque components compared to conventional magnetic tunnel junctions. The fieldlike torque is driven by the spin-dependent reflection at the MI/FM interface, which results in a small reduction of its amplitude when an insulating spacer (S) is inserted to decouple MI and FM layers. Meanwhile, the dampinglike torque is dominated by the tunneling electrons that experience the lowest barrier height. We propose a device of the form FM/(S)/MI/(S)/FM that takes advantage of these characteristics and allows for tuning the spin-torque magnitudes over a wide range just by rotation of the magnetization of the insulating layer.

  16. Spin-transfer torque in spin filter tunnel junctions

    KAUST Repository

    Ortiz Pauyac, Christian; Kalitsov, Alan; Manchon, Aurelien; Chshiev, Mairbek

    2014-01-01

    Spin-transfer torque in a class of magnetic tunnel junctions with noncollinear magnetizations, referred to as spin filter tunnel junctions, is studied within the tight-binding model using the nonequilibrium Green's function technique within Keldysh formalism. These junctions consist of one ferromagnet (FM) adjacent to a magnetic insulator (MI) or two FM separated by a MI. We find that the presence of the magnetic insulator dramatically enhances the magnitude of the spin-torque components compared to conventional magnetic tunnel junctions. The fieldlike torque is driven by the spin-dependent reflection at the MI/FM interface, which results in a small reduction of its amplitude when an insulating spacer (S) is inserted to decouple MI and FM layers. Meanwhile, the dampinglike torque is dominated by the tunneling electrons that experience the lowest barrier height. We propose a device of the form FM/(S)/MI/(S)/FM that takes advantage of these characteristics and allows for tuning the spin-torque magnitudes over a wide range just by rotation of the magnetization of the insulating layer.

  17. Effect of Annealing Temperature on Structural, Optical, and Electrical Properties of Sol-Gel Spin-Coating-Derived Cu2ZnSnS4 Thin Films

    Science.gov (United States)

    Hosseinpour, Rabie; Izadifard, Morteza; Ghazi, Mohammad Ebrahim; Bahramian, Bahram

    2018-02-01

    The effect of annealing temperature on structural, optical, and electrical properties of Cu2ZnSnS4 (CZTS) thin films grown on a glass substrate by spin coating sol-gel technique has been studied. Structural study showed that all samples had kesterite crystalline structure. Scanning electron microscopy images showed that the crystalline quality of the samples was improved by heat treatment. Optical study showed that the energy gap values for the samples ranged from 1.55 eV to 1.78 eV. Moreover, good optical conductivity values (1012 S-1 to 1014 S-1) were obtained for the samples. Investigation of the electrical properties of the CZTS thin films showed that the carrier concentration increased significantly with the annealing temperature. The photoelectrical behavior of the samples revealed that the photocurrent under light illumination increased significantly. Overall, the results show that the CZTS thin films annealed at 500°C had better structural, optical, and electrical properties and that such CZTS thin films are desirable for use as absorber layers in solar cells. The photovoltaic properties of the CZTS layer annealed at 500°C were also investigated and the associated figure of merit calculated. The results showed that the fabricated ZnS-CZTS heterojunction exhibited good rectifying behavior but rather low fill factor.

  18. Max Auwaerter symposium: spin mapping and spin manipulation on the atomic scale

    International Nuclear Information System (INIS)

    Wiesendanger, R.

    2008-01-01

    Full text: A fundamental understanding of magnetic and spin-dependent phenomena requires the determination of spin structures and spin excitations down to the atomic scale. The direct visualization of atomic-scale spin structures has first been accomplished for magnetic metals by combining the atomic resolution capability of Scanning Tunnelling Microscopy (STM) with spin sensitivity, based on vacuum tunnelling of spin-polarized electrons. The resulting technique, Spin-Polarized Scanning Tunnelling Microscopy (SP-STM), nowadays provides unprecedented insight into collinear and non-collinear spin structures at surfaces of magnetic nanostructures and has already led to the discovery of new types of magnetic order at the nanoscale. More recently, the development of subkelvin SP-STM has allowed studies of ground-state magnetic properties of individual magnetic adatoms on non-magnetic substrates as well as the magnetic interactions between them. Based on SP-STM experiments performed at temperatures of 300 mK, indirect magnetic exchange interactions at the sub-milli-electronvolt energy scale between individual paramagnetic adatoms as well as between adatoms and nearby magnetic nanostructures could directly be revealed in real space up to distances of several nanometers. In both cases we have observed an oscillatory behavior of the magnetic exchange coupling, alternating between ferromagnetic and antiferromagnetic, as a function of distance. Moreover, the detection of spin-dependent exchange and correlation forces has allowed a first direct real-space observation of spin structures at surfaces of antiferromagnetic insulators. This new type of scanning probe microscopy, called Magnetic Exchange Force Microscopy (MExFM), offers a powerful new tool to investigate different types of spin-spin interactions based on direct-, super-, or RKKY-type exchange down to the atomic level. By combining MExFM with high-precision measurements of damping forces, localized or confined spin

  19. Role of spin mixing conductance in spin pumping: Enhancement of spin pumping efficiency in Ta/Cu/Py structures

    Energy Technology Data Exchange (ETDEWEB)

    Deorani, Praveen; Yang, Hyunsoo, E-mail: eleyang@nus.edu.sg [Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore (Singapore)

    2013-12-02

    From spin pumping measurements in Ta/Py devices for different thicknesses of Ta, we determine the spin Hall angle to be 0.021–0.033 and spin diffusion length to be 8 nm in Ta. We have also studied the effect of changing the properties of non-magnet/ferromagnet interface by adding a Cu interlayer. The experimental results show that the effective spin mixing conductance increases in the presence of Cu interlayer for Ta/Cu/Py devices whereas it decreases in Pt/Cu/Py devices. Our findings allow the tunability of the spin pumping efficiency by adding a thin interlayer at the non-magnet/ferromagnet interface.

  20. Synthesis of Y{sub 2}O{sub 3}:(Li,Eu) films using phosphor powders coated with SiO{sub 2} nano particles

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In-Gyu; Park, Sangmoon [Center for Green Fusion Technology and Department of Engineering in Energy and Applied Chemistry, Silla University, Busan 617-736 (Korea, Republic of); Kang, Seong-Gu [Department of Chemical Engineering, Hoseo University, Chungnam 336-795 (Korea, Republic of); Park, Jung-Chul, E-mail: parkjc@silla.ac.k [Center for Green Fusion Technology and Department of Engineering in Energy and Applied Chemistry, Silla University, Busan 617-736 (Korea, Republic of)

    2010-08-15

    Y{sub 1.9-x}Li{sub 0.1}Eu{sub x}O{sub 3} (x=0.02, 0.05, 0.08, and 0.12) films were fabricated by spin-coating method. A colloidal silica suspension with Y{sub 1.9-x}Li{sub 0.1}Eu{sub x}O{sub 3} phosphor powder was exploited to obtain the highly stable and effective luminescent films onto the glass substrate. After heating as-prepared Y{sub 1.9-x}Li{sub 0.1}Eu{sub x}O{sub 3} films at 700 {sup o}C for 1 h, the phosphor films exhibit a high luminescent brightness as well as a strong adhesiveness on the glass substrate. The emission spectra of spin-coated and pulse-laser deposited Y{sub 1.82}Li{sub 0.1}Eu{sub 0.08}O{sub 3} films were compared. The cathodoluminescence of the phosphor films was carried out at the anode voltage 1 kV.

  1. Biocorrosion of TiO2 nanoparticle coating of Ti-6Al-4V in DMEM under specific in vitro conditions

    Science.gov (United States)

    Höhn, Sarah; Virtanen, Sannakaisa

    2015-02-01

    A TiO2 nanoparticle coating was prepared on a biomedical Ti-6Al-4V alloy using "spin-coating" technique with a colloidal suspension of TiO2 nanopowders with the aim to optimize the surface morphology (e.g., roughness) for improved biocompatibility. The influence of a TiO2 nanoparticle (NP) coating on the corrosion behavior, metal ion release, and biomimetic apatite formation was studied in DMEM, at 37.5 °C with a continuous supply of 5% CO2. Electrochemical impedance spectroscopy measurements indicate a formation of a new layer on the surface of the NP-coated sample upon 28 days immersion in DMEM. Scanning electron microscopy (SEM) and X-ray spectroscopy confirm that the surface of the NP-coated Ti-6Al-4V shows a complete coverage by a Ca-phosphate layer in contrast to the non-coated Ti-6Al-4V alloy. Hence, the TiO2-NP coating strongly enhances biomimetic apatite formation on the alloy surface. In addition, the TiO2-NP coating can efficiently reduce Al-release from the alloy, for which the bare Ti-6Al-4V alloy is significant for at least 28 days of immersion in DMEM.

  2. PREFACE: Spin Electronics

    Science.gov (United States)

    Dieny, B.; Sousa, R.; Prejbeanu, L.

    2007-04-01

    Conventional electronics has in the past ignored the spin on the electron, however things began to change in 1988 with the discovery of giant magnetoresistance in metallic thin film stacks which led to the development of a new research area, so called spin-electronics. In the last 10 years, spin-electronics has achieved a number of breakthroughs from the point of view of both basic science and application. Materials research has led to several major discoveries: very large tunnel magnetoresistance effects in tunnel junctions with crystalline barriers due to a new spin-filtering mechanism associated with the spin-dependent symmetry of the electron wave functions new magnetic tunnelling barriers leading to spin-dependent tunnelling barrier heights and acting as spin-filters magnetic semiconductors with increasingly high ordering temperature. New phenomena have been predicted and observed: the possibility of acting on the magnetization of a magnetic nanostructure with a spin-polarized current. This effect, due to a transfer of angular momentum between the spin polarized conduction electrons and the local magnetization, can be viewed as the reciprocal of giant or tunnel magnetoresistance. It can be used to switch the magnetization of a magnetic nanostructure or to generate steady magnetic excitations in the system. the possibility of generating and manipulating spin current without charge current by creating non-equilibrium local accumulation of spin up or spin down electrons. The range of applications of spin electronics materials and phenomena is expanding: the first devices based on giant magnetoresistance were the magnetoresistive read-heads for computer disk drives. These heads, introduced in 1998 with current-in plane spin-valves, have evolved towards low resistance tunnel magnetoresistice heads in 2005. Besides magnetic recording technology, these very sensitive magnetoresistive sensors are finding applications in other areas, in particular in biology. magnetic

  3. Possible evidence for spin-transfer torque induced by spin-triplet supercurrent

    KAUST Repository

    Li, Lailai; Zhao, Yuelei; Zhang, Xixiang; Sun, Young

    2017-01-01

    Cooper pairs in superconductors are normally spin singlet. Nevertheless, recent studies suggest that spin-triplet Cooper pairs can be created at carefully engineered superconductor-ferromagnet interfaces. If Cooper pairs are spin

  4. Spin Coherence in Semiconductor Nanostructures

    National Research Council Canada - National Science Library

    Flatte, Michael E

    2006-01-01

    ... dots, tuning of spin coherence times for electron spin, tuning of dipolar magnetic fields for nuclear spin, spontaneous spin polarization generation and new designs for spin-based teleportation and spin transistors...

  5. Spin-orbit torques from interfacial spin-orbit coupling for various interfaces

    Science.gov (United States)

    Kim, Kyoung-Whan; Lee, Kyung-Jin; Sinova, Jairo; Lee, Hyun-Woo; Stiles, M. D.

    2017-09-01

    We use a perturbative approach to study the effects of interfacial spin-orbit coupling in magnetic multilayers by treating the two-dimensional Rashba model in a fully three-dimensional description of electron transport near an interface. This formalism provides a compact analytic expression for current-induced spin-orbit torques in terms of unperturbed scattering coefficients, allowing computation of spin-orbit torques for various contexts, by simply substituting scattering coefficients into the formulas. It applies to calculations of spin-orbit torques for magnetic bilayers with bulk magnetism, those with interface magnetism, a normal-metal/ferromagnetic insulator junction, and a topological insulator/ferromagnet junction. It predicts a dampinglike component of spin-orbit torque that is distinct from any intrinsic contribution or those that arise from particular spin relaxation mechanisms. We discuss the effects of proximity-induced magnetism and insertion of an additional layer and provide formulas for in-plane current, which is induced by a perpendicular bias, anisotropic magnetoresistance, and spin memory loss in the same formalism.

  6. High frequency spin torque oscillators with composite free layer spin valve

    International Nuclear Information System (INIS)

    Natarajan, Kanimozhi; Arumugam, Brinda; Rajamani, Amuda

    2016-01-01

    We report the oscillations of magnetic spin components in a composite free layer spin valve. The associated Landau–Lifshitz–Gilbert–Slonczewski (LLGS) equation is studied by stereographically projecting the spin on to a complex plane and the spin components were found. A fourth order Runge–Kutta numerical integration on LLGS equation also confirms the similar trajectories of the spin components. This study establishes the possibility of a Spin Torque Oscillator in a composite free layer spin valve, where the exchange coupling is ferromagnetic in nature. In-plane and out-of-plane precessional modes of magnetization oscillations were found in zero applied magnetic field and the frequencies of the oscillations were calculated from Fast Fourier Transform of the components of magnetization. Behavior of Power Spectral Density for a range of current density is studied. Finally our analysis shows the occurrence of highest frequency 150 GHz, which is in the second harmonics for the specific choice of system parameters.

  7. High frequency spin torque oscillators with composite free layer spin valve

    Energy Technology Data Exchange (ETDEWEB)

    Natarajan, Kanimozhi; Arumugam, Brinda; Rajamani, Amuda

    2016-07-15

    We report the oscillations of magnetic spin components in a composite free layer spin valve. The associated Landau–Lifshitz–Gilbert–Slonczewski (LLGS) equation is studied by stereographically projecting the spin on to a complex plane and the spin components were found. A fourth order Runge–Kutta numerical integration on LLGS equation also confirms the similar trajectories of the spin components. This study establishes the possibility of a Spin Torque Oscillator in a composite free layer spin valve, where the exchange coupling is ferromagnetic in nature. In-plane and out-of-plane precessional modes of magnetization oscillations were found in zero applied magnetic field and the frequencies of the oscillations were calculated from Fast Fourier Transform of the components of magnetization. Behavior of Power Spectral Density for a range of current density is studied. Finally our analysis shows the occurrence of highest frequency 150 GHz, which is in the second harmonics for the specific choice of system parameters.

  8. European coatings conference - Marine coatings. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    This volume contains 13 lectures (manuscripts or powerpoint foils) with the following topics: 1. Impact of containerization on polyurethane and polyurea in marine and protective coatings (Malte Homann); 2. The application of combinatorial/high-throughput methods to the development of marine coatings (Bret Chisholm); 3. Progress and perspectives in the AMBIO (advanced nanostructured surfaces for the control of biofouling) Project (James Callow); 4. Release behaviour due to shear and pull-off of silicone coatings with a thickness gradient (James G. Kohl); 5. New liquid rheology additives for high build marine coatings (Andreas Freytag); 6. Effective corrosion protection with polyaniline, polpyrrole and polythiophene as anticorrosice additives for marine paints (Carlos Aleman); 7. Potential applications of sol gel technology for marine applications (Robert Akid); 8: Performance of biocide-free Antifouling Coatings for leisure boats (Bernd Daehne); 9. Novel biocidefree nanostructured antifouling coatings - can nano do the job? (Corne Rentrop); 10. One component high solids, VOC compliant high durability finish technology (Adrian Andrews); 11. High solid coatings - the hybrid solution (Luca Prezzi); 12. Unique organofunctional silicone resins for environmentally friendly high-performance coatings (Dieter Heldmann); 13. Silicone-alkyd paints for marine applications: from battleship-grey to green (Thomas Easton).

  9. Spin glasses

    CERN Document Server

    Bovier, Anton

    2007-01-01

    Spin glass theory is going through a stunning period of progress while finding exciting new applications in areas beyond theoretical physics, in particular in combinatorics and computer science. This collection of state-of-the-art review papers written by leading experts in the field covers the topic from a wide variety of angles. The topics covered are mean field spin glasses, including a pedagogical account of Talagrand's proof of the Parisi solution, short range spin glasses, emphasizing the open problem of the relevance of the mean-field theory for lattice models, and the dynamics of spin glasses, in particular the problem of ageing in mean field models. The book will serve as a concise introduction to the state of the art of spin glass theory, usefull to both graduate students and young researchers, as well as to anyone curious to know what is going on in this exciting area of mathematical physics.

  10. Calculation of nuclear spin-spin coupling constants using frozen density embedding

    Energy Technology Data Exchange (ETDEWEB)

    Götz, Andreas W., E-mail: agoetz@sdsc.edu [San Diego Supercomputer Center, University of California San Diego, 9500 Gilman Dr MC 0505, La Jolla, California 92093-0505 (United States); Autschbach, Jochen [Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260-3000 (United States); Visscher, Lucas, E-mail: visscher@chem.vu.nl [Amsterdam Center for Multiscale Modeling (ACMM), VU University Amsterdam, Theoretical Chemistry, De Boelelaan 1083, 1081 HV Amsterdam (Netherlands)

    2014-03-14

    We present a method for a subsystem-based calculation of indirect nuclear spin-spin coupling tensors within the framework of current-spin-density-functional theory. Our approach is based on the frozen-density embedding scheme within density-functional theory and extends a previously reported subsystem-based approach for the calculation of nuclear magnetic resonance shielding tensors to magnetic fields which couple not only to orbital but also spin degrees of freedom. This leads to a formulation in which the electron density, the induced paramagnetic current, and the induced spin-magnetization density are calculated separately for the individual subsystems. This is particularly useful for the inclusion of environmental effects in the calculation of nuclear spin-spin coupling constants. Neglecting the induced paramagnetic current and spin-magnetization density in the environment due to the magnetic moments of the coupled nuclei leads to a very efficient method in which the computationally expensive response calculation has to be performed only for the subsystem of interest. We show that this approach leads to very good results for the calculation of solvent-induced shifts of nuclear spin-spin coupling constants in hydrogen-bonded systems. Also for systems with stronger interactions, frozen-density embedding performs remarkably well, given the approximate nature of currently available functionals for the non-additive kinetic energy. As an example we show results for methylmercury halides which exhibit an exceptionally large shift of the one-bond coupling constants between {sup 199}Hg and {sup 13}C upon coordination of dimethylsulfoxide solvent molecules.

  11. High-Resolution Spin-on-Patterning of Perovskite Thin Films for a Multiplexed Image Sensor Array.

    Science.gov (United States)

    Lee, Woongchan; Lee, Jongha; Yun, Huiwon; Kim, Joonsoo; Park, Jinhong; Choi, Changsoon; Kim, Dong Chan; Seo, Hyunseon; Lee, Hakyong; Yu, Ji Woong; Lee, Won Bo; Kim, Dae-Hyeong

    2017-10-01

    Inorganic-organic hybrid perovskite thin films have attracted significant attention as an alternative to silicon in photon-absorbing devices mainly because of their superb optoelectronic properties. However, high-definition patterning of perovskite thin films, which is important for fabrication of the image sensor array, is hardly accomplished owing to their extreme instability in general photolithographic solvents. Here, a novel patterning process for perovskite thin films is described: the high-resolution spin-on-patterning (SoP) process. This fast and facile process is compatible with a variety of spin-coated perovskite materials and perovskite deposition techniques. The SoP process is successfully applied to develop a high-performance, ultrathin, and deformable perovskite-on-silicon multiplexed image sensor array, paving the road toward next-generation image sensor arrays. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Quantum spin correction scheme based on spin-correlation functional for Kohn-Sham spin density functional theory

    International Nuclear Information System (INIS)

    Yamanaka, Shusuke; Takeda, Ryo; Nakata, Kazuto; Takada, Toshikazu; Shoji, Mitsuo; Kitagawa, Yasutaka; Yamaguchi, Kizashi

    2007-01-01

    We present a simple quantum correction scheme for ab initio Kohn-Sham spin density functional theory (KS-SDFT). This scheme is based on a mapping from ab initio results to a Heisenberg model Hamiltonian. The effective exchange integral is estimated by using energies and spin correlation functionals calculated by ab initio KS-SDFT. The quantum-corrected spin-correlation functional is open to be designed to cover specific quantum spin fluctuations. In this article, we present a simple correction for dinuclear compounds having multiple bonds. The computational results are discussed in relation to multireference (MR) DFT, by which we treat the quantum many-body effects explicitly

  13. Charge and Spin Transport in Spin-orbit Coupled and Topological Systems

    KAUST Repository

    Ndiaye, Papa Birame

    2017-10-31

    In the search for low power operation of microelectronic devices, spin-based solutions have attracted undeniable increasing interest due to their intrinsic magnetic nonvolatility. The ability to electrically manipulate the magnetic order using spin-orbit interaction, associated with the recent emergence of topological spintronics with its promise of highly efficient charge-to-spin conversion in solid state, offer alluring opportunities in terms of system design. Although the related technology is still at its infancy, this thesis intends to contribute to this engaging field by investigating the nature of the charge and spin transport in spin-orbit coupled and topological systems using quantum transport methods. We identified three promising building blocks for next-generation technology, three classes of systems that possibly enhance the spin and charge transport efficiency: (i)- topological insulators, (ii)- spin-orbit coupled magnonic systems, (iii)- topological magnetic textures (skyrmions and 3Q magnetic state). Chapter 2 reviews the basics and essential concepts used throughout the thesis: the spin-orbit coupling, the mathematical notion of topology and its importance in condensed matter physics, then topological magnetism and a zest of magnonics. In Chapter 3, we study the spin-orbit torques at the magnetized interfaces of 3D topological insulators. We demonstrated that their peculiar form, compared to other spin-orbit torques, have important repercussions in terms of magnetization reversal, charge pumping and anisotropic damping. In Chapter 4, we showed that the interplay between magnon current jm and magnetization m in homogeneous ferromagnets with Dzyaloshinskii-Moriya (DM) interaction, produces a field-like torque as well as a damping-like torque. These DM torques mediated by spin wave can tilt the imeaveraged magnetization direction and are similar to Rashba torques for electronic systems. Moreover, the DM torque is more efficient when magnons are

  14. Dynamic nuclear spin polarization

    Energy Technology Data Exchange (ETDEWEB)

    Stuhrmann, H B [GKSS-Forschungszentrum Geesthacht GmbH (Germany)

    1996-11-01

    Polarized neutron scattering from dynamic polarized targets has been applied to various hydrogenous materials at different laboratories. In situ structures of macromolecular components have been determined by nuclear spin contrast variation with an unprecedented precision. The experiments of selective nuclear spin depolarisation not only opened a new dimension to structural studies but also revealed phenomena related to propagation of nuclear spin polarization and the interplay of nuclear polarisation with the electronic spin system. The observation of electron spin label dependent nuclear spin polarisation domains by NMR and polarized neutron scattering opens a way to generalize the method of nuclear spin contrast variation and most importantly it avoids precontrasting by specific deuteration. It also likely might tell us more about the mechanism of dynamic nuclear spin polarisation. (author) 4 figs., refs.

  15. Nuclear spin polarized H and D by means of spin-exchange optical pumping

    Science.gov (United States)

    Stenger, Jörn; Grosshauser, Carsten; Kilian, Wolfgang; Nagengast, Wolfgang; Ranzenberger, Bernd; Rith, Klaus; Schmidt, Frank

    1998-01-01

    Optically pumped spin-exchange sources for polarized hydrogen and deuterium atoms have been demonstrated to yield high atomic flow and high electron spin polarization. For maximum nuclear polarization the source has to be operated in spin temperature equilibrium, which has already been demonstrated for hydrogen. In spin temperature equilibrium the nuclear spin polarization PI equals the electron spin polarization PS for hydrogen and is even larger than PS for deuterium. We discuss the general properties of spin temperature equilibrium for a sample of deuterium atoms. One result are the equations PI=4PS/(3+PS2) and Pzz=PSṡPI, where Pzz is the nuclear tensor polarization. Furthermore we demonstrate that the deuterium atoms from our source are in spin temperature equilibrium within the experimental accuracy.

  16. Spin relaxation in quantum dots: Role of the phonon modulated spin-orbit interaction

    Science.gov (United States)

    Alcalde, A. M.; Romano, C. L.; Sanz, L.; Marques, G. E.

    2010-01-01

    We calculate the spin relaxation rates in a parabolic InSb quantum dots due to the spin interaction with acoustical phonons. We considered the deformation potential mechanism as the dominant electron-phonon coupling in the Pavlov-Firsov spin-phonon Hamiltonian. We analyze the behavior of the spin relaxation rates as a function of an external magnetic field and mean quantum dot radius. Effects of the spin admixture due to Dresselhaus contribution to spin-orbit interaction are also discussed.

  17. Microstructure and corrosion performance of steam-based conversion coatings produced in the presence of TiO2 particles on aluminium alloys

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Gudla, Visweswara Chakravarthy; Jellesen, Morten Stendahl

    2016-01-01

    The steam-based conversion coatings containing TiO2 particleswere prepared using a two-step process comprising of spin coating of particles onto an aluminiumsubstrate followed by a high-pressure steam treatment. Process has resulted in the formation of aluminium oxide layer (~1.3 μm thick) embedded...... to the coatings without TiO2 particles, while the shift in thepitting potential was a function of the steam treatment time and degree of particle incorporation into the oxide....... with TiO2 particles. The electrochemical measurements showthe beneficial effect of TiO2 particles in the oxide layer by exhibiting lowestanodic and cathodic activities, and reduced pit depth. The presence of TiO2 particles shifts the corrosion potentialvalues to positive side (noble side) when compared...

  18. Exact solution of the mixed spin-1/2 and spin-S Ising-Heisenberg diamond chain

    Directory of Open Access Journals (Sweden)

    L. Čanová

    2009-01-01

    Full Text Available The geometric frustration in a class of the mixed spin-1/2 and spin-S Ising-Heisenberg diamond chains is investigated by combining three exact analytical techniques: Kambe projection method, decoration-iteration transformation and transfer-matrix method. The ground state, the magnetization process and the specific heat as a function of the external magnetic field are particularly examined for different strengths of the geometric frustration. It is shown that the increase of the Heisenberg spin value S raises the number of intermediate magnetization plateaux, which emerge in magnetization curves provided that the ground state is highly degenerate on behalf of a sufficiently strong geometric frustration. On the other hand, all intermediate magnetization plateaux merge into a linear magnetization versus magnetic field dependence in the limit of classical Heisenberg spin S → ∞. The enhanced magnetocaloric effect with cooling rate exceeding the one of paramagnetic salts is also detected when the disordered frustrated phase constitutes the ground state and the external magnetic field is small enough.

  19. Spin diffusion in bulk GaN measured with MnAs spin injector

    KAUST Repository

    Jahangir, Shafat; Dogan, Fatih; Kum, Hyun; Manchon, Aurelien; Bhattacharya, Pallab

    2012-01-01

    Spin injection and precession in bulk wurtzite n-GaN with different doping densities are demonstrated with a ferromagnetic MnAs contact using the three-terminal Hanle measurement technique. Theoretical analysis using minimum fitting parameters indicates that the spin accumulation is primarily in the n-GaN channel rather than at the ferromagnet (FM)/semiconductor (SC) interface states. Spin relaxation in GaN is interpreted in terms of the D’yakonov-Perel mechanism, yielding a maximum spin lifetime of 44 ps and a spin diffusion length of 175 nm at room temperature. Our results indicate that epitaxial ferromagnetic MnAs is a suitable high-temperature spin injector for GaN.

  20. Spin diffusion in bulk GaN measured with MnAs spin injector

    KAUST Repository

    Jahangir, Shafat

    2012-07-16

    Spin injection and precession in bulk wurtzite n-GaN with different doping densities are demonstrated with a ferromagnetic MnAs contact using the three-terminal Hanle measurement technique. Theoretical analysis using minimum fitting parameters indicates that the spin accumulation is primarily in the n-GaN channel rather than at the ferromagnet (FM)/semiconductor (SC) interface states. Spin relaxation in GaN is interpreted in terms of the D’yakonov-Perel mechanism, yielding a maximum spin lifetime of 44 ps and a spin diffusion length of 175 nm at room temperature. Our results indicate that epitaxial ferromagnetic MnAs is a suitable high-temperature spin injector for GaN.