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Sample records for superconducting thick film

  1. Stoichiometry and thickness dependence of superconducting properties of niobium nitride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Beebe, Melissa R., E-mail: mrbeebe@email.wm.edu; Beringer, Douglas B.; Burton, Matthew C.; Yang, Kaida; Lukaszew, R. Alejandra [Department of Physics, The College of William & Mary, Small Hall, 300 Ukrop Way, Williamsburg, Virginia 23185 (United States)

    2016-03-15

    The current technology used in linear particle accelerators is based on superconducting radio frequency (SRF) cavities fabricated from bulk niobium (Nb), which have smaller surface resistance and therefore dissipate less energy than traditional nonsuperconducting copper cavities. Using bulk Nb for the cavities has several advantages, which are discussed elsewhere; however, such SRF cavities have a material-dependent accelerating gradient limit. In order to overcome this fundamental limit, a multilayered coating has been proposed using layers of insulating and superconducting material applied to the interior surface of the cavity. The key to this multilayered model is to use superconducting thin films to exploit the potential field enhancement when these films are thinner than their London penetration depth. Such field enhancement has been demonstrated in MgB{sub 2} thin films; here, the authors consider films of another type-II superconductor, niobium nitride (NbN). The authors present their work correlating stoichiometry and superconducting properties in NbN thin films and discuss the thickness dependence of their superconducting properties, which is important for their potential use in the proposed multilayer structure. While there are some previous studies on the relationship between stoichiometry and critical temperature T{sub C}, the authors are the first to report on the correlation between stoichiometry and the lower critical field H{sub C1}.

  2. Effect of layer thickness on the superconducting properties in ultrathin Pb films

    Science.gov (United States)

    Durajski, A. P.

    2015-09-01

    Recently, superconductivity was found in one atomic layer of Pb film, promising a new field of research where superconductors can be studied on the atomic level. In the presented paper, we report a theoretical study of the superconductivity in ultrathin Pb films consisting of five to ten monolayers. Using the strong coupling Eliashberg formalism we reproduced the experimental values of critical temperature (TC) and we estimated the superconducting energy gap (Δ (0)), thermodynamic critical field (HC) and the specific heat jump at critical temperature (Δ C≤ft({T}{{C}}\\right)\\equiv {C}{{S}}≤ft({T}{{C}}\\right)-{C}{{N}}≤ft({T}{{C}}\\right)) for a wide range of film thicknesses. In these systems, we found an oscillatory behaviour of the above thermodynamic properties modulated by quantum size effects. Moreover, the large values of 2Δ (0){/k}{{B}}{T}{{C}} and Δ C≤ft({T}{{C}}\\right)/{C}{{N}}≤ft({T}{{C}}\\right), and the small values of {T}{{C}}{C}{{N}}≤ft({T}{{C}}\\right)/{H}{{C}}2(0) prove that the thermodynamic properties of Pb films cannot be correctly described using the Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity due to the strong coupling and retardation effects.

  3. Thick REBaCuO superconducting films through single-coating of low-fluorine metallorganic solution

    Science.gov (United States)

    Boubeche, M.; Cai, C. B.; Jian, H. B.; Li, M. J.; Yang, W. T.; Liu, Z. Y.; Bai, C. Y.

    2016-10-01

    A high critical current Ic is crucial for the application of high temperature superconductors YBa2Cu3O7-δ in energy efficient power devices and wires. In this paper we report the fabrication of thick (YGd)1.3Ba2Cu3O7-x films on a metal substrate using low-fluorine metal organic deposition method. The effects of the film thickness on the microstructure, texture and superconductivity properties of the films were evaluated. In order to increase the film thicknesses by single coating, the influence of withdrawal speed during the dip coating on resulting thickness are investigated with the other processing parameters fixed. It is revealed that there is a maximum thickness for a certain starting solution. Here we used 3 different solutions, Conventional Low Fluorine solutions with 2 M and 2.5 M, and super low-fluorine solution with 2.5 M. The maximum thicknesses of about 710 nm, 1280 nm and 1460 nm were obtained, respectively.

  4. Prototype Superconducting Planar Transformers Using High-Tc Thin and Thick Films

    Science.gov (United States)

    1992-01-01

    Japanese Journal of Applied Physics , vol...Diffraction Pattern of Superconductor Bi 2 (Sr,Ca) 3-.Cu 2Oy," Japanese Journal of Applied Physics , vol. 27, p. L833. Peterson, R.L., and J.W. Ekin. 1988...34Crystallinity and Morphology of Superconducting Thin Films Prepared by Sputtering," Japanese Journal of Applied Physics , vol. 28, p. L441. Tarascon,

  5. Superconducting YBa2Cu3O7– thick film (c (0)$ = 92 K) on a newly developed perovskite ceramic substrate

    Indian Academy of Sciences (India)

    S U K Nair; P R S Warriar; J Koshy

    2002-04-01

    A complex perovskite oxide, YbBa2NbO6, as a non-reacting substrate for YBa2Cu3O7– superconducting film has been developed. The dielectric constant and loss factor values of the material are in the range suitable for its use as substrate for microwave application. A YBa2Cu3O7– superconducting thick film dip coated on YbBa2NbO6 substrate gave a c (0) of 92 K and current density of ∼ 1.3 × 104 A cm-2.

  6. Percolation effect in thick film superconductors: Using a Bi(Pb)SrCaCuO based paste to prepare a superconducting planar transformer

    Science.gov (United States)

    Sali, Robert; Harsanyi, Gabor

    1995-01-01

    A thick film superconductor paste has been developed to study the properties of granulated superconductor materials, to observe the percolation effect and to confirm the theory of the conducting mechanism in the superconducting thick films. This paste was also applied to make a superconducting planar transformer. Due to the T(sub c) and advantageous current density properties the base of the past was chosen to be of Bi(Pb)SrCaCu) system. For contacts a conventional Ag/Pt paste was used. The critical temperature of the samples were between 110 K and 115 K depending on the printed layer thickness. The critical current density -at the boiling temperature of the liquid He- was between 200 - 300 A/sq cm. The R(T) and V(I) functions were measured with different parameters. The results of the measurements have confirmed the theory of conducting mechanism in the material. The percolation structure model has been built and described. As an application, a superconducting planar thick film transformer was planned and produced. Ten windings of the transformer were printed on one side of the alumina substrate and one winding was printed on the other side. The coupling between the two sides was possible through the substrate. The samples did not need special drying and firing parameters. After the preparation, the properties of the transformer were measured. The efficiency ans the losses were determined. Finally, some fundamental advantages and problems of the process were discussed.

  7. Thick film hydrogen sensor

    Science.gov (United States)

    Hoffheins, Barbara S.; Lauf, Robert J.

    1995-01-01

    A thick film hydrogen sensor element includes an essentially inert, electrically-insulating substrate having deposited thereon a thick film metallization forming at least two resistors. The metallization is a sintered composition of Pd and a sinterable binder such as glass frit. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors.

  8. Superconducting Electronic Film Structures

    Science.gov (United States)

    1991-02-14

    cubic, yttria stabilized, zirconia (YSZ) single crystals with (100) orientation and ao = 0.512 to 0.516 nm. Films were magnetron-sputtered... Crown by Solid-State and Vapor-Phase Epitaxy," IEEE Trans. Uagn. 25(2), 2538 (1989). 6. J. H. Kang, R. T. Kampwirth, and K. E. Gray, "Superconductivity...summarized in Fig. 1, are too high for SrTiO3 or yttria- stabilized zirconia (YSZ) to be used in rf applications. MgO, LaAIO 3 , and LaGaO3 have a tan 6

  9. Niobium films for superconducting accelerating cavities

    Energy Technology Data Exchange (ETDEWEB)

    Benvenuti, C.; Circelli, N.; Hauer, M.

    1984-09-01

    Superconducting accelerating cavities made of Nb-coated copper were produced. Niobium films of a thickness ranging from 1.4 to 4 ..mu..m were deposited onto the inside of 3-GHz cavities and 500-MHz frequency by bias diode sputtering. A maximum accelerating field of 8.6 MV m/sup -1/ was reached without quench which is attributed to the large thermal conductivity of copper at liquid helium temperatures.

  10. Percolation effect in thick film superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Sali, R.; Harsanyi, G. [Technical Univ. of Budapest (Hungary)

    1994-12-31

    A thick film superconductor paste has been developed to study the properties of granulated superconductor materials, to observe the percolation effect and to confirm the theory of the conducting mechanism in the superconducting thick films. This paste was also applied to make a superconducting planar transformer. Due to high T{sub c} and advantageous current density properties the base of the paste was chosen to be of Bi(Pb)SrCaCuO system. For contacts a conventional Ag/Pt paste was used. The critical temperature of the samples were between 110 K and 115 K depending on the printed layer thickness. The critical current density at the boiling temperature of the liquid He- was between 200-300 A/cm{sup 2}. The R(T) and V(I) functions were measured with different parameters. The results of the measurements have confirmed the theory of conducting mechanism in the material. The percolation structure model has been built and described. As an application, a superconducting planar thick film transformer was planned and produced. Ten windings of the transformer were printed on one side of the alumina substrate and one winding was printed on the other side. The coupling between the two sides was possible through the substrate. The samples did not need special drying and firing parameters. After the preparation, the properties of the transformer were measured. The efficiency and the losses were determined. Finally, some fundamental advantages and problems of the process were discussed.

  11. Amorphous molybdenum silicon superconducting thin films

    Directory of Open Access Journals (Sweden)

    D. Bosworth

    2015-08-01

    Full Text Available Amorphous superconductors have become attractive candidate materials for superconducting nanowire single-photon detectors due to their ease of growth, homogeneity and competitive superconducting properties. To date the majority of devices have been fabricated using WxSi1−x, though other amorphous superconductors such as molybdenum silicide (MoxSi1−x offer increased transition temperature. This study focuses on the properties of MoSi thin films grown by magnetron sputtering. We examine how the composition and growth conditions affect film properties. For 100 nm film thickness, we report that the superconducting transition temperature (Tc reaches a maximum of 7.6 K at a composition of Mo83Si17. The transition temperature and amorphous character can be improved by cooling of the substrate during growth which inhibits formation of a crystalline phase. X-ray diffraction and transmission electron microscopy studies confirm the absence of long range order. We observe that for a range of 6 common substrates (silicon, thermally oxidized silicon, R- and C-plane sapphire, x-plane lithium niobate and quartz, there is no variation in superconducting transition temperature, making MoSi an excellent candidate material for SNSPDs.

  12. Vortices in superconducting bulk, films and SQUIDs

    Indian Academy of Sciences (India)

    Ernst Helmut Brandt

    2006-01-01

    The properties of the ideal periodic vortex lattice in bulk superconductors and in films of any thickness can be calculated from Ginzburg-Landau theory by an iteration method using Fourier series. The London theory yields general analytic expressions for the magnetic field and energy of arbitrary arrangements of straight or curved vortex lines. The elasticity of the vortex lattice is highly nonlocal. The magnetic response of superconductors of realistic shapes like thin and thick strips and disks or thin rectangular plates or films, containing pinned vortices, can be computed within continuum theory by solving an integral equation. A useful example is a thin square with a central hole and a radial slit, used as superconducting quantum interference device (SQUID).

  13. Microwave study of superconducting Sn films above and below percolation

    Science.gov (United States)

    Beutel, Manfred H.; Ebensperger, Nikolaj G.; Thiemann, Markus; Untereiner, Gabriele; Fritz, Vincent; Javaheri, Mojtaba; Nägele, Jonathan; Rösslhuber, Roland; Dressel, Martin; Scheffler, Marc

    2016-08-01

    The electronic properties of superconducting Sn films ({T}{{c}}≈ 3.8 {{K}}) change significantly when reducing the film thickness down to a few {nm}, in particular close to the percolation threshold. The low-energy electrodynamics of such Sn samples can be probed via microwave spectroscopy, e.g. with superconducting stripline resonators. Here we study Sn thin films, deposited via thermal evaporation—ranging in thickness between 38 and 842 {nm}—which encompasses the percolation transition. We use superconducting Pb stripline resonators to probe the microwave response of these Sn films in a frequency range between 4 and 20 {GHz} at temperatures from 7.2 down to 1.5 {{K}}. The measured quality factor of the resonators decreases with rising temperature due to enhanced losses. As a function of the sample thickness we observe three regimes with significantly different properties: samples below percolation, i.e. ensembles of disconnected superconducting islands, exhibit dielectric properties with negligible losses, demonstrating that macroscopic current paths are required for appreciable dynamical conductivity of Sn at GHz frequencies. Thick Sn films, as the other limit, lead to low-loss resonances both above and below T c of Sn, as expected for bulk conductors. But in an intermediate thickness regime, just above percolation and with labyrinth-like morphology of the Sn, we observe a quite different behavior: the superconducting state has a microwave response similar to the thicker, completely covering films with low microwave losses; but the metallic state of these Sn films is so lossy that resonator operation is suppressed completely.

  14. Ba2ErNbO6: A new perovskite ceramic substrate for Bi(2223) superconducting thick films (c(0) = 110 K)

    Indian Academy of Sciences (India)

    S U K Nair; P R S Warriar; J Koshy

    2005-02-01

    Barium erbium niobate (Ba2ErNbO6) has been developed as a new substrate for (Bi,Pb)2Sr2Ca2Cu3O [Bi(2223)] superconductor film. Ba2ErNbO6 (BENO) has a cubic perovskite structure with lattice constant, = 8.318 Å. The Bi(2223) superconductor does not show any detectable chemical reaction with BENO even under extreme processing conditions. Dip coated Bi (2223) thick film, Ba2ErNbO6 substrate, gave a c (0) of 110 K and current density of ∼ 4 × 103 A cm-2 at 77 K and zero magnetic field.

  15. New Fast Response Thin Film-Based Superconducting Quench Detectors

    CERN Document Server

    Dudarev, A; van de Camp, W; Ravaioli, E; Teixeira, A; ten Kate, H H J

    2014-01-01

    Quench detection on superconducting bus bars and other devices with a low normal zone propagation velocity and low voltage build-up is quite difficult with conventional quench detection techniques. Currently, on ATLAS superconducting bus bar sections, superconducting quench detectors (SQD) are mounted to detect quench events. A first version of the SQD essentially consists of an insulated superconducting wire glued to a superconducting bus line or windings, which in the case of a quench rapidly builds up a relatively high resistance that can be easily and quietly detected. We now introduce a new generation of drastically improved SQDs. The new version makes the detection of quenches simpler, more reliable, and much faster. Instead of a superconducting wire, now a superconducting thin film is used. The layout of the sensor shows a meander like pattern that is etched out of a copper coated 25 mu m thick film of Nb-Ti glued in between layers of Kapton. Since the sensor is now much smaller and thinner, it is easi...

  16. 1D superconductivity in porous Nb ultrathin films

    Energy Technology Data Exchange (ETDEWEB)

    Trezza, M., E-mail: trezza@sa.infn.it [CNR-SPIN Salerno and Dipartimento di Fisica, ' E. R. Caianiello' , Universita degli Studi di Salerno, Via Ponte don Melillo, Fisciano I-84084 (Italy); Prischepa, S.L. [State University of Informatics and RadioElectronics, P. Brovka Street 6, Minsk 220013 (Belarus); Cirillo, C.; Attanasio, C. [CNR-SPIN Salerno and Dipartimento di Fisica, ' E. R. Caianiello' , Universita degli Studi di Salerno, Via Ponte don Melillo, Fisciano I-84084 (Italy)

    2012-09-15

    We report on the measurements of the transport properties of superconducting Nb ultrathin bridges grown by UHV magnetron sputtering on porous Si substrates. The films are about 10 nm thick and inherit from the substrate a structure made of holes with diameter of 10 nm and interpore spacing in the range 20-40 nm. Due to their reduced dimensions, they are sensitive to thermal fluctuations typical of 1D superconductors and exhibit a nonzero resistance below the superconducting transition temperature, T{sub c}. Clear hysteresis and finite jumps in the I-V curves are also observed.

  17. Percolation and electronic properties of superconducting (YBa sub 2 Cu sub 3 O sub 7 minus. delta. ) sub 1 minus x Ag sub x ceramics and thick films

    Energy Technology Data Exchange (ETDEWEB)

    Dwir, B.; Pavuna, D.; Affronte, M.; Berger, H. (Swiss Federal Institute of Technology, Lausanne (Switzerland)); Tholence, J.L. (C.R.T.B.T., Grenoble (France))

    1989-09-01

    The authors present the percolation and electronic properties of (Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}){sub 1{minus}x}Ag{sub x} compounds in which silver fills the intergranular space without reducing {Tc}, which remains at 92 {plus minus} 1 K. Normal-state resistivity is decreased by up to two orders of magnitude when adding up to 50 wt.% Ag({Tc} = 87 K), and samples exhibit improved contact resistance, better mechanical properties, and resistance to water. They analyzed the percolation properties of these compounds and found that the critical indices t, s are in agreement with percolation theory, but p{sub c} is higher than expected, probably due to the effect of holes. The J{sub c} estimated from magnetization reaches 5 {center dot} 10{sup 4} A/cm{sup 2} (at T = 4.2 K, H = 0) and shows enhancement of 15-50% by addition of {approximately} 10 wt.% Ag, which exists also in samples having a higher J{sub c} due to preparation conditions (temperature). They present preliminary results on the 2D percolation problem in (Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}){sub 1{minus}x}Ag{sub x} samples, obtained by preparing Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} thick films using the spin-on technique. Preliminary results show good adhesion but a reduced {Tc} of Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} films compared with bulk samples.

  18. Superconductivity in CVD diamond films.

    Science.gov (United States)

    Takano, Yoshihiko

    2009-06-24

    A beautiful jewel of diamond is insulator. However, boron doping can induce semiconductive, metallic and superconducting properties in diamond. When the boron concentration is tuned over 3 × 10(20) cm(-3), diamonds enter the metallic region and show superconductivity at low temperatures. The metal-insulator transition and superconductivity are analyzed using ARPES, XAS, NMR, IXS, transport and magnetic measurements and so on. This review elucidates the physical properties and mechanism of diamond superconductor as a special superconductivity that occurs in semiconductors.

  19. Self-field effects on critical current density and current-voltage characteristics in superconducting YBaCuO thick films

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, A.D.; Hart, C.; Martinez, C.M.; Ares, O. [Superconductivity Lab, IMRE-University of Havana, Vedado 10400, Havana (Cuba)

    1999-07-01

    The self-field and percolative influences on transport measurements of polycrystalline bridges engraved on YBaCuO thick film have been investigated. A maximum in the dependence of the critical current density on cross-sectional area of the bridge (A = 0.003 mm{sup 2}-0.3 mm{sup 2}) has been found experimentally, in samples with low critical current densities (J{sub c}<50 A cm{sup -2}). The result of the measurements are in agreement with Mulet and coworkers, who have predicted that, under certain conditions, the self-field effects on transport measurements are negligible and the J{sub c} dependence on the sample dimensions is determined by the percolative character of the transport current. Self-field influences have also been observed in current-voltage characteristics, which have been analysed using the Ambegaokar-Halperin phase-slip theory. By allowing the noise parameter ({gamma}) to change with temperature, magnetic field and transport current, adequate agreement between theoretical and experimental current-voltage characteristics has been obtained. The dependence of the noise parameter with the transport current is demonstrated to be related with the self-field. (author)

  20. Deposition of MgB2 Superconducting Thick Films in Sol-Gel Method%溶液法制备MgB2超导膜研究

    Institute of Scientific and Technical Information of China (English)

    郭峥山; 陈艺灵; 冯庆荣

    2012-01-01

    The superconducting MgB2 thick films were deposited in sol-gel method on SiC and Al2O3 substrates. The viscous precursor solution, Mg( BH4 )2· Et2O, of the MgB2, was first prepared via chemical route. Next, the precursor sol, painted on the substrates, was annealed at a high temperature. Repetition of the painting procedure increased the film thickness, from 200 nm to 1 μm. Finally, the MgB2 thick films were obtained by carefully annealing the precursor coatings in the reactor, filled with low pressure hydrogen, mixed with a small amount of Mg vapor generated by evaporation of Mg ingot. The impacts of the solution processing and annealing conditions on the microstructures and properties of the MgB2 thick films were evaluated. The MgB2 thick films were characterized with X-ray diffraction, and canning electron microscopy - The transition temperature of the 10 μm thick MgB2 coating was found to be 37 K. The possible means to reduce the surface pore and defect densities, and the feasibility of scaling up the MgB2 deposition in sol-get method were also tentatively discussed.%介绍了利用溶液法制备Mg(BH4)2前驱体,进而在衬底上涂抹粘稠的Mg(BH4)2乙醚溶胶(Mg(BH4)2·Et2O)制备MgB2厚膜的方法,也可称为溶胶凝胶法制备MgB2.运用此种方法制备出了10 μm级厚度、转变温度达到37 K的MgB2超导厚膜.这种方法设备简单、制膜所需温度低、原料便宜,并且无毒无污染.更为重要的是,这种方法克服了困扰工业上因为硼(B)在采购、运输和存储过程中易于氧化的缺点,可以通过将Mg(BH4)2·Et2O溶胶直接在衬底上均匀甩胶,进而大规模制备MgB2带材.可见溶液法制备MgB2是一种有着很大应用潜力的方法.

  1. Observation of Double-Dome Superconductivity in Potassium-Doped FeSe Thin Films.

    Science.gov (United States)

    Song, Can-Li; Zhang, Hui-Min; Zhong, Yong; Hu, Xiao-Peng; Ji, Shuai-Hua; Wang, Lili; He, Ke; Ma, Xu-Cun; Xue, Qi-Kun

    2016-04-15

    We report on the emergence of two disconnected superconducting domes in alkali-metal potassium- (K-)doped FeSe ultrathin films grown on graphitized SiC(0001). The superconductivity exhibits hypersensitivity to K dosage in the lower-T_{c} dome, whereas in the heavily electron-doped higher-T_{c} dome it becomes spatially homogeneous and robust against disorder, supportive of a conventional Cooper-pairing mechanism. Furthermore, the heavily K-doped multilayer FeSe films all reveal a large superconducting gap of ∼14  meV, irrespective of film thickness, verifying the higher-T_{c} superconductivity only in the topmost FeSe layer. The unusual finding of a double-dome superconducting phase is a step towards the mechanistic understanding of superconductivity in FeSe-derived superconductors.

  2. A new model analysis of the third harmonic voltage in inductive measurement for critical current density of superconducting films

    Institute of Scientific and Technical Information of China (English)

    Zhang Xu; Wu Zhi-Zhen; Zhou Tie-Ge; He Ming; Zhao Xin-Jie; Yan Shao-Lin; Fang Lan

    2011-01-01

    The critical current density Jc is one of the most important parameters of high temperature superconducting films in superconducting applications, such as superconducting filter and superconducting Josephson devices. This paper presents a new model to describe inhomogeneous current distribution throughout the thickness of superconducting films applying magnetic field by solving the differential equation derived from Maxwell equation and the second London equation. Using this model, it accurately calculates the inductive third-harmonic voltage when the film applying magnetic field with the inductive measurement for Jc. The theoretic curve is consistent with the experimental results about measuring superconducting film, especially when the third-harmonic voltage just exceeds zero. The Jc value of superconducting films determined by the inductive method is also compared with results measured by four-probe transport method. The agreements between inductive method and transport method are very good.

  3. Quantum device prospects of superconducting nanodiamond films

    Science.gov (United States)

    Mtsuko, D.; Churochkin, D.; Bhattacharyya, S.

    2016-02-01

    Nanostructured semiconducting carbon system, described by as a superlattice-like structure demonstrated its potential in switching device applications based on the quantum tunneling through the insulating carbon layer. This switching property can be enhanced further with the association of Josephson's tunneling between two superconducting carbon (diamond) grains separated by a very thin layer of carbon which holds the structure of the film firmly. The superconducting nanodiamond heterostructures form qubits which can lead to the development of quantum computers provided the effect of disorder present in these structure can be firmly understood. Presently we concentrate on electrical transport properties of heavily boron-doped nanocrystalline diamond films around the superconducting transition temperature measured as a function of magnetic fields and the applied bias current. Microstructure of these films is described by a two dimensional superlattice system which can also contain paramagnetic impurities. We report observation of anomalous negative Hall resistance in these films close to the superconductor-insulator-normal phase transition in the resistance versus temperature plots at low bias currents at zero and low magnetic field. The negative Hall effect is found to be suppressed as the bias current increase. Magnetoresistance study shows a distinct peak at zero field when measured in the low current regimes which suggest a superconductor-insulator-superconductor structure of films. Current vs. voltage characteristics show signature of π-Josephson like behaviour which can give rise to a characteristic frequency of several hundred of gigahertz. Signature of spin flipping also shows novel spintronic device applications.

  4. Micro-droplets lubrication film thickness dynamics

    Science.gov (United States)

    Huerre, Axel; Theodoly, Olivier; Cantat, Isabelle; Leshansky, Alexander; Valignat, Marie-Pierre; Jullien, Marie-Caroline; MMN Team; LAI Team; IPR Team; Department of Chemical Engineering Team

    2014-11-01

    The motion of droplets or bubbles in confined geometries has been extensively studied; showing an intrinsic relationship between the lubrication film thickness and the droplet velocity. When capillary forces dominate, the lubrication film thickness evolves non linearly with the capillary number due to viscous dissipation between meniscus and wall. However, this film may become thin enough that intermolecular forces come into play and affect classical scalings. We report here the first experimental evidence of the disjoining pressure effect on confined droplets by measuring droplet lubrication film thicknesses in a microfluidic Hele-Shaw cell. We find and characterize two distinct dynamical regimes, dominated respectively by capillary and intermolecular forces. In the former case rolling boundary conditions at the interface are evidenced through film thickness dynamics, interface velocity measurement and film thickness profile.

  5. Film thickness determination by grazing incidence diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Battiston, G. A.; Gerbasi, R. [CNR, Padua (Italy). Istituto di Chimica e Tecnologie Inorganiche e dei Materiali Avanzati

    1996-09-01

    Thin films deposited via MOCVD (Metal Organic Chemical Vapour Deposition) are layers in the thickness range of a few manometers to about ten micrometers. An understanding of the physics and chemistry of films is necessary for a better comprehension of the phenomena involved in the film deposition procedure and its optimisation. Together with the crystalline phase a parameter that must be determined is the thickness of the layer. In this work the authors present a method for the measurement of the film thickness. This procedure, based on diffraction intensity absorption of the X-rays, both incident and diffracted in passing through the layers, resulted quite simple, rapid and non-destructive.

  6. Nonequilibrium Properties of Variable-Thickness Superconducting Micro-bridges.

    Science.gov (United States)

    1978-01-01

    shor t is always lef t near the leads to prevent acci- dental burnout. This short is only removed once the leads are soldered (with an unplugged and...interest here, by overlaying a superconduct- ing film with a normal metal,14 by optical, phonon or quasi— 15 16particle injection, by ion implantation or...which might not be justified in the regimes of interest. Experimentall y, further work is requir ed in order to understand the low voltage I—V

  7. Effect of geometry on hydrodynamic film thickness

    Science.gov (United States)

    Brewe, D. E.; Hamrock, B. J.; Taylor, C. M.

    1978-01-01

    The influence of geometry on the isothermal hydrodynamic film separating two rigid solids was investigated. Pressure-viscosity effects were not considered. The minimum film thickness is derived for fully flooded conjunctions by using the Reynolds boundary conditions. It was found that the minimum film thickness had the same speed, viscosity, and load dependence as Kapitza's classical solution. However, the incorporation of Reynolds boundary conditions resulted in an additional geometry effect. Solutions using the parabolic film approximation are compared with those using the exact expression for the film in the analysis. Contour plots are shown that indicate in detail the pressure developed between the solids.

  8. Superconducting detector of IR single-photons based on thin WSi films

    CERN Document Server

    Seleznev, V A; Vakhtomin, Yu B; Morozov, P V; Zolotov, P I; Vasilev, D D; Moiseev, K M; Malevannaya, E I; Smirnov, K V

    2016-01-01

    We have developed the deposition technology of WSi thin films 4 to 9 nm thick with high temperature values of superconducting transition (Tc~4 K). Based on deposed films there were produced nanostructures with indicative planar sizes ~100 nm, and the research revealed that even on nanoscale the films possess of high critical temperature values of the superconducting transition (Tc~3.3-3.7K ) which certifies high quality and homogeneity of the films created. The first experiments on creating superconducting single-photon detectors showed that the detectors SDE (system detection efficiency) with increasing bias current (Ib) reaches a constant value of ~30% (for 1550 nm) defined by infrared radiation absorption by the superconducting structure. To enhance radiation absorption by the superconductor there were created detectors with cavity structures which demonstrated a practically constant value of quantum efficiency >65% for bias currents Ib>=0.6Ic. The minimal dark counts level (DC) made 1 s^-1 limited with ba...

  9. Enhancement of high-TC superconducting thin film devices by nanoscale polishing

    Science.gov (United States)

    Michalowski, P.; Shapoval, T.; Meier, D.; Katzer, C.; Schmidl, F.; Schultz, L.; Seidel, P.

    2012-11-01

    The effects of mechanical nanoscale polishing on the superconducting parameters of YBa2Cu3O7-δ (YBCO) thin films and bi-crystal grain boundary Josephson junctions have been investigated. We prepared samples with additional gold nanocrystallites in the YBCO film. As they are distributed throughout the whole YBCO film, they provide a low-resistance ohmic contact even if parts of the film are removed. Polishing was performed either before or after the patterning and did not change the properties of the grain boundary. However, nanopolishing reduces the film roughness in a significant way, which makes it an indispensable tool for the preparation of integrated superconducting circuits. We also succeeded in tuning the IC and RN of the Josephson junctions of direct current superconducting quantum interference devices (dc-SQUIDs) by systematically reducing the film thickness, which opens up new possibilities in the application of magnetic field sensors.

  10. Quasi-two-dimensional superconductivity in FeSe0.3Te0.7 thin films and electric-field modulation of superconducting transition.

    Science.gov (United States)

    Lin, Zhu; Mei, Chenguang; Wei, Linlin; Sun, Zhangao; Wu, Shilong; Huang, Haoliang; Zhang, Shu; Liu, Chang; Feng, Yang; Tian, Huanfang; Yang, Huaixin; Li, Jianqi; Wang, Yayu; Zhang, Guangming; Lu, Yalin; Zhao, Yonggang

    2015-09-18

    We report the structural and superconducting properties of FeSe0.3Te0.7 (FST) thin films with different thicknesses grown on ferroelectric Pb(Mg1/3Nb2/3)0.7Ti0.3O3 substrates. It was shown that the FST films undergo biaxial tensile strains which are fully relaxed for films with thicknesses above 200 nm. Electrical transport measurements reveal that the ultrathin films exhibit an insulating behavior and superconductivity appears for thicker films with Tc saturated above 200 nm. The current-voltage curves around the superconducting transition follow the Berezinskii-Kosterlitz-Thouless (BKT) transition behavior and the resistance-temperature curves can be described by the Halperin-Nelson relation, revealing quasi-two-dimensional phase fluctuation in FST thin films. The Ginzburg number decreases with increasing film thickness indicating the decrease of the strength of thermal fluctuations. Upon applying electric field to the heterostructure, Tc of FST thin film increases due to the reduction of the tensile strain in FST. This work sheds light on the superconductivity, strain effect as well as electric-field modulation of superconductivity in FST films.

  11. Nano-engineered pinning centres in YBCO superconducting films

    Science.gov (United States)

    Crisan, A.; Dang, V. S.; Mikheenko, P.

    2017-02-01

    For practical applications of superconducting materials in applied magnetic fields, artificial pinning centres in addition to natural ones are required to oppose the Lorentz force. These pinning centres are actually various types of defects in the superconductor matrix. The pinning centres can be categorised on their dimension (volume, surface or point) and on their character (normal cores or Δκ cores). Different samples have been produced by Pulsed Laser Deposition, with various thicknesses, temperatures and nanostructured additions to the superconducting matrix. They have been characterized by SQUID Magnetic Properties Measurement System and Physical Properties Measurement System, as well as by Transmission Electron Microscopy (TEM). Correlations between pinning architecture, TEM images, and critical currents at various fields and field orientations will be shown for a large number of YBa2Cu3Ox films with various types and architectures of artificial pinning centres.

  12. In situ electrical transport measurement of superconductive ultrathin films

    Institute of Scientific and Technical Information of China (English)

    刘灿华; 贾金锋

    2015-01-01

    The discovery of an extraordinarily superconductive large energy gap in SrTiO3 supported single-layer FeSe films has recently initiated a great deal of research interests in surface-enhanced superconductivity and superconductive ultrathin films fabricated on crystal surfaces. On account of the instability of ultra-thin films in air, it is desirable to perform elec-trical transport measurement in ultra-high vaccum (UHV). Here we review the experimental techniques of in situ electrical transport measurement and their applications on superconductive ultrathin films.

  13. Influence of hydrostatic pressure on superconducting properties of niobium thin film

    Energy Technology Data Exchange (ETDEWEB)

    Pristáš, Gabriel; Gabáni, Slavomír; Gažo, Emil [Centre of Low Temperature Physics, Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01 Košice (Slovakia); Komanický, Vladimír; Orendáč, Matúš [Centre of Low Temperature Physics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9, SK-04154 Košice (Slovakia); You, Hoydoo [Materials Science Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2014-04-01

    We have studied superconducting properties of niobium thin films under hydrostatic pressures up to 3 GPa. The films with thickness of 100 nm were prepared in the high vacuum DC magnetron sputtering system (with critical temperature TC = 8.95 K at ambient pressure). The produced high quality films have been characterized using electrical resistivity and magnetization measurements, X-ray diffraction, and atomic force microscope imaging. We have observed increase of TC with increasing value of applied pressure (dTC/dp = 73 mK/GPa) up to 3 GPa. This observation is different to pressure effect observed on bulk sample of Nb. In this paper we are discussing the origin of this discrepancy. - Highlights: • We have studied superconducting properties of niobium thin films under pressure. • The 100 nm thick films were prepared in DC magnetron sputtering system. • We have observed different behavior of T{sub C} for thin film and for bulk sample.

  14. Effects of Surface Electron Doping and Substrate on the Superconductivity of Epitaxial FeSe Films.

    Science.gov (United States)

    Zhang, W H; Liu, X; Wen, C H P; Peng, R; Tan, S Y; Xie, B P; Zhang, T; Feng, D L

    2016-03-09

    Superconductivity in FeSe is greatly enhanced in films grown on SrTiO3 substrates, although the mechanism behind remains unclear. Recently, surface potassium (K) doping has also proven able to enhance the superconductivity of FeSe. Here, by using scanning tunneling microscopy, we compare the K doping dependence of the superconductivity in FeSe films grown on two substrates: SrTiO3 (001) and graphitized SiC (0001). For thick films (20 unit cells (UC)), the optimized superconducting (SC) gaps are of similar size (∼9 meV) regardless of the substrate. However, when the thickness is reduced to a few UC, the optimized SC gap is increased up to ∼15 meV for films on SrTiO3, whereas it remains unchanged for films on SiC. This clearly indicates that the FeSe/SrTiO3 interface can further enhance the superconductivity, beyond merely doping electrons. Intriguingly, we found that this interface enhancement decays exponentially as the thickness increases, with a decay length of 2.4 UC, which is much shorter than the length scale for relaxation of the lattice strain, pointing to interfacial electron-phonon coupling as the likely origin.

  15. Local imaging of magnetic flux in superconducting thin films

    Energy Technology Data Exchange (ETDEWEB)

    Shapoval, Tetyana

    2010-01-26

    Local studies of magnetic flux line (vortex) distribution in superconducting thin films and their pinning by natural and artificial defects have been performed using low-temperature magnetic force microscopy (LT-MFM). Taken a 100 nm thin NbN film as an example, the depinning of vortices from natural defects under the influence of the force that the MFM tip exerts on the individual vortex was visualized and the local pinning force was estimated. The good agreement of these results with global transport measurements demonstrates that MFM is a powerful and reliable method to probe the local variation of the pinning landscape. Furthermore, it was demonstrated that the presence of an ordered array of 1-{mu}m-sized ferromagnetic permalloy dots being in a magneticvortex state underneath the Nb film significantly influences the natural pinning landscape of the superconductor leading to commensurate pinning effects. This strong pinning exceeds the repulsive interaction between the superconducting vortices and allows vortex clusters to be located at each dot. Additionally, for industrially applicable YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} thin films the main question discussed was the possibility of a direct correlation between vortices and artificial defects as well as vortex imaging on rough as-prepared thin films. Since the surface roughness (droplets, precipitates) causes a severe problem to the scanning MFM tip, a nanoscale wedge polishing technique that allows to overcome this problem was developed. Mounting the sample under a defined small angle results in a smooth surface and a monotonic thickness reduction of the film along the length of the sample. It provides a continuous insight from the film surface down to the substrate with surface sensitive scanning techniques. (orig.)

  16. High-temperature superconductivity in potassium-coated multilayer FeSe thin films.

    Science.gov (United States)

    Miyata, Y; Nakayama, K; Sugawara, K; Sato, T; Takahashi, T

    2015-08-01

    The recent discovery of possible high-temperature (T(c)) superconductivity over 65 K in a monolayer FeSe film on SrTiO3 (refs 1-6) triggered a fierce debate on how superconductivity evolves from bulk to film, because bulk FeSe crystal exhibits a T(c) of no higher than 10 K (ref. 7). However, the difficulty in controlling the carrier density and the number of FeSe layers has hindered elucidation of this problem. Here, we demonstrate that deposition of potassium onto FeSe films markedly expands the accessible doping range towards the heavily electron-doped region. Intriguingly, we have succeeded in converting non-superconducting films with various thicknesses into superconductors with T(c) as high as 48 K. We also found a marked increase in the magnitude of the superconducting gap on decreasing the FeSe film thickness, indicating that the interface plays a crucial role in realizing the high-temperature superconductivity. The results presented provide a new strategy to enhance and optimize T(c) in ultrathin films of iron-based superconductors.

  17. Preparation and characterization of microcrack-free thick YBa2Cu3O7-δ films

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    High quality epitaxial YBa2Cu3O7-δ (YBCO) superconducting films were fabricated on (00l) LaAlO3 substrates using the direct-current sputtering method. The attainment of an unusually high film thickness (up to 2.0 μm) without microcracking was attributed in part to the presence of pores correlated with yttrium-rich composition in the films. The influence of the film thickness on the microstructure was investigated by X-ray diffraction conventional scan (θ-2θ, ω-scan, pole figure) and high-resolution reciprocal space mapping. The films were c-axis oriented with no a-axis-oriented grains up to the thickness of 2 μm. The surface morphology and the critical current density (Jc) strongly depended on the film thickness.Furthermore, the reasons for these thickness dependences were elucidated in derail.

  18. Fabrication of MgB2 superconducting films by different methods

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    MgB2 superconducting films have been successfully fabricated on single crystal MgO( 111 ) and c-AL2O3 substrates by different methods. The film deposited by pulsed laser deposition is c-axis oriented with zero resistance transition temperature of 38.4 K,while the other two films fabricated by chemical vapor deposition and electrophoresis are c-axis textured with the zero resistance transition temperature of 38 K and 39 K, respectively. Magnetization hysteresis measurements yield critical current density Jc of 107 A/cm2 at 15 K in zero field for the thin film and of 105 A/cm2 for the thick film. For the thin film deposited by chemical vapor deposition, the microwave surface resistance at 10 K is found to be as low as 100 μΩ, which is comparable with that of a high-quality high-temperature superconducting thin film of YBCO.

  19. Impact of Edge-Barrier Pinning in Superconducting Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    Jones, W. A.; Barnes, P.N.; Mullins, M. J.; Baca, F. J.; Emergo, R. L. S.; Wu, J.; Haugan, T. J.; Clem, J. R.

    2010-12-30

    It has been suggested that edge-barrier pinning might cause the critical current density (J{sub c}) in bridged superconducting films to increase. Subsequent work indicated that this edge-barrier effect does not impact bridges larger than 1 {micro}m. However, we provide a theoretical assessment with supporting experimental data suggesting edge-barrier pinning can significantly enhance J{sub c} for bridges of a few microns or even tens of microns thus skewing any comparisons among institutions. As such, when reporting flux pinning and superconductor processing improvements for J{sub c} comparisons, the width of the sample has to be taken into consideration as is currently done with film thickness.

  20. Homogeneous superconducting phase in TiN film: A complex impedance study

    Science.gov (United States)

    Diener, P.; Schellevis, H.; Baselmans, J. J. A.

    2012-12-01

    The low frequency complex impedance of a high resistivity 92 μ Ω cm and 100 nm thick TiN superconducting film has been measured via the transmission of several high sensitivity GHz microresonators, down to TC/50. The temperature dependence of the kinetic inductance follows closely BCS local electrodynamics, with one well defined superconducting gap. This evidences the recovery of a homogeneous superconducting phase in TiN far from the disorder and composition driven transitions. Additionally, we observe a linearity between resonator quality factor and frequency temperature changes, which can be described by a two fluid model.

  1. Homogeneous superconducting phase in TiN film: A complex impedance study

    NARCIS (Netherlands)

    Diener, P.; Schellevis, H.; Baselmans, J.J.A.

    2012-01-01

    The low frequency complex impedance of a high resistivity 92 μ Ω cm and 100 nm thick TiN superconducting film has been measured via the transmission of several high sensitivity GHz microresonators, down to TC/50. The temperature dependence of the kinetic inductance follows closely BCS local electrod

  2. MgB2 thick films with remarkable ductility on stainless steel substrate

    Institute of Scientific and Technical Information of China (English)

    ZHUANG Cheng-gang; AN Ling; CHEN Li-ping; DING Li-li; ZHANG Kai-cheng; CHEN Chin-ping; XU Jun; FENG Qing-rong; GAN Zi-zhao

    2006-01-01

    We fabricated several superconducting MgB2 thick films on stainless steel (SS) substrates by using hybrid physical-chemical vapor deposition (HPCVD) technique.The thickness was in the 10 pμm to 20 pμm range,and the onset critical transition temperature Te (onset) and the width of the superconducting transition ( △ T) were about 37.8 and 1.2 K.They were dense and textured along (101) direction with high tenacity,despite the existence of a little amount of MgO and Mg.We bent the films at different degrees and studied the ductility and transport properties of these MgB2 thick films under applied force.The results demonstrated that the superconducting properties of these thick films,prepared by HPCVD,stay almost unaffected even with the films bent to a large degree with a curvature of 0.5 nun.This indicated that the superconducting wires or tapes of MgB2 with a core of SS had the advantages of avoiding rigidity and brittleness in industrial handling.The technique of HPCVD has,therefore,a high application potential.

  3. The effect of thickness and substrate tilt on the BZO splay and superconducting properties of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} films

    Energy Technology Data Exchange (ETDEWEB)

    Emergo, R L S; Baca, F J; Wu, J Z; Barnes, P N [Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045 (United States); Haugan, T J [Air Force Research Laboratory, Wright-Patterson Air Force Base, OH 45433-7919 (United States)

    2010-11-15

    Highly splayed BaZrO{sub 3} nanorods (BZO-NRs) were generated in YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) films doped with 2 vol% BZO on 5{sup 0} vicinal SrTiO{sub 3} (STO) substrates. It was observed that the splay angle of the BZO-NRs around the c-axis increases with film thickness from about 10{sup 0} at 0.2 {mu}m to 35{sup 0}-40{sup 0} at 1 {mu}m. Although the same trend was observed in BZO-NRs in flat YBCO films, the splay angle at a given thickness and its increase with film thickness are significantly smaller. The enhanced dispersion of BZO-NRs in vicinal YBCO/BZO-NR films results in a much reduced strain on the YBCO lattice as compared to its flat counterpart. This led to less disturbed normal-state electron conduction along the ab-plane, higher T{sub c} values and enhanced J{sub c} values due to improved magnetic pinning.

  4. On Ginzburg-Landau Vortices of Superconducting Thin Films

    Institute of Scientific and Technical Information of China (English)

    Shi Jin DING; Qiang DU

    2006-01-01

    In this paper, we discuss the vortex structure of the superconducting thin films placed in a magnetic field. We show that the global minimizer of the functional modelling the superconducting thin films has a bounded number of vortices when the applied magnetic field hex < Hc1 + K log |log ε|where Hc1 is the lower critical field of the film obtained by Ding and Du in SIAM J. Math. Anal.,2002. The locations of the vortices are also given.

  5. Scaling Laws for Thin Films near the Superconducting-to-Insulating Transition

    Science.gov (United States)

    Tao, Yong

    2016-03-01

    We propose a Lagrangian function, which combines Landau-Ginzburg term and Chern-Simons term, for describing the competition between disorder and superconductivity. To describe the normal-to-superconducting transition in the thin superconducting films, we apply Wilson’s renormalization group methods into this Lagrangian function. Finally, we obtain a scaling law between critical temperature (Tc), film thickness (d), sheet resistance of the film at the normal state (Rs), and number density of the electrons at the normal state (N). Such a scaling law is in agreement with recent experimental investigations [Ivry, Y. et al., Physical Review B 90, 214515 (2014)]. Our finding may have potential benefits for improving transition temperature Tc.

  6. Elimination of bubbles and improvement of the superconducting properties in MgB2 films annealed using electron beam

    Science.gov (United States)

    Xu, Zhuang; Kong, Xiangdong; Han, Li; Pang, Hua; Wu, Yue; Gao, Zhaoshun; Li, Xiaona

    2017-03-01

    MgB2 superconducting films can be readily obtained using the electron-beam annealing method. However, many bubbles existing in the film severely damage the surface morphology, which is known as the deleterious current-limiting mechanism. Based on morphology images and energy-dispersive spectroscopy spectra, we found that, during the annealing process, solid Mg-rich layers evaporate to form Mg vapour in the precursor film, resulting in bubbles in the film. By reducing the cycle thickness of the precursor film, we obtained MgB2 films with better properties. The root-mean-square surface roughness was 2.7 nm over a 10 × 10 μm area for a 100 nm-thick film, and the critical current density at 20 K was increased to 3.8 × 106 A cm‑2. These MgB2 films are suitable for fabricating MgB2 superconducting devices.

  7. Misfit dislocations and phase transformations in high-T sub c superconducting films

    CERN Document Server

    Gutkin, M Y

    2002-01-01

    A theoretical model is suggested that describes the effects of misfit stresses on defect structures, phase content and critical transition temperature T sub c in high-T sub c superconducting films. The focus is placed on the exemplary case of YBaCuO films deposited onto LaSrAlO sub 4 substrates. It is theoretically revealed here that misfit stresses are capable of inducing phase transformations controlled by the generation of misfit dislocations in growing cuprate films. These transformations, in the framework of the suggested model, account for experimental data on the influence of the film thickness on phase content and critical temperature T sub c of superconducting cuprate films, reported in the literature. The potential role of stress-assisted phase transformations in suppression of critical current density across grain boundaries in high-T sub c superconductors is briefly discussed.

  8. PREFACE: Superconductivity in ultrathin films and nanoscale systems Superconductivity in ultrathin films and nanoscale systems

    Science.gov (United States)

    Bianconi, Antonio; Bose, Sangita; Garcia-Garcia, Antonio Miguel

    2012-12-01

    The recent technological developments in the synthesis and characterization of high-quality nanostructures and developments in the theoretical techniques needed to model these materials, have motivated this focus section of Superconductor Science and Technology. Another motivation is the compelling evidence that all new superconducting materials, such as iron pnictides and chalcogenides, diborides (doped MgB2) and fullerides (alkali-doped C60 compounds), are heterostrucures at the atomic limit, such as the cuprates made of stacks of nanoscale superconducting layers intercalated by different atomic layers with nanoscale periodicity. Recently a great amount of interest has been shown in the role of lattice nano-architecture in controlling the fine details of Fermi surface topology. The experimental and theoretical study of superconductivity in the nanoscale started in the early 1960s, shortly after the discovery of the BCS theory. Thereafter there has been rapid progress both in experiments and the theoretical understanding of nanoscale superconductors. Experimentally, thin films, granular films, nanowires, nanotubes and single nanoparticles have all been explored. New quantum effects appear in the nanoscale related to multi-component condensates. Advances in the understanding of shape resonances or Fano resonances close to 2.5 Lifshitz transitions near a band edge in nanowires, 2D films and superlattices [1, 2] of these nanosized modules, provide the possibility of manipulating new quantum electronic states. Parity effects and shell effects in single, isolated nanoparticles have been reported by several groups. Theoretically, newer techniques based on solving Richardson's equation (an exact theory incorporating finite size effects to the BCS theory) numerically by path integral methods or solving the entire Bogoliubov-de Gennes equation in these limits have been attempted, which has improved our understanding of the mechanism of superconductivity in these confined

  9. Research on Y-Ba-Cu-O superconducting thin films at liquid nitrogen temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Li Yuan; Yang Senzu; Ji Zhengming; Sun Zhijian; Jing Dong; Wu Peiheng; Zhang Shiyan; Wang Hao; Zhou Ningsheng; Fan Depei; and others

    1988-12-01

    The Y-Ba-Cu-O superconducting thin films on several kinds of substrates of single crystal ZrO/sub 2/, YSZ and polycrystalline SrTiO/sub 3/ have been successfully prepared by mean of /ital rf/ reactive magnetron sputtering. The zero resistance temperature obtained is 81 K. The thickness of the films is about 1--2 ..mu..m. In this paper the composition of the films, the substrates, /ital R/-/ital T/ curves, X-ray diffraction patterns and the heat treatment process of the films are described.

  10. Loss mechanisms in superconducting thin film microwave resonators

    Energy Technology Data Exchange (ETDEWEB)

    Goetz, Jan, E-mail: jan.goetz@wmi.badw.de; Haeberlein, Max; Wulschner, Friedrich; Zollitsch, Christoph W.; Meier, Sebastian; Fischer, Michael; Fedorov, Kirill G.; Menzel, Edwin P. [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany); Physik-Department, Technische Universität München, 85748 Garching (Germany); Deppe, Frank; Eder, Peter; Xie, Edwar; Gross, Rudolf, E-mail: rudolf.gross@wmi.badw.de [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany); Physik-Department, Technische Universität München, 85748 Garching (Germany); Nanosystems Initiative Munich (NIM), Schellingstraße 4, 80799 München (Germany); Marx, Achim [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany)

    2016-01-07

    We present a systematic analysis of the internal losses of superconducting coplanar waveguide microwave resonators based on niobium thin films on silicon substrates. In particular, we investigate losses introduced by Nb/Al interfaces in the center conductor, which is important for experiments where Al based Josephson junctions are integrated into Nb based circuits. We find that these interfaces can be a strong source for two-level state (TLS) losses, when the interfaces are not positioned at current nodes of the resonator. In addition to TLS losses, for resonators including Al, quasiparticle losses become relevant above 200 mK. Finally, we investigate how losses generated by eddy currents in conductive material on the backside of the substrate can be minimized by using thick enough substrates or metals with high conductivity on the substrate backside.

  11. Nano-Hydroxyapatite Thick Film Gas Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Khairnar, Rajendra S.; Mene, Ravindra U.; Munde, Shivaji G.; Mahabole, Megha P. [School of Physical Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431606 (India)

    2011-12-10

    In the present work pure and metal ions (Co and Fe) doped hydroxyapatite (HAp) thick films have been successfully utilized to improve the structural, morphological and gas sensing properties. Nanocrystalline HAp powder is synthesized by wet chemical precipitation route, and ion exchange process is employed for addition of Co and Fe ions in HAp matrix. Moreover, swift heavy ion irradiation (SHI) technique is used to modify the surface of pure and metal ion exchanged HAp with various ion fluence. The structural investigation of pure and metal ion exchanged HAp thick films are carried out using X-ray diffraction and the presence of functional group is observed by means FTIR spectroscopy. Furthermore, surface morphology is visualized by means of SEM and AFM analysis. CO gas sensing study is carried out for, pure and metal ions doped, HAp thick films with detail investigation on operating temperature, response/recovery time and gas uptake capacity. The surface modifications of sensor matrix by SHI enhance the gas response, response/recovery and gas uptake capacity. The significant observation is here to note that, addition of Co and Fe in HAp matrix and surface modification by SHI improves the sensing properties of HAp films drastically resulting in gas sensing at relatively lower temperatures.

  12. Studies to Enhance Superconductivity in Thin Film Carbon

    Science.gov (United States)

    Pierce, Benjamin; Brunke, Lyle; Burke, Jack; Vier, David; Steckl, Andrew; Haugan, Timothy

    2012-02-01

    With research in the area of superconductivity growing, it is no surprise that new efforts are being made to induce superconductivity or increase transition temperatures (Tc) in carbon given its many allotropic forms. Promising results have been published for boron doping in diamond films, and phosphorus doping in highly oriented pyrolytic graphite (HOPG) films show hints of superconductivity.. Following these examples in the literature, we have begun studies to explore superconductivity in thin film carbon samples doped with different elements. Carbon thin films are prepared by pulsed laser deposition (PLD) on amorphous SiO2/Si and single-crystal substrates. Doping is achieved by depositing from (C1-xMx) single-targets with M = B4C and BN, and also by ion implantation into pure-carbon films. Previous research had indicated that Boron in HOPG did not elicit superconducting properties, but we aim to explore that also in thin film carbon and see if there needs to be a higher doping in the sample if trends were able to be seen in diamond films. Higher onset temperatures, Tc , and current densities, Jc, are hoped to be achieved with doping of the thin film carbon with different elements.

  13. Quench-condensing superconducting thin films using the Fab on a Chip approach

    Science.gov (United States)

    Han, Han; Imboden, Matthias; Del Corro, Pablo; Stark, Thomas; Lally, Richard; Pardo, Flavio; Bolle, Cristian; Bishop, David

    Micro-electromechanical systems (MEMS) being manufactured in a macroscopic fab inspires the idea of getting the process further down to fabricate even smaller structures, namely nano-structures, using MEMS. The Fab on a Chip concept was proposed based on such ideas. By implementing the final-step, additive fabrication approach, manufacturing, characterization and experiments of nano-structures are integrated in-situ. Due to the miniature size of MEMS, the thickness precision is significantly improved while the power consumption is significantly depressed, making the quench-condensation of very thin films well controlled and easily achievable. Among various types of nano-structures, quench-condensed superconducting thin films are of great interest for physicists. Here we present such experiments done on superconducting thin films quench-condensed using the Fab on a Chip. We show that we are able to fabricate very thin films with its thickness precisely controlled, and the base temperature kept under ~3K during the process. The resistivity data demonstrates the high purity and uniformity of the film, as well as the annealing effect when cycling to higher temperatures. Based on the tremendous results obtained from the superconducting thin films, more complex nano-circuits can be fabricated and investigated using the Fab on a Chip, enabling a new approach for novel condensed matter physics experiments. This research is funded by the NSF through their CMMI division. This research is funded by the NSF through their CMMI division.

  14. Properties of conductive thick-film inks

    Science.gov (United States)

    Holtze, R. F.

    1972-01-01

    Ten different conductive inks used in the fabrication of thick-film circuits were evaluated for their physical and handling properties. Viscosity, solid contents, and spectrographic analysis of the unfired inks were determined. Inks were screened on ceramic substrates and fired for varying times at specified temperatures. Selected substrates were given additional firings to simulate the heat exposure received if thick-film resistors were to be added to the same substrate. Data are presented covering the (1) printing characteristics, (2) solderability using Sn-63 and also a 4 percent silver solder, (3) leach resistance, (4) solder adhesion, and (5) wire bonding properties. Results obtained using different firing schedules were compared. A comparison was made between the various inks showing general results obtained for each ink. The changes in firing time or the application of a simulated resistor firing had little effect on the properties of most inks.

  15. Conduction Mechanisms in Thick Film Microcircuits

    Science.gov (United States)

    1975-12-01

    AREMCO 3100 Screen Printing Machine 53 3.11 Squeegee Design 55 3.12 Effect of Screen Printer Parameters on Filin Weight Deposited 59 3.13 Variation of...deviation of printing performance. This is discussed in greater detail sIfter the materials and machine are described. 3.5.2 Screening Material and...beyoni the range of monolithic technology can be satisfied by combining monolithic and thick film technologies. Design functions such as flexibility

  16. Growth and characterization of superconducting spinel oxide LiTiO thin films

    Science.gov (United States)

    Chopdekar, Rajesh V.; Wong, Franklin J.; Takamura, Yayoi; Arenholz, Elke; Suzuki, Yuri

    2009-11-01

    Epitaxial films of LiTiO on single crystalline substrates of MgAlO, MgO, and SrTiO provide model systems to systematically explore the effects of lattice strain and microstructural disorder on the superconducting state. Lattice strain that affects bandwidth gives rise to variations in the superconducting and normal state properties. Microstructural disorder, such as antiphase boundaries that give rise to Ti network disorder, reduces the critical temperature, and Ti network disorder combined with Mg interdiffusion lead to a much more dramatic effect on the superconducting state. Surface sensitive X-ray absorption spectroscopy has identified Ti to retain site symmetry and average valence of the bulk material regardless of film thickness.

  17. Tuning Superconductivity in FeSe Thin Films via Magnesium Doping.

    Science.gov (United States)

    Qiu, Wenbin; Ma, Zongqing; Liu, Yongchang; Shahriar Al Hossain, Mohammed; Wang, Xiaolin; Cai, Chuanbing; Dou, Shi Xue

    2016-03-01

    In contrast to its bulk crystal, the FeSe thin film or layer exhibits better superconductivity performance, which recently attracted much interest in its fundamental research as well as in potential applications around the world. In the present work, tuning superconductivity in FeSe thin films was achieved by magnesium-doping technique. Tc is significantly enhanced from 10.7 K in pure FeSe films to 13.4 K in optimized Mg-doped ones, which is approximately 1.5 times higher than that of bulk crystals. This is the first time achieving the enhancement of superconducting transition temperature in FeSe thin films with practical thickness (120 nm) via a simple Mg-doping process. Moreover, these Mg-doped FeSe films are quite stable in atmosphere with Hc2 up to 32.7 T and Tc(zero) up to 12 K, respectively, implying their outstanding potential for practical applications in high magnetic fields. It was found that Mg enters the matrix of FeSe lattice, and does not react with FeSe forming any other secondary phase. Actually, Mg first occupies Fe-vacancies, and then substitutes for some Fe in the FeSe crystal lattices when Fe-vacancies are fully filled. Simultaneously, external Mg-doping introduces sufficient electron doping and induces the variation of electron carrier concentration according to Hall coefficient measurements. This is responsible for the evolution of superconducting performance in FeSe thin films. Our results provide a new strategy to improve the superconductivity of 11 type Fe-based superconductors and will help us to understand the intrinsic mechanism of this unconventional superconducting system.

  18. Impact of thickness on microscopic and macroscopic properties of Fe-Te-Se superconductor thin films

    Directory of Open Access Journals (Sweden)

    N. Zhang

    2015-04-01

    Full Text Available A series of iron based Fe-Te-Se superconductor thin films depositing on 0.7wt% Nb-doped SrTiO3 at substrate temperatures in the 250°C -450°C range by pulsed laser ablation of a constituents well defined precursor FeTe0.55Se0.55 target sample. We study the possible growth mechanism and its influence on the superconductor properties. Experimental results indicate the superconductive and non-superconductive properties are modulated only by the thickness of the thin films through the temperature range. The films appear as superconductor whenever the thickness is above a critical value ∼30nm and comes to be non-superconductor below this value. Relative ratios of Fe to (Te+Se in the films retained Fe/(Te+Se1 for non-superconductor no matter what the film growth temperature was. The effect of film growth temperature takes only the role of modulating the ratio of Te/Se and improving crystallinity of the systems. According to the experimental results we propose a sandglass film growth mechanism in which the interfacial effect evokes to form a Fe rich area at the interface and Se or Te starts off a consecutive filling up process of chalcogenide elements defect sides, the process is significant before the film thickness reaches at ∼30nm.

  19. Flow fields in soap films: Relating viscosity and film thickness

    Science.gov (United States)

    Prasad, V.; Weeks, Eric R.

    2009-08-01

    We follow the diffusive motion of colloidal particles in soap films with varying h/d , where h is the thickness of the film and d is the diameter of the particles. The hydrodynamics of these films are determined by looking at the correlated motion of pairs of particles as a function of separation R . The Trapeznikov approximation [A. A. Trapeznikov, Proceedings of the 2nd International Congress on Surface Activity (Butterworths, London, 1957), p. 242] is used to model soap films as an effective two-dimensional (2D) fluid in contact with bulk air phases. The flow fields determined from correlated particle motions show excellent agreement with what is expected for the theory of 2D fluids for all our films where 0.6≤h/d≤14.3 , with the 2D shear viscosity matching that predicted by Trapeznikov. However, the parameters of these flow fields change markedly for thick films (h/d>7±3) . Our results indicate that three-dimensional effects become important for these thicker films, despite the flow fields still having a 2D character.

  20. An AFM study of the morphology and local mechanical properties of superconducting YBCO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Soifer, Ya.M.; Verdyan, A.; Azoulay, J.; Kazakevich, M.; Rabkin, E

    2004-02-01

    The morphology of thin superconducting YBCO films deposited on sapphire and on SrTiO{sub 3} was studied with the help of atomic force and scanning electron microscopies. The intrinsic mechanical properties in the flat, particles-free and chemically homogeneous regions of the films were determined with the aid of nanoindenting atomic force microscope. Also the microscopy studies revealed the difference in topography of the films, the nanohardness and Young's modulus of two films were very close to each other. For the indents shallower than 0.2 of the film thickness the Young's modulus and hardness of the films on two different substrates converged to the values of 210 and 8.5 GPa, respectively. The possible deformation mechanisms determining the localized deformation of intrinsically brittle ceramic films are discussed.

  1. An AFM study of the morphology and local mechanical properties of superconducting YBCO thin films

    Science.gov (United States)

    Soifer, Ya. M.; Verdyan, A.; Azoulay, J.; Kazakevich, M.; Rabkin, E.

    2004-02-01

    The morphology of thin superconducting YBCO films deposited on sapphire and on SrTiO 3 was studied with the help of atomic force and scanning electron microscopies. The intrinsic mechanical properties in the flat, particles-free and chemically homogeneous regions of the films were determined with the aid of nanoindenting atomic force microscope. Also the microscopy studies revealed the difference in topography of the films, the nanohardness and Young’s modulus of two films were very close to each other. For the indents shallower than 0.2 of the film thickness the Young’s modulus and hardness of the films on two different substrates converged to the values of 210 and 8.5 GPa, respectively. The possible deformation mechanisms determining the localized deformation of intrinsically brittle ceramic films are discussed.

  2. Residual Stress Analysis in Thick Uranium Films

    Energy Technology Data Exchange (ETDEWEB)

    Hodge, A M; Foreman, R J; Gallegos, G F

    2004-12-06

    Residual stress analysis was performed on thick, 1.0 to 25 {micro}m, depleted Uranium (DU) films deposited on an Al substrate by magnetron sputtering. Two distinct characterization techniques were used to measure substrate curvature before and after deposition. Stress evaluation was performed using the Benabdi/Roche equation, which is based on beam theory of a bi-layer material. The residual stress evolution was studied as a function of coating thickness and applied negative bias voltage (0-300V). The stresses developed were always compressive; however, increasing the coating thickness and applying a bias voltage presented a trend towards more tensile stresses and thus an overall reduction of residual stresses.

  3. Losses in superconducting Niobium Films caused by Interface Tunnel Exchange

    CERN Document Server

    Junginger, Tobias; Welsch, Carsten

    2012-01-01

    Identifying the loss mechanisms of niobium film cavities enables an accurate determination of applications for future accelerator projects and points to research topics required to mitigate their limitations. Measurements on samples show that the electric field is a dominant loss mechanism for niobium films, acting through interface tunneling between localized states in surface oxides and delocalized states in the superconducting niobium.

  4. Pulsed laser deposition and characterisation of thin superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Morone, A. [CNR, zona industriale di Tito Scalo, Potenza (Italy). Istituto per i Materiali Speciali

    1996-09-01

    Same concepts on pulsed laser deposition of thin films will be discussed and same examples of high transition temperature (HTc) BiSrCaCuO (BISCO) and low transition temperature NbN/MgO/NbN multilayers will be presented. X-ray and others characterizations of these films will be reported and discussed. Electrical properties of superconducting thin films will be realized as a function of structural and morphological aspect.

  5. Growth of thick MgB{sub 2} films by impinging-jet hybrid physical-chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lamborn, D.R. [Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Wilke, R.H.T.; Li, Q. [Department of Physics, The Pennsylvania State University, University Park, PA 16802 (United States); Xi, X. [Department of Physics, Department of Materials Science and Engineering, Materials Research Institute, The Pennsylvania State University, University Park, PA 16801 (United States); Snyder, D.W. [Applied Research Laboratory, The Pennsylvania State University, University Park, PA 16802 (United States); Redwing, J.M. [Department of Materials Science and Engineering, Materials Research Institute, The Pennsylvania State University, University Park, PA 16801 (United States)

    2008-01-18

    Thick MgB{sub 2} films are grown using a novel impinging-jet hybrid physical-chemical vapor deposition process. An increased amount of the boron source gas generates high growth rates. Superconducting properties of the thick films are comparable to previous results from other processes, which indicate that this is a promising new process for MgB{sub 2} deposition for coated conductor applications, such as wires and tapes for MRI magnets. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  6. Thickness Dependence of Resistivity and Optical Reflectance of ITO Films

    Institute of Scientific and Technical Information of China (English)

    GAO Mei-Zhen; JOB R; XUE De-Sheng; FAHRNER W R

    2008-01-01

    @@ Indium-tin-oxide (ITO) films deposited on crystalline silicon wafer and Coming glass are prepared by directcurrent magnetron sputtering method at room temperature with various thicknesses. The thickness dependences of structure, resistance and optical reflectance of ITO films are characterized. The results show that when the film thickness is less than 4Ohm, the resistivity and optical reflectance of the ITO tilm changes remarkably with thickness. The optoelectrical properties trend to stabilize when the thickness is over 55 nm. The GXRD result implies that the ITO film begins to crystallize if only the thickness is large enough.

  7. Determination of thin film refractive index and thickness by means of film phase thickness

    Science.gov (United States)

    Nenkov, Milen; Pencheva, Tamara

    2008-06-01

    A new approach for determination of refractive index dispersion n(λ) (the real part of the complex refractive index) and thickness d of thin films of negligible absorption and weak dispersion is proposed. The calculation procedure is based on determination of the phase thickness of the film in the spectral region of measured transmittance data. All points of measured spectra are included in the calculations. Barium titanate thin films are investigated in the spectral region 0.38-0.78 μm and their n(λ) and d are calculated. The approach is validated using Swanepoel's method and it is found to be applicable for relatively thin films when measured transmittance spectra have one minimum and one maximum only.

  8. Superconducting detector of IR single-photons based on thin WSi films

    Science.gov (United States)

    Seleznev, V. A.; Divochiy, A. V.; Vakhtomin, Yu B.; Morozov, P. V.; Zolotov, P. I.; Vasil'ev, D. D.; Moiseev, K. M.; Malevannaya, E. I.; Smirnov, K. V.

    2016-08-01

    We have developed the deposition technology of WSi thin films 4 to 9 nm thick with high temperature values of superconducting transition (Tc~4 K). Based on deposed films there were produced nanostructures with indicative planar sizes ~100 nm, and the research revealed that even on nanoscale the films possess of high critical temperature values of the superconducting transition (Tc~3.3-3.7 K) which certifies high quality and homogeneity of the films created. The first experiments on creating superconducting single-photon detectors showed that the detectors’ SDE (system detection efficiency) with increasing bias current (I b) reaches a constant value of ~30% (for X=1.55 micron) defined by infrared radiation absorption by the superconducting structure. To enhance radiation absorption by the superconductor there were created detectors with cavity structures which demonstrated a practically constant value of quantum efficiency >65% for bias currents Ib>0.6-Ic. The minimal dark counts level (DC) made 1 s-1 limited with background noise. Hence WSi is the most promising material for creating single-photon detectors with record SDE/DC ratio and noise equivalent power (NEP).

  9. Oriented Growth of PZT thick film embedded with PZT nanoparticles

    Institute of Scientific and Technical Information of China (English)

    DUAN Zhong-xia; YUAN Jie; ZHAO Quan-liang; LU Ran; CAO Mao-sheng

    2009-01-01

    This paper reports that dense and crack-free (100) oriented lead zirconate titanate (Pb(Zr0.52Ti0.48)O3,PZT) thick film embedded with PZT nanoparticles has been successfully fabricated on Pt/Cr/SiO2/Si substrate by using PT transition layer and PVP additive. The thick film possesses single-phase perovskite structure and perfectly (100) oriented. The (100) orientation degree of the PZT films strongly depended on annealing time and for the 4 μm-thick PZT film which was annealed at 700 ℃ for 5 min is the largest. The (100) orientation degree of the PZT thick film gradually strengthen along with the thickness of film decreasing. The 3 μm-thick PZT thick film which was annealed at 700 ℃ for 5 min has the strongest (100) orientation degree, which is 82. 3%.

  10. Thickness dependence of Jc (0) in MgB2 films

    Science.gov (United States)

    Chen, Yiling; Yang, Can; Jia, Chunyan; Feng, Qingrong; Gan, Zizhao

    2016-06-01

    MgB2 superconducting films, whose thicknesses range from 10 nm to 8 μm, have been fabricated on SiC substrates by hybrid physical-chemical vapor deposition (HPCVD) method. It is the first time that the Tc and the Jc of MgB2 films are studied on such a large scale. It is found that with the increasing of thickness, Tc elevates first and then keeps roughly stable except for some slight fluctuations, while Jc (5 K, 0 T) experiences a sharp increase followed by a relatively slow fall. The maximum Jc (5 K, 0 T) = 2.3 × 108 A cm-2 is obtained for 100 nm films, which is the experimental evidence for preparing high-quality MgB2 films by HPCVD method. Thus, this work may provide guidance on choosing the suitable thickness for applications. Meanwhile, the films prepared by us cover ultrathin films, thin films and thick films, so the study on them will bring a comprehensive understanding of MgB2 films.

  11. Interstitial vortex in superconducting film with periodic hole arrays

    Institute of Scientific and Technical Information of China (English)

    He Shi-Kun; Zhang Wei-Jun; Wen Zhen-Chao; Xiao Hong; Han Xiu-Feng; Gu Chang-Zhi; Qiu Xiang-Gang

    2012-01-01

    The response of superconducting Nb films with a diluted triangular and square array of holes to a perpendicular magnetic field are investigated.Due to small edge-to-edge separation of the holes,the patterned films are similar to multi-connected superconducting islands.Two regions in the magnetoresistance R(H) curves can be identified according to the field intervals of the resistance minima.Moreover,in between these two regions,variation of the minima spacing was observed.Our results provide strong evidence of the coexistence of interstitial vortices in the islands and fluxoids in the holes.

  12. Thick film traps with an irregular film. Preparation and evaluation.

    Science.gov (United States)

    Kloskowski, Adam; Pettersson, Johan; Roeraade, Johan

    2004-05-07

    A new method for preparation of sorbent-based ultra-thick film traps for concentration of trace volatile components from gaseous matrices is described. The procedure is based on blowing a prepolymer (polydimethylsiloxane) through a capillary tube, forming an irregular film of stationary phase. Subsequently, the prepolymer is immobilized in a few seconds by heating to 200 degrees C. Evaluation of the performance of the new traps showed that the loss of efficiency, compared to regular smooth film traps is only on the order of 20-30%. In terms of breakthrough volume, this loss in performance is rather insignificant. The technology is extremely simple and allows a rapid and cheap production of a large number of ultra-thick film traps, even in non-specialized laboratories. The method can be applied to any type of cross-linkable stationary phase, thereby expanding the scope of sorbent-based trapping and preconcentration concept. Many applications are anticipated in trace and ultra-trace analysis in a wide range of fields, such as environmental chemistry, polymers, food and process analysis.

  13. Fabrication of superconducting nanowires from ultrathin MgB2 films via focused ion beam milling

    Directory of Open Access Journals (Sweden)

    Chen Zhang

    2015-02-01

    Full Text Available High quality superconducting nanowires were fabricated from ultrathin MgB2 films by a focused ion beam milling technique. The precursor MgB2 films in 10 nm thick were grown on MgO substrates by using a hybrid physical-chemical vapor deposition method. The nanowires, in widths of about 300-600 nm and lengths of 1 or 10 μm, showed high superconducting critical temperatures (Tc’s above 34 K and narrow superconducting transition widths (ΔTc’s of 1-3 K. The superconducting critical current density Jc of the nanowires was above 5 × 107 A/cm2 at 20 K. The high Tc, narrow ΔTc, and high Jc of the nanowires offered the possibility of making MgB2-based nano-devices such as hot-electron bolometers and superconducting nanowire single-photon detectors with high operating temperatures at 15-20 K.

  14. Broadband microwave response of superconducting NbN and TaN thin films

    Energy Technology Data Exchange (ETDEWEB)

    Felger, M. Maximilian; Pracht, Uwe S.; Dressel, Martin; Scheffler, Marc [1. Physikalisches Institut, Universitaet Stuttgart, D-70669 Stuttgart (Germany); Ilin, Konstantin; Siegel, Michael [Institut fuer Mikro- und Nanoelektronische Systeme, Karlsruher Institut fuer Technologie, D-76187 Karlsruhe (Germany)

    2015-07-01

    Ultrathin NbN and TaN films with their peculiar superconducting behavior are of interest both for fundamental physics (e.g. concerning the superconductor-insulator transition) and novel applications (e.g. for single-photon detectors). Here microwave spectroscopy is a powerful tool to characterize essential superconducting properties and to investigate the charge dynamics (Cooper pairs and quasiparticles). We have prepared by sputtering thin films of NbN (thickness between 3 nm and 20 nm; T{sub c} between 5 K and 13 K) and TaN (thickness 5 nm; T{sub c} between 8.5 K and 9.5 K) on sapphire substrates. We performed broadband microwave spectroscopy on these samples using a Corbino spectrometer at temperatures down to 1.1 K and at frequencies up to 50 GHz. From these data we determine the superconducting penetration depth and we evaluate the frequency-dependent conductivity. While many of the observed features can be described within expectations of conventional BCS theory, we also find deviations that are caused by fluctuations near the superconducting transition.

  15. Preparation of YBa2Cu3O7-δsuperconducting thick film on Ni-W tapes via electrophoretic deposition%电泳沉积法在Ni-W基带上制备YBa2Cu3O7-δ超导厚膜

    Institute of Scientific and Technical Information of China (English)

    罗清威; 李英楠; 李凤华; 樊占国

    2014-01-01

    The preparation of La0.4Sr0.6TiO3 (LSTO) buffer layer and YBa2Cu3O7-δ(YBCO) superconducting thick film by a low cost technology was studied. The crystal orientation of LSTO and YBCO films was detected by X-ray diffraction, the conductivity of LSTO film and superconductivity of YBCO coating were investigated by standard four-probe method. Excellent in-plane alignment, smooth and dense LSTO buffer layer was successfully prepared on textured Ni-W taps by metal organic deposition (MOD). YBCO thick film was fabricated by electrophoretic deposition (EPD). The effects of applied voltage and deposition time on the YBCO coatings properties were studied. The results show that the critical current density of the YBCO coating deposited under 138 V for 35 min was about 600 A/cm2 (0 T, 77 K).%研究La0.4Sr0.6TiO3(LSTO)缓冲层和YBa2Cu3O7-δ(YBCO)超导厚膜的低成本制备技术。采用X射线衍射分析LSTO和YBCO膜的晶体取向,利用标准四引线法分析LSTO薄膜的导电性能和YBCO厚膜的超导性能。首先采用金属有机沉积法(MOD)成功在Ni-W基带上制备取向较好、表面光滑致密的LSTO缓冲层;然后采用电泳沉积(EPD)技术制备YBCO超导厚膜。研究电泳沉积电压和沉积时间对YBCO涂层性能的影响。结果表明:138 V下电泳沉积35 min所制备的YBCO涂层,临界电流密度可达600 A/cm2(0 T,77 K)。

  16. Measurement Method of the Thickness Uniformity for Polymer Films

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Several methods for investigating the thickness uniformity of polymer thin films are presented as well as their measurement principles. A comparison of these experimental methods is given.The cylindrical lightwave reflection method is found to can obtain the thickness distribution along a certain direction.It is a simple and suitable method to evaluate the film thickness uniformity.

  17. Highly-textured thallium-barium-calcium-copper-oxide polycrystalline superconducting films on silver substrates

    Energy Technology Data Exchange (ETDEWEB)

    Arendt, P.; Elliott, N.; Cooke, D.W.; Dye, R.; Gray, E.; Hubbard, K.; Martin, J.; Reeves, G.; Brown, D.; Klapetzky, A.

    1990-01-01

    Thick (8 to 10 {mu}m) Ba--Ca--Cu--O films have been rf magnetron sputtered onto Ag alloy (Consil 995) substrates. The films were given a post-deposition anneal in an over pressure of Tl in order to form the superconducting phases. Annealing protocols were done which result in predominantly the 1212 and 2212 phases. The substrate orientation was varied to determine its effect on film orientation. Material properties of the films were characterized by x-ray diffraction (XRD), ion beam backscattering spectroscopy, energy dispersive x-ray analysis (EDAX), and scanning electron microscopy (SEM). Electrical characterization of the films was done using dynamic impedance (DI) at 10 kHz and rf surface resistance (R{sub s}) at 18 GHz in a TE{sub 011} fundamental mode cavity. 19 refs., 7 figs.

  18. Berezinskii-Kosterlitz-Thouless transition in homogeneously disordered superconducting films

    Science.gov (United States)

    König, E. J.; Levchenko, A.; Protopopov, I. V.; Gornyi, I. V.; Burmistrov, I. S.; Mirlin, A. D.

    2015-12-01

    We develop a theory for the vortex-unbinding transition in homogeneously disordered superconducting films. This theory incorporates the effects of quantum, mesoscopic, and thermal fluctuations stemming from length scales ranging from the superconducting coherence length down to the Fermi wavelength. In particular, we extend the renormalization group treatment of the diffusive nonlinear sigma model to the superconducting side of the transition. Furthermore, we explore the mesoscopic fluctuations of parameters in the Ginzburg-Landau functional. Using the developed theory, we determine the dependence of essential observables (including the vortex-unbinding temperature, the superconducting density, as well as the temperature-dependent resistivity and thermal conductivity) on microscopic characteristics such as the disorder-induced scattering rate and bare interaction couplings.

  19. High quality superconducting NbN thin films on GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Marsili, Francesco; Fiore, Andrea [COBRA Research Institute, Eindhoven University of Technology, PO Box 513, NL-5600MB Eindhoven (Netherlands); Gaggero, Alessandro; Leoni, Roberto [Istituto di Fotonica e Nanotecnologie (IFN), CNR, via Cineto Romano 42, I-00156 Roma (Italy); Li, Lianhe H; Surrente, Alessandro [Institute of Photonics and Quantum Electronics (IPEQ), Ecole Polytechnique Federale de Lausanne (EPFL), Station 3, CH-1015 Lausanne (Switzerland); Levy, Francis, E-mail: francesco.marsili@epfl.c [Institute of Condensed Matter Physics (IPMC), Ecole Polytechnique Federale de Lausanne (EPFL), Station 3, CH-1015 Lausanne (Switzerland)

    2009-09-15

    A very promising way to increase the detection efficiency of nanowire superconducting single-photon detectors (SSPDs) consists in integrating them with advanced optical structures such as distributed Bragg reflectors (DBRs) and optical waveguides. This requires transferring the challenging SSPD technology from the usual substrates, i.e. sapphire and MgO, to an optical substrate like GaAs, on which DBRs and waveguides can be easily obtained. Therefore, we optimized the deposition process of few-nm thick superconducting NbN films on GaAs and AlAs/GaAs-based DBRs at low temperatures (substrate temperature T{sub S} = 400 {sup 0}C), in order to prevent As evaporation. NbN films ranging from 150 to 3 nm in thickness were then deposited on single-crystal MgO, GaAs, MgO-buffered GaAs and DBRs by current-controlled DC magnetron sputtering (planar, circular, balanced configuration) of Nb in an Ar+N{sub 2} plasma. 5.5 nm thick NbN films on GaAs exhibit T{sub C} = 10.7 K, {Delta}T{sub C} = 1.1 K and RRR = 0.7. The growth of such high quality thin NbN films on GaAs and DBRs has never been reported before.

  20. Multiple High Voltage Pulse Stressing of Polymer Thick Film Resistors

    Directory of Open Access Journals (Sweden)

    Busi Rambabu

    2014-01-01

    Full Text Available The purpose of this paper is to study high voltage interactions in polymer thick film resistors, namely, polyvinyl chloride- (PVC- graphite thick film resistors, and their applications in universal trimming of these resistors. High voltages in the form of impulses for various pulse durations and with different amplitudes have been applied to polymer thick film resistors and we observed the variation of resistance of these resistors with high voltages. It has been found that the resistance of polymer thick film resistors decreases in the case of higher resistivity materials and the resistance of polymer thick film resistor increases in the case of lower resistivity materials when high voltage impulses are applied to them. It has been also found that multiple high voltage pulse (MHVP stressing can be used to trim the polymer thick film resistors either upwards or downwards.

  1. Controllable injector for local flux entry into superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Carmo, D.; Colauto, F.; de Andrade, A. M. H.; Oliveira, A. A. M.; Ortiz, W. A.; Johansen, T. H.

    2016-07-21

    A superconducting flux injector (SFI) has been designed to allow for controlled injections of magnetic flux into a superconducting film from a predefined location along the edge. The SFI is activated by an external current pulse, here chosen to be 200 ms long, and it is demonstrated on films of Nb that the amount of injected flux is controlled by the pulse height. Examples of injections at two different temperatures where the flux enters by stimulated flux-flow and by triggered thermomagnetic avalanches are presented. The boundary between the two types of injection is determined and discussed. The SFI opens up for active use of phenomena which up to now have been considered hazardous for a safe operation of superconducting devices.

  2. Integrated thick-film nanostructures based on spinel ceramics.

    Science.gov (United States)

    Klym, Halyna; Hadzaman, Ivan; Shpotyuk, Oleh; Brunner, Michael

    2014-03-26

    Integrated temperature-humidity-sensitive thick-film structures based on spinel-type semiconducting ceramics of different chemical compositions and magnesium aluminate ceramics were prepared and studied. It is shown that temperature-sensitive thick-film structures possess good electrophysical characteristics in the region from 298 to 358 K. The change of electrical resistance in integrated thick-film structures is 1 order, but these elements are stable in time and can be successfully used for sensor applications.

  3. Integrated thick-film nanostructures based on spinel ceramics

    OpenAIRE

    Klym, Halyna; Hadzaman, Ivan; Shpotyuk, Oleh; Brunner, Michael

    2014-01-01

    Integrated temperature-humidity-sensitive thick-film structures based on spinel-type semiconducting ceramics of different chemical compositions and magnesium aluminate ceramics were prepared and studied. It is shown that temperature-sensitive thick-film structures possess good electrophysical characteristics in the region from 298 to 358 K. The change of electrical resistance in integrated thick-film structures is 1 order, but these elements are stable in time and can be successfully used for...

  4. Narrow dip around zero magnetic field in magnetization hysteresis loops of thin YBCO superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Delimova, L [Wihuri Physical Laboratory, Department of Physics, University of Turku, FIN-20014 Turku (Finland); Liniichuk, I [A F Ioffe Physico-Technical Institute, St. Petersburg (Russian Federation); Laehderanta, E [Wihuri Physical Laboratory, Department of Physics, University of Turku, FIN-20014 Turku (Finland); Safonchik, M [Wihuri Physical Laboratory, Department of Physics, University of Turku, FIN-20014 Turku (Finland); Traito, K B [Wihuri Physical Laboratory, Department of Physics, University of Turku, FIN-20014 Turku (Finland)

    2003-01-01

    A narrow dip is observed around zero magnetic field in magnetization curves M(B) of superconducting YBCO films with about 10 nm thickness. This anomaly occurs in the same field range with an anomaly of ac surface impedance Z(B) found recently in thin YBCO films. Because the thickness of our films is considerably less than the London penetration depth, two-dimensional limit of the critical state model is applied. In the framework of this model the magnetic field dependence of the critical current density j{sub c}(B) is found. The obtained j{sub c}(B) function agrees well with that found in the ac surface impedance investigation.

  5. Performance Comparison of Thin and Thick Film Microstrip Rejection Filters

    OpenAIRE

    Mandhare, M. M.; S.A. Gangal; M. S. Setty; Karekar, R. N.

    1988-01-01

    A performance comparison of microstripline circuits using thin and thick film techniques has been studied, in which a Microstrip rejection filter, in the X-band of microwaves, is used as test circuit. A thick film technique is capable of giving good adhesive films with comparable d.c. sheet resistivity, but other parameters such as open area (porosity), particle size, and edge definition are inferior to thin-film microstrip filters. Despite this drawback, the average value of transmission, tr...

  6. Use of buffy coat thick films in detecting malaria parasites in patients with negative conventional thick films

    Institute of Scientific and Technical Information of China (English)

    Chatnapa Duangdee; Noppadon Tangpukdee; Srivicha Krudsood; Polrat Wilairatana

    2012-01-01

    Objective: To determine the frequency of malaria parasite detection from the buffy coat blood ilms by using capillary tube in falciparum malaria patients with negative conventional thick ilms. Methods: Thirty six uncomplicated falciparum malaria patients confirmed by conventional thick and thin films were included in the study. The patients were treated with artemisinin combination therapy at Hospital for Tropical Diseases, Bangkok, Thailand for 28 day. Fingerpricks for conventional blood films were conducted every 6 hours until negative parasitemia, then daily fingerpricks for parasite checks were conducted until the patients were discharged from hospital. Blood samples were also concurrently collected in 3 heparinized capillary tubes at the same time of fingerpricks for conventional blood films when the prior parasitemia was negative on thin films and parasitemia was lower than 50 parasites/200 white blood cells by thick film. The first negative conventional thick films were compared with buffy coat thick films for parasite identification.Results:Out of 36 patients with thick films showing negative for asexual forms of parasites, buffy coat films could detect remaining 10 patients (27.8%) with asexual forms of Plasmodium falciparum. Conclusions: The study shows that buffy coat thick films are useful and can detect malarial parasites in 27.8% of patients whose conventional thick films show negative parasitemia.

  7. Dissipation in thin superconducting current biased films due to vortex motion

    Energy Technology Data Exchange (ETDEWEB)

    Bulaevskii, Lev N [Los Alamos National Laboratory

    2009-01-01

    Recently, the problem of dissipation in thin superconducting films with thickness d on the order of the coherence length {zeta}, and width {omega} much narrower than the Pearl length, {Lambda} >> {omega} >> {zeta}, was discussed as the main cause for the behavior of I-V characteristics observed in thin high-temperature superconducting films. In thin and narrow films or strips with width w >> {zeta} the barrier for phase slips by creation of temporary normal regions across the entire film width is too big, thus phase slips become highly improbable. Instead, we consider a vortex crossing the strip from one edge to the other, perpendicular to the bias current, as the dominant mechanism for generalized phase slips resulting in detectable voltage pulses. We derive the rate of vortex crossings using the general theory of transition rates between metastable states. In mean field theory, the saddle point solution of the rate equation gives the vortex position inside the strip, where the kinetic energy of supercurrents is maximum. However, the free energy barrier derived in such an approach is strongly renormalized by superconducting fluctuations and this effect was not accounted for previously. They drastically reduce the rate of vortex crossings and, consequently, dissipation. We present results for the amplitude and duration of voltage pulses induced by vortex motion and their consequences on I-V characteristics, when heating due to vortex crossings is negligible. We found ohmic behavior at low bias currents, power law behavior at intermediate currents and exponential I-V characteristics at currents close to the critical one. The impact of vortex motion in superconducting strips on the observation of so-called dark counts (voltage pulses) in superconducting nanowire single-photon detectors is discussed.

  8. Electrodeposition and characterisation of lead tin superconducting films for application in heavy ion booster

    Energy Technology Data Exchange (ETDEWEB)

    Lobanov, Nikolai R., E-mail: Nikolai.Lobanov@anu.edu.au

    2015-12-15

    The ANU has developed experimental systems and procedures for lead–tin (PbSn) film deposition and characterisation. The 12 split loop resonators have been electroplated with 96%Pb4%Sn film to the final thickness of 1.5 micron using methanesulfonic acid (MSA) chemistry. As a result, an average acceleration field of 3.6 MV/m off-line at 6 W rf power was achieved at extremely low technological cost. Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Heavy Ion Elastic Detection Analyses (HIERDA), Rutherford Backscattering Spectroscopy (RBS), Secondary Ion Mass Spectroscopy (SIMS) and Electron Backscattering Diffraction (EBSD) revealed correlation between the substrate and film structure, morphology and the rf performance of the cavity. The PbSn plating, exercised on the existing split loop resonators (SLR), has been extended to the two stub quarter wave resonator (QWR) as a straightforward step to quickly explore the superconducting performance of the new geometry. The oxygen free copper (OHFC) substrate for two stub QWR was prepared by reverse pulse electropolishing. The ultimate superconducting properties and long-term stability of the coatings have been assessed by operation of the ANU superconducting linac over the last few years. - Highlights: • PbSn alloy is investigated as a material for superconducting low and medium velocity rf resonators. • It is easily electrodeposited with MSA chemistry at very low cost, has high T{sub c}, and good performance at high fields. • The optimum substrate preparation and coating conditions are established based on examination of the properties of substrate and superconducting films. • A long term stability of the electroplated resonators has been showing no evidence of degradation of the rf properties over the last decade. • The resonators high field performance limiting factors and their possible elimination have been evaluated.

  9. Influence of thickness on properties of plasticized oat starch films

    Directory of Open Access Journals (Sweden)

    Melicia Cintia Galdeano

    2013-08-01

    Full Text Available The aim of this study was to investigate the effect of thickness (between 80 and 120 µm on apparent opacity, water vapor permeability and mechanical properties (tensile and puncture of oat starch films plasticized with glycerol, sorbitol, glycerol:sorbitol mixture, urea and sucrose. Films were stored under 11, 57, 76 and 90% relative humidity (RH to study the mechanical properties. It was observed that the higher the thickness, the higher was the opacity values. Films without the plasticizer were more opaque in comparison with the plasticized ones. Glycerol:sorbitol films presented increased elongation with increasing thickness at all RH. Puncture force showed a strong dependence on the film thickness, except for the films plasticized with sucrose. In general, thickness did not affect the water permeability.

  10. Pulsed-laser deposition of vicinal and c-axis oriented high temperature superconducting thin films

    CERN Document Server

    Rössler, R

    2000-01-01

    respect to the temperature, oxygen pressure and laser fluence. (Re,Hg)Ba sub 2 Ca sub ( n-1)Cu sub n O sub x films are synthesized on (001) and vicinal SrTiO sub 3 substrates in a two step process employing pulsed-laser deposition of Hg-free precursor films and Hg-vapour annealing in a sealed quartz tube. The sealed quartz tube technique is described in detail and the thermodynamics and the phase formation are discussed. The influence of the Hg-vapour pressure and the annealing temperature on the film properties are investigated. The influence of Hg-vapour annealing on Bi sub 2 Sr sub 2 CaCu sub 2 O sub x films is described. YBa sub 2 Cu sub 3 O sub x films with thicknesses 20 to 480 nm are deposited on vicinal SrTiO sub 3 substrates (10 degrees tilt angle). Variation of the resistivities and changes in the film morphology depending on film thickness are described. The influence of post-annealing treatments on the film properties is discussed. Pulsed-laser deposition (PLD) of high temperature superconducting ...

  11. Structural and superconducting properties of ion beam sputtered Nb thin films and Nb/Cu bilayers

    Science.gov (United States)

    Nath, S. K.; Dhawan, R.; Rai, S.; Lodha, G. S.; Sokhey, K. J. S.

    2012-01-01

    We present the results of a study of structural and superconducting properties of polycrystalline Nb thin films (200 Å, 300 Å, 400 Å, 700 Å and 1000 Å) and Nb/Cu bilayers (300 Å/300 Å and 400 Å/300 Å) prepared on Si substrates by ion beam sputtering at room temperature. The thicknesses, roughnesses at the surfaces and interfaces were determined by X-ray reflectivity whereas the grain sizes were determined from grazing incidence X-ray diffraction and transmission electron microscopic studies. The superconducting transition temperature ( T C) of Nb thin films are smaller than T C of bulk Nb. The Nb-200 Å sample does not show T C down to 2.3 K. The average size of the grains varies from 42 Å for Nb-200 Å sample to 69 Å for Nb-1000 Å sample. Our results show that the T C in these polycrystalline films is not only limited by its thickness but also by the size of the grains. The Nb films deposited in situ on the Cu layer (Nb/Cu) show a marginal increase in average sizes of the grains as compare to their respective values in Nb films of same thicknesses. As a result a marginal increase in T C of these films is also observed. The maximum decrease in T C due to oxygen intake during deposition should be about 0.5 K from its bulk value (9.28 K). We have attributed the large decrease in T C in our case on the basis of decrease in the Debye temperature and density of states at the Fermi level for Nb thin films as compared to their respective values for bulk Nb.

  12. Room-Temperature Deposition of NbN Superconducting Films

    Science.gov (United States)

    Thakoor, S.; Lamb, J. L.; Thakoor, A. P.; Khanna, S. K.

    1986-01-01

    Films with high superconducting transition temperatures deposited by reactive magnetron sputtering. Since deposition process does not involve significantly high substrate temperatures, employed to deposit counter electrode in superconductor/insulator/superconductor junction without causing any thermal or mechanical degradation of underlying delicate tunneling barrier. Substrates for room-temperature deposition of NbN polymeric or coated with photoresist, making films accessible to conventional lithographic patterning techniques. Further refinements in deposition technique yield films with smaller transition widths, Tc of which might approach predicted value of 18 K.

  13. A Method for Suppressing Superconductivity of Thin Films

    Science.gov (United States)

    Suppula, Tarmo; Pekola, Jukka; Kauppinen, Juha

    2003-03-01

    We have developed a method for suppressing superconductivity of thin films. Thin stripes of cobalt grown by e-gun evaporation and patterned by e-beam lithography were placed in the vicinity of aluminium thin film structures. The cobalt stripes were magnetized at 4.2 K with a superconducting coil and the remanence suppressed superconductivity of the Al stripe at temperatures down to 50 mK at least. The magnetization remained in thermal cycling and in a longer storage at room temperature. Motivation for this work is the Coulomb Blockade Thermometer(CBT)^1 which has to be in a normal state to operate. The CBT sensor contains aluminium which is superconducting at temperatures below 1.4 K. An external magnetic field is not always available or acceptable in cryostats. A small grain of permanent magnet mounted to the sensor is another solution, but suspicious if the sensor is put in strong magnetic fields or if "zero field" environment is required. We have shown that suitably patterned and magnetized Co stripes in the vicinity of tunnel junctions of the CBT can solve this problem. The amount of magnetic material in the sensor, as well as the stray field, is very small. This technique may be useful in other low temperature thin film devices also. 1) Product of Nanoway Ltd.

  14. Surface Impedance Measurements of Single Crystal MgB2 Films for Radiofrequency Superconductivity Applications

    Energy Technology Data Exchange (ETDEWEB)

    Binping Xiao, Xin Zhao, Joshua Spradlin, Charles Reece, Michael Kelley, Teng Tan, Xi Xiaoxing

    2012-07-01

    We report microstructure analyses and superconducting radiofrequency (SRF) measurements of large scale epitaxial MgB{sub 2} films. MgB{sub 2} films on 5 cm dia. sapphire disks were fabricated by a Hybrid Physical Chemical Vapor Deposition (HPCVD) technique. The electron-beam backscattering diffraction (EBSD) results suggest that the film is a single crystal complying with a MgB{sub 2}(0001) {parallel} Al{sub 2}O{sub 3}(0001) epitaxial relationship. The SRF properties of different film thicknesses (200 nm and 350 nm) were evaluated under different temperatures and applied fields at 7.4 GHz. A surface resistance of 9 {+-} 2 {mu}{Omega} has been observed at 2.2 K.

  15. Superconductivity and Properties of FeTeOx Films

    Energy Technology Data Exchange (ETDEWEB)

    D Telesca; j Budnick; B Sinkovic; R Ramprasad; B Wells

    2011-12-31

    Films of the parent compound FeTe can be made superconducting via the addition of interstitial oxygen. The process is reversible. We have characterized the new superconductors with a variety of experiments. X-ray diffraction shows that the superconductor has the same overall structure but a small lattice constant change compared to pure FeTe. X-ray absorption shows that superconducting FeTeO{sub x} has a nominal valence of 3+. DFT calculations show the most likely position for interstitial oxygen and confirm that such oxygen incorporation does not produce a large change in structure.

  16. Critical thickness for ferromagnetism in insulating LaMnO3 films

    Science.gov (United States)

    Renshaw Wang, X.; Poccia, N.; Leusink, D. P.; Paudel, Tura R.; Tsymbal, E. Y.; Li, C. J.; Lv, W. M.; Venkatesan, T.; Ariando, Ariando; Hilgenkamp, H.

    2014-03-01

    The interplay between exchange interactions, interfacial charges, and confinement effects controls the electronic, magnetic, and transport properties of complex oxide thin films. Here we report the emergence of ferromagnetism in insulating LaMnO3 thin films grown on SrTiO3 substrates beyond a critical thickness. LaMnO3 (001) films are deposited by a pulsed laser deposition technique with thicknesses varying from 1 unit cell to 24 unit cells. The position dependent local magnetization is then mapped with micrometer resolution using scanning superconducting quantum interference device microscopy. We find that the magnetic ground state switches from non-ferromagnetic to ferromagnetic within a change of one unit cell above the critical thickness of 5 unit cells with characteristic domain size of about 20 μm. Further increase of film thickness up to 24 unit cells leads to reduction of the domain size to about 10 μm. The critical thickness is qualitatively explained in terms of the charge transfer in polar LaMnO3 (001) thin films based on results of additional experimental data, density-functional calculations, and the electrostatic modeling.

  17. Interface-Induced High-Temperature Superconductivity in Single Unit-Cell FeSe Films on SrTiO3

    Institute of Scientific and Technical Information of China (English)

    WANG Qing-Yan; CHANG Kai; WEN Jing; SONG Can-Li; HE Ke; JIA Jin-Feng; JI Shuai-Hua; WANG Ya-Yu; WANG Li-Li; CHEN Xi; MA Xu-Cun; LI Zhi; XUE Qi-Kun; ZHANG Wen-Hao; ZHANG Zuo-Cheng; ZHANG Jin-Song; LI Wei; DING Hao; OU Yun-Bo; DENG Peng

    2012-01-01

    We report high transition temperature superconductivity in one unit-cell (UC) thick FeSe films grown on a Seetched SrTiO3 (001) substrate by molecular beam epitaxy (MBE).A superconducting gap as large as 20 meV and the magnetic field induced vortex state revealed by in situ scanning tunneling microscopy (STM) suggest that the superconductivity of the 1 UC FeSe films could occur around 77K.The control transport measurement shows that the onset superconductivity temperature is well above 50K.Our work not only demonstrates a powerful way for finding new superconductors and for raising Tc,but also provides a well-defined platform for systematic studies of the mechanism of unconventional superconductivity by using different superconducting materials and substrates.

  18. Superconducting energy scales and anomalous dissipative conductivity in thin films of molybdenum nitride

    Science.gov (United States)

    Simmendinger, Julian; Pracht, Uwe S.; Daschke, Lena; Proslier, Thomas; Klug, Jeffrey A.; Dressel, Martin; Scheffler, Marc

    2016-08-01

    We report investigations of molybdenum nitride (MoN) thin films with different thickness and disorder and with superconducting transition temperature 9.89 K ≥Tc≥2.78 K . Using terahertz frequency-domain spectroscopy we explore the normal and superconducting charge carrier dynamics for frequencies covering the range from 3 to 38 cm-1 (0.1 to 1.1 THz). The superconducting energy scales, i.e., the critical temperature Tc, the pairing energy Δ , and the superfluid stiffness J , and the superfluid density ns can be well described within the Bardeen-Cooper-Schrieffer theory for conventional superconductors. At the same time, we find an anomalously large dissipative conductivity, which cannot be explained by thermally excited quasiparticles, but rather by a temperature-dependent normal-conducting fraction, persisting deep into the superconducting state. Our results on this disordered system constrain the regime, where discernible effects stemming from the disorder-induced superconductor-insulator transition possibly become relevant, to MoN films with a transition temperature lower than at least 2.78 K.

  19. Film thickness in grease lubricated slow rotating rolling bearings

    NARCIS (Netherlands)

    Morales-Espejel, G.E.; Lugt, Pieter Martin; Pasaribu, H.R.; Cen, H.

    2014-01-01

    Film thickness measurements in grease lubricated contacts are presented for different greases. The conditions used in the experiments are similar to the ones expected in fully-flooded slow rotating bearings. The results show that at very low speeds grease produces film thicknesses substantially thic

  20. Thickness dependence of vortex critical velocity in wide Nb films

    Energy Technology Data Exchange (ETDEWEB)

    Grimaldi, Gaia [CNR-INFM Regional Laboratory SuperMat, Via S. Allende, Baronissi, SA, I-84081 (Italy)], E-mail: grimaldi@sa.infn.it; Leo, Antonio; Nigro, Angela; Pace, Sandro; Cirillo, Carla; Attanasio, Carmine [CNR-INFM Regional Laboratory SuperMat, Via S. Allende, Baronissi, SA, I-84081 (Italy); Dipartimento di Fisica ' E.R. Caianiello' , Universita di Salerno, Via S. Allende, Baronissi, SA, I-84081 (Italy)

    2008-04-01

    Pulsed I-V measurements performed on wide Nb films of different thickness show the electronic instability, at high driving currents, predicted by Larkin and Ovchinnikov (LO). We find that the associated vortex critical velocity v* decreases with the film thickness, and its temperature and magnetic field dependences exhibit some discrepancies with respect to the LO theoretical results.

  1. Superconductivity of very thin films: The superconductor–insulator transition

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yen-Hsiang; Nelson, J.; Goldman, A.M., E-mail: goldman@physics.umn.edu

    2015-07-15

    Highlights: • This manuscript reviews work on the superconductor–insulator transitions of investigated in metallic film, cuprates and metallic interfaces. • Superconductor–insulator transitions are examples of quantum phase transitions. • The systems discussed serve as model systems for behaviors found in more complex systems of contemporary interest. • The concept of a quantum phase transition is an important paradigm in condensed matter physics. • The review also includes discussions of open issues. - Abstract: The study of thin superconducting films has been an important component of the science of superconductivity for more than six decades. It played a major role in the development of currently accepted views of the macroscopic and microscopic nature of the superconducting state. In recent years the focus of research in the field has shifted to the study of ultrathin films and surface and interface layers. This has permitted the exploration of one of the important topics of condensed matter physics, the superconductor–insulator transition. This review will discuss this phenomenon as realized in the study of metallic films, cuprates, and metallic interfaces. These are in effect model systems for behaviors that may be found in more complex systems of contemporary interest.

  2. Enhancement of lower critical field by reducing the thickness of epitaxial and polycrystalline MgB2 thin films

    Directory of Open Access Journals (Sweden)

    Teng Tan

    2015-04-01

    Full Text Available For potential applications in superconducting RF cavities, we have investigated the properties of polycrystalline MgB2 films, including the thickness dependence of the lower critical field Hc1. MgB2 thin films were fabricated by hybrid physical-chemical vapor deposition on (0001 SiC substrate either directly (for epitaxial films or with a MgO buffer layer (for polycrystalline films. When the film thickness decreased from 300 nm to 100 nm, Hc1 at 5 K increased from around 600 Oe to 1880 Oe in epitaxial films and to 1520 Oe in polycrystalline films. The result is promising for using MgB2/MgO multilayers to enhance the vortex penetration field.

  3. Alginate-magnesium aluminum silicate composite films: effect of film thickness on physical characteristics and permeability.

    Science.gov (United States)

    Pongjanyakul, Thaned; Puttipipatkhachorn, Satit

    2008-01-04

    The different film thicknesses of the sodium alginate-magnesium aluminum silicate (SA-MAS) microcomposite films were prepared by varying volumes of the composite dispersion for casting. Effect of film thickness on thermal behavior, solid-state crystallinity, mechanical properties, water uptake and erosion, and water vapor and drug permeability of the microcomposite films were investigated. The film thickness caused a small change in thermal behavior of the films when tested using DSC and TGA. The crystallinity of the thin films seemed to increase when compared with the thick films. The thin films gave higher tensile strength than the thick films, whereas % elongation of the films was on the contrary resulted in the lower Young's modulus of the films when the film thickness was increased. This was due to the weaker of the film bulk, suggesting that the microscopic matrix structure of the thick films was looser than that of the thin films. Consequently, water uptake and erosion, water vapor permeation and drug diffusion coefficient of the thick films were higher than those of the thin films. The different types of drug on permeability of the films also showed that a positive charge and large molecule of drug, propranolol HCl, had higher lag time and lower diffusion coefficient that acetaminophen, a non-electrolyte and small molecule. This was because of a higher affinity of positive charge drug on MAS in the films. The findings suggest that the evaporation rate of solvent in different volumes of the composite dispersion used in the preparation method could affect crystallinity and strength of the film surface and film bulk of the microcomposite films. This led to a change in water vapor and drug permeability of the films.

  4. Film-thickness Error Analysis of Optical Disk Systems

    Institute of Scientific and Technical Information of China (English)

    WANG Yang; GU Donghong; GAN Fuxi

    2001-01-01

    It is difficult to exactly control the film thickness of optical disk multilayer in the actual coating process. The thickness error becomes a main factor affecting the optical characters of the film system. The thickness error′s sensitivity factor of dielectric optical multilayer is derived from the optical matrix in this paper. The effect of the thickness error on the reflectivity or reflectivity contrast of the optical disk multilayer is analyzed with a numerical calculation. The sensitivities to thickness error for different layers or in different film-thickness ranges are compared and discussed. A sketchy method defining allowable thickness error is given. Some experimental results verify the applicability of our theoretical analysis.

  5. Critical field of two-dimensional superconducting Sn1-x/Six bimetallic composite cluster assembled films with energetic cluster impact deposition

    Science.gov (United States)

    Kurokawa, Yuichiro; Hihara, Takehiko; Ichinose, Ikuo

    2013-05-01

    Sn1-x/Six cluster assembled films have been prepared by an energetic cluster impact deposition using a plasma-gas-condensation cluster beam deposition apparatus. Transmission electron microscope images indicated that individual clusters have composite morphologies, where Sn and Si were separated from each other. The superconducting critical magnetic fields, Hc, of Sn1-x/Six cluster assembled films were measured and found to be much higher than the critical magnetic field of the bulk Sn. We estimated the Hc values by using a theory of the superconducting thin film. The estimated values are in good agreement with the experiments, indicating that the Sn1-x/Six cluster assembled films can be regarded as a two-dimensional system although thickness, t, of Sn1-x/Six cluster assembled films (t ≈ 1000 nm) is thicker than conventional superconducting thin film (t < 100 nm).

  6. Thick antiwear films in elastohydrodynamic contacts. I. Film growth in rolling/sliding EHD contacts

    Energy Technology Data Exchange (ETDEWEB)

    Lacey, I.N.; Kelsall, G.H.; Spikes, H.A.; Macpherson, P.B.

    1986-07-01

    The formation and characteristics of thick films in elastohydrodynamic (EHD) contacts using pure phosphonate additives are described. Several alkyl and aryl group, pure phosphonate additives were added to rolling/sliding EHD contacts; the performance of the phosphonate additives is evaluated. It is observed that all phosphonates formed thick films from base oil solutions in rolling EHD contacts; the films have a thickness greater than a half a micron, withstand up to 10 percent sliding, and are formed in the presence of other additives. The effects of phosphonate group and temperature on the rate of film formation are investigated. The chemical properties of the viscous reaction product and the thick films formed by the phosphonates are analyzed. The reaction product and films consist of an iron-phosphate-monoester polymer with the phosphate acting as a bridge between iron(III) species. The use of the thick antiwear films to increase specific film thickness in EHD lubrication is discussed. 31 references.

  7. RF Characterization of Niobium Films for Superconducting Cavities

    CERN Document Server

    Aull† , S; Doebert, S; Junginger, T; Ehiasarian, AP; Knobloch, J; Terenziani, G

    2013-01-01

    The surface resistance RS of superconductors shows a complex dependence on the external parameters such as temperature, frequency or radio-frequency (RF) field. The Quadrupole Resonator modes of 400, 800 and 1200 MHz allow measurements at actual operating frequencies of superconducting cavities. Niobium films on copper substrates have several advantages over bulk niobium cavities. HIPIMS (High-power impulse magnetron sputtering) is a promising technique to increase the quality and therefore the performance of niobium films. This contribution will introduce CERNs recently developed HIPIMS coating apparatus. Moreover, first results of niobium coated copper samples will be presented, revealing the dominant loss mechanisms.

  8. Advantages of PZT thick film for MEMS sensors

    DEFF Research Database (Denmark)

    Hindrichsen, Christian Carstensen; Lou-Moller, R.; Hansen, K.;

    2010-01-01

    For all MEMS devices a high coupling between the mechanical and electrical domain is desired. Figures of merit describing the coupling are important for comparing different piezoelectric materials. The existing figures of merit are discussed and a new figure of merit is introduced for a fair...... comparison of piezoelectric thin and thick films based MEMS devices, as cantilevers, beams, bridges and membranes. Simple analytical modeling is used to define the new figure of merit. The relevant figure of merits is compared for the piezoelectric material of interest for MEMS applications: ZnO, AIN, PZT...... thin film and PZT thick film. It is shown that MEMS sensors with the PZT thick film TF2100 from InSensor A/S have potential for significant higher voltage sensitivities compared to PZT thin film base MEMS sensors when the total thickness of the MEMS cantilever, beam, bridge or membrane is high...

  9. Barium titanate thick films prepared by screen printing technique

    Directory of Open Access Journals (Sweden)

    Mirjana M. Vijatović

    2010-06-01

    Full Text Available The barium titanate (BaTiO3 thick films were prepared by screen printing technique using powders obtained by soft chemical route, modified Pechini process. Three different barium titanate powders were prepared: i pure, ii doped with lanthanum and iii doped with antimony. Pastes for screen printing were prepared using previously obtained powders. The thick films were deposited onto Al2O3 substrates and fired at 850°C together with electrode material (silver/palladium in the moving belt furnace in the air atmosphere. Measurements of thickness and roughness of barium titanate thick films were performed. The electrical properties of thick films such as dielectric constant, dielectric losses, Curie temperature, hysteresis loop were reported. The influence of different factors on electrical properties values was analyzed.

  10. Optimisation of superconducting thin films by TEM

    NARCIS (Netherlands)

    Bals, S.; van Tendeloo, G.; Rijnders, Augustinus J.H.M.; Blank, David H.A.; Leca, V.; Salluzzo, M.

    2002-01-01

    High-resolution electron microscopy is used to study the initial growth of different REBa2Cu3O7−δ thin films. In DyBa2Cu3O7−δ ultra-thin films, deposited on TiO2 terminated SrTiO3, two different types of interface arrangements occur: bulk–SrO–TiO2–BaO–CuO–BaO–CuO2–Dy–CuO2–BaO–bulk and bulk–SrO–TiO2–

  11. Thickness-dependent spontaneous dewetting morphology of ultrathin Ag films.

    Science.gov (United States)

    Krishna, H; Sachan, R; Strader, J; Favazza, C; Khenner, M; Kalyanaraman, R

    2010-04-16

    We show here that the morphological pathway of spontaneous dewetting of ultrathin Ag films on SiO2 under nanosecond laser melting is dependent on film thickness. For films with thickness h of 2 nm intermolecular forces, we have estimated the morphological transition thickness for the intermolecular forces for Ag on SiO2. The theory predictions agree well with observations for Ag. These results show that it is possible to form a variety of complex Ag nanomorphologies in a consistent manner, which could be useful in optical applications of Ag surfaces, such as in surface enhanced Raman sensing.

  12. Refractive index of nanoscale thickness films measured by Brewster refractometry

    CERN Document Server

    Tikhonov, E A; Malyukin, Yu V

    2015-01-01

    It is shown that reflective laser refractometery at Brewster angle can be usefull for precision measurements of refractive indexes (RI) in the transparency band of various films of nanoscale thickness. The RI measurements of nanoscale porous film on the basis of gadolinium orthosilicate and quartz have been carried out as first experience. It is shown that surface light scattering in such films that is connected with clustering of nanoscale pores can decrease the accuracy of the RI measurements at Brewster angle. Estimated physical dependence RI stipulated by the film thickness reduction (3D-2D transition) in the range of (20-160)nm has not been not detected.

  13. Liquid film thickness measurement by two-line TDLAS

    Science.gov (United States)

    Yang, Huinan; Chen, Jun; Cai, Xiaoshu; Greszik, Daniel; Dreier, Thomas; Schulz, Christof

    2014-04-01

    A fiber-based two-line tunable diode-laser absorption sensor with two near-infrared (NIR) distributed-feedback (DFB) diode lasers at ˜1.4 μm was used for non-intrusive time-resolved liquid water film thickness measurement. When probing the liquid film at two different wavelengths with significantly different absorption cross-sections, the additional signal losses due to surface fowling, reflection and beam steering can be eliminated. In this work, the evaporation process of a liquid film on transparent quartz plate was tracked and large fluctuations of film thickness were found at the end of the evaporation.

  14. Liquid film thickness measurement by two-line TDLAS

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Huinan [School of Energy and Power Engineering, University of Shanghai for Science and Technology, 200093, Shanghai, China and IVG, University of Duisburg-Essen, 47057, Duisburg (Germany); Chen, Jun; Cai, Xiaoshu [School of Energy and Power Engineering, University of Shanghai for Science and Technology, 200093, Shanghai (China); Greszik, Daniel; Dreier, Thomas; Schulz, Christof [IVG, University of Duisburg-Essen, 47057, Duisburg (Germany)

    2014-04-11

    A fiber-based two-line tunable diode-laser absorption sensor with two near-infrared (NIR) distributed-feedback (DFB) diode lasers at ∼1.4 μm was used for non-intrusive time-resolved liquid water film thickness measurement. When probing the liquid film at two different wavelengths with significantly different absorption cross-sections, the additional signal losses due to surface fowling, reflection and beam steering can be eliminated. In this work, the evaporation process of a liquid film on transparent quartz plate was tracked and large fluctuations of film thickness were found at the end of the evaporation.

  15. Self-assembled film thickness determination by focused ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Dejeu, J. [Institut UTINAM, UMR 6213 CNRS-UFC - equipe Materiaux et Surfaces Structures, Universite de Franche-Comte, UFR Sciences et Techniques, 16 route de Gray - 25030 Besancon Cedex (France)], E-mail: jerome.dejeu@univ-fcomte.fr; Salut, R. [Institut FEMTO-ST, UMR 6174 CNRS-UFC-UTBM-ENSMM, Centrale MIMENTO, Universite de Franche-Comte, 32 avenue de l' Observatoire - 25044 Besancon Cedex (France); Spajer, M. [Institut FEMTO-ST, UMR 6174 CNRS-UFC-UTBM-ENSMM, Centrale MIMENTO, Universite de Franche-Comte, 32 avenue de l' Observatoire - 25044 Besancon Cedex (France); Institut FEMTO-ST, UMR 6174 CNRS-UFC-UTBM-ENSMM, Departement d' Optique, Universite de Franche-Comte, UFR Sciences et Techniques, 16 route de Gray - 25030 Besancon Cedex (France); Membrey, F.; Foissy, A. [Institut UTINAM, UMR 6213 CNRS-UFC - equipe Materiaux et Surfaces Structures, Universite de Franche-Comte, UFR Sciences et Techniques, 16 route de Gray - 25030 Besancon Cedex (France); Charraut, D. [Institut FEMTO-ST, UMR 6174 CNRS-UFC-UTBM-ENSMM, Departement d' Optique, Universite de Franche-Comte, UFR Sciences et Techniques, 16 route de Gray - 25030 Besancon Cedex (France)

    2008-06-30

    The thickness evolution of multilayer film is investigated by focused ion beam (FIB) in the domain of polymer multilayers. This method, currently used in the modification and the characterization of integrated circuits, proves it is possible to determine the polymer film thickness. Sample cutting and its observation of the cross-section are performed in the FIB without leaving the vacuum chamber. Two main conclusions can be drawn: (1) the roughness of the film increases with the number of layer deposit, (2) the film growth changes from nonlinear (called exponential) to linear beyond 300 nm (70 layers)

  16. Granular superconductivity in metallic and insulating nanocrystalline boron-doped diamond thin films

    Energy Technology Data Exchange (ETDEWEB)

    Willems, B L; Zhang, G; Vanacken, J; Moshchalkov, V V [INPAC-Institute for Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200-D, 3000-Leuven (Belgium); Janssens, S D; Haenen, K; Wagner, P, E-mail: bramleo@hotmail.co [Institute for Materials Research (IMO), Hasselt University, BE-3590 Diepenbeek (Belgium)

    2010-09-22

    The low-temperature electrical transport properties of nanocrystalline boron-doped diamond (b-NCD) thin films have been found to be strongly affected by the system's granularity. The important differences between the high and low-temperature behaviour are caused by the inhomogeneous nucleation of superconductivity in the samples. In this paper we will discuss the experimental data obtained on several b-NCD thin films, which were studied by either varying their thickness or boron concentration. It will be shown that the low-temperature properties are influenced by the b-NCD grain boundaries as well as by the appearance of an intrinsic granularity inside these granules. Moreover, superconducting effects have been found to be present even in insulating b-NCD films and are responsible for the negative magnetoresistance regime observed at low temperatures. On the other hand, the low-temperature electrical transport properties of b-NCD films show important similarities with those observed for granular superconductors.

  17. Negative magnetoresistance slope in superconducting granular films

    Energy Technology Data Exchange (ETDEWEB)

    Shapiro, Boris Ya., E-mail: shapib@mail.biu.ac.il; Shapiro, Irina; Levi, Daniel; Shaulov, Avner; Yeshurun, Yosef

    2014-06-15

    Highlights: • The theory explaining recently observed negative magneto-resistance slope in ultra-thin YBa{sub 2}Cu{sub 2}O{sub 7−δ} films is developed. • Considering film as an array of the Josephson junctions, we solve the sine-Gordon equations including a viscosity term. • The solution yields a negative magneto-resistance slope setting in agreement with the experimental results. - Abstract: A phenomenological theory is developed to explain the recently observed negative magnetoresistance slope in ultra-thin granular YBa{sub 2}Cu{sub 2}O{sub 7−δ} films. Viewing this system as a two-dimensional array of extended Josephson junctions, we numerically solve the sine-Gordon equations including a viscosity term that increases linearly with the external field. The solution yields a negative magnetoresistance slope setting in at a field that is determined by the geometry and thus independent of temperature, in agreement with the experimental results.

  18. Strain-relaxation and critical thickness of epitaxial La1.85Sr0.15CuO4 films

    Directory of Open Access Journals (Sweden)

    T. L. Meyer

    2015-12-01

    Full Text Available We report the thickness-dependent strain-relaxation behavior and the associated impacts upon the superconductivity in epitaxial La1.85Sr0.15CuO4 films grown on different substrates, which provide a range of strain. We have found that the critical thickness for the onset of superconductivity in La1.85Sr0.15CuO4 films is associated with the finite thickness effect and epitaxial strain. In particular, thin films with tensile strain greater than ∼0.25% revealed no superconductivity. We attribute this phenomenon to the inherent formation of oxygen vacancies that can be minimized via strain relaxation.

  19. MBE growth of Fe-based superconducting films

    Science.gov (United States)

    Ueda, S.; Yamagishi, T.; Takeda, S.; Agatsuma, S.; Takano, S.; Mitsuda, A.; Naito, M.

    2011-11-01

    We report MBE growth of the iron-based superconductors, Sr1-xKxFe2As2, Ba1-xKxFe2As2, and SmFeAs(O,F). In the growth of Sr1-xKxFe2As2 and Ba1-xKxFe2As2 films, the key to incorporating volatile K in films is low-temperature (300-350 °C) growth in reduced As flux. The highest Tc so far obtained are Tcon (Tcend) = 33.4K (31.0 K) and 38.3 K (35.5 K) for Sr1-xKxFe2As2 and Ba1-xKxFe2As2, respectively. In the growth of superconducting SmFeAs(O,F), we have adopted two approaches. In the first approach, we first grew F-free SmFeAsO films, and subsequently introduced F to the films via F diffusion from an overlayer of SmF3 or NdF3. In the second approach, we attempted the growth of as-grown superconducting SmFeAs(O,F) films by coevaporating Sm, SmF3, Fe, and As. In both the approaches, the growth temperature was as high as 650 °C. So far better results have been obtained by the first F diffusion method. The films prepared by F diffusion showed Tcon (Tcend) = 52 K (48.6 K) whereas the as-grown films showed Tcon = 47 K but with a long transition tail.

  20. Superconducting NbTiN Thin Films with Highly Uniform Properties over a 100 mm diameter Wafer

    CERN Document Server

    Thoen, D J; Haalebos, E A F; Klapwijk, T M; Baselmans, J J A; Endo, A

    2016-01-01

    Uniformity in thickness and electronic properties of superconducting niobium titanium nitride (NbTiN) thin films is a critical issue for upscaling superconducting electronics, such as microwave kinetic inductance detectors for submillimeter wave astronomy. In this article we make an experimental comparison between the uniformity of NbTiN thin films produced by two DC magnetron sputtering systems with vastly different target sizes: the Nordiko 2000 equipped with a circular 100mm diameter target, and the Evatec LLS801 with a rectangular target of 127 mm x 444.5 mm. In addition to the films deposited staticly in both systems, we have also deposited films in the LLS801 while shuttling the substrate in front of the target, with the aim of further enhancing the uniformity. Among these three setups, the LLS801 system with substrate shuttling has yielded the highest uniformity in film thickness (+/-2%), effective resistivity (decreasing by 5% from center to edge), and superconducting critical temperature (T_c = 15.0 ...

  1. A new type of HTc superconducting film comb-shape resonator for radio frequency superconducting quantum interference devices

    Institute of Scientific and Technical Information of China (English)

    MAO Hai-yan; WANG Fu-ren; MENG Shu-chao; MAO Bo; LI Zhuang-zhi; NIE Rui-juan; LIU Xin-yuan; DAI Yuan-dong

    2006-01-01

    A new type of HTc superconducting film combshape resonator for radio frequency superconducting quantum interference devices (RF SQUID) has been designed.This new type of superconducting film comb-shape resonator is formed by a foursquare microstrip line without a flux concentrator.The range of the center frequency of this type of resonator varies from 800 MHz to 1300 MHz by changing the length of the teeth.In this paper,we report on simulating the relationship of the value of the center frequency and the length of the teeth,and testing the noise of HTc RF SQUID coupling this comb-shape resonator.

  2. Development of solid state thick film zirconia oxygen gas sensors.

    OpenAIRE

    Ioannou, Andreas Stylianou

    1992-01-01

    Aspects relating to and including the development of thick film amperometric zirconia oxygen sensors were investigated. These devices, which were operated in the range 550-950°C, had a laminated structure in which a cathode, an electrolyte and an anode were printed, in that order, onto a planar alumina substrate. The anode and electrolyte were porous and during sensor Operation also acted as a diffusion barrier, restricting the rate of oxygen diffusion to the cathode. A thick film platinum he...

  3. Electrophoretic deposition and constrained sintering of strontium titanate thick films

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, Luís; Vilarinho, Paula M., E-mail: paula.vilarinho@ua.pt; Senos, Ana M.R.

    2015-01-15

    Thick films of functional oxides are currently substituting counterparts bulk ceramics, as in the case of low loss dielectrics. For SrTiO{sub 3} (ST) based compositions it is demonstrated that electrophoretic deposition (EPD), using acetone as a suspension media with iodine addition, is a suitable technology to fabricate 12 μm thick films. The microstructural analysis of the films sintered at 1500 °C shows that highly densified microstructures can be obtained and, by slightly varying the Sr/Ti stoichiometry in the powder composition, increased densification and grain size and enlargement of the distribution with decreasing Sr/Ti ratio can be observed. In spite of the high densification of the films, it is also demonstrated that due to the constraint imposed by the substrate a smaller grain size is observed in thick films as compared to equivalent bulk ceramics. In addition, a preferential vertical pore orientation is observed in ST thick films. These results may have broad implications if one considers that the dielectric losses and dielectric tunability is affected by pore orientation, since it affects the electric field distribution. - Highlights: • Nonstoichiometry effect on microstructure of constrained sintered thick films and bulk is similar. • Increased densification and grain size and enlargement of distribution with decreasing Sr/Ti ratio. • Independent of Sr/Ti ratio smaller grain size for thick films compared to ceramics. • Preferential vertical pore orientation for constrained sintering of thick films. • Anisotropic porosity as tailoring factor to engineer permittivity and tunability.

  4. Effect of strain on the critical current density of Bi-2223 thick films sandwiched between Ag sheets

    Energy Technology Data Exchange (ETDEWEB)

    Jia, J.H. (Academia Sinica, Hefei (China). Inst. of Solid State Physics); Kong, Q.P. (Academia Sinica, Hefei (China). Inst. of Solid State Physics); Wang, S.X. (Academia Sinica, Hefei, Anhui (China). Inst. of Plasma Physics); Han, H.M. (Academia Sinica, Hefei, Anhui (China). Inst. of Plasma Physics)

    1994-08-16

    The tapes of (Bi, Pb)[sub 2]Sr[sub 2]Ca[sub 2]Cu[sub 3]O[sub x] (Bi-2223) thick film sandwiched between Ag sheets are known to have very high J[sub c]. In this note, the stress-strain behaviour and the strain dependence of critical current density of the Ag/Bi-2223/Ag tapes are investigated. The microstructure of superconducting thick films subjected to various amounts of deformation was examined with a scanning electron microscope (SEM). (orig.)

  5. Intrinsic Josephson effects on superconducting films

    CERN Document Server

    Chana, O S

    2002-01-01

    Films of the high-T sub c superconductor Tl sub 2 Ba sub 2 CaCu sub 2 O sub 8 with the crystal c-axis misaligned from the substrate normal have been used to make intrinsic Josephson junctions. The copper-oxide layers in the cuprate superconductor are weakly coupled in the c-direction. This weak interplanar coupling is analogous to superconductor- insulator-superconductor stacks parallel to the c-direction in the film and this maps out to a series array of intrinsic Josephson junctions. A novel device geometry has been used to exploit this and series arrays of intrinsic Josephson junctions have been fabricated. The junctions are optimised in quality and have a high and critical-current- independent value for the product of the critical current and normal state resistance. The temperature dependence of the critical current fits the Ambegaokar-Baratoff theory for SIS tunnelling. X-band emission at around 12 GHz has been detected from the intrinsic Josephson bridge at 103 K. This confirms that the junctions are s...

  6. Sputtering of Thick Deuterium Films by KeV Electrons

    DEFF Research Database (Denmark)

    Thestrup Nielsen, Birgitte; Svendsen, Winnie Edith; Schou, Jørgen;

    1994-01-01

    Sputtering of thick films of solid deuterium up to several μm by keV electrons is reported for the first time. The sputtering yield increases within a narrow range of thicknesses around 1.6 μm by about 2 orders of magnitude for 1.5 keV electrons. A similar behavior has not been observed for ion...

  7. MgB{sub 2} thick film with T{sub C}=40.2 K deposited on sapphire substrate

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Kaicheng; Ding, Li-li; Zhuang, Cheng-gang; Chen, Li-ping; Chen, Chinping; Feng, Qing-rong [Department of Physics, Peking University, Beijing 100871 (China)

    2006-08-15

    A thick MgB{sub 2} film has been successfully deposited on a (001) crystalline surface of sapphire by the method of hybrid physical-chemical vapor deposition (HPCVD). The film thickness is about 1.3 {mu}m, having a dense and interlaced structure. The film surface, as shown by scanning electron microscopy, is stacked with MgB{sub 2} microcrystals. Transport measurements using the four-probe technique demonstrate that its critical temperature is about 40.2 K, with a sharp transition width of 0.15 K. The transition is higher by 1 K than those commonly reported at 39 K. The residual resistivity ratio (RRR) is about 11. By extrapolation, H{sub C2}(0) is determined as 13.7 T from magneto-transport measurements. Also, from hysteresis measurements and applying the Bean model, the critical current density is estimated as 5 x 10{sup 10} A/m{sup 2} in zero magnetic field. The investigation demonstrates that HPCVD is an effective technique to fabricate MgB{sub 2} thick films with decent superconducting properties. Hence, it is important for future superconducting applications, in particular as a crucial preliminary stage in the fabrication of superconducting tape. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. MgB2 thick films deposited on stainless steel substrate with Tc higher than 39K

    Institute of Scientific and Technical Information of China (English)

    LI Fen; GUO Tao; ZHANG Kai-cheng; CHEN Chin-ping; FENG Qing-rong

    2006-01-01

    Thick MgB2 (magnesium diborate) films,~10 μm,with Tc (onset)=39.4 K and Tc (zero)=39.2 K have been successfully grown on a stainless steel substrate using a technique called hybrid physical-chemical deposition (HPCVD).The deposition rate is high,~6.7 nm/s.The X-ray diffraction (XRD) indicates that it is highly (101) and c-axis oriented.The scanning electron microscope (SEM) images demonstrate that the film grown is in"island-mode".The uniform superconducting phase in the film is shown by the M-T measurement.

  9. Fabrication of YBCO/YSZ and YBCO/MgO thick films using electrophoretic deposition with top-seeded melt growth process

    Institute of Scientific and Technical Information of China (English)

    Zhu Ya-Bin; Zhou Yue-Liang; Wang Shu-Fang; Liu Zhen; Zhang Qin; Chen Zheng-Hao; Lü Hui-Bin; Yang Guo-Zhen

    2004-01-01

    Superconducting thick films were grown on single crystals MgO and YSZ by electrophoretic deposition with Y2BaCuOs(Y211) addition. YBCO thick films were then accomplished by sintering the precursor films above the peritectic temperature. Single crystals of MgO (3×3×0.5mm3) were used as top-seed to control crystal structure of the thick films. As shown by scanning electron microscopy, the morphologies of YBCO/YSZ and YBCO/MgO thick films are spherulitic texture and platelet type. The critical temperature is ~89 K for the YBCO/YSZ thick film; the onset transition temperature is 86.4 K and the transition width is ~3 K for YBCO/MgO thick film. The critical current densities (as determined by Bean model) are, in A/cm2, 3870 (77K) for YBCO/YSZ thick films and 2399 (77K) for YBCO/MgO thick films, which are comparable to the best Jc reported of the thick films prepared by the same method.

  10. Grain-size dependence of superconductivity in dc sputtered Nb films

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The superconducting transition temperature and grain size of dc sputtered Nb films are systematically investigated. The results show that the superconductivity is closely related to the grain size, rather than to the scattering strength of electrons or the surface layer proximity effect of the films.

  11. Evaluating Superconducting YBCO Film Properties Using X-Ray Photoelectron Spectroscopy (Postprint)

    Science.gov (United States)

    2012-02-01

    AFRL-RZ-WP-TP-2012-0093 EVALUATING SUPERCONDUCTING YBCO FILM PROPERTIES USING X-RAY PHOTOELECTRON SPECTROSCOPY (POSTPRINT) Paul N. Barnes...2012 Conference Paper Postprint 01 January 2002 – 01 January 2004 4. TITLE AND SUBTITLE EVALUATING SUPERCONDUCTING YBCO FILM PROPERTIES USING X-RAY

  12. Superconducting thin films. (Latest citations from the EI Compendex*plus database). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-01

    The bibliography contains citations concerning the design, fabrication, structures, and properties of superconducting thin films used in microelectronics and optoelectronics. References discuss high temperature superconductors, oxide superconductors, superconducting transition temperatures, critical current density, yttrium barium copper oxide thin films, and yttrium stabilized substrates. Superconducting devices, filters, resonators, and circuits are also reviewed. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  13. Enhanced pinning in superconducting thin films with graded pinning landscapes

    Science.gov (United States)

    Motta, M.; Colauto, F.; Ortiz, W. A.; Fritzsche, J.; Cuppens, J.; Gillijns, W.; Moshchalkov, V. V.; Johansen, T. H.; Sanchez, A.; Silhanek, A. V.

    2013-05-01

    A graded distribution of antidots in superconducting a-Mo79Ge21 thin films has been investigated by magnetization and magneto-optical imaging measurements. The pinning landscape has maximum density at the sample border, decreasing linearly towards the center. Its overall performance is noticeably superior than that for a sample with uniformly distributed antidots: For high temperatures and low fields, the critical current is enhanced, whereas the region of thermomagnetic instabilities in the field-temperature diagram is significantly suppressed. These findings confirm the relevance of graded landscapes on the enhancement of pinning efficiency, as recently predicted by Misko and Nori [Phys. Rev. B 85, 184506 (2012)].

  14. Continued improvment of large area, in situ sputter deposition of superconducting YBCO thin films

    Science.gov (United States)

    Truman, J. K.; White, W. R.; Ballentine, P. H.; Mallory, D. S.; Kadin, A. M.

    1993-01-01

    The deposition of thin films of superconducting YBa2Cu3O7-x onto substrates of up to 3-in diameter by an integrated off-axis sputtering is reported. The substrate is located above the center of an 8-in-diameter YBCO planar target, and, in conjunction with a negative ion shield, negative ion effects are avoided. A large radiant heater provides backside, noncontact heating of the bare substrates. YBCO films have been grown on polished 1-cm2 MgO and LaAlO3 substrates with Tc = 90 K or greater, Jc = 2.5 x 10 exp 6 A/sq cm or greater at 77 K, and microwave surface resistance Rs less than 0.4 micro-ohm at 77 K and 10 GHz. The films have a very smooth surface morphology. Uniformity data for LaAlO3 substrates are less than +/-5 percent in Rs. Thickness uniformity results for 3-in substrates indicate less than 10 percent variation. The growth of epitaxial insulating films for use with YBCO films and application of the YBCO films in microwave devices are briefly discussed.

  15. Resistive current states in wide superconducting films in zero magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Dmitriev, V M [B Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 61103 Kharkiv (Ukraine); Zolochevskii, I V [B Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 61103 Kharkiv (Ukraine)

    2006-04-15

    The temperature dependence of the current-voltage characteristics of high-quality thin films of tin from 7 to 50 {mu}m thick are investigated in the absence of an external magnetic field. For the first time, we have experimentally observed phase slip centres (PSCs) and phase slip lines (PSLs) on the same superconducting tin film with known parameters in the temperature intervals corresponding to the mechanisms of their formation and existence. We have shown that the states of a wide film with increasing transport current appear in the following order: the superconducting state for current less than critical; the resistive vortex state for current more than critical, but less than maximum current for the uniform flux flow (instability current); the critical state due to the onset of instability of the steady pattern of viscous motion of the vortices; a vortex-free resistive state with PSLs for current more than instability current, but less than the upper critical current; and the normal state at a current higher than the upper critical current.

  16. Molecular beam epitaxy and superconductivity of stoichiometric FeSe and KxFe2-ySe2 crystalline films

    Institute of Scientific and Technical Information of China (English)

    Wang Li-Li; Ma Xu-Cun; Chen Xi; Xue Qi-Kun

    2013-01-01

    Our recent progress in the fabrication of FeSe and KxFe2-ySe2 ultra thin films and the understanding of their superconductivity properties is reviewed.The growth of high-quality FeSe and KxFe2-ySe2 films is achieved in a well controlled manner by molecular beam epitaxy.The high-quality stoichiometric and superconducting crystalline thin films allow us to investigate the intrinsic superconductivity properties and the interplay between the superconductivity and the film thickness,the local structure,the substrate,and magnetism.In situ low-temperature scanning tunneling spectra reveal the nodes and the twofold symmetry in FeSe,high-temperature superconductivity at the FeSe/SrTiO3 interface,phase separation and magnetic order in KxFe2-ySe2,and the suppression of superconductivity by twin boundaries and Fe vacancies.Our findings not only provide fundamental information for understanding the mechanism of unconventional superconductivity,but also demonstrate a powerful way of engineering superconductors and raising the transition temperature.

  17. MBE growth of Fe-based superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, S. [Department of Applied Physics, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan)] [TRIP, Japan Science and Technology Agency (JST), Chiyoda, Tokyo 102-0075 (Japan)] [New Energy and Industrial Technology Development Organization (NEDO), Kawasaki, Kanagawa 212-8554 (Japan); Yamagishi, T.; Takeda, S. [Department of Applied Physics, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan)] [TRIP, Japan Science and Technology Agency (JST), Chiyoda, Tokyo 102-0075 (Japan); Agatsuma, S.; Takano, S. [Department of Applied Physics, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan); Mitsuda, A. [Department of Physics, Kyushu Univeristy, Hakozaki, Fukuoka 812-8588 (Japan); Naito, M., E-mail: minaito@cc.tuat.ac.jp [Department of Applied Physics, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan)] [TRIP, Japan Science and Technology Agency (JST), Chiyoda, Tokyo 102-0075 (Japan)

    2011-11-15

    Successful MBE growth of (AE,K)-122 (AE = Sr and Ba) with T{sub c} = 38 K and Ln-1111 (Ln = Sm) films with T{sub c} = 52 K. (Sr,K)-122 and (Ba,K)-122 films including volatile K were grown at temperatures as low as 300{approx}350 deg. C in reduced As flux. SmFeAs(O,F) films were prepared by two approaches. In the first approach, F was diffused to F-free SmFeAsO films from a thin SmF{sub 3} (or NdF{sub 3}) overlayer. In the second approach, as-grown superconducting SmFeAsO films were grown by coevaporation of Sm, SmF{sub 3}, Fe, and As in oxygen atmosphere. We report MBE growth of the iron-based superconductors, Sr{sub 1-x}K{sub x}Fe{sub 2}As{sub 2}, Ba{sub 1-x}K{sub x}Fe{sub 2}As{sub 2}, and SmFeAs(O,F). In the growth of Sr{sub 1-x}K{sub x}Fe{sub 2}As{sub 2} and Ba{sub 1-x}K{sub x}Fe{sub 2}As{sub 2} films, the key to incorporating volatile K in films is low-temperature (300-350 deg. C) growth in reduced As flux. The highest T{sub c} so far obtained are T{sub c}{sup on}(T{sub c}{sup end})=33.4K (31.0 K) and 38.3 K (35.5 K) for Sr{sub 1-x}K{sub x}Fe{sub 2}As{sub 2} and Ba{sub 1-x}K{sub x}Fe{sub 2}As{sub 2}, respectively. In the growth of superconducting SmFeAs(O,F), we have adopted two approaches. In the first approach, we first grew F-free SmFeAsO films, and subsequently introduced F to the films via F diffusion from an overlayer of SmF{sub 3} or NdF{sub 3}. In the second approach, we attempted the growth of as-grown superconducting SmFeAs(O,F) films by coevaporating Sm, SmF{sub 3}, Fe, and As. In both the approaches, the growth temperature was as high as 650 deg. C. So far better results have been obtained by the first F diffusion method. The films prepared by F diffusion showed T{sub c}{sup on} (T{sub c}{sup end}) = 52 K (48.6 K) whereas the as-grown films showed T{sub c}{sup on} = 47 K but with a long transition tail.

  18. Thickness-modulated tungsten–carbon superconducting nanostructures grown by focused ion beam induced deposition for vortex pinning up to high magnetic fields

    Directory of Open Access Journals (Sweden)

    Ismael García Serrano

    2016-11-01

    Full Text Available We report efficient vortex pinning in thickness-modulated tungsten–carbon-based (W–C nanostructures grown by focused ion beam induced deposition (FIBID. By using FIBID, W–C superconducting films have been created with thickness modulation properties exhibiting periodicity from 60 to 140 nm, leading to a strong pinning potential for the vortex lattice. This produces local minima in the resistivity up to high magnetic fields (2.2 T in a broad temperature range due to commensurability effects between the pinning potential and the vortex lattice. The results show that the combination of single-step FIBID fabrication of superconducting nanostructures with built-in artificial pinning landscapes and the small intrinsic random pinning potential of this material produces strong periodic pinning potentials, maximizing the opportunities for the investigation of fundamental aspects in vortex science under changing external stimuli (e.g., temperature, magnetic field, electrical current.

  19. Changes in the temperature-dependent specific volume of supported polystyrene films with film thickness

    Science.gov (United States)

    Huang, Xinru; Roth, Connie B.

    2016-06-01

    Recent studies have measured or predicted thickness-dependent shifts in density or specific volume of polymer films as a possible means of understanding changes in the glass transition temperature Tg(h) with decreasing film thickness with some experimental works claiming unrealistically large (25%-30%) increases in film density with decreasing thickness. Here we use ellipsometry to measure the temperature-dependent index of refraction of polystyrene (PS) films supported on silicon and investigate the validity of the commonly used Lorentz-Lorenz equation for inferring changes in density or specific volume from very thin films. We find that the density (specific volume) of these supported PS films does not vary by more than ±0.4% of the bulk value for film thicknesses above 30 nm, and that the small variations we do observe are uncorrelated with any free volume explanation for the Tg(h) decrease exhibited by these films. We conclude that the derivation of the Lorentz-Lorenz equation becomes invalid for very thin films as the film thickness approaches ˜20 nm, and that reports of large density changes greater than ±1% of bulk for films thinner than this likely suffer from breakdown in the validity of this equation or in the difficulties associated with accurately measuring the index of refraction of such thin films. For larger film thicknesses, we do observed small variations in the effective specific volume of the films of 0.4 ± 0.2%, outside of our experimental error. These shifts occur simultaneously in both the liquid and glassy regimes uniformly together starting at film thicknesses less than ˜120 nm but appear to be uncorrelated with Tg(h) decreases; possible causes for these variations are discussed.

  20. Thickness of residual wetting film in liquid-liquid displacement

    Science.gov (United States)

    Beresnev, Igor; Gaul, William; Vigil, R. Dennis

    2011-08-01

    Core-annular flow is common in nature, representing, for example, how streams of oil, surrounded by water, move in petroleum reservoirs. Oil, typically a nonwetting fluid, tends to occupy the middle (core) part of a channel, while water forms a surrounding wall-wetting film. What is the thickness of the wetting film? A classic theory has been in existence for nearly 50 years offering a solution, although in a controversial manner, for moving gas bubbles. On the other hand, an acceptable, experimentally verified theory for a body of one liquid flowing in another has not been available. Here we develop a hydrodynamic, testable theory providing an explicit relationship between the thickness of the wetting film and fluid properties for a blob of one fluid moving in another, with neither phase being gas. In its relationship to the capillary number Ca, the thickness of the film is predicted to be proportional to Ca2 at lower Ca and to level off at a constant value of ˜20% the channel radius at higher Ca. The thickness of the film is deduced to be approximately unaffected by the viscosity ratio of the fluids. We have conducted our own laboratory experiments and compiled experimental data from other studies, all of which are mutually consistent and confirm the salient features of the theory. At the same time, the classic law, originally deduced for films surrounding moving gas bubbles but often believed to hold for liquids as well, fails to explain the observations.

  1. Determination of hydration film thickness using atomic force microscopy

    Institute of Scientific and Technical Information of China (English)

    PENG Changsheng; SONG Shaoxian; GU Qingbao

    2005-01-01

    Dispersion of a solid particle in water may lead to the formation of hydration film on the particle surface, which can strongly increase the repulsive force between the particles and thus strongly affect the stability of dispersions. The hydration film thickness, which varies with the variation of property of suspension particles, is one of the most important parameters of hydration film, and is also one of the most difficult parameters that can be measured accurately. In this paper, a method, based on force-distance curve of atomic force microscopy, for determining the hydration film thickness of particles is developed. The method utilizes the difference of cantilever deflection before, between and after penetrating the hydration films between tip and sample, which reflect the difference of slope on the force-distance curve. 3 samples, mica, glass and stainless steel, were used for hydration thickness determination, and the results show that the hydration film thickness between silicon tip and mica, glass and stainless steel are 30.0(2.0, 29.0(1.0 and 32.5(2.5 nm, respectively.

  2. Superconducting properties of very high quality NbN thin films grown by high temperature chemical vapor deposition

    Science.gov (United States)

    Hazra, D.; Tsavdaris, N.; Jebari, S.; Grimm, A.; Blanchet, F.; Mercier, F.; Blanquet, E.; Chapelier, C.; Hofheinz, M.

    2016-10-01

    Niobium nitride (NbN) is widely used in high-frequency superconducting electronics circuits because it has one of the highest superconducting transition temperatures ({T}{{c}}˜ 16.5 {{K}}) and largest gap among conventional superconductors. In its thin-film form, the T c of NbN is very sensitive to growth conditions and it still remains a challenge to grow NbN thin films (below 50 nm) with high T c. Here, we report on the superconducting properties of NbN thin films grown by high-temperature chemical vapor deposition (HTCVD). Transport measurements reveal significantly lower disorder than previously reported, characterized by a Ioffe-Regel parameter ({k}{{F}}{\\ell }) ˜ 12. Accordingly we observe {T}{{c}}˜ 17.06 {{K}} (point of 50% of normal state resistance), the highest value reported so far for films of thickness 50 nm or less, indicating that HTCVD could be particularly useful for growing high quality NbN thin films.

  3. Changing the flux flow state in weak pinning superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Leo, A., E-mail: antoleo@sa.infn.it [Physics Department E.R. Caianiello, University of Salerno, Via Giovanni Paolo II, 132, Stecca 9, I-84084 Fisciano, SA (Italy); CNR-SPIN Salerno, Via Giovanni Paolo II, 132, Stecca 9, I-84084 Fisciano, SA (Italy); Grimaldi, G. [CNR-SPIN Salerno, Via Giovanni Paolo II, 132, Stecca 9, I-84084 Fisciano, SA (Italy); Nigro, A. [Physics Department E.R. Caianiello, University of Salerno, Via Giovanni Paolo II, 132, Stecca 9, I-84084 Fisciano, SA (Italy); CNR-SPIN Salerno, Via Giovanni Paolo II, 132, Stecca 9, I-84084 Fisciano, SA (Italy); Bruno, E.; Priolo, F. [Matis IMM-CNR and Physics-Astronomy Department, Catania University, CT 95123 (Italy); Pace, S. [Physics Department E.R. Caianiello, University of Salerno, Via Giovanni Paolo II, 132, Stecca 9, I-84084 Fisciano, SA (Italy); CNR-SPIN Salerno, Via Giovanni Paolo II, 132, Stecca 9, I-84084 Fisciano, SA (Italy)

    2014-08-15

    Highlights: • We analyzed the effect of light ion irradiation on weak pinning superconductors. • We found the light ion irradiation has a strong impact on current currying stability. • We compared the results to the ones of the case of moderate strong pinning materials. - Abstract: The current carrying dissipative state well above the critical current it is known to be related to the pinning properties of the material and to the microscopic mechanisms of vortex dynamics. Moreover, it has been demonstrated that in low temperature superconducting films exhibiting moderately strong pinning the light ion irradiation has the effect of changing the distribution of the pinning centers without changing their pinning strength and this results into an increase of current stability in the flux flow state. Here we present the results of light ion irradiation on weak pinning superconducting films focusing on the influence of pinning properties of the material in the flux flow state. We realize that the possibility to switch to low dissipations by changing weak pinning is not straightforward.

  4. Aspects of passive magnetic levitation based on high-T(sub c) superconducting YBCO thin films

    Science.gov (United States)

    Schoenhuber, P.; Moon, F. C.

    1995-01-01

    Passive magnetic levitation systems reported in the past were mostly confined to bulk superconducting materials. Here we present fundamental studies on magnetic levitation employing cylindrical permanent magnets floating above high-T(sub c) superconducting YBCO thin films (thickness about 0.3 mu m). Experiments included free floating rotating magnets as well as well-established flexible beam methods. By means of the latter, we investigated levitation and drag force hysteresis as well as magnetic stiffness properties of the superconductor-magnet arrangement. In the case of vertical motion of the magnet, characteristic high symmetry of repulsive (approaching) and attractive (withdrawing) branches of the pronounced force-displacement hysteresis could be detected. Achievable force levels were low as expected but sufficient for levitation of permanent magnets. With regard to magnetic stiffness, thin films proved to show stiffness-force ratios about one order of magnitude higher than bulk materials. Phenomenological models support the measurements. Regarding the magnetic hysteresis of the superconductor, the Irie-Yamafuji model was used for solving the equation of force balance in cylindrical coordinates allowing for a macroscopic description of the superconductor magnetization. This procedure provided good agreement with experimental levitation force and stiffness data during vertical motion. For the case of (lateral) drag force basic qualitative characteristics could be recovered, too. It is shown that models, based on simple asymmetric magnetization of the superconductor, describe well asymptotic transition of drag forces after the change of the magnet motion direction. Virgin curves (starting from equilibrium, i.e. symmetric magnetization) are approximated by a linear approach already reported in literature only. This paper shows that basic properties of superconducting thin films allow for their application to magnetic levitation or - without need of levitation

  5. Aspects of passive magnetic levitation based on high-T(sub c) superconducting YBCO thin films

    Science.gov (United States)

    Schoenhuber, P.; Moon, F. C.

    1995-04-01

    Passive magnetic levitation systems reported in the past were mostly confined to bulk superconducting materials. Here we present fundamental studies on magnetic levitation employing cylindrical permanent magnets floating above high-T(sub c) superconducting YBCO thin films (thickness about 0.3 mu m). Experiments included free floating rotating magnets as well as well-established flexible beam methods. By means of the latter, we investigated levitation and drag force hysteresis as well as magnetic stiffness properties of the superconductor-magnet arrangement. In the case of vertical motion of the magnet, characteristic high symmetry of repulsive (approaching) and attractive (withdrawing) branches of the pronounced force-displacement hysteresis could be detected. Achievable force levels were low as expected but sufficient for levitation of permanent magnets. With regard to magnetic stiffness, thin films proved to show stiffness-force ratios about one order of magnitude higher than bulk materials. Phenomenological models support the measurements. Regarding the magnetic hysteresis of the superconductor, the Irie-Yamafuji model was used for solving the equation of force balance in cylindrical coordinates allowing for a macroscopic description of the superconductor magnetization. This procedure provided good agreement with experimental levitation force and stiffness data during vertical motion. For the case of (lateral) drag force basic qualitative characteristics could be recovered, too. It is shown that models, based on simple asymmetric magnetization of the superconductor, describe well asymptotic transition of drag forces after the change of the magnet motion direction. Virgin curves (starting from equilibrium, i.e. symmetric magnetization) are approximated by a linear approach already reported in literature only. This paper shows that basic properties of superconducting thin films allow for their application to magnetic levitation or - without need of levitation

  6. Observations of flux motion in niobium films. [study of magnetic field trapped in superconducting coatings of gyroscope rotor

    Science.gov (United States)

    Xiao, Y. M.; Keiser, G. M.

    1991-01-01

    A magnetic field trapped in a superconducting sphere was examined at temperatures from 4.6 K to 5.5 K. The sphere was the rotor of a precision gyroscope and was made of fused quartz and coated with a sputtered niobium film. The rotor diameter was 3.8 cm. The film thickness was 2.5 microns. The tests were carried out at an ambient magnetic field of about 1 mG. Unexpected instability of the trapped field was observed. The experimental results and possible explanations are presented.

  7. Superconducting thin films of BiSrCaCuO made by sequential electron beam evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Steinbeck, J.; Anderson, A.C.; Tsauer, B.Y.; Strauss, A.J.

    1989-03-01

    Superconducting thin films of Bi/sub 2/Sr/sub 2/Ca/sub 1/Cu/sub 2/O/sub x/ have been made by sequential electron-beam evaporation of multiple layers of Bi and Cu metals and (Sr,Ca)F/sub 2/ on MgO substrates. The films were annealed at high temperature, first in wet O/sub 2/ and then in dry O/sub 2/, and cooled to room temperature in dry O/sub 2/. The resulting films which are -- 1 ..mu..m thick, have transition temperatures of -- 85 K. X-ray diffraction shows that the films are preferentially oriented with their c-axis perpendicular to the MgO substrate. The authors' best film has a zero-resistance temperature of 90 K and critical current densities of 8 x 10/sup 4/ A/cm/sup 2/ at 77 K and 2.5 x 10/sup 5/ A/cm/sup 2/ at 4.2 K.

  8. Thick-film materials for silicon photovoltaic cell manufacture

    Science.gov (United States)

    Field, M. B.

    1977-01-01

    Thick film technology is applicable to three areas of silicon solar cell fabrication; metallization, junction formation, and coating for protection of screened ohmic contacts, particularly wrap around contacts, interconnection and environmental protection. Both material and process parameters were investigated. Printed ohmic contacts on n- and p-type silicon are very sensitive to the processing parameters of firing time, temperature, and atmosphere. Wrap around contacts are easily achieved by first printing and firing a dielectric over the edge and subsequently applying a low firing temperature conductor. Interconnection of cells into arrays can be achieved by printing and cofiring thick film metal pastes, soldering, or with heat curing conductive epoxies on low cost substrates. Printed (thick) film vitreous protection coatings do not yet offer sufficient optical uniformity and transparency for use on silicon. A sprayed, heat curable SiO2 based resin shows promise of providing both optical matching and environmental protection.

  9. MEMS-based thick film PZT vibrational energy harvester

    DEFF Research Database (Denmark)

    Lei, Anders; Xu, Ruichao; Thyssen, Anders

    2011-01-01

    We present a MEMS-based unimorph silicon/PZT thick film vibrational energy harvester with an integrated proof mass. We have developed a process that allows fabrication of high performance silicon based energy harvesters with a yield higher than 90%. The process comprises a KOH etch using a mechan......We present a MEMS-based unimorph silicon/PZT thick film vibrational energy harvester with an integrated proof mass. We have developed a process that allows fabrication of high performance silicon based energy harvesters with a yield higher than 90%. The process comprises a KOH etch using...... a mechanical front side protection of an SOI wafer with screen printed PZT thick film. The fabricated harvester device produces 14.0 μW with an optimal resistive load of 100 kΩ from 1g (g=9.81 m s-2) input acceleration at its resonant frequency of 235 Hz....

  10. High-Tc superconductivity in ultrathin Bi2Sr2CaCu2O(8+x) down to half-unit-cell thickness by protection with graphene.

    Science.gov (United States)

    Jiang, Da; Hu, Tao; You, Lixing; Li, Qiao; Li, Ang; Wang, Haomin; Mu, Gang; Chen, Zhiying; Zhang, Haoran; Yu, Guanghui; Zhu, Jie; Sun, Qiujuan; Lin, Chengtian; Xiao, Hong; Xie, Xiaoming; Jiang, Mianheng

    2014-12-08

    High-Tc superconductors confined to two dimension exhibit novel physical phenomena, such as superconductor-insulator transition. In the Bi2Sr2CaCu2O(8+x) (Bi2212) model system, despite extensive studies, the intrinsic superconducting properties at the thinness limit have been difficult to determine. Here, we report a method to fabricate high quality single-crystal Bi2212 films down to half-unit-cell thickness in the form of graphene/Bi2212 van der Waals heterostructure, in which sharp superconducting transitions are observed. The heterostructure also exhibits a nonlinear current-voltage characteristic due to the Dirac nature of the graphene band structure. More interestingly, although the critical temperature remains essentially the same with reduced thickness of Bi2212, the slope of the normal state T-linear resistivity varies by a factor of 4-5, and the sheet resistance increases by three orders of magnitude, indicating a surprising decoupling of the normal state resistance and superconductivity. The developed technique is versatile, applicable to investigate other two-dimensional (2D) superconducting materials.

  11. Fabrication of FeSe superconducting films with chemical transport deposition process

    Science.gov (United States)

    Feng, J. Q.; Zhang, S. N.; Liu, J. X.; Hao, Q. B.; Li, C. S.; Zhang, P. X.

    2017-07-01

    FeSe Superconducting films were fabricated with a chemical transport deposition process. During the fabrication process, Fe foils were adopted as substrates and Se powders were put at one end of the tube furnace. During the heating process, Se powders were vaporized, and vaporized atoms were carried by Ar flow and deposited on the Fe substrates. With a heat treatment process under proper temperature, superconducting tetragonal β-FeSe phase can be obtained. The effects of key parameters, including the sintering temperatures and the distances between Fe substrates and Se source on the phase composition and morphology of the obtained films were systematically investigated. The superconducting transition temperature of 7.8 K was obtained on the optimized film. By further optimization of the heat treatment process, it is promising to fabricate FeSe films with higher superconducting phase content and better superconducting properties.

  12. High quality MgB{sub 2} thick films and large-area films fabricated by hybrid physical-chemical vapor deposition with a pocket heater

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S F; Chen, Ke; Li, Qi; Xi, X X [Department of Physics, Pennsylvania State University, University Park, PA 16802 (United States); Lee, C-H; Soukiassian, A; DeFrain, R; Redwing, J M; Schlom, D G [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Lamborn, D R [Department of Chemical Engineering, Pennsylvania State University, University Park, PA 16802 (United States)], E-mail: suw16@psu.edu

    2008-08-15

    A hybrid physical-chemical vapor deposition process using a pocket heater was developed for the growth of high quality epitaxial large-area MgB{sub 2} thin films and c-axis textured MgB{sub 2} thick films. This technique is able to independently control the substrate and Mg source temperatures and maintain sufficient Mg overpressure to ensure phase stability. The two-inch large-area MgB{sub 2} thin films showed uniform superconducting properties with the superconducting transition temperature T{sub c} of about 40 K, residual resistivity ratio (RRR) of about 10, and critical current density J{sub c} of about 10{sup 7} A cm{sup -2} (0 T, 5 K). The thick films ({approx}10 {mu}m) on sapphire substrates showed a maximum T{sub c} of 40 K and RRR of 15, and a J{sub c} of 1.6 x 10{sup 6} A cm{sup -2} at low applied magnetic fields even at 20 K. High quality thick films also have been obtained on metal substrates.

  13. Quasiparticle Transport in Thick Aluminum Films Coupled to Tungsten Transition Edge Sensors

    Science.gov (United States)

    Yen, J. J.; Kreikebaum, J. M.; Young, B. A.; Cabrera, B.; Moffatt, R.; Redl, P.; Shank, B.; Brink, P. L.; Cherry, M.; Tomada, A.

    2016-07-01

    We have fabricated and characterized test devices of a new geometry for cryogenic dark matter search superconducting sensors. The modified design uses the same photolithography masks used to fabricate earlier-generation devices, but with the Al and W films deposited in reverse order. This inverted film geometry (Al over W instead of our conventional W over Al) offers a simplified and robust way to dramatically increase the thickness of Al energy-collecting fins coupled to thin W-TESs—tungsten-transition edge sensors. Data are presented from experiments with inverted geometry test devices exposed to X-rays from a NaCl fluorescence source. The results are compared to data obtained with similar devices fabricated in the standard, non-inverted geometry.

  14. Grain size and film thickness effect on the thermal expansion coefficient of FCC metallic thin films.

    Science.gov (United States)

    Hwang, Seulgi; Kim, Youngman

    2011-08-01

    Thin films are used in wide range of applications in industry, such as solar cells and LEDs. When thin films are deposited on substrates, various stresses are generated due to the mechanical difference between the film and substrate. These stresses can cause defects, such as cracking and buckling. Therefore, knowledge of the mechanical properties is important for improving their reliability and stability. In this study, the thermal expansion coefficient of FCC metallic thin films, such as Ag and Cu, which have different grain sizes and thicknesses, were calculated using the thermal cycling method. As a result, thermal expansion coefficient increased with increasing grain size. However, the film thickness had no remarkable effect.

  15. High-throughput characterization of film thickness in thin film materials libraries by digital holographic microscopy.

    Science.gov (United States)

    Lai, Yiu Wai; Krause, Michael; Savan, Alan; Thienhaus, Sigurd; Koukourakis, Nektarios; Hofmann, Martin R; Ludwig, Alfred

    2011-10-01

    A high-throughput characterization technique based on digital holography for mapping film thickness in thin-film materials libraries was developed. Digital holographic microscopy is used for fully automatic measurements of the thickness of patterned films with nanometer resolution. The method has several significant advantages over conventional stylus profilometry: it is contactless and fast, substrate bending is compensated, and the experimental setup is simple. Patterned films prepared by different combinatorial thin-film approaches were characterized to investigate and demonstrate this method. The results show that this technique is valuable for the quick, reliable and high-throughput determination of the film thickness distribution in combinatorial materials research. Importantly, it can also be applied to thin films that have been structured by shadow masking.

  16. Fabrication of BIT thick films patterned by proton beam writing

    Science.gov (United States)

    Yamaguchi, Masaki; Watanabe, Kazuki; Nishikawa, Hiroyuki; Masuda, Yoichiro

    2017-07-01

    In this study, we fabricated thick films with polyvinylpyrrolidone (PVP) added to bismuth titanate (Bi4Ti3O12) to form a lead-free ferroelectric material. We examined the direct patterning of these materials by using proton-beam irradiation. When 50% PVP was added to the organic source solution, the c-axis orientation was promoted and cracks were suppressed due to stress relaxation. In addition, a dot and an arbitrary-shape micro-pattern were formed on bismuth-titanate thick film by micromachining using a proton beam.

  17. Electroplated thick-film cobalt platinum permanent magnets

    Science.gov (United States)

    Oniku, Ololade D.; Qi, Bin; Arnold, David P.

    2016-10-01

    The material and magnetic properties of multi-micron-thick (up to 6 μm) L10 CoPt magnetic films electroplated onto silicon substrates are investigated as candidate materials for integration in silicon-based microsystems. The influence of various process conditions on the structure and magnetic properties of electroplated CoPt thick-films is studied in order to better understand the complex process/structure/property relationships associated with the electroplated films. Process variables studied here include different seed layers, electroplating current densities (ranging from 25-200 mA/cm2), deposition times (up to 60 min), and post-deposition annealing times and temperatures. Analyses include film morphology, film thickness, composition, surface roughness, grain size, phase volume fractions, and L10 ordering parameter. Key correlations are found relating process and structure variations to the extrinsic magnetic properties (remanence, coercivity, squareness, and energy product). Strong hard magnetic properties (Br ~0.8 T, Hci ~800 kA/m, squareness close to 0.9, and BHmax of 100 kJ/m3) are obtained for films deposited on Si/TiN/Ti/Cu at current densities of 100 mA/cm2, pH of 7, and subsequently annealed at 675 °C for 30 min.

  18. Proximity effect of iron-based superconductor in conventional s-wave superconducting thin films

    Science.gov (United States)

    Groll, Nick; Proslier, Thomas; Koshelev, Alex; Stantev, Valentin; Chung, Duck-Young

    2012-02-01

    The proximity effect has been proposed as a mechanism to unambiguously identify the possible s±-state in iron-based superconductors.ootnotetextA. E. Koshelev, V. Stanev, Europhysics Letters, Vol. 96, 27014 (2011) With a thin s-wave superconductor atop a s±-superconductor it is suggested that the s-wave order parameter will couple to the s±-gaps differently, inducing a correction to the s-wave density of states that can be probed using electron tunneling spectroscopy. In this talk, we will present recent results of the superconducting proximity effect in s-wave MoGe thin films sputtered on top of bulk superconducting Ba0.6K0.4Fe2As2 (Tc=35K) pnictide. Electron tunneling spectroscopy measurements were performed for several MoGe film thicknesses using a homemade point contact setup. Finally, results will also be presented for similar measurements using two conventional s-wave superconductors.

  19. Analysis of the proximity function in electron-beam lithography on high-? superconducting thin-films

    Science.gov (United States)

    Gueorguiev, Y. M.; Vutova, K. G.; Mladenov, G. M.

    1996-07-01

    In this paper we approximate by the combination of double Gaussian and exponential functions the radial distributions of the absorbed electron energy density in a 125 nm PMMA resist layer on 0953-2048/9/7/009/img2 thin-film/substrate targets obtained by means of Monte Carlo simulation for a zero-width 0953-2048/9/7/009/img3-function and the following variables (i) the substrate material (0953-2048/9/7/009/img4 and MgO), (ii) the electron beam energy 0953-2048/9/7/009/img5 (25, 50 and 75 keV) and (iii) the 0953-2048/9/7/009/img2 film thickness d (0, 100, 200 and 300 nm). The values of the parameters of the analytical function are calculated using an original Monte Carlo technique. These values are presented in the form of 3D diagrams which show their dependences on beam energy and on high-temperature superconducting film thickness and can also be used for approximate determination of the parameters at different initial conditions.

  20. Superconducting YBCO thin film on multicrystalline Ag film evaporated on MgO substrate

    Science.gov (United States)

    Azoulay, Jacob; Verdyan, Armen; Lapsker, Igor

    Superconducting YBa 2Cu 3O 7-δ films were grown by resistive evaporation on multicrystalline silver film which was evaporated on MgO substrate. A simple inexpensive vacuum system equipped with resistively heated boat was used for the whole process. Silver film was first evaporated on MgO substrate kept at 400°C during the evaporation after which with no further annealing a precursor mixture of yttrium small grains and Cu and BaF2 in powder form weighed in the atomic proportion to yield stoichiometric YBa 2Cu 3O 7 was evaporated. The films thus obtained were annealed at 740°C under low oxygen partial pressure of about 1Pa for 30 minutes to form the superconducting phase. X-ray diffraction and scanning electron microscopy techniques were used for texture and surface analysis. Electrical properties were determined using a standard dc four-probe for electrical measurements. The physical and electrical properties of the YBCO films are discussed in light of the fact that X-ray diffraction measurements done on the silver film have revealed a multicrystalline structure

  1. The thickness dependence of dielectric permittivity in thin films

    Science.gov (United States)

    Starkov, Ivan A.; Starkov, Alexander S.

    2016-08-01

    It is well known that the physical properties of thin films depend on their thickness. For a description of such dependences, it is proposed to use a classical model taking into account the presence of film interfaces. A dielectric ball near the half-space was chosen to adopt the approach. The dependence of the effective permittivity of the ball on geometrical and physical parameters of the system is analyzed. It is demonstrated that the dielectric constant of a film can be presented as a sum of the constant of a bulk material and the interface term.

  2. Superconducting niobium nitride films deposited by unbalanced magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Olaya, J.J. [Departamento de Ingenieria Mecanica y Mecatronica, Universidad Nacional de Colombia, Ciudad Universitaria, Carrera 30 Numero 45-03, Bogota (Colombia); Huerta, L. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito exterior s/n, CU Coyoacan, Mexico D.F. 04510 (Mexico); Rodil, S.E. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito exterior s/n, CU Coyoacan, Mexico D.F. 04510 (Mexico)], E-mail: ser42@iim.unam.mx; Escamilla, R. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito exterior s/n, CU Coyoacan, Mexico D.F. 04510 (Mexico)

    2008-10-01

    Niobium nitride (NbN) thin films were deposited under different configurations of the magnetic field using a magnetron sputtering system. The magnetic field configuration varied from balanced to unbalanced leading to different growth conditions and film properties. The aim of the paper was to identify correlations between deposition conditions, film properties and the electrical properties, specially the superconductive critical temperature (T{sub C}). The results suggested that there is a critical deposition condition, having an optimum ion-atom arrival ratio that promotes a well ordered and textured nanocrystalline structure (cubic phase) with the minimum residual stress and only under this condition a high critical temperature (16K) was obtained. Lower T{sub C} values around 12K were obtained for the NbN samples having a lower degree of structural perfection and texture, and a larger fraction of intergranular voids. On the other hand, analysis of valence-band spectra showed that the contribution of the Nb 4d states remained essentially constant while the higher T{sub C} was correlated to a higher contribution of the N 2p states.

  3. Fault Current Limitation with Superconducting YBCO Thin Films

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The behavior of YBCO/metal bilayers under transport currents was explored in the framework of fault current limitation (FCL). Properties of the superconducting-normal transition were first studied phenomenologically during sweep current experiments. For current rates higher than 500 A/s, the transition into the normal state was based on non-thermal phenomena and was characterized by a flux creep regime ended by a jump into the normal state. At lower sweep rates, a total diversion of the current in the metallic shunt was observed for temperatures higher than 85 K. In this regime, a partial recovery of the superconducting state took place due to a finite thermal resistance between the superconductingand the metallic films. These two properties of partial diversion into the shunt and of fast switching for a quick rise of the current during a default were exploited for current limitation at 77 K. FCL experiments at 50 Hz show that YBCO/Au bilayers limit the current in about 1 ms at a valueof 2.5Ic by developing electrical fields as high as 3 kV/m. Moreover, a recovery of the zero resistance state could occur under rated mode. A straightforward application of this property would be the transformer connection. Finally, results on DC current limitation and recovery under nominal mode were presented for the first time.

  4. Screen printed thick film based pMUT arrays

    DEFF Research Database (Denmark)

    Hedegaard, Tobias; Pedersen, T; Thomsen, Erik Vilain;

    2008-01-01

    This article reports on the fabrication and characterization of lambda-pitched piezoelectric micromachined ultrasound transducer (pMUT) arrays fabricated using a unique process combining conventional silicon technology and low cost screen printing of thick film PZT. The pMUTs are designed as 8...

  5. MEMS Accelerometer with Screen Printed Piezoelectric Thick Film

    DEFF Research Database (Denmark)

    Hindrichsen, Christian Carstensen; Lau-Moeller, R.; Bove, T.

    2006-01-01

    A bulk-micromachined piezoelectric MEMS accelerometer with screen printed piezoelectric Pb(ZrxTil )O3(PZT) thick film (TF) as the sensing material has been fabricated and characterized. The accelerometer has a four beam structure with a central seismic mass (3600x3600x500 pm3) and a total chip size...

  6. Shearing Nanometer-Thick Confined Hydrocarbon Films: Friction and Adhesion

    DEFF Research Database (Denmark)

    Sivebæk, I. M.; Persson, B. N. J.

    2016-01-01

    We present molecular dynamics (MD) friction and adhesion calculations for nanometer-thick confined hydrocarbon films with molecular lengths 20, 100 and 1400 carbon atoms. We study the dependency of the frictional shear stress on the confining pressure and sliding speed. We present results...

  7. Presentation and characterization of novel thick-film PZT microactuators

    Energy Technology Data Exchange (ETDEWEB)

    Chalvet, Vincent; Habineza, Didace, E-mail: didace.habineza@femto-st.fr; Rakotondrabe, Micky; Clévy, Cédric

    2016-04-01

    We propose in this paper the characterization of a new generation of piezoelectric cantilevers called thick-films piezoelectric actuators. Based on the bonding and thinning process of a bulk PZT layer onto a silicon layer, these cantilevers can provide better static and dynamic performances compared to traditional piezocantilevers, additionally to the small dimensions.

  8. Screen-printed piezoceramic thick films for miniaturised devices

    DEFF Research Database (Denmark)

    Lou-Moeller, R.; Hindrichsen, Christian Carstensen; Thamdrup, Lasse Højlund;

    2007-01-01

    The development towards smaller devices with more functions integrated calls for new and improved manufacturing processes. The screen-printing process is quite well suited for miniaturised and integrated devices, since thick films can be produced in this manner without the need for further machin...

  9. Triaxial MEMS accelerometer with screen printed PZT thick film

    DEFF Research Database (Denmark)

    Hindrichsen, Christian Carstensen; Almind, Ninia Sejersen; Brodersen, Simon Hedegaard

    2010-01-01

    . In this work integration of a screen printed piezoelectric PZT thick film with silicon MEMS technology is shown. A high bandwidth triaxial accelerometer has been designed, fabricated and characterized. The voltage sensitivity is 0.31 mV/g in the vertical direction, 0.062 mV/g in the horizontal direction...

  10. Polymer thick-film sensors: possibilities for smartcard biometrics

    NARCIS (Netherlands)

    Henderson, N.J.; Papakostas, T.V.; White, N.M.; Hartel, P.H.

    2002-01-01

    In this paper the potential of polymer thick-film sensors are assessed for use as biometric sensors on smartcards. Piezoelectric and piezoresistive sensors have been printed on flexible polyester, then bonded to smartcard blanks. The tactile interaction of a person with these sensors has been invest

  11. Relaxation in Thin Polymer Films Mapped across the Film Thickness by Astigmatic Single-Molecule Imaging

    KAUST Repository

    Oba, Tatsuya

    2012-06-19

    We have studied relaxation processes in thin supported films of poly(methyl acrylate) at the temperature corresponding to 13 K above the glass transition by monitoring the reorientation of single perylenediimide molecules doped into the films. The axial position of the dye molecules across the thickness of the film was determined with a resolution of 12 nm by analyzing astigmatic fluorescence images. The average relaxation times of the rotating molecules do not depend on the overall thickness of the film between 20 and 110 nm. The relaxation times also do not show any dependence on the axial position within the films for the film thickness between 70 and 110 nm. In addition to the rotating molecules we observed a fraction of spatially diffusing molecules and completely immobile molecules. These molecules indicate the presence of thin (<5 nm) high-mobility surface layer and low-mobility layer at the interface with the substrate. (Figure presented) © 2012 American Chemical Society.

  12. Effect of Film Thickness on Properties of a-Si∶H Films

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The a-Si∶H films with different thickness smaller than 1μm were deposited by plasma enhanced chemical vapor deposition (PECVD) under the optimum deposition conditions. The effect of different thickness on film properties is analyzed.The results show that,with the increase of the film thickness,the dark conductivity, photoconductivity and threshold voltage increase, the optical gap and peak ratio of TA to TO in the Raman spectra decrease, the refractive index keeps almost constant, and the optical absorption coefficient and current ratio of on/off state first maximize and then reduce.

  13. Film-thickness dependence of structure formation in ultra-thin polymer blend films

    CERN Document Server

    Gutmann, J S; Stamm, M

    2002-01-01

    We investigated the film-thickness dependence of structure formation in ultra-thin polymer blend films prepared from solution. As a model system we used binary blends of statistical poly(styrene-co-p-bromostyrene) copolymers of different degrees of bromination. Ultra-thin-film samples differing in miscibility and film thickness were prepared via spin coating of common toluene solutions onto silicon (100) substrates. The resulting morphologies were investigated with scanning force microscopy, reflectometry and grazing-incidence scattering techniques using both X-rays and neutrons in order to obtain a picture of the sample structure at and below the sample surface. (orig.)

  14. Influence of substrate and film thickness on polymer LIPSS formation

    Science.gov (United States)

    Cui, Jing; Nogales, Aurora; Ezquerra, Tiberio A.; Rebollar, Esther

    2017-02-01

    Here we focus on the influence of both, substrate and film thickness on polymer Laser Induced Periodic Surface Structures (LIPSS) formation in polymer films. For this aim a morphological description of ripples structures generated on spin-coated polystyrene (PS) films by a linearly polarized laser beam with a wavelength of 266 nm is presented. The influence of different parameters on the quality and characteristics of the formed laser-induced periodic surface structures (LIPSS) was investigated. We found that well-ordered LIPSS are formed either on PS films thinner than 200 nm or thicker than 400 nm supported on silicon substrates as well as on thicker free standing films. However less-ordered ripples are formed on silicon supported films with intermediate thicknesses in the range of 200-380 nm. The effect of the thermal and optical properties of the substrate on the quality of LIPSS was analyzed. Differences observed in the fluence and number of pulses needed for the onset of surface morphological modifications is explained considering two main effects which are: (1) The temperature increase on polymer surface induced by the action of cumulative laser irradiation and (2) The differences in thermal conductivity between the polymer and the substrate which strongly affect the heat dissipation generated by irradiation.

  15. Growth of YBCO superconducting thin films on CaF sub 2 buffered silicon

    CERN Document Server

    Bhagwat, S S; Patil, J M; Shirodkar, V S

    2000-01-01

    CaF sub 2 films were grown on silicon using the neutral cluster beam deposition technique. These films were highly crystalline and c-axis oriented. Superconducting YBCO thin films were grown on the Ca F sub 2 buffered silicon using the laser ablation technique. These films showed T sub c (onset) at 90 K and Tc(zero) at 86 K. X-ray diffraction analysis showed that the YBCO films were also oriented along the c-axis.

  16. Experimental evidence of non-linear behaviour in YBCO superconducting thin films

    Energy Technology Data Exchange (ETDEWEB)

    Palenque, E.R.; Appleyard, N.J.; Jackson, T.J.; Palmer, S.B. [Dept. of Phys., Warwick Univ., Coventry (United Kingdom)

    1995-05-01

    Preliminary measurements of the non-linear dynamics of a thin (two dimensional) YBa{sub 2}Cu{sub 3}O{sub 7} superconducting film in a small AC magnetic field are presented, a peak in third harmonic generation which may provide evidence of the Kosterlitz-Thouless transition is found just below the superconducting transition temperature. (author)

  17. Superconducting thin films of (100) and (111) oriented indium doped topological crystalline insulator SnTe

    Energy Technology Data Exchange (ETDEWEB)

    Si, Weidong, E-mail: wds@bnl.gov, E-mail: qiangli@bnl.gov; Zhang, Cheng; Wu, Lijun; Ozaki, Toshinori; Gu, Genda; Li, Qiang, E-mail: wds@bnl.gov, E-mail: qiangli@bnl.gov [Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)

    2015-08-31

    Recent discovery of the topological crystalline insulator SnTe has triggered a search for topological superconductors, which have potential application to topological quantum computing. The present work reports on the superconducting properties of indium doped SnTe thin films. The (100) and (111) oriented thin films were epitaxially grown by pulsed-laser deposition on (100) and (111) BaF{sub 2} crystalline substrates, respectively. The onset superconducting transition temperatures are about 3.8 K for (100) and 3.6 K for (111) orientations, slightly lower than that of the bulk. Magneto-resistive measurements indicate that these thin films may have upper critical fields higher than that of the bulk. With large surface-to-bulk ratio, superconducting indium doped SnTe thin films provide a rich platform for the study of topological superconductivity and potential device applications based on topological superconductors.

  18. Anisotropic resistivity in plasma-sprayed silicon thick films

    Science.gov (United States)

    Kharas, Boris Dave; Sampath, Sanjay; Gambino, Richard J.

    2005-05-01

    Silicon thick films deposited by thermal plasma spray are of interest as inexpensive electronic materials for conformal meso-scale electronics applications. In addition they also serve as a model system for the investigation of electrical properties of coatings with layered anisotropy. In this study impedance spectroscopy was used to measure the complex resistivity of free-standing 64μm-thick polycrystalline silicon films deposited by thermal plasma spraying in an atmospheric ambient. Impedance spectroscopy measurements were taken in the through-thickness (across-splat) and edge-to-edge (in-splat) directions and revealed a resistivity difference of approximately 7.5±0.23 between the two directions. The complex resistivity results are explained on the basis of a brick-layer type model, associated with the layered splat microstructure obtained from cross-sectional transmission electron microscope imaging of the films. In addition a circuit-based model made up of parallel, resistor-capacitor elements in series, and Cole-Cole and Davidson-Cole impedance functions were used to fit the impedance data to extract material parameters and contributions from the grains and splat boundaries. Furthermore, thermal processing and phosphorus doping is shown to lead to higher and lower resistivity, respectively, in the films.

  19. Effects of thickness on electronic structure of titanium thin films

    Indian Academy of Sciences (India)

    Güvenç Akgül

    2014-02-01

    Effects of thickness on the electronic structure of e-beam evaporated thin titanium films were studied using near-edge X-ray absorption fine structure (NEXAFS) technique at titanium 2,3 edge in total electron yield (TEY) mode and transmission yield mode. Thickness dependence of 2,3 branching ratio (BR) of titanium was investigated and it was found that BR below 3.5 nm shows a strong dependence on film thickness. Mean electron escape depth () in titanium, an important parameter for surface applications, was determined to be = 2.6 ± 0.1 nm using 2,3 resonance intensity variation as a function of film thickness. The average 3/2 white line intensity ratio of titanium was obtained as 0.89 from the ratio of amplitudes of each 3 and 2 peaks and 0.66 from the integrated area under each 3 and 2 peaks. In addition, a theoretical calculation for pure titanium was presented for comparison with experimental data.

  20. Superconductivity

    CERN Document Server

    Poole, Charles P; Farach, Horacio A

    1995-01-01

    Superconductivity covers the nature of the phenomenon of superconductivity. The book discusses the fundamental principles of superconductivity; the essential features of the superconducting state-the phenomena of zero resistance and perfect diamagnetism; and the properties of the various classes of superconductors, including the organics, the buckministerfullerenes, and the precursors to the cuprates. The text also describes superconductivity from the viewpoint of thermodynamics and provides expressions for the free energy; the Ginzburg-Landau and BCS theories; and the structures of the high

  1. Effect of film thickness on microstructure parameters and optical constants of CdTe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Shaaban, E.R., E-mail: esam_ramadan2008@yahoo.co [Physics Department, Faculty of Science, Qassim University, Buridah 51452 (Saudi Arabia); Physics Department, Faculty of Science, Al-Azhar University, Assiut, P.O. 71452 (Egypt); Afify, N. [Physics Department, Assiut University, Assiut (Egypt); El-Taher, A. [Physics Department, Faculty of Science, Qassim University, Buridah 51452 (Saudi Arabia); Physics Department, Faculty of Science, Al-Azhar University, Assiut, P.O. 71452 (Egypt)

    2009-08-12

    Different thickness of cadmium telluride (CdTe) thin films was deposited onto glass substrates by the thermal evaporation technique. Their structural characteristics were studied by X-ray diffraction (XRD). The XRD experiments showed that the films are polycrystalline and have a zinc-blende (cubic) structure. The microstructure parameters, crystallite size and microstrain were calculated. It is observed that the crystallite size increases and microstrain decreases with the increase in the film thickness. The fundamental optical parameters like band gap and extinction coefficient are calculated in the strong absorption region of transmittance and reflectance spectrum. The possible optical transition in these films is found to be allowed direct transition with energy gap increase from 1.481 to 1.533 eV with the increase in the film thickness. It was found that the optical band gap increases with the increase in thickness. The refractive indices have been evaluated in transparent region in terms of envelope method, which has been suggested by Swanepoul in the transparent region. The refractive index can be extrapolated by Cauchy dispersion relationship over the whole spectral range, which extended from 400 to 2500 nm. It is observed that the refractive index, n increases on increasing the film thickness up to 671 nm and then the variation of n with higher thickness lie within the experimental errors.

  2. Chemical vapor deposition reactor. [providing uniform film thickness

    Science.gov (United States)

    Chern, S. S.; Maserjian, J. (Inventor)

    1977-01-01

    An improved chemical vapor deposition reactor is characterized by a vapor deposition chamber configured to substantially eliminate non-uniformities in films deposited on substrates by control of gas flow and removing gas phase reaction materials from the chamber. Uniformity in the thickness of films is produced by having reactive gases injected through multiple jets which are placed at uniformally distributed locations. Gas phase reaction materials are removed through an exhaust chimney which is positioned above the centrally located, heated pad or platform on which substrates are placed. A baffle is situated above the heated platform below the mouth of the chimney to prevent downdraft dispersion and scattering of gas phase reactant materials.

  3. Different approaches to generate matching effects using arrays in contact with superconducting films.

    Science.gov (United States)

    del Valle, J.; Gomez, A.; Luis-Hita, J.; Rollano, V.; Gonzalez, E. M.; Vicent, J. L.

    2017-02-01

    Superconducting films in contact with non-superconducting regular arrays can exhibit commensurability effects between the vortex lattice and the unit cell of the pinning array. These matching effects yield a slowdown of the vortex flow and the corresponding dissipation decrease. The superconducting samples are Nb films grown on Si substrates. We have studied these matching effects with the array on top, embedded or threading the Nb superconducting films and using different materials (Si, Cu, Ni, Py dots and dots fabricated with Co/Pd multilayers). These hybrids allow for studying the contribution of different pinning potentials to the matching effects. The main findings are: (i) Periodic roughness induced in the superconducting film is enough to generate resistivity minima; (ii) A minor effect is achieved by magnetic pinning from periodic magnetic field potentials obtained by dots with out of plane magnetization grown on top of the superconducting film, (iii) In the case of array of magnetic dots embedded in the films, vortex flow probes the magnetic state; i.e. magnetoresistance measurements detect the magnetic state of very small nanomagnets. In addition, we have studied the role played by the local order in the commensurability effects. This was attained using an array that mimics a smectic crystal. We have found that preserving the local order is crucial. If the local order is not retained the magnetoresistance minima vanish.

  4. Thickness-Dependent Properties of YBCO Films Grown on GZO/CLO-Buffered NiW Substrates

    Science.gov (United States)

    Malmivirta, M.; Huhtinen, H.; Zhao, Y.; Grivel, J.-C.; Paturi, P.

    2017-01-01

    To study the role of novel Gd_2Zr_2O_7/Ce_{0.9}La_{0.1}O_2 buffer layer structure on a biaxially textured NiW substrate, a set of YBa_2Cu_3O_{7-δ } (YBCO) films with different thicknesses were prepared by pulsed laser deposition (PLD). Interface imperfections as well as thickness-dependent structural properties were observed in the YBCO thin films. The structure is also reflected into the improved superconducting properties with the highest critical current densities in films with intermediate thicknesses. Therefore, it can be concluded that the existing buffer layers need more optimization before they can be successfully used for films with various thicknesses. This issue is linked to the extremely susceptible growth method of PLD when compared to the commonly used chemical deposition methods. Nevertheless, PLD-grown films can give a hint on what to concentrate to be able to further improve the buffer layer structures for future coated conductor technologies.

  5. l/f Noise in the Superconducting Transition of a MgB2 Thin Film

    Science.gov (United States)

    Lakew, B.; Aslam, S.; Jones, H.; Stevenson, T.; Cao, N.

    2010-01-01

    The noise voltage spectral density in the superconducting transition of a MgB2 thin film on a SiN-coated Si thick substrate was measured over the frequency range 1 Hz-to-1 KHz. Using established bolometer noise theory the theoretical noise components due to Johnson, 1/f(excess) and phonon noise are modeled to the measured data. It is shown that for the case of a MgB2 thin film in the vicinity of the mid-point of transition, coupled to a heat sink via a fairly high thermal conductance (approximately equal to 10(sup -1) W/K)) that the measured noise voltage spectrum is 1/f limited and exhibits lit dependence with a varying between 0.3 and 0.5 in the measured frequency range. At a video frame rate frequency of 30 Hz the measured noise voltage density in the film is approximately equal to 61 nV /the square root of HZ, using this value an upper limit of electrical NEP approximately equal to 0.67pW / the square root of Hz is implied for a practical MgB2 bolometer operating at 36.1 K.

  6. Thickness-dependent coherent phonon frequency in ultrathin FeSe/SrTiO3 films

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Shuolong [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); Sobota, Jonathan A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Leuenberger, Dominik [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); Kemper, Alexander F. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lee, James J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); Schmitt, Felix T. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); Li, Wei [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); Moore, Rob G. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); Kirchmann, Patrick S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Shen, Zhi -Xun [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States)

    2015-06-01

    Ultrathin FeSe films grown on SrTiO3 substrates are a recent milestone in atomic material engineering due to their important role in understanding unconventional superconductivity in Fe-based materials. By using femtosecond time- and angle-resolved photoelectron spectroscopy, we study phonon frequencies in ultrathin FeSe/SrTiO3 films grown by molecular beam epitaxy. After optical excitation, we observe periodic modulations of the photoelectron spectrum as a function of pump–probe delay for 1-unit-cell, 3-unit-cell, and 60-unit-cell thick FeSe films. The frequencies of the coherent intensity oscillations increase from 5.00 ± 0.02 to 5.25 ± 0.02 THz with increasing film thickness. By comparing with previous works, we attribute this mode to the Se A1g phonon. The dominant mechanism for the phonon softening in 1-unit-cell thick FeSe films is a substrate-induced lattice strain. Results demonstrate an abrupt phonon renormalization due to a lattice mismatch between the ultrathin film and the substrate.

  7. Depairing current density through a low-angle grain boundary in a superconducting film

    Directory of Open Access Journals (Sweden)

    Feng Xue

    2016-05-01

    Full Text Available In this paper, the effect of a grain boundary (GB on the depairing current density of a high-temperature superconducting film is investigated. The modified effective free energy is proposed by considering the interaction of the superconducting condensate with the deformation of the superconductor due to the dislocations which constitute a grain boundary. After the elastic strain field of the dislocation is obtained, we analyzed the depress effect of the GB on the depairing current density of a superconducting film. The results are qualitatively agreement with the classic exponential relationship with the misorientation angles of the critical current density of high-temperature superconductors.

  8. Discrete component bonding and thick film materials study

    Science.gov (United States)

    Kinser, D. L.

    1975-01-01

    The results are summarized of an investigation of discrete component bonding reliability and a fundamental study of new thick film resistor materials. The component bonding study examined several types of solder bonded components with some processing variable studies to determine their influence upon bonding reliability. The bonding reliability was assessed using the thermal cycle: 15 minutes at room temperature, 15 minutes at +125 C 15 minutes at room temperature, and 15 minutes at -55 C. The thick film resistor materials examined were of the transition metal oxide-phosphate glass family with several elemental metal additions of the same transition metal. These studies were conducted by preparing a paste of the subject composition, printing, drying, and firing using both air and reducing atmospheres. The resulting resistors were examined for adherence, resistance, thermal coefficient of resistance, and voltage coefficient of resistance.

  9. Electric field-induced superconducting transition of insulating FeSe thin film at 35 K.

    Science.gov (United States)

    Hanzawa, Kota; Sato, Hikaru; Hiramatsu, Hidenori; Kamiya, Toshio; Hosono, Hideo

    2016-04-12

    It is thought that strong electron correlation in an insulating parent phase would enhance a critical temperature (Tc) of superconductivity in a doped phase via enhancement of the binding energy of a Cooper pair as known in high-Tc cuprates. To induce a superconductor transition in an insulating phase, injection of a high density of carriers is needed (e.g., by impurity doping). An electric double-layer transistor (EDLT) with an ionic liquid gate insulator enables such a field-induced transition to be investigated and is expected to result in a high Tc because it is free from deterioration in structure and carrier transport that are in general caused by conventional carrier doping (e.g., chemical substitution). Here, for insulating epitaxial thin films (∼10 nm thick) of FeSe, we report a high Tc of 35 K, which is 4× higher than that of bulk FeSe, using an EDLT under application of a gate bias of +5.5 V. Hall effect measurements under the gate bias suggest that highly accumulated electron carrier in the channel, whose area density is estimated to be 1.4 × 10(15) cm(-2) (the average volume density of 1.7 × 10(21) cm(-3)), is the origin of the high-Tc superconductivity. This result demonstrates that EDLTs are useful tools to explore the ultimate Tc for insulating parent materials.

  10. A sensitive magnetic field sensor using BPSCCO thick film

    Indian Academy of Sciences (India)

    S Vijay Srinivas; Abhijit Ray; T K Dey

    2001-08-01

    A highly sensitive magnetic sensor operating at liquid nitrogen temperature and based on BPSCCO screen-printed thick film, is reported. The sensor resistance for an applied magnetic field of 100 × 10–4T(100 gauss) exhibits an increase by 360% of its value in zero field at 77.4 K. The performance of the sensor in presence of magnetic field, the hysteretic features and the effect of thermal cycling, has been discussed.

  11. High-performance PMN-PT thick films.

    Science.gov (United States)

    Kosec, Marija; Ursic, Hana; Holc, Janez; Hrovat, Marko; Kuscer, Danjela; Malic, Barbara

    2010-10-01

    This article describes some of our work on ₀.₆₅Pb(Mg₁/₃Nb(₂/₃)O₃-₀.₃₅PbTiO₃ (0.65PMN-0.35PT) thick films printed on alumina substrates. These thick films, with the nominal composition ₀.₆₅Pb(Mg₁/₃Nb(₂/₃)O₃-₀.₃₅PbTiO₃, were produced by screen-printing and firing a paste prepared from an organic vehicle and pre-reacted fine particles of avery chemically homogeneous powder. To improve the adhesion of the 0.65PMN-0.35PT to the platinized alumina substrate,a Pb(Zr₀.₅₃Ti₀.₄₇)O₃ layer was deposited between the electrode and the substrate. The samples were then sintered at 950 °C for 2 h with various amounts of packing powder on the alumina (Al₂O₃) substrates. The sintering procedure was optimized to obtain dense 0.65PMN-0.35PT films. The films were then characterized using scanning electron microscopy as well as measurements of the dielectric and piezoelectric constants.The electrostrictive behavior of the 0.65PMN-0.35PT thick films was investigated using an atomic force microscope(AFM). Finally, substrate-free, large-displacement bending type actuators were prepared and characterized, and the normalized displacement (i.e., the displacement per unit length) of the actuators was determined to be 55 μm/cm at 3.6 kV/cm.

  12. The Effect of Thickness of Aluminium Films on Optical Reflectance

    Directory of Open Access Journals (Sweden)

    Robert Lugolole

    2015-01-01

    Full Text Available In Uganda and Africa at large, up to 90% of the total energy used for food preparation and water pasteurization is from fossil fuels particularly firewood and kerosene which pollute the environment, yet there is abundant solar energy throughout the year, which could also be used. Uganda is abundantly rich in clay minerals such as ball clay, kaolin, feldspar, and quartz from which ceramic substrates were developed. Aluminium films of different thicknesses were deposited on different substrates in the diffusion pump microprocessor vacuum coater (Edwards AUTO 306. The optical reflectance of the aluminium films was obtained using a spectrophotometer (SolidSpec-3700/DUV-UV-VIS-NIR at various wave lengths. The analysis of the results of the study revealed that the optical reflectance of the aluminium films was above 50% and increased with increasing film thickness and wavelength. Thus, this method can be used to produce reflector systems in the technology of solar cooking and other appliances which use solar energy.

  13. Tape casting and partial melting of Bi-2212 thick films

    Energy Technology Data Exchange (ETDEWEB)

    Buhl, D.; Lang, T.; Heeb, B. [Nichtmetallische Werkstoffe, Zuerich (Switzerland)] [and others

    1994-12-31

    To produce Bi-2212 thick films with high critical current densities tape casting and partial melting is a promising fabrication method. Bi-2212 powder and organic additives were mixed into a slurry and tape casted onto glass by the doctor blade tape casting process. The films were cut from the green tape and partially molten on Ag foils during heat treatment. We obtained almost single-phase and well-textured films over the whole thickness of 20 {mu}m. The orientation of the (a,b)-plane of the grains were parallel to the substrate with a misalignment of less than 6{degrees}. At 77K/OT a critical current density of 15`000 A/cm{sup 2} was reached in films of the dimension 1cm x 2cm x 20{mu}m (1{mu}V/cm criterion, resistively measured). At 4K/OT the highest value was 350`000 A/cm{sup 2} (1nV/cm criterion, magnetically measured).

  14. High- T_c superconducting thin film/GaAs MESFET hybrid microwave oscillator

    Institute of Scientific and Technical Information of China (English)

    金飚兵; 康琳; 伍瑞新; 张健羽; 程其恒; 吴培亨; 经东; 焦刚; 邵凯; 蒋明明; 张家宗; 孙敏松; 王蕴仪; 周岳亮; 吕惠宾; 许世发; 何萌; 王小平; 杨秉川; 卢剑; 张其邵

    1997-01-01

    A high- Tc superconducting (HTSC) thin film/GaAs MESFET hybrid microwave oscillator operated at 10 6 GHz has been designed, fabricated and characterized. Microstrip line structures were used throughout the circuit with superconducting thin film YBaiCuiO7 8(YBCO) as the conductor material. The YBCO thin films were deposited on 15 mm×10 mm×0. 5 mm LaAlO3 substrates. The oscillator was common-source, series feedback type using a GaAs-MESFET (NE72084) as the active device and a superconducting microstrip resonator as the frequency stabilizing element. By improving the unloaded quality factor Q0 of the superconducting microstrip resonator and adjusting the coupling coefficient between the resonator and the gate of the MESFET, the phase noise of the oscillator was decreased At 77 K, the phase noise of the oscillator at 10 kHz offset from carrier was - 87 dBc/Hz.

  15. Properties of Superconducting Mo, Mo2n and Trilayer Mo2n-Mo-Mo2n Thin Films

    Science.gov (United States)

    Barrentine, E. M.; Stevenson, T. R.; Brown, A. D.; Lowitz, A. E.; Noroozian, O.; U-Yen, K.; Eshan, N.; Hsieh, W. T.; Moseley, S. H.; Wollack, E. J.

    2014-01-01

    We present measurements of the properties of thin film superconducting Mo, Mo2N and Mo2N/Mo/Mo2N trilayers of interest for microwave kinetic inductance detector (MKID) applications. Using microwave resonator devices, we investigate the transition temperature, energy gaps, kinetic inductance, and internal quality factors of these materials. We present an Usadel-based interpretation of the trilayer transition temperature as a function of trilayer thicknesses, and a 2-gap interpretation to understand the change in kinetic inductance and internal resonance quality factor (Q) as a function of temperature.

  16. Thickness-Dependent Surfactant Behavior in Trilayer Polymer Films

    Science.gov (United States)

    Sun, Yan; Shull, Kenneth; Wang, Jin

    2010-03-01

    The ability for thin liquid films to wet and remain thermodynamically stable on top of one another is a fundamental challenge in developing high quality paints, coatings, adhesives, and other industrial products. Since intermolecular interactions and interfacial energies dominate in the film thickness regime from tens to hundreds of nanometers, it is desirable to tune these long-range and short-range forces in a simple, controllable manner. Starting from an unstable model homopolymer bilayer (poly(styrene)/poly(4-vinylpyridine)), we demonstrate that sandwiching an additional homopolymer layer (poly(4-bromostyrene)) between the two layers can provide needed surfactancy. As the thickness of this center layer is increased, the full trilayer transitions from unstable (thin) to stable (moderate) to unstable (thick). We experimentally show using x-ray standing waves generated via total external reflection (TER-XSW), atomic force microscopy (AFM), and time-of-flight secondary ion mass spectroscopy (ToF-SIMS) that this behavior can be directly attributed to the autophobic dewetting phenomenon, in which the surfactant layer is thin enough to remain stable but thick enough to shield the neighboring layers, highlighting a general approach to stabilizing multilayer systems.

  17. An Investigation of the Relationship between Resistance and Thickness of Deposited Nickel Thin Film Resistors

    Directory of Open Access Journals (Sweden)

    Ericam R.R. Mucunguzi-Rugwebe

    2013-09-01

    Full Text Available The main purpose of this study is finding the relationship between resistance and thickness of deposited Nickel Thin Film Resistors. It was found that the Sheet Resistance, Rs, is inversely proportional to the thickness of the film on the substrate. It was also observed that when the film thickness is greater than 50 nm, films behave like ordinary resistors. In other words in bulk, films obey Ohm’s law if other physical quantities remain constant.

  18. Effect of film thickness on the columnar packing structures of discotic supramolecules in thin films.

    Science.gov (United States)

    Kim, Hyo-Sik; Choi, Sung-Min; Pate, Brian D; Park, Po Gyu

    2009-10-19

    The effects of film thickness on the columnar packing structure of discotic supramolecules in a thin supported film have been investigated by grazing-incidence small-angle X-ray scattering technique using magnetically aligned cobalt octa(n-decylthio)porphyrazine (CoS10) films on octadecyltrichlorosilane (OTS)-functionalized substrates as model systems. Magnetically aligned CoS10 films with a range of film thicknesses (49-845 nm) form uniaxially oriented 'edge-on' columnar superstructures with their columnar directors perpendicular to the applied magnetic field. However, the orientational ordering of the columnar packing in the plane perpendicular to the applied magnetic field is strongly dependent on the film thickness. While being damped by the elasticity of the side chains of CoS10, the strong interfacial interaction at the film-substrate interface propagates up to 50-100 nm from the substrate, maintaining the orientation of columnar packing in the plane perpendicular to the applied magnetic field. When the distance from the film-substrate interface becomes larger than about 100 nm, symmetric tilting of columnar layer orientation, which saturates at 11.5 degrees , occurs due to longitudinal edge dislocations induced by accumulated elastic deformation.

  19. Film thickness of mechanically worked lubricating grease at very low speeds

    NARCIS (Netherlands)

    Cen, H.; Lugt, Pieter Martin; Morales-Espejel, G.E.

    2014-01-01

    Several different types of commercially available greases, aged in a roll stability tester, have been tested in a ball-on-disc machine where the film thickness was measured using the interferometry method. The grease film thickness at very low speed is thicker than the base oil film thickness due to

  20. Highly textured oxypnictide superconducting thin films on metal substrates

    Energy Technology Data Exchange (ETDEWEB)

    Iida, Kazumasa, E-mail: iida@nuap.nagoya-u.ac.jp; Kurth, Fritz; Grinenko, Vadim; Hänisch, Jens [Institute for Metallic Materials, IFW Dresden, D-01171 Dresden (Germany); Chihara, Masashi; Sumiya, Naoki; Hatano, Takafumi; Ikuta, Hiroshi [Department of Crystalline Materials Science, Nagoya University, Chikusa, Nagoya 464-8603 (Japan); Ichinose, Ataru; Tsukada, Ichiro [Central Research Institute of Electric Power Industry, 2-6-1 Nagasaka, Yokosuka, Kanagawa 240-0196 (Japan); Matias, Vladimir [iBeam Materials, Inc., 2778A Agua Fria Street, Santa Fe, New Mexico 87507 (United States); Holzapfel, Bernhard [Institute for Technical Physics, Karlsruhe Institute of Technology, Hermann von Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)

    2014-10-27

    Highly textured NdFeAs(O,F) thin films have been grown on ion beam assisted deposition-MgO/Y{sub 2}O{sub 3}/Hastelloy substrates by molecular beam epitaxy. The oxypnictide coated conductors showed a superconducting transition temperature (T{sub c}) of 43 K with a self-field critical current density (J{sub c}) of 7.0×10{sup 4} A/cm{sup 2} at 5 K, more than 20 times higher than powder-in-tube processed SmFeAs(O,F) wires. Albeit higher T{sub c} as well as better crystalline quality than Co-doped BaFe{sub 2}As{sub 2} coated conductors, in-field J{sub c} of NdFeAs(O,F) was lower than that of Co-doped BaFe{sub 2}As{sub 2}. These results suggest that grain boundaries in oxypnictides reduce J{sub c} significantly compared to that in Co-doped BaFe{sub 2}As{sub 2} and, hence biaxial texture is necessary for high J{sub c.}.

  1. Influence of films thickness and structure on the photo-response of ZnO films

    Science.gov (United States)

    Ali Yıldırım, M.; Ateş, Aytunç

    2010-04-01

    ZnO thin films were grown using Successive Ionic Layer Adsorption and Reaction (SILAR) method on glass substrates at room temperature. Annealing temperatures and film thickness effect on the structural, morphological, optical and electrical properties of the films were studied. For this as-deposited films were annealed at 200, 300, 400 and 500 °C for 30 min in oxygen atmosphere. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies showed that the films are covered well with glass substrates and have good polycrystalline structure and crystalline levels. The film thickness effect on band gap values was investigated and band gap values were found to be within the range of 3.49-3.19 eV. The annealing temperature and light effect on electrical properties of the films were investigated and it was found that the current increased with increasing light intensity. The resistivity values were found as 10 5 Ω-cm for as-deposited films from electrical measurements. The resistivity decreased decuple with annealing temperature and decreased centuple with light emission for annealed films.

  2. Generation of coherent electromagnetic radiation by superconducting films at nitrogen temperatures

    CERN Document Server

    Lykov, A N

    2001-01-01

    One detected generation of coherent electromagnetic radiation by GdBa sub 2 Cu sub 3 O sub 7 sub - sub x superconducting films within 1-10 MHz range at temperature of liquid nitrogen boiling. This type generation is caused by synchronization realized due to the feedback of abrupt changes of the Abrikosov's vortices produced by the external low-frequency magnetic field. Possibility to reach more intensive radiation due to increase of the area of superconducting film, as well as, via increase of amplitude and of frequency of electromagnetic field exciting a vortex system in films is the most important advantage of the given technique of generation

  3. Tunability of the superconductivity of tungsten films grown by focused-ion-beam direct writing

    Science.gov (United States)

    Li, Wuxia; Fenton, J. C.; Wang, Yiqian; McComb, D. W.; Warburton, P. A.

    2008-11-01

    We have grown tungsten-containing films by focused-ion-beam (FIB)-induced chemical vapor deposition. The films lie close to the metal-insulator transition with an electrical conductivity which changes by less than 5% between room temperature and 7 K. The superconducting transition temperature Tc of the films can be controlled between 5.0 and 6.2 K by varying the ion-beam deposition current. The Tc can be correlated with how far the films are from the metal-insulator transition, showing a nonmonotonic dependence, which is well described by the heuristic model of [Osofsky et al., Phys. Rev. Lett. 87, 197004 (2001)]. Our results suggest that FIB direct-writing of W composites might be a potential approach to fabricate mask-free superconducting devices as well as to explore the role of reduced dimensionality on superconductivity.

  4. Characterization of superconducting magnesium-diboride films on glassy carbon and sapphire substrates

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, E.; Zavala, E. P. [Instituto de Fisica, UNAM, Apartado Postal 20-364, 01000 Mexico D. F. (Mexico); Rocha, M. F. [Escuela Superior de Ingenieria Mecanica y Electrica, IPN, Mexico D. F. (Mexico); Jergel, M.; Falcony, C. [Departamento de Fisica, CINVESTAV-IPN, Apartado postal 14-740, 07000 Mexico D. F. (Mexico)

    2008-02-15

    IBA methods were applied to measure elemental depth profiles of precursors and superconducting MgB{sub 2} thin films deposited on glassy carbon (Good Fellows) and sapphire (Al{sub 2}O{sub 3}) substrates. For each type of substrates we obtained a pair of samples i.e. one amorphous precursor and one superconducting film which were then characterized. A 3{sup H}e{sup +} beam was used to bombard both, precursors and superconducting films in order to obtain the samples elemental composition profiles. The zero resistance T{sub co} and the middle of transition T{sub cm} values were 26.0 K and 29.7 K for the MgB{sub 2} film deposited on glassy carbon substrate. In the case of sapphire substrate the T{sub co} and T{sub cm} values were 25.0 K and 27.9 K, respectively. (Author)

  5. Degradation of superconducting Nb/NbN films by atmospheric oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Henry, Michael David; Wolfley, Steven L.; Young, Travis Ryan; Monson, Todd; Pearce, Charles Joseph; Lewis, Rupert M.; Clark, Blythe; Brunke, Lyle Brent; Missert, Nancy A.

    2017-03-01

    Niobium and niobium nitride thin films are transitioning from fundamental research toward wafer scale manufacturing with technology drivers that include superconducting circuits and electronics, optical single photon detectors, logic, and memory. Successful microfabrication requires precise control over the properties of sputtered superconducting films, including oxidation. Previous work has demonstrated the mechanism in oxidation of Nb and how film structure could have deleterious effects upon the superconducting properties. This study provides an examination of atmospheric oxidation of NbN films. By examination of the room temperature sheet resistance of NbN bulk oxidation was identified and confirmed by secondary ion mass spectrometry. As a result, Meissner magnetic measurements confirmed the bulk oxidation not observed with simple cryogenic resistivity measurements.

  6. Superconductivity in One-atomic-layer Metal Films

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tong; CHEN Xi; WANG Yayu; LIU Ying; LIN Haiqing; JIA Jinfeng; XUE Qikun; CHENG Peng; LI Wenjuan; SUN Yujie; WANG Guang; ZHU Xicgang; HE Ke; WANG Lili; MA Xucun

    2011-01-01

    @@ Superconductivity is a peculiar quantum phenomenon which originates from the pairing of conduction electrons, followed by phase coherent condensation.Since the discovery by K.Onnes in 1911, superconductivity has been one of the hottest topics in physics for an entire century, and still attracts people's great interest.One of the intriguing issues is how superconductivity appears in low dimensional system where quantum size effect and surface/interface effect that large bulk material doesn't have may become crucial.

  7. Superconductivity in One-atomic-layer Metal Films

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tong; CHENG Peng; LI Wenjuan; SUN Yujie; WANG Guang; ZHU Xiegang; HE Ke; WANG Lili; MA Xucun; CHEN Xi; WANG Yayu; LIU Ying; LIN Haiqing; JIA Jinfeng; XUE Qikun

    2011-01-01

    Superconductivity is a peculiar quantum phenomenon which originates from the pairing of conduction electrons, tbllowed by phase coherent condensation, Since the discovery by K. Onnes in 1911, superconductivity has been one of the hottest topics in physics for an entire century, and still attracts people's great interest. One of the intriguing issues is how superconductivity appears in low dimensional system where quantum size effect and surface/interface effect that large bulk material doesn't have may become crucial.

  8. Optimized Performances of Thick Film Organic Lighting-Emitting Diodes

    Institute of Scientific and Technical Information of China (English)

    WANG Xiu-Ru; ZHANG Zhi-Qiang; MA Dong-Ge; SUN Run-Guang

    2008-01-01

    @@ The performance of organic light-emitting diodes (OLEDs) with thick film is optimized.The alternative vana-dium oxide (V2O5) and N,N'-di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (NPB) layers are used to enhance holes in the emissive region, and 4,7-dipheny-1,10-phenanthroline (Bphen) doped 8-tris-hydroxyquinoline alu-minium (Alq3) is used to enhance electrons is the emissive region, thus ITO/V2O5 (8nm)/NPB (52nm)/V2O5 (8nm)/NPB (52 nm)/Alq3 (30 and 45 nm)/Alq3:Bphen (30wt%, 30 and 45 nm)/LiF (1 nm)/Al (120nm) devices are fabricated.The thick-film devices show the turn-on voltage of about 3 V and the maximal power efficiency of 4.51m/W, which is 1.46 times higher than the conventional thin-film OLEDs.

  9. Superconductivity

    CERN Document Server

    Thomas, D B

    1974-01-01

    A short general review is presented of the progress made in applied superconductivity as a result of work performed in connection with the high-energy physics program in Europe. The phenomenon of superconductivity and properties of superconductors of Types I and II are outlined. The main body of the paper deals with the development of niobium-titanium superconducting magnets and of radio-frequency superconducting cavities and accelerating structures. Examples of applications in and for high-energy physics experiments are given, including the large superconducting magnet for the Big European Bubble Chamber, prototype synchrotron magnets for the Super Proton Synchrotron, superconducting d.c. beam line magnets, and superconducting RF cavities for use in various laboratories. (0 refs).

  10. Deposition of ZnO Films on Freestanding CVD Thick Diamond Films

    Institute of Scientific and Technical Information of China (English)

    SUN Jian; BAI Yi-Zhen; YANG Tian-Peng; XU Yi-Bin; WANG Xin-Sheng; DU Guo-Tong; WU Han-Hua

    2006-01-01

    @@ For ZnO/diamond structured surface acoustic wave (SAW) filters, performance is sensitively dependent on the quality of the ZnO films. In this paper, we prepare highly-oriented and fine grained polycrystalline ZnO thin films with excellent surface smoothness on the smooth nucleation surfaces of freestanding CVD diamond films by metal organic chemical vapour deposition (MOCVD). The properties of the ZnO films are characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) spectrum. The influences of the deposition conditions on the quality of ZnO films are discussed briefly. ZnO/freestanding thick-diamond-film layered SAW devices with high response frequencies are expected to be developed.

  11. Synthesis of novel strontium-based cuprate superconducting thin films, and the relationship between their crystal structures and electrical properties

    Science.gov (United States)

    Chang, Kuo-Wei

    2000-12-01

    films. A model based on thermally activated flux flow (TAFF) was developed to describe the vortex line motion. The activation energies of the TAFF process were extracted from the magnetoresistivity measurements. Because of the thinner blocking layers, the Tl-(Sr,Ba)-1212 thin film has a higher activation energy of 77 meV compared to 27 meV of the Tl-2212 thin film at 77K and 1 tesla. The activation process was ascribed to the formation of double kinks in the flux lines. The activation energies for Tl-based and Bi-based superconducting cuprates were found to decrease exponentially with the increase of blocking layer thickness.

  12. Effect of film thickness on the phase behaviors of diblock copolymer thin film.

    Science.gov (United States)

    Jung, Jueun; Park, Hae-Woong; Lee, Sekyung; Lee, Hyojoon; Chang, Taihyun; Matsunaga, Kazuyuki; Jinnai, Hiroshi

    2010-06-22

    A phase diagram was constructed for a polystyrene-block-polyisoprene (PS-b-PI, M(W) = 32 700, f(PI) = 0.670) in thin films on Si wafer as a function of film thickness over the range of 150-2410 nm (7-107L(0) (L(0): domain spacing)). The PS-b-PI exhibits a variety of ordered phases from hexagonally perforated lamellar (HPL) via double gyroid (DG) to hexagonally packed cylinder (HEX) before going to the disordered (DIS) phase upon heating. The morphology of the PS-b-PI in thin film was investigated by grazing incidence small-angle X-ray scattering, transmission electron microscopy, and transmission electron microtomography. In thin film, the phase transition temperature is difficult to be determined unequivocally with in situ heating processes since the phase transition is slow and two phases coexist over a wide temperature range. Therefore, in an effort to find an "equilibrium" phase, we determined the long-term stable phase formed after cooling the film from the DIS phase to a target temperature and annealing for 24 h at the temperature. The temperature windows of stable ordered phases are strongly influenced by the film thickness. As the film thickness decreases, the temperature window of layer-like structures such as HPL and HEX becomes wider, whereas that of the DG stable region decreases. For the films thinner than 160 nm (8L(0)), only the HPL phase was found. In the films exhibiting DG phase, a perforated layer structure at the free surface was found, which gradually converts to the internal DG structure. The relief of interfacial tension by preferential wetting appears to play an important role in controlling the morphology in very thin films.

  13. Thickness Dependence of Magnetic Properties in DyFeCo Films

    Institute of Scientific and Technical Information of China (English)

    Xiong Rui; Liu Hai-lin; Mei Xue-fei; Li Zuo-yi; Yang Xiao-fei; Shi Jing

    2004-01-01

    Films of amorphous DyFeCo were deposited on glass substrates using RF sputtering deposition system. The thickness dependence of the coercivity of DyFeCo films prepared under the same sputtering conditions was investigated. It is found that the composition is nearly thickness independent, while the coercivity is shown to increase with the film thickness increasing at the beginning, then above a certain thickness decrease with the thickness increasing. The thickness dependence of the coercivity is believed to be due to microstructure-induced variations in the short-range order during the film growth.

  14. Thickness effect on the microstructure, morphology and optoelectronic properties of ZnS films

    Science.gov (United States)

    Prathap, P.; Revathi, N.; Venkata Subbaiah, Y. P.; Ramakrishna Reddy, K. T.

    2008-01-01

    Thin films of ZnS with thicknesses ranging from 100 to 600 nm have been deposited on glass substrates by close spaced thermal evaporation. All the films were grown at the same deposition conditions except the deposition time. The effect of thickness on the physical properties of ZnS films has been studied. The experimental results indicated that the thickness affects the structure, lattice strain, surface morphology and optoelectronic properties of ZnS films significantly. The films deposited at a thickness of 100 nm showed hexagonal structure whereas films of thickness 300 nm or more showed cubic structure. However, coexistence of both cubic and hexagonal structures was observed in the films of 200 nm thickness. The surface roughness of the films showed an increasing trend at higher thicknesses of the films. A blue-shift in the energy band gap along with an intense UV emission band was observed with the decrease of film thickness, which are ascribed to the quantum confinement effect. The behaviour of optical constants such as refractive index and extinction coefficient were analysed. The variation of refractive index and extinction coefficient with thickness was explained on the basis of the contribution from the packing density of the layers. The electrical resistivity as well as the activation energy were evaluated and found to decrease with the increase of film thickness. The thickness had a significant influence on the optical band gap as well as the luminescence intensity.

  15. Numerical simulation on the flux avalanche behaviors of microstructured superconducting thin films

    Science.gov (United States)

    Jing, Ze; Yong, Huadong; Zhou, Youhe

    2017-01-01

    Controlling and suppressing the propagation of magnetic flux avalanches is an important issue for the application of type-II superconductors. The effects of engineered pinning centers (antidots) on the guidance of flux avalanche propagation paths in type-II superconducting thin films are numerically investigated by solving the coupled nonlinear Maxwell's equations and the thermal diffusion equations. The field dependence of critical current density is considered in the simulation in this paper. Dynamic propagations of the thermomagnetic avalanches within the superconducting films patterned with different arrangements of antidots (like random, periodic square, and conformal mapping arrays) are presented. We reveal that presence of the antidots significantly modifies the propagation paths of the avalanches. The flux avalanche patterns of the superconducting films change with the variation of the arrangements of antidots. The patterned antidots in the form of conformal mapping arrays within the superconducting film exhibit strong guidance to the thermomagnetic avalanches. In addition, introducing the antidots in the form of conformal mapping arrays into the superconducting film can effectively lower the magnetic flux jump sizes.

  16. Optical properties and structures of silver thin films deposited by magnetron sputtering with different thicknesses

    Institute of Scientific and Technical Information of China (English)

    Xilian Sun; Ruijin Hong; Haihong Hou; Zhengxiu Fan; Jianda Shao

    2006-01-01

    A series of thin Ag films with different thicknesses grown under identical conditions are analyzed by means of spectrophotometer. From these measurements the values of refractive index and extinction coefficient are calculated. The films are deposited onto BK7 glass substrates by direct current (DC) magnetron sputtering. It is found that the optical properties of the Ag films can be affected by films thickness.Below critical thickness of 17 nm, which is the thickness at which Ag films form continuous films, the optical properties and constants vary significantly with thickness increasing and then tend to a stable value up to about 40 nm. At the same time, X-ray diffraction measurement is carried out to examine the microstructure evolution of Ag films as a function of films thickness. The relation between optical properties and microstructure is discussed.

  17. Thick film magnetic nanoparticulate composites and method of manufacture thereof

    Science.gov (United States)

    Ma, Xinqing (Inventor); Zhang, Yide (Inventor); Ge, Shihui (Inventor); Zhang, Zongtao (Inventor); Yan, Dajing (Inventor); Xiao, Danny T. (Inventor)

    2009-01-01

    Thick film magnetic/insulating nanocomposite materials, with significantly reduced core loss, and their manufacture are described. The insulator coated magnetic nanocomposite comprises one or more magnetic components, and an insulating component. The magnetic component comprises nanometer scale particles (about 1 to about 100 nanometers) coated by a thin-layered insulating phase. While the intergrain interaction between the immediate neighboring magnetic nanoparticles separated by the insulating phase provides the desired soft magnetic properties, the insulating material provides high resistivity, which reduces eddy current loss.

  18. Thick film fabrication of aluminum nitride microcircuits. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Perdieu, L.H.

    1994-03-01

    A new substrate material, aluminum nitride (AlN), and 11 new thick film inks were analyzed to determine their chemical compatibility, their electrical properties, their mechanical properties, and their overall suitability for use in the manufacturing of high-power microcircuits with efficient thermal properties. Because high-power chips emit a great deal of heat in a small surface area, a new substrate material was needed to dissipate that heat faster than the substrate material currently in use. Overall, the new materials were found to be acceptable for accomplishing this purpose.

  19. Laser sintering of thick-film conductors for microelectronic applications

    Science.gov (United States)

    Kinzel, Edward C.; Sigmarsson, Hjalti H.; Xu, Xianfan; Chappell, William J.

    2007-03-01

    This paper investigates fabrication of functional thick metal films using simultaneous laser sintering and patterning along with the fundamental physical phenomena that govern the laser sintering process. The effects of the processing parameters on the quality of the fabricated components are investigated through a heat transfer analysis. We show that our process has potentials for metallization of microelectronics directly onto substrates whose melting temperatures are much lower than the temperature needed for sintering, which is only possible by properly controlling the temperature field during laser sintering. Optimum properties of the fabricated components are obtained when certain thermal conditions are produced during laser heating.

  20. Effect of film thickness on magnetic properties of Cr/SmCo/Cr films

    Institute of Scientific and Technical Information of China (English)

    LI Ning; LI Baohe; FENG Chun; LI Minghua; YU Guanghua

    2012-01-01

    Cr/SmCo/Cr films with different SmCo thickness were deposited on glass substrates by magnetron sputtering,followed by an annealing process at 550℃for 20 min.Experimental results showed that the SmCo fihn of 30 nm exhibited two-phase behavior in the demagnetization process,the obvious kink was observed near zero.For the SmCo film of 50 nm,the kink was invisible,and a single phase like behavior was obtained in the demagnetization process.The reversal behavior became consistent in the thicker films.Moreover,the coercivity reduced and the saturated magnetization increased obviously with the increasing thickness.X-ray diffraction results indicated that the average grain size of SmCo5 in the thicker films were almost 30 nm,but the quantity of SmCo5 grains increased with the increasing thickness,which enhanced the intergrain exchange coupling (IEC) of the SmCo5 hard phases.The increase of lEC improved the magnetic properties of SmCo films with increasing thickness.

  1. Superconducting properties of Tl-Ba-Ca-Cu-O films on silver substrates

    Energy Technology Data Exchange (ETDEWEB)

    Dye, R.C.; Arendt, P.N.; Martin, J.A.; Hubbard, K.M.; Elliott, N.; Reeves, G. (Los Alamos National Lab., NM (United States))

    1991-03-01

    Films of Ba-Ca-Cu-O have been rf magnetron sputtered onto Consil 995 substrates. A post deposition anneal in an over pressure of Tl produces the superconducting 1212 and 2212 phases. Varying the annealing procedures changes the electrical properties of the final films dramatically. Dynamic impedance, an approach to the electrical characterization of these films on a conductive substrate is discussed and compared in this paper, with SEM, XRD and RBS measurements as a function of differing annealing protocols.

  2. Superconducting properties of Tl-Ba-Ca-Cu-O films on silver substrates

    Energy Technology Data Exchange (ETDEWEB)

    Dye, R.C.; Arendt, P.N.; Martin, J.A.; Hubbard, K.M.; Elliott, N.; Reeves, G.

    1990-01-01

    Films of Ba-Ca-Cu-O have been rf magnetron sputtered onto Consil 995 substrates. A post deposition anneal in an over pressure of Tl produces the superconducting 1212 and 2212 phases. Varying the annealing procedures changes the electrical properties of the final films dramatically. Dynamic impedance, a novel approach to the electrical characterization of these films on a conductive substrate is discussed and compared with SEM, XRD and RBS measurements as a function of differing annealing protocols. 3 refs., 9 figs.

  3. Thickness optimization of Mo films for Cu(InGa)Se2 solar cell applications

    Institute of Scientific and Technical Information of China (English)

    Li Wei; Zhao Yan-Min; Liu Xing-Jiang; Ao Jian-Ping; Sun Yun

    2011-01-01

    Mo thin films are deposited on soda lime glass (SLG) substrates using DC magnetron sputtering. The Mo film thicknesses are varied from 0.08 μm to 1.5 μm to gain a better understanding of the growth process of the film. The residual stresses and the structural properties of these films are investigated, with attention paid particularly to the film thickness dependence of these properties. Residual stress decreases and yields a typical tensile-to-compressive stress transition with the increase of film thickness at the first stages of film growth. The stress tends to be stable with the further increase of film thickness. Using the Mo film with an optimum thickness of 1 μm as the back contact, the Cu(InGa)Se2 solar cell can reach a conversion efficiency of 13.15%.

  4. Superconducting MgB{sub 2} films with introduced artificial pinning centers

    Energy Technology Data Exchange (ETDEWEB)

    Sidorenko, Anatoli [Institute of Electronic Engineering and Industrial Technologies ASM, Kishinev MD2028 (Moldova); Institute of Applied Physics, University of Karlsruhe, D-76128 Karlsruhe (Germany); Zdravkov, Vladimir; Surdu, Andrei [Institute of Electronic Engineering and Industrial Technologies ASM, Kishinev MD2028 (Moldova); Obermeier, Guenter [Institute of Applied Physics, University Augsburg, 86159 Augsburg (Germany); Frommen, Christoph; Walheim, Stefan [Institute of Nanotechnology, Forschungszentrum Karlsruhe, D-76021 Karlsruhe (Germany); Koch, Thomas; Schimmel, Thomas [Institute of Applied Physics, University of Karlsruhe, D-76128 Karlsruhe (Germany); Institute of Nanotechnology, Forschungszentrum Karlsruhe, D-76021 Karlsruhe (Germany)

    2008-07-01

    High quality superconducting magnesium diboride films were prepared using DC-magnetron sputtering and post annealing in Mg vapor within a specially designed Nb reactor. The influence of embedded gold nano particles on resistive transition broadening in external magnetic field has been investigated. The transition broadening in strong magnetic fields could be explained by the change of the effective dimensionality of superconductivity nucleation in magnesium diboride, because of the dimensional crossover of fluctuations.

  5. Nitrogen dioxide sensing properties of sprayed tungsten oxide thin film sensor: Effect of film thickness.

    Science.gov (United States)

    Ganbavle, V V; Mohite, S V; Agawane, G L; Kim, J H; Rajpure, K Y

    2015-08-01

    We report a study on effect of film thickness on NO2 sensing properties of sprayed WO3 thin films. WO3 thin films varying in thicknesses are deposited onto the glass substrates by simple spray pyrolysis technique by varying the volume of spray solution.Thin film gas sensors are characterized by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM) and photoluminescence (PL) techniques to study their physical properties. Film having thickness 745nm has shown highest gas response of 97% with 12 and 412s response and recovery times, respectively towards 100ppm NO2 concentration. Gas response of 20% is observed towards 10ppm NO2 at 200°C operating temperature. Sensitivity of the optimal sensor is 0.83%/ppm when operating at 200°C with 10ppm lower detection limit. The response of the sensor is reproducible and WO3 films are highly selective towards NO2 in presence of mist of various interfering gases viz. H2S, NH3, LPG, CO and SO2.

  6. A review of basic phenomena and techniques for sputter-deposition of high temperature superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Auciello, O. (Microelectronics Center of North Carolina, Research Triangle Park, NC (USA) North Carolina State Univ., Raleigh, NC (USA). Dept. of Materials Science and Engineering); Ameen, M.S.; Kingon, A.I.; Lichtenwalner, D.J. (North Carolina State Univ., Raleigh, NC (USA). Dept. of Materials Science and Engineering); Krauss, A.R. (Argonne National Lab., IL (USA))

    1990-01-01

    The processes involved in plasma and ion beam sputter-deposition of high temperature superconducting thin films are critically reviewed. Recent advances in the development of these techniques are discussed in relation to basic physical phenomena, specific to each technique, which must be understood before high quality films can be produced. Control of film composition is a major issue in sputter-deposition of multicomponent materials. Low temperature processing of films is a common goal for each technique, particularly in relation to integrating high temperature superconducting films with the current microelectronics technology. It has been understood for some time that for Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7} deposition, the most intensely studied high-{Tc} compound, incorporation of sufficient oxygen into the film during deposition is necessary to produce as-deposited superconducting films at relatively substrate temperatures. Recent results have shown that with the use of suitable buffer layers, high quality Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7} sputtered films can be obtained on Si substrates without the need for post-deposition anneal processing. This review is mainly focussed on issues related to sputter-deposition of Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7} thin films, although representative results concerning the bismuth and thallium based compounds are included. 143 refs., 11 figs.

  7. Controlling flux flow dissipation by changing flux pinning in superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Grimaldi, G.; Leo, A.; Nigro, A.; Pace, S. [CNR SPIN Salerno and Dipartimento di Fisica ' ' E. R. Caianiello' ' , Universita degli Studi di Salerno, via Ponte Don Melillo, 84084 Fisciano (Italy); Silhanek, A. V. [Department de Physique, Universite de Liege, B-4000 Sart Tilman (Belgium); INPAC-Institute for Nanoscale Physics and Chemistry, Nanoscale Superconductivity and Magnetism Group, K. U. Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Verellen, N.; Moshchalkov, V. V. [INPAC-Institute for Nanoscale Physics and Chemistry, Nanoscale Superconductivity and Magnetism Group, K. U. Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Milosevic, M. V. [Departement Fysica, Universiteit Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen (Belgium); Casaburi, A.; Cristiano, R. [Istituto di Cibernetica ' ' E. Caianiello' ' , CNR, 80078 Pozzuoli (Italy)

    2012-05-14

    We study the flux flow state in superconducting materials characterized by rather strong intrinsic pinning, such as Nb, NbN, and nanostructured Al thin films, in which we drag the superconducting dissipative state into the normal state by current biasing. We modify the vortex pinning strength either by ion irradiation, by tuning the measuring temperature or by including artificial pinning centers. We measure critical flux flow voltages for all materials and the same effect is observed: switching to low flux flow dissipations at low fields for an intermediate pinning regime. This mechanism offers a way to additionally promote the stability of the superconducting state.

  8. High Critical Current Density of YBa2Cu3O7-x Superconducting Films Prepared through a DUV-assisted Solution Deposition Process.

    Science.gov (United States)

    Chen, Yuanqing; Bian, Weibai; Huang, Wenhuan; Tang, Xinni; Zhao, Gaoyang; Li, Lingwei; Li, Na; Huo, Wen; Jia, Jiqiang; You, Caiyin

    2016-12-01

    Although the solution deposition of YBa2Cu3O7-x (YBCO) superconducting films is cost effective and capable of large-scale production, further improvements in their superconductivity are necessary. In this study, a deep UV (DUV) irradiation technique combined with a low-fluorine solution process was developed to prepare YBCO films. An acrylic acidic group as the chelating agent was used in the precursor solution. The acrylic acidic group was highly sensitive to DUV light at 254 nm and significantly absorbed UV light. The coated gel films exposed to DUV light decomposed at 150 °C and copper aggregation was prevented. The UV irradiation promoted the removal of the carbon residue and other by-products in the films, increased the density and enhanced the crystallinity and superconductivity of the YBCO films. Using a solution with F/Ba = 2, YBCO films with thicknesses of 260 nm and enhanced critical current densities of nearly 8 MA/cm(2) were produced on the LaAlO3 (LAO) substrates.

  9. High Critical Current Density of YBa2Cu3O7‑x Superconducting Films Prepared through a DUV-assisted Solution Deposition Process

    Science.gov (United States)

    Chen, Yuanqing; Bian, Weibai; Huang, Wenhuan; Tang, Xinni; Zhao, Gaoyang; Li, Lingwei; Li, Na; Huo, Wen; Jia, Jiqiang; You, Caiyin

    2016-12-01

    Although the solution deposition of YBa2Cu3O7‑x (YBCO) superconducting films is cost effective and capable of large-scale production, further improvements in their superconductivity are necessary. In this study, a deep UV (DUV) irradiation technique combined with a low-fluorine solution process was developed to prepare YBCO films. An acrylic acidic group as the chelating agent was used in the precursor solution. The acrylic acidic group was highly sensitive to DUV light at 254 nm and significantly absorbed UV light. The coated gel films exposed to DUV light decomposed at 150 °C and copper aggregation was prevented. The UV irradiation promoted the removal of the carbon residue and other by-products in the films, increased the density and enhanced the crystallinity and superconductivity of the YBCO films. Using a solution with F/Ba = 2, YBCO films with thicknesses of 260 nm and enhanced critical current densities of nearly 8 MA/cm2 were produced on the LaAlO3 (LAO) substrates.

  10. Superconductivity

    Science.gov (United States)

    1989-07-01

    SUPERCONDUCTIVITY HIGH-POWER APPLICATIONS Electric power generation/transmission Energy storage Acoustic projectors Weapon launchers Catapult Ship propulsion • • • Stabilized...temperature superconductive shields could be substantially enhanced by use of high-Tc materials. 27 28 NRAC SUPERCONDUCTIVITY SHIP PROPULSION APPLICATIONS...motor shown in the photograph. As a next step in the evolution of electric-drive ship propulsion technology, DTRC has proposed to scale up the design

  11. Superconducting MgB{sub 2} films as radiation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, Takekazu; Fujiwara, Daisuke; Nishikawa, Masatoshi; Kato, Masaru [Osaka Prefecture University, Osaka (Japan); Miki, Shigehito; Shimakage, Hisashi; Wang, Zhen [National Institute of Information and Communications Technology, Hyogo (Japan); Satoh, Kazuo; Yotsuya, Tsutomu [Technology Research Institute of Osaka Prefecture, Osaka (Japan); Machida, Masahiko [Japan Atomic Energy Agency, Tokyo (Japan)

    2006-05-15

    The thermal response of a membrane-structured MgB{sub 2} film can be used to detect various sorts of radiations. High-quality MgB{sub 2} films were prepared by a sputtering technique. The MgB{sub 2} radiation detector consisted of an MgB{sub 2} thin-film meander line on a 0.5-{mu}m-thick SiN membrane. The detector devices were placed in a 4 K refrigerator, and the operating temperature was controlled at a certain temperature below T{sub c}. Light from a 20-ps pulsed laser directly irradiated the MgB{sub 2} device; the end of the optical fiber was fixed in front of the device. An erbium-doped fiber amplifier (EDFA) and a GP-IB attenuator were used to control the laser power, and the output voltage was observed through a low-noise amplifier by using a digital oscilloscope. The output signals caused by thermal response were clearly observed. Systematic studies of the output signals were conducted, and effects of device design, dc bias conditions, bias temperature, and input laser power were considered. We report the out-of-equilibrium thermodynamics, which was investigated by means of extensive computer simulations based on the time-dependent Ginzburg-Landau equations, thermodynamics, and electrodynamics. Large-scale calculations were carried out under the realistic conditions of actual devices by using an Earth Simulator (ES). One attractive application is to use the device as a novel neutron detector by employing the {sup 10}B(n,{alpha}){sup 7}Li nuclear reaction with a local energy release of 2.3 MeV.

  12. Thick Films acoustic sensors devoted to MTR environment measurements. Thick Films acoustic sensors devoted to Material Testing Reactor environment measurements

    Energy Technology Data Exchange (ETDEWEB)

    Very, F.; Rosenkrantz, E.; Combette, P.; Ferrandis, J.Y. [University Montpellier, IES, UMR 5214, F-34000, Montpellier (France); CNRS, IES, UMR 5214, F-34000, Montpellier (France); Fourmentel, D.; Destouches, C.; Villard, J.F. [CEA, DEN, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St Paul lez Durance (France)

    2015-07-01

    The development of advanced instrumentation for in-pile experiments in Material Testing Reactor constitutes a main goal for the improvement of the nuclear fuel behavior knowledge. An acoustic method for fission gas release detection was tested with success during a first experiment called REMORA 3 in 2010 and 2011, and the results were used to differentiate helium and fission gas release kinetics under transient operating conditions. This experiment was lead at OSIRIS reactor (CEA Saclay, France). The maximal temperature on the sensor during the irradiation was about 150 deg. C. In this paper we present a thick film transducer produce by screen printing process. The screen printing of piezoelectric offers a wide range of possible applications for the development of acoustic sensors and piezoelectric structure for measurements in high temperature environment. We firstly produced a Lead Zirconate Titanate (PZT) based paste composed of Pz27 powder from Ferroperm, CF7575 glass, and organic solvent ESL 400. Likewise a Bismuth Titanate based paste synthesized in our laboratory was produced. With these inks we produced thick film up to 130 μm by screen printing process. Material properties characterizations of these thick-film resonators are essential for device design and applications. The piezoelectric coefficients d33 and pyro-electric P(T) coefficient are investigated. The highest P(T) and d33 are respectively 80 μC.m{sup -2}.K{sup -1} and 130 μC.N{sup -1} for the PZT transducer -which validates the fabrication process-. In view of the development of this transducer oriented for high temperature and irradiation environment, we investigated the electrical properties of the transducers for different ranges of frequencies and temperature - from 20 Hz up to 40 MHz between 30 and 400 deg. C. We highlight the evolution of the impedance response and piezoelectric parameters of screen printed piezoelectric structures on alumina. Shortly an irradiation will be realized in

  13. Characterization of NbN films for superconducting nanowire single photon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Mcdonald, Ross D [Los Alamos National Laboratory; Ayala - Valenzuela, Oscar E [Los Alamos National Laboratory; Weisse - Bernstein, Nina R [Los Alamos National Laboratory; Williamson, Todd L [Los Alamos National Laboratory; Hoffbauer, M. A. [Los Alamos National Laboratory; Graf, M. J. [Los Alamos National Laboratory; Rabin, M. W. [Los Alamos National Laboratory

    2011-01-14

    Nanoscopic superconducting meander patterns offer great promise as a new class of cryogenic radiation sensors capable of single photon detection. To realize this potential, control of the superconducting properties on the nanoscale is imperative. To this end, Superconducting Nanowire Single Photon Detectors (SNSPDs) are under development by means Energetic Neutral Atom Beam Lithography and Epitaxy, or ENABLE. ENABLE can growth highly-crystalline, epitaxial thin-film materials, like NbN, at low temperatures; such wide-ranging control of fabrication parameters is enabling the optimization of film properties for single photon detection. T{sub c}, H{sub c2}, {zeta}{sub GL} and J{sub c} of multiple thin films and devices have been studied as a function of growth conditions. The optimization of which has already produced devices with properties rivaling all reports in the existing literature.

  14. Environmentally compatible solder materials for thick film hybrid assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Hosking, F.M.; Vianco, P.T.; Rejent, J.A.; Hernandez, C.L. [Sandia National Labs., Albuquerque, NM (United States). Materials and Process Sciences Center

    1997-02-01

    New soldering materials and processes have been developed over the last several years to address a variety of environmental issues. One of the primary efforts by the electronics industry has involved the development of alternative solders to replace the traditional lead-containing alloys. Sandia National Laboratories is developing such alternative solder materials for printed circuit board and hybrid microcircuit (HMC) applications. This paper describes the work associated with low residue, lead-free soldering of thick film HMC`s. The response of the different materials to wetting, aging, and mechanical test conditions was investigated. Hybrid test vehicles were designed and fabricated with a variety of chip capacitors and leadless ceramic chip carriers to conduct thermal, electrical continuity, and mechanical evaluations of prototype joints. Microstructural development along the solder and thick film interface, after isothermal solid state aging over a range of elevated temperatures and times, was quantified using microanalytical techniques. Flux residues on soldered samples were stressed (temperature-humidity aged) to identify potential corrosion problems. Mechanical tests also supported the development of a solder joint lifetime prediction model. Progress of this effort is summarized.

  15. Preparation of very thin superconducting films of Y-Ba-Cu-O by a layer-by-layer resistive evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Azoulay, J.; Goldschmidt, D. (Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel, and Center for Technological Education, Holon, P.O. Box 305, Holon 58680, Israel (IL)); Brener, R. (Solid State Institute, Technion, Israel Institute of Technology, Haifa 3200, Israel)

    1989-10-15

    We report here on 1/4 -{mu}m-thick superconducting Y-Ba-Cu-O films, produced by a sequential layer-by-layer deposition of Cu, BaF{sub 2}, and YF{sub 3}, utilizing solely resistive evaporation from tungsten boats onto SrTiO{sub 3} substrates. The films are composed primarily of quasioriented elongated grains and have, on the average, the correct stoichiometry. A transition onset at 75 K and width of {similar to}25 K have been observed in these films. The shape of the current-voltage curve indicates that Josephson-coupled weak links limit the transport in these films. However, the magnitude of critical current (3000 A/cm{sup 2} at {similar to}10 K) is larger than that found in bulk ceramic superconductors. The origin of weak links in these films is probably in the regions of contact between the elongated grains. The relatively large critical current density, as compared to regular bulk ceramic superconductors, is presumably related to the quasioriented nature of the film.

  16. Ethanol vapour sensing properties of screen printed WO3 thick films

    Indian Academy of Sciences (India)

    R S Khadayate; R B Waghulde; M G Wankhede; J V Sali; P P Patil

    2007-04-01

    This paper presents ethanol vapour sensing properties of WO3 thick films. In this work, the WO3 thick films were prepared by standard screen-printing method. These films were characterized by X-ray diffraction (XRD) measurements and scanning electron microscopy (SEM). The ethanol vapour sensing properties of these thick films were investigated at different operating temperatures and ethanol vapour concentrations. The WO3 thick films exhibit excellent ethanol vapour sensing properties with a maximum sensitivity of ∼1424.6% at 400°C in air atmosphere with fast response and recovery time.

  17. Superconducting transistor

    Science.gov (United States)

    Gray, Kenneth E.

    1979-01-01

    A superconducting transistor is formed by disposing three thin films of superconducting material in a planar parallel arrangement and insulating the films from each other by layers of insulating oxides to form two tunnel junctions. One junction is biased above twice the superconducting energy gap and the other is biased at less than twice the superconducting energy gap. Injection of quasiparticles into the center film by one junction provides a current gain in the second junction.

  18. Influence of colorant and film thickness on thermal aging characteristics of oxo-biodegradable plastic bags

    Science.gov (United States)

    Leuterio, Giselle Lou D.; Pajarito, Bryan B.; Domingo, Carla Marie C.; Lim, Anna Patricia G.

    2016-05-01

    Functional, lightweight, strong and cheap plastic bags incorporated with pro-oxidants undergo accelerated degradation under exposure to heat and oxygen. This work investigated the effect of colorant and film thickness on thermal aging characteristics of commercial oxo-biodegradable plastic bag films at 70 °C. Degradation is monitored through changes in infrared absorption, weight, and tensile properties of thermally aged films. The presence of carbonyl band in infrared spectrum after 672 h of thermal aging supports the degradation behavior of exposed films. Results show that incorporation of colorant and increasing thickness exhibit low maximum weight uptake. Titanium dioxide as white colorant in films lowers the susceptibility of films to oxygen uptake but enhances physical degradation. Higher amount of pro-oxidant loading also contributes to faster degradation. Opaque films are characterized by low tensile strength and high elastic modulus. Decreasing the thickness contributes to lower tensile strength of films. Thermally aged films with colorant and low thickness promote enhanced degradation.

  19. Effect of preheating on the film thickness of contemporary composite restorative materials

    Directory of Open Access Journals (Sweden)

    Dimitrios Dionysopoulos

    2014-12-01

    Conclusion: The film thickness of the composites tested is material dependent. The thickness of the preheated conventional composites is significantly lower than those at room temperature. The conventional composites provide film thickness values greater than those of the flowable composites regardless of preheating temperature.

  20. Film thickness dependent ordering dynamics of lamellar forming diblock copolymer thin films.

    Science.gov (United States)

    Peters, Robert D; Dalnoki-Veress, Kari

    2012-12-01

    Ellipsometry is used in a novel way to study the ordering dynamics of symmetric poly(styrene-methyl methacrylate) diblock copolymer thin films. Ordered thin films form lamellae parallel to the substrate which can form islands or holes at the free surface to ensure commensurability of the layers. The sensitivity of ellipsometry provides the unique ability to probe morphological changes during the ordering process before the ultimate formation of islands or holes at the free surface. We observe three distinct stages in the ordering process: i) an ordering into an intermediate state, ii) an incubation time where the film structure remains constant and iii) the nucleation of islands or holes to achieve equilibrium lamellar morphology. The time-resolved measurement of an incubation period and initial ordering stage provides a means for studying the effect of thickness on the ordering kinetics. The dependence of incubation time on the commensurability of the initial film height is explained using strong segregation theory.

  1. Temperature- and thickness-dependent elastic moduli of polymer thin films.

    Science.gov (United States)

    Ao, Zhimin; Li, Sean

    2011-03-22

    The mechanical properties of polymer ultrathin films are usually different from those of their counterparts in bulk. Understanding the effect of thickness on the mechanical properties of these films is crucial for their applications. However, it is a great challenge to measure their elastic modulus experimentally with in situ heating. In this study, a thermodynamic model for temperature- (T) and thickness (h)-dependent elastic moduli of polymer thin films Ef(T,h) is developed with verification by the reported experimental data on polystyrene (PS) thin films. For the PS thin films on a passivated substrate, Ef(T,h) decreases with the decreasing film thickness, when h is less than 60 nm at ambient temperature. However, the onset thickness (h*), at which thickness Ef(T,h) deviates from the bulk value, can be modulated by T. h* becomes larger at higher T because of the depression of the quenching depth, which determines the thickness of the surface layer δ.

  2. In situ epitaxial MgB2 thin films for superconducting electronics.

    Science.gov (United States)

    Zeng, Xianghui; Pogrebnyakov, Alexej V; Kotcharov, Armen; Jones, James E; Xi, X X; Lysczek, Eric M; Redwing, Joan M; Xu, Shengyong; Li, Qi; Lettieri, James; Schlom, Darrell G; Tian, Wei; Pan, Xiaoqing; Liu, Zi-Kui

    2002-09-01

    The newly discovered 39-K superconductor MgB2 holds great promise for superconducting electronics. Like the conventional superconductor Nb, MgB2 is a phonon-mediated superconductor, with a relatively long coherence length. These properties make the prospect of fabricating reproducible uniform Josephson junctions, the fundamental element of superconducting circuits, much more favourable for MgB2 than for high-temperature superconductors. The higher transition temperature and larger energy gap of MgB2 promise higher operating temperatures and potentially higher speeds than Nb-based integrated circuits. However, success in MgB2 Josephson junctions has been limited because of the lack of an adequate thin-film technology. Because a superconducting integrated circuit uses a multilayer of superconducting, insulating and resistive films, an in situ process in which MgB2 is formed directly on the substrate is desirable. Here we show that this can be achieved by hybrid physical-chemical vapour deposition. The epitaxially grown MgB2 films show a high transition temperature and low resistivity, comparable to the best bulk samples, and their surfaces are smooth. This advance removes a major barrier for superconducting electronics using MgB2.

  3. Overlay mark optimization for thick-film resist overlay metrology

    Institute of Scientific and Technical Information of China (English)

    Zhu Liang; Li Jie; Zhou Congshu; Gu Yili; Yang Huayue

    2009-01-01

    For thick resist implant layers, such as a high voltage P well and a deep N well, systematic and uncorrectable overlay residues brought about by the tapered resist profiles were found. It was found that the tapered profile is closely related to the pattern density. Potential solutions of the manufacturing problem include hardening the film solidness or balancing the exposure density. In this paper, instead of focusing on the process change methodology,we intend to solve the issue of the overlay metrology error from the perspective of the overlay mark design. Based on the comparison of the overlay performances between the proposed overlay mark and the original design, it is shown that the optimized overlay mark target achieves better performance in terms of profiles, dynamic precision,tool induced shift (TIS), and residues. Furthermore, five types of overlay marks with dummy bars are studied, and a recommendation for the overlay marks is given.

  4. Preparation of Lead-free Thick-film Resistor Pastes

    Institute of Scientific and Technical Information of China (English)

    LUO Hui; LI Shihong; LIU Jisong; CHEN Liqiao; YING Xingang; WANG Ke

    2012-01-01

    The preparation of lead-free thick-film resistors are reported:using RuO2 and ruthenates as conductive particles,glass powders composed of B2O3,SiO2,CaO and Al2O3 as insulating phase,adding organic matter which mainly consists of ethyl cellulose and terpineol to form printable pastes.Resistors were fabricated and sintered by conventional screen-printing on 96%Al2O3 substrates,and then sintering in a belt furnace.X-ray diffraction (XRD) and electron scanning microscopy (SEM) have been used to characterize the conductive particles.The resistors exhibit good retiring stability and low temperature coefficient of resistance.Sheet resistance spans from about 80 Ω/□ to 600 Ω/□.The resistors prepared are qualified for common use.

  5. Development of metal oxide impregnated stilbite thick film ethanol sensor

    Energy Technology Data Exchange (ETDEWEB)

    Mahabole, M. P., E-mail: kashinath.bogle@gmail.com; Lakhane, M. A.; Choudhari, A. L.; Khairnar, R. S. [School of Physical Sciences, Swami Ramanand Teerth Marathwada University, Nanded - 431606 (India)

    2016-05-06

    This paper presents the study of the sensing efficiency of Titanium oxide/ Stilbite and Copper oxide /Stilbite composites towards detection of hazardous pollutants like ethanol. Stilbite based composites are prepared by physically mixing zeolite with metal oxides namely TiO{sub 2} and CuO with weight ratios of 25:75, 50:50 and 75:25. The resulting sensor materials are characterized by X-ray diffraction and Fourier Transform Infrared Spectroscopy techniques. Composite sensors are fabricated in the form of thick film by using screen printing technique. The effect of metal oxide concentration on various ethanol sensing parameters such as operating temperature, maximum uptake capacity and response/recovery time are investigated. The results indicate that metal oxide impregnated stilbite composites have great potential as low temperature ethanol sensor.

  6. Spin-orbit-coupled superconductivity.

    Science.gov (United States)

    Lo, Shun-Tsung; Lin, Shih-Wei; Wang, Yi-Ting; Lin, Sheng-Di; Liang, C-T

    2014-06-25

    Superconductivity and spin-orbit (SO) interaction have been two separate emerging fields until very recently that the correlation between them seemed to be observed. However, previous experiments concerning SO coupling are performed far beyond the superconducting state and thus a direct demonstration of how SO coupling affects superconductivity remains elusive. Here we investigate the SO coupling in the critical region of superconducting transition on Al nanofilms, in which the strength of disorder and spin relaxation by SO coupling are changed by varying the film thickness. At temperatures T sufficiently above the superconducting critical temperature T(c), clear signature of SO coupling reveals itself in showing a magneto-resistivity peak. When T superconductivity. By studying such magneto-resistivity peaks under different strength of spin relaxation, we highlight the important effects of SO interaction on superconductivity.

  7. The effect of grain size and film thickness on the thermal expansion coefficient of copper thin films.

    Science.gov (United States)

    Hwang, Seulgi; Kim, Youngman

    2011-02-01

    Cu thin films underwent thermal cycling to determine their coefficient of thermal expansion (CTE). The thermal stress of the Cu thin films with various microstructures (different grain size and film thickness) was measured using a curvature measurement system. The thermal expansion coefficients of the films were obtained from the slope of the stress-temperature curve with the knowledge of the Young's modulus and Poisson's ratio. The change in thermal stress with temperature of the Cu thin films tended to decrease with increasing grain size, resulting in an increase in the CTE. The thickness of Cu thin film had little effect on the thermal stress or the CTE.

  8. Structural properties of strained YBa2Cu3O6+x superconducting films grown by pulsed laser deposition

    Science.gov (United States)

    Ariosa, Daniel; Abrecht, M.; Pavuna, Davor; Onellion, Marshall

    2000-09-01

    In YBa2Cu3O6+x compound the tetragonal to orthorhombic transition occurs around x equals 0.3, followed by a continuum variation of lattice parameters. Hence both, the structural and superconducting properties, depend upon the oxygen content in CuO chains. Conversely, the epitaxial stress, exerted by the substrate on YBCO films, modified the lattice parameters influencing the oxygen stability in the chains. The understanding of this mechanism is essential when growing epitaxial films for in- situ photoemission studies as well as for tunneling experiments, since the oxygen stability up to the top surface unit-cell is a central issue. We have studied this effect on c-axis oriented YBCO films grown by laser ablation on (001) STO single crystals. Accurate x-ray diffraction analysis of thick films (t GRT 500 angstrom) indicates the presence of two distinct layers, one strained and the other relaxed. Detailed analysis shows that the relaxed layer is as well oxidized as bulk samples, while the strained one is oxygen deficient. Furthermore, despite an oxygen content of about x equals 0.65, the strained layer is in the tetragonal phase (in bulk, the tetragonal phase exists for x < 0.3). We discuss these results in terms of competition between the chemical pressure induced by oxygen inclusion in the chains, and the uniaxial stress within the film.

  9. In vivo tear film thickness measurement and tear film dynamics visualization using spectral domain optical coherence tomography.

    Science.gov (United States)

    Aranha Dos Santos, Valentin; Schmetterer, Leopold; Gröschl, Martin; Garhofer, Gerhard; Schmidl, Doreen; Kucera, Martin; Unterhuber, Angelika; Hermand, Jean-Pierre; Werkmeister, René M

    2015-08-10

    Dry eye syndrome is a highly prevalent disease of the ocular surface characterized by an instability of the tear film. Traditional methods used for the evaluation of tear film stability are invasive or show limited repeatability. Here we propose a new non-invasive fully automated approach to measure tear film thickness based on spectral domain optical coherence tomography and on an efficient delay estimator. Silicon wafer phantom were used to validate the thickness measurement. The technique was applied in vivo in healthy subjects. Series of tear film thickness maps were generated, allowing for the visualization of tear film dynamics. Our results show that the in vivo central tear film thickness measurements are precise and repeatable with a coefficient of variation of about 0.65% and that repeatable tear film dynamics can be observed. The presented approach could be used in clinical setting to study patients with dry eye disease and monitor their treatments.

  10. Morphology of superconducting FeSe thin films grown by MBE and RF-sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Kronenberg, Alexander; Venzmer, Eike; Haaf, Sebastian ten; Jourdan, Martin [Institut fuer Physik, Johannes Gutenberg Universitaet Mainz (Germany); Maletz, Janek [Institut fuer Physik, Johannes Gutenberg Universitaet Mainz (Germany); Leibniz-Institut fuer Festkoerper- und Werkstoffforschung, Dresden (Germany)

    2013-07-01

    Tunneling spectroscopy on planar junctions is the most direct approach for the investigation of superconducting coupling mechanisms. However, it requires smooth interfaces at the tunneling barrier. The morphology of superconducting thin films of FeSe grown by MBE and co-sputtering (RF) from an iron and a selenium target are compared. MBE deposited films show an extreme sensitivity to stoichiometry, deposition temperature and choice of substrate. These films exhibit macroscopic crevices and a pronounced roughness, rendering the preparation of tunneling junctions impossible. However, sputter deposited epitaxial FeSe thin films clearly show a more favorable morphology. Optical microscopy, AFM and SEM demonstrate a smooth surface with segregations which are eliminated by proper choice of the deposition parameters.

  11. The application of the barrier-type anodic oxidation method to thickness testing of aluminum films

    Science.gov (United States)

    Chen, Jianwen; Yao, Manwen; Xiao, Ruihua; Yang, Pengfei; Hu, Baofu; Yao, Xi

    2014-09-01

    The thickness of the active metal oxide film formed from a barrier-type anodizing process is directly proportional to its formation voltage. The thickness of the consumed portion of the metal film is also corresponding to the formation voltage. This principle can be applied to the thickness test of the metal films. If the metal film is growing on a dielectric substrate, when the metal film is exhausted in an anodizing process, because of the high electrical resistance of the formed oxide film, a sudden increase of the recorded voltage during the anodizing process would occur. Then, the thickness of the metal film can be determined from this voltage. As an example, aluminum films are tested and discussed in this work. This method is quite simple and is easy to perform with high precision.

  12. Superconductivity

    CERN Document Server

    Ketterson, John B

    2008-01-01

    Conceived as the definitive reference in a classic and important field of modern physics, this extensive and comprehensive handbook systematically reviews the basic physics, theory and recent advances in the field of superconductivity. Leading researchers, including Nobel laureates, describe the state-of-the-art in conventional and unconventional superconductors at a particularly opportune time, as new experimental techniques and field-theoretical methods have emerged. In addition to full-coverage of novel materials and underlying mechanisms, the handbook reflects continued intense research into electron-phone based superconductivity. Considerable attention is devoted to high-Tc superconductivity, novel superconductivity, including triplet pairing in the ruthenates, novel superconductors, such as heavy-Fermion metals and organic materials, and also granular superconductors. What’s more, several contributions address superconductors with impurities and nanostructured superconductors. Important new results on...

  13. CO2 Selective Potentiometric Sensor in Thick-film Technology

    Directory of Open Access Journals (Sweden)

    Ralf Moos

    2008-08-01

    Full Text Available A potentiometric sensor device based on screen-printed Nasicon films was investigated. In order to transfer the promising sensor concept of an open sodium titanate reference to thick film technology, “sodium-rich” and “sodium-poor” formulations were compared. While the “sodium-rich” composition was found to react with the ion conducting Nasicon during thermal treatment, the “sodium-poor” reference mixture was identified as an appropriate reference composition. Screen-printed sensor devices were prepared and tested with respect to CO2 response, reproducibility, and cross-interference of oxygen. Excellent agreement with the theory was observed. With the integration of a screen-printed heater, sensor elements were operated actively heated in a cold gas stream.

  14. Reentrant Resistive Behavior and Dimensional Crossover in Disordered Superconducting TiN Films.

    Science.gov (United States)

    Postolova, Svetlana V; Mironov, Alexey Yu; Baklanov, Mikhail R; Vinokur, Valerii M; Baturina, Tatyana I

    2017-05-11

    A reentrant temperature dependence of the normal state resistance often referred to as the N-shaped temperature dependence, is omnipresent in disordered superconductors - ranging from high-temperature cuprates to ultrathin superconducting films - that experience superconductor-to-insulator transition. Yet, despite the ubiquity of this phenomenon its origin still remains a subject of debate. Here we investigate strongly disordered superconducting TiN films and demonstrate universality of the reentrant behavior. We offer a quantitative description of the N-shaped resistance curve. We show that upon cooling down the resistance first decreases linearly with temperature and then passes through the minimum that marks the 3D-2D crossover in the system. In the 2D temperature range the resistance first grows with decreasing temperature due to quantum contributions and eventually drops to zero as the system falls into a superconducting state. Our findings demonstrate the prime importance of disorder in dimensional crossover effects.

  15. Charge transport in films of Geobacter sulfurreducens on graphite electrodes as a function of film thickness

    KAUST Repository

    Jana, Partha Sarathi

    2014-01-01

    Harnessing, and understanding the mechanisms of growth and activity of, biofilms of electroactive bacteria (EAB) on solid electrodes is of increasing interest, for application to microbial fuel and electrolysis cells. Microbial electrochemical cell technology can be used to generate electricity, or higher value chemicals, from organic waste. The capability of biofilms of electroactive bacteria to transfer electrons to solid anodes is a key feature of this emerging technology, yet the electron transfer mechanism is not fully characterized as yet. Acetate oxidation current generated from biofilms of an EAB, Geobacter sulfurreducens, on graphite electrodes as a function of time does not correlate with film thickness. Values of film thickness, and the number and local concentration of electrically connected redox sites within Geobacter sulfurreducens biofilms as well as a charge transport diffusion co-efficient for the biofilm can be estimated from non-turnover voltammetry. The thicker biofilms, of 50 ± 9 μm, display higher charge transport diffusion co-efficient than that in thinner films, as increased film porosity of these films improves ion transport, required to maintain electro-neutrality upon electrolysis. This journal is © the Partner Organisations 2014.

  16. Anisotropy of superconductivity of as-grown MgB$_2$ thin films by molecular beam epitaxy

    OpenAIRE

    Harada, Y.; Udsuka, M.; Nakanishi, Y.; Yoshizawa, M.

    2004-01-01

    Superconducting thin films of magnesium diboride (MgB$_2$) were prepared on MgO (001) substrate by a molecular beam epitaxy (MBE) method with the co-evaporation conditions of low deposition rate in ultra-high vacuum. The structural and physical properties of the films were studied by RHEED, XRD, XPS, resistivity and magnetization measurements.All films demonstrated superconductivity without use of any post-annealing process.The highest {\\it T}$_{c,onset}$ determined by resistivity measurement...

  17. Novel Ballistic Processing of Sn-0.7Cu Thick Films

    Science.gov (United States)

    Cavero, D.; Stewart, K.; Morsi, K.

    2016-11-01

    The present paper discusses a novel process (Ballistic Processing) for the ultra-rapid processing of textured and un-textured thick and potentially thin films. The effect of processing velocity (14.6 to 36.1 m/s) on the developed external structure and internal microstructure of Sn-0.7Cu thick film is discussed. Film thicknesses ranging from 6.08 to 12.79 μm were produced and characterized by two-dimensional hypoeutectic microstructures. Both film thickness and dendrite arm spacing decreased with an increase in processing velocity.

  18. Thick-film acoustic emission sensors for use in structurally integrated condition-monitoring applications.

    Science.gov (United States)

    Pickwell, Andrew J; Dorey, Robert A; Mba, David

    2011-09-01

    Monitoring the condition of complex engineering structures is an important aspect of modern engineering, eliminating unnecessary work and enabling planned maintenance, preventing failure. Acoustic emissions (AE) testing is one method of implementing continuous nondestructive structural health monitoring. A novel thick-film (17.6 μm) AE sensor is presented. Lead zirconate titanate thick films were fabricated using a powder/sol composite ink deposition technique and mechanically patterned to form a discrete thick-film piezoelectric AE sensor. The thick-film sensor was benchmarked against a commercial AE device and was found to exhibit comparable responses to simulated acoustic emissions.

  19. Non-linear dynamics of inlet film thickness during unsteady rolling process

    Science.gov (United States)

    Fu, Kuo; Zang, Yong; Gao, Zhiying; Qin, Qin; Wu, Diping

    2016-05-01

    The inlet film thickness directly affects film and stress distribution of rolling interfaces. Unsteady factors, such as unsteady back tension, may disturb the inlet film thickness. However, the current models of unsteady inlet film thickness lack unsteady disturbance factors and do not take surface topography into consideration. In this paper, based on the hydrodynamic analysis of inlet zone an unsteady rolling film model which concerns the direction of surface topography is built up. Considering the small fluctuation of inlet angle, absolute reduction, reduction ratio, inlet strip thickness and roll radius as the input variables and the fluctuation of inlet film thickness as the output variable, the non-linear relationship between the input and output is discussed. The discussion results show that there is 180° phase difference between the inlet film thickness and the input variables, such as the fluctuant absolute reduction, the fluctuant reduction ratio and non-uniform inlet strip thickness, but there is no phase difference between unsteady roll radius and the output. The inlet angle, the steady roll radius and the direction of surface topography have significant influence on the fluctuant amplitude of unsteady inlet film thickness. This study proposes an analysis method for unsteady inlet film thickness which takes surface topography and new disturbance factors into consideration.

  20. Microstructure and texture analysis of YBCO thick film with peritectic growth on unoriented silver substrate

    Institute of Scientific and Technical Information of China (English)

    WANG Jue; MALOUFI Nabila; FAN Zhanguo; XUE Xiangxin; ESLING Claude

    2009-01-01

    YBCO textured thick film was prepared by direct periteetic growth method. Microstructure of the film was characterized. Electron backscattered diffraction (EBSD) technique was applied to the film for quantitative texture analysis. The main difficulty in resolving the ori-entation of YBCO pseudo-cubic structure was investigated. Automated orientation mapping was performed on YBCO thick film. Local tex-ture was presented in the form of orientation maps. Misorientation distribution and crystal growth characterization in the YBCO thick film were revealed. Large domains with well-aligned YBCO grains were formed. Each domain presented clear in-plane and out-plane textures.

  1. Development of Strontium Titanate Thin films on Technical Substrates for Superconducting Coated Conductors

    DEFF Research Database (Denmark)

    Pallewatta, Pallewatta G A P; Yue, Zhao; Grivel, Jean-Claude

    2012-01-01

    SrTiO3 is a widely studied perovskite material due to its advantages as a template for high temperature superconducting tapes. Heteroepitaxial SrTiO3 thin films were deposited on Ni/W tapes using dip-coating in a precursor solution followed by drying and annealing under reducing conditions. Nearl...

  2. Buffer layers for REBCO films for use in superconducting devices

    Science.gov (United States)

    Goyal, Amit; Wee, Sung-Hun

    2014-06-10

    A superconducting article includes a substrate having a biaxially textured surface. A biaxially textured buffer layer, which can be a cap layer, is supported by the substrate. The buffer layer includes a double perovskite of the formula A.sub.2B'B''O.sub.6, where A is rare earth or alkaline earth metal and B' and B'' are different transition metal cations. A biaxially textured superconductor layer is deposited so as to be supported by the buffer layer. A method of making a superconducting article is also disclosed.

  3. Localization and pair breaking parameter in superconducting molybdenum nitride thin films

    Science.gov (United States)

    Tsuneoka, Takuya; Makise, Kazumasa; Maeda, Sho; Shinozaki, Bunju; Ichikawa, Fusao

    2017-01-01

    We have investigated the superconductor-insulator transition in molybdenum nitride films prepared by deposition onto MgO substrates. It is indicated that the T c depression from ≈ 6.6 \\text{K} for thick films with increase of the normal state sheet resistance R\\text{sq}\\text{N} was well explained by the Finkel’stein formula from the localization theory. Present analysis suggests that the superconducting-insulator transition occurs at a critical sheet resistance {{R}\\text{c}}≈ 2 \\text{k} Ω . It is found that the {{R}\\text{sq}}(T) above {{R}\\text{c}} shows different characteristics of {{R}\\text{sq}}(T)={{R}\\text{sq,0}}-A\\ln T and {{R}\\text{sq}}(T)\\propto \\exp ≤ft[{≤ft({{T}0}/T\\right)}1/2}\\right] in the regions {{R}\\text{c}}\\text{sq}\\text{N}{{R}\\text{Q}} , respectively, where {{R}\\text{sq,0}} is the classical residual resistance and A is a constant. The excess conductance {{σ\\prime}{}(T) due to thermal fluctuation has been analyzed by the sum of the Aslamazov-Larkin and Maki-Thompson correction terms with use of the pair breaking parameter δ in the latter term. The sum agrees well with the data, although the experimental results of the R\\text{sq}\\text{N} dependence of δ , that is, δ \\propto {{≤ft(R\\text{sq}\\text{N}\\right)}≈ 1.7} shows the disagreement with a linear relation δ \\propto ≤ft(R\\text{sq}\\text{N}\\right) derived from the localization theory.

  4. Thickness dependent CARS measurement of polymeric thin films without depth-profiling.

    Science.gov (United States)

    Choi, Dae Sik; Jeoung, Sae Chae; Chon, Byung-Hyuk

    2008-02-18

    Coherent anti-Stokes Raman scattering (CARS) microscopy is demonstrated to be a promising optical method for the characterization of polymer films with film thickness varying between 180 nm to 4300 nm. In case of PMMA films with a thickness of few hundreds of nanometers, the observed CARS signal was mainly associated with the interference effect of large nonresonant CARS field from glass substrate and the weak resonant field of PMMA. The dependence of resonant CARS intensity of PMMA film on film thickness is in good agreement with the theoretical prediction on a CARS field. The current work offers potential possibilities of noninvasive thickness measurement of polymeric thin film of thickness less than 180 nm by multiplex CARS microscopy without depth-profiling.

  5. Development of Dual-light Path Monitoring System of Optical Thin-film Thickness

    Institute of Scientific and Technical Information of China (English)

    XU Shi-jun

    2005-01-01

    The accurate monitoring of optical thin-film thickness is a key technique for depositing optical thin-film. For existing coating equipments, which are low precision and automation level on monitoring thin-film thickness, a new photoelectric control and analysis system has been developed. In the new system, main techniques include a photoelectric system with dual-light path, a dual-lock-phase circuit system and a comprehensive digital processing-control-analysis system.The test results of new system show that the static and dynamic stabilities and the control precision of thin-film thickness are extremely increased. The standard deviation of thin-film thickness, which indicates the duplication of thin-film thickness monitoring, is equal to or less than 0.72%. The display resolution limit on reflectivity is 0.02 %. In the system, the linearity of drift is very high, and the static drift ratio approaches zero.

  6. Use of thin films in high-temperature superconducting bearings.

    Energy Technology Data Exchange (ETDEWEB)

    Hull, J. R.; Cansiz, A.

    1999-09-30

    In a PM/HTS bearing, locating a thin-film HTS above a bulk HTS was expected to maintain the large levitation force provided by the bulk with a lower rotational drag provided by the very high current density of the film. For low drag to be achieved, the thin film must shield the bulk from inhomogeneous magnetic fields. Measurement of rotational drag of a PM/HTS bearing that used a combination of bulk and film HTS showed that the thin film is not effective in reducing the rotational drag. Subsequent experiments, in which an AC coil was placed above the thin-film HTS and the magnetic field on the other side of the film was measured, showed that the thin film provides good shielding when the coil axis is perpendicular to the film surface but poor shielding when the coil axis is parallel to the surface. This is consistent with the lack of reduction in rotational drag being due to a horizontal magnetic moment of the permanent magnet. The poor shielding with the coil axis parallel to the film surface is attributed to the aspect ratio of the film and the three-dimensional nature of the current flow in the film for this coil orientation.

  7. Quasi-one-dimensional intermittent flux behavior in superconducting films

    DEFF Research Database (Denmark)

    Qviller, A. J.; Yurchenko, V. V.; Galperin, Y. M.

    2012-01-01

    . The intermittent behavior shows no threshold value in the applied field, in contrast to conventional flux jumping. The results strongly suggest that the quasi-one-dimensional flux jumps are of a different nature than the thermomagnetic dendritic (branching) avalanches that are commonly found in superconducting...

  8. A study of two-level system defects in dielectric films using superconducting resonators

    Science.gov (United States)

    Khalil, Moe Shwan

    In this dissertation I describe measurements of dielectric loss at microwave frequencies due to two level systems (TLS) using superconducting resonators. Most measurements were performed in a dilution refrigerator at temperatures between 30 and 200 mK and all resonators discussed were fabricated with thin-film superconducting aluminum. I derive the transmission through a non-ideal (mismatched) resonant circuit and find that in general the resonance line-shape is asymmetric. I describe an analysis method for extracting the internal quality factor (Q i), the diameter correction method (DCM), and compare it to a commonly used phenomenological method, the phi rotation method (phiRM). I analytically find that the phiRM deterministically overestimates Qi when the asymmetry of the resonance line-shape is high. Four coplanar resonator geometries were studied, with frequencies spanning 5-7 GHz. They were all superconducting aluminum fabricated on sapphire and silicon substrates. These include a quasi-lumped element resonator, a coplanar strip transmission line resonator, and two hybrid designs that contain both a coplanar strip and a quasi-lumped element. Measured Qi's were as high as 2 x 105 for single photon excitations and there was no systematic variation in loss between quasi-lumped and coplanar strip resonance modes. I also measured the microwave loss tangent of several atomic layer deposition (ALD) grown dielectrics and obtained secondary ion mass spectrometry (SIMS) measurements of the same films. I found that hydrogen defect concentrations were correlated with low temperature microwave loss. In amorphous films that showed excess hydrogen defects on the surface, two independent TLS distributions were required to fit the loss tangent, one for the surface and one for the bulk. In crystalline dielectrics where hydrogen contamination was uniform throughout the bulk, a single bulk TLS distribution was sufficient. Finally, I measured the TLS loss in 250 nm thick HD

  9. Gate-induced superconductivity in a solution-processed organic polymer film.

    Science.gov (United States)

    Schön, J H; Dodabalapur, A; Bao, Z; Kloc, C; Schenker, O; Batlogg, B

    2001-03-08

    The electrical and optical properties of conjugated polymers have received considerable attention in the context of potentially low-cost replacements for conventional metals and inorganic semiconductors. Charge transport in these organic materials has been characterized in both the doped-metallic and the semiconducting state, but superconductivity has not hitherto been observed in these polymers. Here we report a distinct metal-insulator transition and metallic levels of conductivity in a polymer field-effect transistor. The active material is solution-cast regioregular poly(3-hexylthiophene), which forms relatively well ordered films owing to self-organization, and which yields a high charge carrier mobility (0.05-0.1 cm2 V(-1) s(-1)) at room temperature. At temperatures below approximately 2.35 K with sheet carrier densities exceeding 2.5 x 10(14) cm(-2), the polythiophene film becomes superconducting. The appearance of superconductivity seems to be closely related to the self-assembly properties of the polymer, as the introduction of additional disorder is found to suppress superconductivity. Our findings therefore demonstrate the feasibility of tuning the electrical properties of conjugated polymers over the largest range possible-from insulating to superconducting.

  10. Growth of superconducting SmFeAs(O, F) epitaxial films by F diffusion

    Science.gov (United States)

    Takeda, S.; Ueda, S.; Takano, S.; Yamamoto, A.; Naito, M.

    2012-03-01

    We report on our growth of superconducting SmFeAs(O, F) films by F diffusion. In our process, F-free SmFeAsO films were grown by molecular beam epitaxy (MBE) first, and subsequently F was introduced to the films via F diffusion from an overlayer of SmF3. We compared the growth conditions and also the properties of resultant films for CaF2 and LaAlO3 substrates. The best films on CaF2 exhibited a high transition temperature, {T}_{{c}}^{{on}}~({T}_{{c}}^{{end}})=57.8 K (56.4 K) at the highest, which may exceed the highest Tc ever reported for bulk samples. Furthermore, the films on CaF2 also showed high critical current density over 1 MA cm-2 in self-field at 5 K. On the other hand, the {T}_{{c}}^{{on}}~({T}_{{c}}^{{end}}) of the film on LaAlO3 was 50.3 K (49.3 K). The deteriorated superconducting properties on LaAlO3 appear to be due to oxygen diffusion from LaAlO3 to films.

  11. Superconductivity and mesoscopic physics in planar and cylindrical films of gold-indium alloy

    Science.gov (United States)

    Zadorozhny, Yuri Kostyantinovich

    Superconducting properties of planar and cylindrical thin films of Au 0.7In0.3 alloy have been investigated by electrical transport measurements at low temperature and in the presence of applied magnetic field. The films were grown on flat substrates and on insulating fibers of sub-micron diameter, respectively, by sequential deposition and interdiffusion of alternating gold and indium layers. The primary focus of the study was the effects of disorder, sample size, sample topology, and quantum interferences on the superconducting properties of these samples. Structural and compositional analysis and transport measurements were carried out, which showed that the films were granular, with varying local indium concentrations, apparently corresponding to several distinct alloy phases. This variation, in turn, led to the variation in the local amplitude of the superconducting order parameter, and in the local superconducting transition temperature (Tc). In planar films, the presence of disorder in the sample leads to a broad superconducting transition regime, typically with a gradual resistance drop at the onset of the transition, followed by a more abrupt one as the temperature is lowered. At the lowest temperatures in transition regime, deviations from the behavior expected in Kosterlitz-Thouless-Berezinskii (KTB) vortex-antivortex pair unbinding model were found in the I-V characteristics of the films. This deviation could originate from vortex-antivortex pair unbinding by quantum tunneling rather than thermal activation. Magnetoresistance oscillations in cylindrical Au0.7In 0.3 films at low temperatures were also studied. In the high-temperature part of the superconducting transition regime, the resistance oscillated with a period of h/2e in the unit of the enclosed magnetic flux, as expected for Little-Parks effect. Unlike the cylindrical samples discussed above, which were mechanically and thermally anchored, superconducting Au0.7In0.3 cylinders used in the early

  12. Layer-by-layer assembly of nanocomposite films with thickness up to hundreds of nanometers

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ling-de; YAN Yu-hua; YU Hai-hu; GU Er-dan; JIANG De-sheng

    2006-01-01

    Polyelectrolyte/polyelectrolyte, organic molecule/colloidal CdS and polyelectrolyte/MWCNT films were fabricated via the layer-by-layer assembling technique. The assembled films were characterized by UV-vis spectrophotometer, X-ray diffractometry,nano profilometer and scanning electron microscopy. The results demonstrate that the layer-by-layer assembling technique can be used to make the nanoscaled films from polyelectrolytes and thicker composite films from suitable precursor materials. Both organic molecule/colloidal CdS films and PEI/MWCNT films with thickness of hundreds of nanometers were obtained. For the organic molecule/colloidal CdS films, a reasonable explanation for the result is that both the organic molecules and the CdS particles aggregate in the films. For the PEI/MWCNT films, obviously, it is the MWCNT that makes the great contribution to the film thickness.

  13. Effect of hexagonal patterned arrays and defect geometry on the critical current of superconducting films

    CERN Document Server

    Sadovskyy, I A; Xiao, Z -L; Kwok, W -K; Glatz, A

    2016-01-01

    Understanding the effect of pinning on the vortex dynamics in superconductors is a key factor towards controlling critical current values. Large-scale simulations of vortex dynamics can provide a rational approach to achieve this goal. Here, we use the time-dependent Ginzburg-Landau equations to study thin superconducting films with artificially created pinning centers arranged periodically in hexagonal lattices. We calculate the critical current density for various geometries of the pinning centers --- varying their size, strength, and density. Furthermore, we shed light upon the influence of pattern distortion on the magnetic field dependent critical current. We compare our result directly with available experimental measurements on patterned molybdenum-germanium films, obtaining good agreement. Our results give important systematic insights into the mechanisms of pinning in these artificial pinning landscapes and open a path for tailoring superconducting films with desired critical current behavior.

  14. Effect of hexagonal patterned arrays and defect geometry on the critical current of superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Sadovskyy, I. A.; Wang, Y. L.; Xiao, Z. -L.; Kwok, W. -K.; Glatz, A.

    2017-02-07

    Understanding the effect of pinning on the vortex dynamics in superconductors is a key factor towards controlling critical current values. Large-scale simulations of vortex dynamics can provide a rational approach to achieve this goal. Here, we use the time-dependent Ginzburg-Landau equations to study thin superconducting films with artificially created pinning centers arranged periodically in hexagonal lattices. We calculate the critical current density for various geometries of the pinning centers—varying their size, strength, and density. Furthermore, we shed light upon the influence of pattern distortion on the magnetic-field-dependent critical current. We compare our result directly with available experimental measurements on patterned molybdenum-germanium films, obtaining good agreement. Our results give important systematic insights into the mechanisms of pinning in these artificial pinning landscapes and open a path for tailoring superconducting films with desired critical current behavior.

  15. Molecular-Beam Epitaxially Grown MgB2 Thin Films and Superconducting Tunnel Junctions

    Directory of Open Access Journals (Sweden)

    Jean-Baptiste Laloë

    2011-01-01

    Full Text Available Since the discovery of its superconducting properties in 2001, magnesium diboride has generated terrific scientific and engineering research interest around the world. With a of 39 K and two superconducting gaps, MgB2 has great promise from the fundamental point of view, as well as immediate applications. Several techniques for thin film deposition and heterojunction formation have been established, each with its own advantages and drawbacks. Here, we will present a brief overview of research based on MgB2 thin films grown by molecular beam epitaxy coevaporation of Mg and B. The films are smooth and highly crystalline, and the technique allows for virtually any heterostructure to be formed, including all-MgB2 tunnel junctions. Such devices have been characterized, with both quasiparticle and Josephson tunneling reported. MgB2 remains a material of great potential for a multitude of further characterization and exploration research projects and applications.

  16. Superconductivity

    CERN Document Server

    Poole, Charles P; Creswick, Richard J; Prozorov, Ruslan

    2014-01-01

    Superconductivity, Third Edition is an encyclopedic treatment of all aspects of the subject, from classic materials to fullerenes. Emphasis is on balanced coverage, with a comprehensive reference list and significant graphics from all areas of the published literature. Widely used theoretical approaches are explained in detail. Topics of special interest include high temperature superconductors, spectroscopy, critical states, transport properties, and tunneling. This book covers the whole field of superconductivity from both the theoretical and the experimental point of view. This third edition features extensive revisions throughout, and new chapters on second critical field and iron based superconductors.

  17. Study of dielectric films in superconducting resonators using pulse echo techniques

    Science.gov (United States)

    Ramanayaka, A. N.; Sarabi, B.; Stoutimore, M. J. A.; Osborn, K. D.

    2013-03-01

    Energy absorption by two-level systems (TLS) in amorphous dielectric films is a source of decoherence in superconducting qubits, but their microscopic nature is unknown in specific films. To reveal their nature it is helpful to study their dynamics, which we do by embedding them in the parallel-plate capacitor of a linear resonator that is coupled to probing fields through a coplanar waveguide. Measurements are performed at 4-8 GHz and 25-200 mK on amorphous silicon nitride films. We will report on progress to extract the coherence times, field coupling, and the corresponding distributions of these tunneling states.

  18. A novel electron beam evaporation technique for the deposition of superconducting thin films

    Science.gov (United States)

    Krishna, M. G.; Muralidhar, G. K.; Rao, K. N.; Rao, G. M.; Mohan, S.

    1991-05-01

    Superconducting thin films of BiSrCaCuO have been deposited using a novel electron beam evaporation technique. In this technique the crucible has a groove around its circumference and rotates continuously during deposition. The source material is loaded in the form of pellets of the composite. Both oxides as well as flourides have been used in the starting material and a comparison of the film properties has been made. The best film was obtained on a MgO(100) substrate with a Tc onset at 85 K and Tc zero at 77 K using calcium flouride in the source material.

  19. Finite-element simulations of field and current distributions in multifilamentary superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Lucarelli, Andrea [Laboratorium fuer Festkoerperphysik, ETH-Zuerich, CH-8093 Zuerich (Switzerland); Grilli, Francesco [Ecole Polytechnique Montreal, Montreal (Canada); Luepke, Gunter [Department of Applied Science, The College of William and Mary, Williamsburg, VA 23187-8795 (United States); Haugan, Timothy J; Barnes, Paul N [Air Force Research Laboratory, Wright-Patterson AFB, OH 45433-7919 (United States)

    2009-10-15

    We present a finite-element model for computing current and field distributions in multifilamentary superconducting thin films subjected to simultaneous effects of a transport ac current and a perpendicularly applied dc field. The model is implemented in the finite-element software package COMSOL Multiphysics and this solves Maxwell equations using a highly nonlinear resistivity to describe electrical superconducting characteristics. The time-dependent magnetic flux, current distributions, and ac losses are studied for different distances between filaments. We find that increasing the interfilamentary distance affects the transport and screening current distributions, reducing both the magnetic coupling and ac losses.

  20. Thin-film superconducting resonator tunable to the ground-state hyperfine splitting of $^{87}$Rb

    CERN Document Server

    Kim, Z; Hoffman, J E; Grover, J A; Voigt, K D; Cooper, B K; Ballard, C J; Palmer, B S; Hafezi, M; Taylor, J M; Anderson, J R; Dragt, A J; Lobb, C J; Orozco, L A; Rolston, S L; Wellstood, F C

    2011-01-01

    We describe a thin-film superconducting Nb microwave resonator, tunable to within 0.3 ppm of the hyperfine splitting of $^{87}$Rb at $f_{Rb}=6.834683$ GHz. We coarsely tuned the resonator using electron-beam lithography, decreasing the resonance frequency from 6.8637 GHz to 6.8278 GHz. For \\emph{in situ} fine tuning at 15 mK, the resonator inductance was varied using a piezoelectric stage to move a superconducting pin above the resonator. We found a maximum frequency shift of about 8.7 kHz per 60-nm piezoelectric step and a tuning range of 18 MHz.

  1. Frustrated magnetic response of a superconducting Nb film with a square lattice of columnar defects

    Energy Technology Data Exchange (ETDEWEB)

    Zadorosny, R; Ortiz, W A [Grupo de Supercondutividade e Magnetismo, Departamento de Fisica, Universidade Federal de Sao Carlos, Sao Carlos, SP (Brazil); Lepienski, C M [Universidade Federal do Parana, Departamento de Fisica, Curitiba, PR (Brazil); Patino, E; Blamire, M G [Department of Materials Science, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom)], E-mail: rafazad@df.ufscar.br

    2008-02-01

    The magnetic response of a superconducting system presenting a frustrated state is investigated. The system is a superconducting film with mechanically pierced columns, cooled in a field which is then removed. Frustration originates from the competition between return flux of a dipole - created by flux trapped in the empty columns - and flux exclusion by the surrounding superconductor in the Meissner state. The system resolves the incompatibility among conflicting constraints, leading to frustration, by eliminating return flux, which is possibly assimilated by nearby columns, as manifested by a sudden reduction of the magnetic moment on the decreasing field branch of the hysteresis loop.

  2. Homogeneous lattice disorder and superconducting properties of YBa2Cu3O6.9 films.

    Science.gov (United States)

    Pavuna, Davor; Gauzzi, Andrea

    We discuss the striking changes of the superconducting properties of YBa2Cu3O6.9 films to the homogeneous lattice disorder, induced by varying growth temperatures: Tc decreases with increasing disorder, while the width of the resistive transition and the normal state resistivity increase. We estimate the length scale of such dis- order from the broadening DJ of the lt; 005 > X-ray diffraction rocking curves. The suppression of superconductivity and normal conductivity scales as DJ and appears for in-plane lattice coherence lengths rc ≫ 1/DJ smaller than about 10 nm.

  3. Investigation of Top/Bottom electrode and Diffusion Barrier Layer for PZT Thick Film MEMS Sensors

    DEFF Research Database (Denmark)

    Hindrichsen, Christian Carstensen; Pedersen, Thomas; Thomsen, Erik Vilain

    2008-01-01

    Top and bottom electrodes for screen printed piezoelectric lead zirconate titanate, Pb(ZrxTi1 - x)O3 (PZT) thick film are investigated with respect to future MEMS devices. Down to 100 nm thick E-beam evaporated Al and Pt films are patterned as top electrodes on the PZT using a lift-off process...

  4. On the film thickness of grease-lubricated contacts at low speed

    NARCIS (Netherlands)

    Cen, H.; Lugt, Pieter Martin; Morales-Espejel, G.E.

    2014-01-01

    The contribution of the thickener to the thickness of the lubricating film in grease-lubricated contacts is investigated. Four different types of greases were tested in a ball/spherical roller-on-disc machine, where the film thickness was measured using the interferometry method, varying the tempera

  5. Raman micro-spectroscopy for quantitative thickness measurement of nanometer thin polymer films

    NARCIS (Netherlands)

    Liszka, Barbara M.; Lenferink, Aufried T.M.; Witkamp, Geert-Jan; Otto, Cees

    2015-01-01

    The sensitivity of far-field Raman micro-spectroscopy was investigated to determine quantitatively the actual thickness of organic thin films. It is shown that the thickness of organic films can be quantitatively determined down to 3 nm with an error margin of 20% and down to 1.5 nm with an error ma

  6. Crossover from negative to positive magnetoresistance in superconductor/ferromagnet composites thick films

    Energy Technology Data Exchange (ETDEWEB)

    Paredes, O. [Centro de Materiales, Facultad de Ingenieria, Universidad de Narino, Ciudad Universitaria Torobajo, Pasto (Colombia); Baca, E. [Grupo de Ingenieria de Nuevos Materiales, Departamento de Fisica, Universidad del Valle, A.A. 25360 Cali (Colombia); Fuchs, D. [Karlsruhe Institute of Technology, Institut fuer Festkoerperphysik, P.O. Box 3640, Karlsruhe (Germany); Moran, O., E-mail: omoranc@unal.edu.c [Laboratorio de Materiales Ceramicos y Vitreos, Departamento de Fisica, Universidad Nacional de Colombia, Sede Medellin, A.A. 568 Medellin (Colombia)

    2010-11-15

    Thick films of ((Bi, Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x}){sub 0.95}/(LaSr{sub 0.7}Mn{sub 0.3}O{sub 3}){sub 0.05} [(Bi-2223){sub 0.95}(LSMO){sub 0.05}] composites were fabricated on (0 0 1)-oriented LaAlO{sub 3} substrates by a simple melting-quenching-annealing method and their structural, morphological and magnetoelectrical properties carefully studied. Analysis of the X-ray diffraction patterns suggested a highly oriented growth along the c-axis of LSMO. This preferred orientation, with the crystal c-axis being perpendicular to the plane of the substrate, was considered to be indicative of a textured growth mode. Electrical and magnetic measurements showed the presence of ferromagnetism and superconductivity in the composite at temperatures above room temperature and below T{approx}50 K, respectively. A clear crossover from negative to positive magnetoresistance was observed at {approx}80 K in a magnetic field as strong as 5 T.

  7. Piezoelectric ceramic thick films deposited on silicon substrates by screen printing

    Science.gov (United States)

    Yao, Kui; He, Xujiang; Xu, Yuan; Chen, Meima

    2004-07-01

    Screen-printing processes offer advantages in producing directly patterned and integrated piezoelectric elements, and fill an important technological gap between thin film and bulk ceramics. However, several existing problems in the screen-printed piezoelectric thick films, such as the poor reliability and the required high sintering temperature, are significantly limiting their applications. In this work, lead zirconate titanate (PZT) ceramic films of 30 μm in thickness were deposited on Pt-coated silicon substrates by the screen-printing process, in which the ceramic pastes were prepared through a chemical liquid-phase doping approach. Porous thick films with good adhesion were formed on the substrates at a temperature of 925°C. Stable out-of-plane piezoelectric vibration of the thick films was observed with a laser scanning vibrometer (LSV), and the piezoelectric dilatation magnitude was determined accordingly. Our piezoelectric measurements through the areal displacement detection with LSV exhibited distinct advantages for piezoelectric film characterization, including high reliability, high efficiency, and comprehensive information. The longitudinal piezoelectric coefficients of the thick films were calculated from the measured dilatation data through a numerical simulation. High piezoelectric voltage constants were obtained due to the very low dielectric constant of the porous thick films. The application potentials of our screen-printed thick films as integrated piezoelectric sensors are discussed.

  8. Effect of thickness on electrical properties of SILAR deposited SnS thin films

    Science.gov (United States)

    Akaltun, Yunus; Astam, Aykut; Cerhan, Asena; ćayir, Tuba

    2016-03-01

    Tin sulfide (SnS) thin films of different thickness were prepared on glass substrates by successive ionic layer adsorption and reaction (SILAR) method at room temperature using tin (II) chloride and sodium sulfide aqueous solutions. The thicknesses of the films were determined using spectroscopic ellipsometry measurements and found to be 47.2, 65.8, 111.0, and 128.7nm for 20, 25, 30 and 35 deposition cycles respectively. The electrical properties of the films were investigated using d.c. two-point probe method at room temperature and the results showed that the resistivity was found to decrease with increasing film thickness.

  9. Measurement of the refractive index and thickness for infrared optical films deposited on rough substrates.

    Science.gov (United States)

    Saito, M; Nakamura, S; Miyagi, M

    1992-10-01

    A novel method is proposed to evaluate the refractive index and thickness of dielectric thin films in the infrared wavelength range. The method is useful for measurement of thin films that are formed on such rough substrates as metal plates, since it utilizes only the wavelengths of interference peaks, which is slightly affected by surface roughness of the sample. The method was applied to the measurement of germanium, zinc selenide, and lead fluoride films deposited on copper substrates. Measured thicknesses agreed well with the values that were obtained by ellipsometry, and refractive indices exhibited a tendency to increase with the film thickness.

  10. Laser desorption of NO from a thick C 60 film

    Science.gov (United States)

    Hoger, T.; Marzok, C.; Jongma, R. T.; Zacharias, H.

    2006-09-01

    The desorption of NO molecules from a thick C 60 film is reported. A thermal desorption spectrum indicates two adsorption sites with binding energies of Eb = 0.30 eV and 0.55 eV. For laser desorption the fullerene surface is exposed to NO and excited by 7 ns UV laser pulses. Desorbing NO molecules are recorded state selectively as well as time resolved. The time-of-flight measurement indicates three different desorption pathways. A fast channel shows rovibronic temperatures of Trot( v″ = 0) = 370 K, Trot( v″ = 1) = 390 K and Tvib = 610 K as well as strong rotational-translational coupling. The desorption yield for the fast channel increases linearly with pulse energy with a desorption cross section of σ = (5.1 ± 0.9) × 10 -17 cm 2. Dominating the signal for small J″ values is a slow channel with low rotational and translational temperatures of about 110 K. We assign this peak to a laser-induced thermal desorption. For large pump-probe delays the data deviate from the Maxwellian flux distribution and a third channel appears with extremely late arrival times.

  11. Relationship between Supplied Oil Flow Rates and Oil Film Thicknesses under Starved Elastohydrodynamic Lubrication

    Directory of Open Access Journals (Sweden)

    Taisuke Maruyama

    2015-04-01

    Full Text Available Many studies have already considered starved lubrication. However, there have been no reports on the oil film thicknesses under steady starved EHL (elastohydrodynamic lubrication, where the ultra-low volume of oil supplied per unit time is uniform. The present study examined the relationship between the supplied oil flow rate and oil film thickness under steady starved lubrication. A ball-on-disk testing machine was used in experiments to measure the oil film thickness by means of optical interferometry. A microsyringe pump was used to accurately control the supplied oil flow rate. The supplied oil flow rate was kept constant, and the minimum oil film thickness was measured for 1 h after the start of the tests to determine the relationship between the supplied oil flow rate and oil film thickness.

  12. Enhanced piezoelectric performance of composite sol-gel thick films evaluated using piezoresponse force microscopy.

    Science.gov (United States)

    Liu, Yuanming; Lam, Kwok Ho; Kirk Shung, K; Li, Jiangyu; Zhou, Qifa

    2013-05-14

    Conventional composite sol-gel method has been modified to enhance the piezoelectric performance of ceramic thick films. Lead zirconate titanate (PZT) and lead magnesium niobate-lead titanate (PMN-PT) thick films were fabricated using the modified sol-gel method for ultrasonic transducer applications. In this work, piezoresponse force microscopy was employed to evaluate the piezoelectric characteristics of PZT and PMN-PT composite sol-gel thick films. The images of the piezoelectric response and the strain-electric field hysteresis loop behavior were measured. The effective piezoelectric coefficient (d33,eff) of the films was determined from the measured loop data. It was found that the effective local piezoelectric coefficient of both PZT and PMN-PT composite films is comparable to that of their bulk ceramics. The promising results suggest that the modified composite sol-gel method is a promising way to prepare the high-quality, crack-free ceramic thick films.

  13. Preparation and characterisation of novel thick sol-gel titania film photocatalysts.

    Science.gov (United States)

    Mills, Andrew; Elliott, Nicholas; Hill, George; Fallis, David; Durrant, James R; Willis, Richard L

    2003-05-01

    The preparation and characterization of thick (9 microns), clear, mechanically robust and photocatalytically active films of nanocrystalline anatase titania are described. XRD and SEM analysis show the films comprise 13 nm particles of anatase TiO2. Thin (54 nm) films of the 'paste' TiO2, along with sol-gel titania films made by a more traditional route are also prepared and characterised. All titania films mediate the photocatalytic destruction of stearic acid with a quantum yield of 0.0016 +/- 0.0003, using either 365 nm (i.e. BLB) or 254 nm (germicidal) light. P25 TiO2 films also appear to mediate the same process with a similar formal quantum efficiency. Of all the films tested, the thick paste TiO2 films are the most ideally suited for use with near UV light, for reasons which are discussed. All the titania films tested exhibit photoinduced superhydrophilicity.

  14. High-J{sub c} superconducting YBCO thin films for SQUIDs

    Energy Technology Data Exchange (ETDEWEB)

    Katsaros, A.; Savvides, N.; Foley, C. [CSIRO, Sydney, NSW (Australia). Applied Physics

    1996-12-31

    Full text: High critical current density, J{sub c}, and reproducibility of film quality are major issues in high-T{sub c} superconducting device technology. Because many factors such as substrate quality, deposition parameters and film stoichiometry impact on film quality the growth of high-J{sub c} YBa{sub 2}Cu{sub 3}O{sub 7} thin films suitable for devices is a demanding task. For optimum device performance c-axis epitaxial films are required with smooth surfaces, controlled microstructure and crystalline orientation, high T{sub c} (> 87 K) and high J{sub c} (> 1x10{sup 6} A cm{sup -2}). Consequently a stable platform in film quality is critical in developing and maintaining world class device technology. In previous Wagga meetings and elsewhere we presented details of our thin film deposition system, results of film growth studies, techniques of film characterisation and SQUID performance. In this paper we present transport properties and lattice parameters for a large number of films deposited over a period of ten months using a single target and under similar sputtering conditions. The data serve to illustrate the level of reproducibility of our deposition technology while closer examination of the data reveal some interesting `correlations` among properties. We have used these correlations to assist us to control both the deposition of films and subsequent processing into test structures and SQUIDs 5 refs.

  15. Film Thickness and Flow Properties of Resin-Based Cements at Different Temperatures

    Directory of Open Access Journals (Sweden)

    Bagheri R.

    2013-06-01

    Full Text Available Statement of Problem: For a luting agent to allow complete seating of prosthetic restorations, it must obtain an appropriate flow rate maintaining a minimum film thickness. The performance of recently introduced luting agents in this regard has not been evaluated. Purpose: To measure and compare the film thickness and flow properties of seven resin-containing luting cements at different temperatures (37°C, 25°C and10°C. Material and Methods: Specimens were prepared from five resin luting cements; seT (SDI, Panavia F (Kuraray, Varioloink II (Ivoclar, Maxcem (Kerr, Nexus2 (Kerr and two resin-modified glass-ionomer luting cements (RM-GICs; GC Fuji Plus (GC Corporation, and RelyX Luting 2 (3 M/ESPE. The film thickness and flow rate of each cement (n=15 was determined using the test described in ISO at three different temperatures. Results: There was a linear correlation between film thickness and flow rate for most of the materials. Cooling increased fluidity of almost all materials while the effect of temperature on film thickness was material dependent. At 37°C, all products revealed a film thickness of less than 25µm except for GC Fuji Plus. At 25°C, all cements pro-duced a film thickness of less than 27 µm except for seT. At 10°C, apart from seT and Rely X Luting 2, the remaining cements showed a film thickness smaller than 20 µm.Conclusion: Cooling increased fluidity of almost all materials, however. the film thickness did not exceed 35 µm in either condition, in spite of the lowest film thickness being demonstrated at the lowest temperature.

  16. High temperature superconducting thin films for microwave filters

    Institute of Scientific and Technical Information of China (English)

    ZHAO; Xinjie(赵新杰); LI; Lin(李林); LEI; Chong(雷冲); TIAN; Ybngjun(田永军)

    2002-01-01

    YBa2Cu3O7-δ and Tl2Ba2CaCu2O8 thin films for microwave filters were synthesized by pulsed laser deposition and the two-step thalliation process. Substrate quality requirements and the relation of thin film morphology, microstructure with microwave surface resistance were discussed.

  17. Spectral characteristics of nanometer-thick chromium films in terahertz frequency range

    Science.gov (United States)

    Andreev, V. G.; Angeluts, A. A.; Vdovin, V. A.; Lukichev, V. F.

    2015-02-01

    The spectral characteristics (reflection, transmission, and absorption coefficients) of thin chromium films on silica substrates have been measured using a pulsed source of terahertz radiation. The spectra of optical coefficients were obtained in a frequency range of 0.25-1.1 THz. Dependences of the optical coefficients on the metal film thickness at 1 THz were constructed. The maximum absorption coefficient (43%) was observed at a film thickness of 10 nm.

  18. Effect of thickness and temperature of copper phthalocyanine films on their properties

    Directory of Open Access Journals (Sweden)

    Alieva Kh. S.

    2012-06-01

    Full Text Available The research has shown that copper phthalocyanine films, having a set of unique properties, can be successfully used as gas-sensitive coating of resistive structures. The thickness of the film, in contrast to its temperature, is not the determining factor for high sensitivity. Low operating temperature of structures with copper phthalocyanine films allows to exploit them in economy mode.

  19. Far-infrared optical conductivity gap in superconducting MgB2 films.

    Science.gov (United States)

    Kaindl, Robert A; Carnahan, Marc A; Orenstein, Joseph; Chemla, Daniel S; Christen, Hans M; Zhai, Hong-Ying; Paranthaman, Mariappan; Lowndes, Doug H

    2002-01-14

    We report the first study of the optical conductivity of MgB2 covering the range of its lowest-energy superconducting gap. Terahertz time-domain spectroscopy is utilized to determine the complex, frequency-dependent conductivity sigma(omega) of thin films. The imaginary part reveals an inductive response due to the emergence of the superconducting condensate. The real part exhibits a strong depletion of oscillator strength near 5 meV resulting from the opening of a superconducting energy gap. The gap ratio of 2Delta0/k(B)TC approximately 1.9 is well below the weak-coupling value, pointing to complex behavior in this novel superconductor.

  20. Anomalous magnetism of superconducting Mg-doped InN film

    Directory of Open Access Journals (Sweden)

    P. H. Chang

    2016-02-01

    Full Text Available We report on the Meissner effect of Mg-doped InN film with superconducting transition onset temperature Tc,onset of 5 K. Mg-doped InN is magnetically ordered and exhibits a simultaneous first-order magnetic and electric transition near 50 K. Its behavior is similar to that of iron-based superconductors. A strong correlation is proposed to exist between structural distortion and superconductivity when Mg is doped into InN. The suppression of magnetic ordering close to Tc by doping is further demonstrated by anisotropic magnetoresistance and M-H measurements. The findings suggest that the superconducting mechanism in the system may not be conventional BCS.

  1. Critical analysis of soft point contact Andreev reflection spectra between superconducting films and pressed In

    Science.gov (United States)

    Parab, Pradnya; Chauhan, Prashant; Muthurajan, H.; Bose, Sangita

    2017-04-01

    We present a critical analysis of an alternative technique of point contact Andreev reflection (PCAR) spectroscopy used to extract energy resolved information of superconductors which is based on making ‘soft-contacts’ between superconductors and indium. This technique is not sensitive to mechanical vibrations and hence can be used in a cryogen free platform increasing its accessibility to users having no access to cryogenic liquids. Through our experiments on large number of superconducting films we show that the PCAR spectra below the T c of In show sub-harmonic gap structures consistent with the theory of multiple Andreev reflection (MAR) and a zero bias conductance (ZBC) anomaly associated with the Josephson supercurrent. Furthermore, we demonstrate that large contact resistance with low transparency ballistic contacts in the PCAR regime are required to obtain reliable spectroscopic data. One limitation of the technique arises for low contact resistance junctions where the superconducting proximity effect (SPE) reduces the value of the superconducting energy gap.

  2. Microstructural parameters and optical constants of ZnTe thin films with various thicknesses

    Science.gov (United States)

    Shaaban, Essam R.; Kansal, Ishu; Mohamed, S. H.; Ferreira, Joés M. F.

    2009-11-01

    Different thickness of polycrystalline ZnTe films have been deposited onto glass substrates at room temperature by vacuum evaporation technique. The structural characteristics studied by X-ray diffraction (XRD) showed that the films are polycrystalline and have a zinc blende (cubic) structure. The calculated microstructure parameters revealed that the crystallite size increases and microstrain decreases with increasing film thickness. The transmittance and reflectance have been measured at normal and near normal incidence, respectively, in the spectral range 400-2500 nm. For ZnTe films of different thicknesses, the dependence of absorption coefficient, α on the photon energy showed the occurrence of a direct transition with band gap energy Egopt=2.21±0.01 eV (For ZnTe films of different thicknesses) confirming the independency of deduced energy gap on film thickness. The refractive indices have been evaluated in terms of envelope method, which has been suggested by Swanepoul in the transparent region. The refractive index could be extrapolated by Cauchy dispersion relationship over the whole spectra range, which extended from 400 to 2500 nm. It was observed that the refractive index, n increased upon increasing the film thickness up to 508 nm, lying within the experimental error for further increases in film thickness.

  3. Thickness-dependent stress in plasma-deposited silicon dioxide films

    Science.gov (United States)

    Au, V.; Charles, C.; Bulla, D. A. P.; Love, J. D.; Boswell, R. W.

    2005-04-01

    Thick silicon dioxide (SiO2) films up to 5 μm have been deposited by helicon activated reactive evaporation (plasma assisted deposition with electron beam evaporation source) as both bilayer and trilayer structures, and the film stress was investigated in the context of optical waveguide fabrication. A model for stress in the SiO2-Si bilayer as a function of film thickness is formulated and interpreted in terms of Volmer-Weber film growth mechanisms. We find that island coalescence begins at a film thickness of less than 165 nm and continues until about 700 nm. Above approximately 1 μm thickness, the film continues growth as a continuous film. The stress in a deposited SiO2 film in an SiO2-Si-SiO2 trilayer structure was investigated by adapting the established Stoney's equation for a trilayer system, and comparing it with a thermally grown SiO2 trilayer. A constant value of stress is obtained for the deposited SiO2 film for film thickness >1μm which was consistently less than both measured and previously reported values of stress in thermally grown SiO2.

  4. Advanced photon detectors using superconducting MgB2 films Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The goals of the proposed work are to Investigate the film thickness (10–50 nm), substrate material (c-plane sapphire, MgO), and temperature (20-35 K)...

  5. Change in Tear Film Lipid Layer Thickness, Corneal Thickness, Volume and Topography after Superficial Cauterization for Conjunctivochalasis.

    Science.gov (United States)

    Chan, Tommy C Y; Ye, Cong; Ng, Paul K F; Li, Emmy Y M; Yuen, Hunter K L; Jhanji, Vishal

    2015-07-17

    We evaluated the change in tear film lipid layer thickness, corneal thickness, volume and topography after superficial cauterization of symptomatic conjunctivochalasis. Bilateral superficial conjunctival cauterization was performed in 36 eyes of 18 patients with symptomatic conjunctivochalasis. The mean age of patients (12 males, 6 females) was 68.6 ± 10.9 years (range: 44-83 years). Preoperatively, 28 eyes (77.8%) had grade 1 conjunctivochalasis, and 8 eyes (22.2%) had grade 2 conjunctivochalasis. At 1 month postoperatively, the severity of conjunctivochalasis decreased significantly (p corneal thickness, thinnest corneal thickness and corneal volume decreased significantly postoperatively (p corneal thickness and volume were observed after surgical correction of conjunctivochalasis.

  6. High-temperature superconductivity in one-unit-cell FeSe films

    Science.gov (United States)

    Wang, Ziqiao; Liu, Chaofei; Liu, Yi; Wang, Jian

    2017-04-01

    Since the dramatic enhancement of the superconducting transition temperature (T c) was reported in a one-unit-cell FeSe film grown on a SrTiO3 substrate (1-UC FeSe/STO) by molecular beam epitaxy (MBE), related research on this system has become a new frontier in condensed matter physics. In this paper, we present a brief review on this rapidly developing field, mainly focusing on the superconducting properties of 1-UC FeSe/STO. Experimental evidence for high-temperature superconductivity in 1-UC FeSe/STO, including direct evidence revealed by transport and diamagnetic measurements, as well as other evidence from scanning tunneling microscopy (STM) and angle-resolved photoemission spectroscopy (ARPES), are overviewed. The potential mechanisms of the enhanced superconductivity are also discussed. There are accumulating arguments to suggest that the strengthened Cooper pairing in 1-UC FeSe/STO originates from the interface effects, specifically the charge transfer and coupling to phonon modes in the TiO2 plane. The study of superconductivity in 1-UC FeSe/STO not only sheds new light on the mechanism of high-temperature superconductors with layered structures, but also provides an insight into the exploration of new superconductors by interface engineering.

  7. Intrinsic flux pinning mechanisms in different thickness MgB2 films

    Directory of Open Access Journals (Sweden)

    C. Yang

    2017-03-01

    Full Text Available MgB2 films in four thickness (60 nm, 200nm, 600nm and 1μm have been fabricated by hybrid physical–chemical vapor deposition technique (HPCVD. By measuring the magnetization hysteresis loops and the resistivity, we have obtained the transport and magnetic properties of the four films. After that, the pinning mechanisms in them were discussed. Comparing the pinning behaviors in these ultrathin films, thin films and thick films, it was found that there exist different pinning types in MgB2 films of different thickness. In combination with the study of the surface morphology, cross-section and XRD results, we concluded that MgB2 films had different growth modes in different growth stages. For thin films, films grew along c axis, and grain boundaries acted as surface pinning. While for thick films, films grew along c axis at first, and then changed to a-b axis growth. As a result, the a-b axis grains acted as strong volume pinning.

  8. High quality YBCO superconductive thin films fabricated by laser molecular beam epitaxy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    High quality YBa2Cu3O6+x (YBCO) superconductive thin films have been fabricated on the SrTiO3(100) substrate using laser molecular beam epitaxy (laser-MBE).The active oxygen source was used,which made the necessary ambient oxygen pressure be 2-3 orders lower than that in pulsed laser deposition (PLD).Tc0 is 85-87 K,and Jc~1.0×106 A/cm2.Atomic force microscopy (AFM) measurements show that no obvious particulates can be observed and the root mean square roughness is 7.8 nm.High stability DC superconducting quantum interference devices (DC-SQUID) was fabricated using this YBCO thin film.

  9. Resistive evaporation of superconducting Y-Ba-Cu-O thin films from a single source

    Energy Technology Data Exchange (ETDEWEB)

    Azoulay, J.; Goldschmidt, D.

    1989-06-12

    A new evaporation method of high-temperature superconducting films, the /ital resistive vaporation/ /ital from/ /ital single/ /ital source/, isreported here for the first time. The source material, inserted into a tungstenboat in a conventional vacuum system, consisted of a pulverized mixture of Cu,YF/sub 3/, and BaF/sub 2/. The handling of the source material required only grindingand mixing of the raw materials. Its deposition onto SrTiO/sub 3/ substratesyielding superconducting films with properties very similar to those obtained ina layer-by-layer resistive evaporation of these materials. In particular, aresistive transition onset at 75 K and zero resistance at /similar to/40 K, and criticalcurrents of 2000 A/cm/sup 2/ at approx.10 K have been measured. The broad transition maybe attributed to a copper concentration gradient, as measured by Auger depthprofiling, or to a residual fluorine-rich phase.

  10. Method for producing microstructured templates and their use in providing pinning enhancements in superconducting films deposited thereon

    Science.gov (United States)

    Aytug, Tolga; Paranthaman, Mariappan Parans; Polat, Ozgur

    2013-07-16

    The present invention relates to a method for producing a phase-separated layer useful as a flux pinning substrate for a superconducting film, wherein the method includes subjecting at least a first and a second target material to a sputtering deposition technique in order that a phase-separated layer is deposited epitaxially on a primary substrate containing an ordered surface layer. The invention is also directed to a method for producing a superconducting tape containing pinning defects therein by depositing a superconducting film on a phase-separated layer produced by the method described above.

  11. Preparation and study of thickness dependent electrical characteristics of zinc sulfide thin films

    Indian Academy of Sciences (India)

    A U Ubale; D K Kulkarni

    2005-02-01

    Zinc sulfide thin films have been deposited onto glass substrates by chemical bath deposition. The various deposition parameters such as volume of sulfide ion source, pH of bath, deposition time, temperature etc are optimized. Thin films of ZnS with different thicknesses of 76–332 nm were prepared by changing the deposition time from 6–20 h at 30°C temperature. The effect of film thickness on structural and electrical properties was studied. The electrical resistivity was decreased from 1.83 × 105 -cm to 0.363 × 105 -cm as film thickness decreased from 332 nm to 76 nm. The structural and activation energy studies support this decrease in the resistivity due to improvement in crystallinity of the films which would increase the charge carrier mobility and decrease in defect levels with increase in the thickness.

  12. The preparation, processing and properties of thin and thick films for microelectric applications

    Science.gov (United States)

    Bagley, B. G.; Greene, L. H.; Barboux, P.; Tarascon, J. M.; Venkatesan, T.

    High-Tc thin and thick films of YBa2Cu2O(7-y) and thick films based on the Bi-Sr-Ca-Cu and Tl-Ba-Ca-Cu systems were prepared and their properties investigated. It was found that YB2Cu3O(7-y) thin films prepared at temperatures up to 400 C, have amorphous structures, and those prepared in the 400-650 C region exhibit polyphase microstructure, due to the rapid crystallization kinetics of the competing phases. Methods for bipassing the 'forbidden' temperature region are described. Preparation of YBa2Cu2O(7-y) thick films was achieved via an aqueous sol-gel technique. Bi-Sr-Ca-Cu- and Tl-Ba-Ca-Cu-based thick films were prepared via the decomposition of glycerol-based solutions containing nitrates of the elements.

  13. Correlation of Gear Surface Fatigue Lives to Lambda Ratio (Specific Film Thickness)

    Science.gov (United States)

    Krantz, Timothy Lewis

    2013-01-01

    The effect of the lubrication regime on gear performance has been recognized, qualitatively, for decades. Often the lubrication regime is characterized by the specific film thickness being the ratio of lubricant film thickness to the composite surface roughness. Three studies done at NASA to investigate gearing pitting life are revisited in this work. All tests were done at a common load. In one study, ground gears were tested using a variety of lubricants that included a range of viscosities, and therefore the gears operated with differing film thicknesses. In a second and third study, the performance of gears with ground teeth and superfinished teeth were assessed. Thicker oil films provided longer lives as did improved surface finish. These datasets were combined into a common dataset using the concept of specific film thickness. This unique dataset of more 258 tests provides gear designers with some qualitative information to make gear design decisions.

  14. Effect of thickness on nonlinear absorption properties of graphite oxide thin films

    Science.gov (United States)

    Sreeja, V. G.; Cheruvalathu, Ajina; Reshmi, R.; Anila, E. I.; Thomas, Sheenu; Jayaraj, M. K.

    2016-10-01

    We report the thickness dependent structural, linear and nonlinear optical properties of graphite oxide (GO) thin films synthesized by spin coating method. We observed that the structural, linear and nonlinear optical properties can be tuned by the film thickness in GO. The nonlinear absorption studies by open aperture z scan technique exhibited a saturable absorption. The nonlinear absorption coefficient and saturation intensity varies with film thickness which is attributed to increased localized defect states in the energy band gap. Our results emphasize relatively large thickness dependent optical nonlinearity of GO thin films and its potential for optical pulse generation, exploring the way to GO based nonlinear applications in Q switched mode locking laser systems. All the coated GO films were characterized by X-Ray diffraction method (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, UV-Vis absorption spectroscopy (UV-Vis), Photoluminescence (PL) and Scanning electron microscope (SEM) measurements.

  15. Studies on gas sensing performance of pure and modified barium strontium titanate thick film resistors

    Indian Academy of Sciences (India)

    G H Jain; L A Patil; P P Patil; U P Mulik; K R Patil

    2007-02-01

    Barium strontium titanate ((Ba0.87Sr0.13)TiO3–BST) ceramic powder was prepared by mechanochemical process. The thick films of different thicknesses of BST were prepared by screen-printing technique and gas-sensing performance of these films was tested for various gases. The films showed highest response and selectivity to ammonia gas. The effect of film thickness on gas response was also studied. As prepared BST thick films were surface modified by dipping them into an aqueous solution of titanium chloride (TiCl3) for different intervals of time. Surface modification shifted response to H2S gas suppressing the responses to ammonia and other gases. The surface modification, using dipping process, altered the adsorbate–adsorbent interactions, which gave the unusual sensitivity and selectivity effect. Sensitivity, selectivity, thermal stability, response and recovery time of the sensor were measured and presented.

  16. Effect of Nanotube Film Thickness on the Performance of Nanotube-Silicon Hybrid Solar Cells

    Science.gov (United States)

    Tune, Daniel D.; Shapter, Joseph G.

    2013-01-01

    The results of measurements on solar cells made from randomly aligned thin films of single walled carbon nanotubes (SWCNTs) on n-type monocrystalline silicon are presented. The films are made by vacuum filtration from aqueous TritonX-100 suspensions of large diameter arc-discharge SWCNTs. The dependence of the solar cell performance on the thickness of the SWCNT film is shown in detail, as is the variation in performance due to doping of the SWCNT film with SOCl2.

  17. Non-contacting Measurement of Oil Film Thickness Between Loaded Metallic Gear Teeth

    Science.gov (United States)

    Cox, Daniel B.; Ceccio, Steven L.; Dowling, David R.

    2013-11-01

    The mechanical power transmission efficiency of gears is depends on the lubrication condition between gear teeth. While the lubrication levels can be generally predicted, an effective in-situ non-contacting measurement of oil film thicknesses between loaded metallic gear teeth has proved elusive. This study explores a novel oil film thickness measurement technique based on optical fluence, the light energy transmitted between loaded gear teeth. A gear testing apparatus that allowed independent control of gear rotation rate, load torque, and oil flow was designed and built. Film thickness measurements made with 5-inch-pitch-diameter 60-tooth spur gears ranged from 0.3 to 10.2 mil. These results are compared with film thickness measurements made in an earlier investigation (MacConochie and Cameron, 1960), as well as with predictions from two film thickness models: a simple two-dimensional squeezed oil film and the industry-accepted model as described by the American Gear Manufacturers Association (AGMA 925, 2003). In each case, the measured film thicknesses were larger than the predicted thicknesses, though these discrepancies might be attributed to the specifics the experiments and to challenges associated with calibrating the fluence measurements. [Sponsored by General Electric].

  18. Direct detection of the Josephson radiation emitted from superconducting thin-film microbridges

    DEFF Research Database (Denmark)

    Pedersen, Niels Falsig; Sørensen, O. H.; Mygind, Jesper;

    1976-01-01

    We report direct measurements of the Josephson radiation emitted in X band from a superconducting thin-film microbridge coupled to a resonance cavity. Power is emitted if one of the harmonics of the Josephson frequency is in the bandwidth of the receiver. The maximum power emitted during our expe...... experiment was 10−13 W. The Josephson radiation could easily be detected at frequencies off resonance. Applied Physics Letters is copyrighted by The American Institute of Physics....

  19. Vortex pinning in superconducting Nb thin films deposited on nanoporous alumina templates

    DEFF Research Database (Denmark)

    Vinckx, W.; Vanacken, J.; Moshchalkov, V.V.

    2006-01-01

    We present a study of magnetization and transport properties of superconducting Nb thin films deposited on nanoporous aluminium oxide templates. Periodic oscillations in the critical temperature vs. field, matching effects in fields up to 700 mT and strongly enhanced critical currents were observ...... centers, which enhances vortex pinning in broad field and temperature ranges. © EDP Sciences/Società Italiana di Fisica/Springer-Verlag 2006....

  20. Influence of Thickness on Ethanol Sensing Characteristics of Doctor-bladed Thick Film from Flame-made ZnO Nanoparticles

    Directory of Open Access Journals (Sweden)

    Sukon Phanichphant

    2007-02-01

    Full Text Available ZnO nanoparticles were produced by flame spray pyrolysis (FSP using zincnaphthenate as a precursor dissolved in toluene/acetonitrile (80/20 vol%. The particleproperties were analyzed by XRD, BET, and HR-TEM. The sensing films were produced bymixing the particles into an organic paste composed of terpineol and ethyl cellulose as avehicle binder and were fabricated by doctor-blade technique with various thicknesses (5,10, 15 μm. The morphology of the sensing films was analyzed by SEM and EDS analyses.The gas sensing characteristics to ethanol (25-250 ppm were evaluated as a function of filmthickness at 400°C in dry air. The relationship between thickness and ethanol sensingcharacteristics of ZnO thick film on Al2O3 substrate interdigitated with Au electrodes wereinvestigated. The effects of film thickness, as well as the cracking phenomenon, though,many cracks were observed for thicker sensing films. Crack widths increased withincreasing film thickness. The film thickness, cracking and ethanol concentration havesignificant effect on the sensing characteristics. The sensing characteristics with variousthicknesses were compared, showing the tendency of the sensitivity to ethanol decreasedwith increasing film thickness and response time. The relationship between gas sensingproperties and film thickness was discussed on the basis of diffusively and reactivity of thegases inside the oxide films. The thinnest sensing film (5 μm showed the highest sensitivityand the fastest response time (within seconds.

  1. Field electron emission from undoped, continuous, submicron-thick diamond films

    Science.gov (United States)

    Ternyak, O.; Akhvlediani, R.; Hoffman, A.; Wong, W. K.; Lee, S. T.; Lifshitz, Y.; Daren, S.; Cheifetz, E.

    2005-12-01

    The present work shows that the field electron emission (FEE) properties of polycrystalline diamond films can be enhanced by control over the film thickness. The FEE properties of undoped, continuous, and smooth submicron-thick diamond films with initial nucleation densities of ˜5×1010particles/cm2 were investigated as a function of diamond film thickness. A set of films with thickness ranging from 70-100to830nm yielded turn-on field values of 6-8V/μm and threshold field values of 8.5-17.5V/μm (for 0.3μA/cm2), respectively, without any conditioning. It was found that the films of thickness up to ˜370nm can sustain stable current density as high as 0.1A/cm2 without morphological modification. The thicker films, however, suffer from a strong degradation of the film and breakdown. The best FEE (lower turn-on and threshold fields and morphological stability) was obtained for a thin (100nm) continuous diamond film. This result is suggested to be attributed mainly to the efficient electron conduction from the back contact to the surface.

  2. Optical coefficients of nanometer-thick copper and gold films in microwave frequency range

    Science.gov (United States)

    Khorin, I.; Orlikovsky, N.; Rogozhin, A.; Tatarintsev, A.; Pronin, S.; Andreev, V.; Vdovin, V.

    2016-12-01

    Ultrathin (1-10 nm) Cu and Au films were prepared on the silicon and quartz substrates by magnetron sputtering at room temperature. We measured the transmission coefficient of the films at a wavelength of 3cm and analyzed a surface morphology of these films. It was shown that the films with thicknesses less than 7.5 nm (Au) and 3 nm (Cu) are almost transparent for microwaves. This effect is explained by quick oxidation of Cu and the complex surface morphology of nanometer thick films. The Au film morphology is evolved with increasing average Au thickness d from hemispherical islands initially (1.0 nm

  3. Evaluation of feasibility of measuring EHD film thickness associated with cryogenic fluids

    Science.gov (United States)

    Kannel, J. W.; Merriman, T. L.; Stockwell, R. D.; Dufrane, K. F.

    1983-08-01

    The feasibility of measuring elastohydrodynamic (EHD) films as formed with a cryogenic (LN2) fluid is evaluated. Modifications were made to an existing twin disk EHD apparatus to allow for disk lubrication with liquid nitrogen. This disk apparatus is equipped with an X-ray system for measuring the thickness of any lubricant film that is formed between the disks. Several film thickness experiments were conducted with the apparatus which indicate that good lubrication films are filmed with LN2. In addition to the film thickness studies, failure analyses of three bearings were conducted. The HPOTP turbine end bearings had experienced axial loads of 36,000 to 44,000 N (8,000 to 10,000 lb). High continuous radial loads were also experienced, which were most likely caused by thermal growth of the inner race. The resulting high internal loads caused race spalling and ball wear to occur.

  4. Effect of Thickness of Single-Phase Antimony and Tellurium Thin Films on Their Thermal Conductivities.

    Science.gov (United States)

    Park, No-Won; Park, Sang-In; Lee, Sang-Kwon

    2015-09-01

    We present the effects of film thickness and grain size on the out-of-plane thermal conductivities of single-phase Sb and Te thin films, which are of great interest for thermoelectric device applications. The thermal conductivities of the films were measured by the four-point-probe 3Ωo method, at room temperature. For this study, 50-, 100-, and 200-nm-thick Sb and Te thin films were prepared by electron-beam evaporation at room temperature. From the measured thermal conductivities, we evaluated that the average thermal conductivities of the Sb and Te thin films were 5.9-10.2 W/(m x K) and 0.8-1.2 W/(m x K), respectively, at room temperature. This result reveals that the thickness and grain size of each thin film strongly affect the modulation of its thermal conductivity at room temperature.

  5. Realistic reflectance spectrum of thin films covering a transparent optically thick substrate

    Energy Technology Data Exchange (ETDEWEB)

    Cesaria, M., E-mail: maura.cesaria@le.infn.it; Caricato, A. P.; Martino, M. [Department of Mathematics and Physics “Ennio De Giorgi,” University of Salento, Via Arnesano, I-73100 Lecce (Italy)

    2014-07-21

    A spectrophotometric strategy is presented and discussed for calculating realistically the reflectance spectrum of an absorbing film deposited over a thick transparent or semi-transparent substrate. The developed route exploits simple mathematics, has wide range of applicability (high-to-weak absorption regions and thick-to-ultrathin films), rules out numerical and curve-fitting procedures as well as model-functions, inherently accounts for the non-measurable contribution of the film-substrate interface as well as substrate backside, and describes the film reflectance spectrum as determined by the experimental situation (deposition approach and parameters). The reliability of the method is tested on films of a well-known material (indium tin oxide) by deliberately changing film thickness and structural quality through doping. Results are found consistent with usual information yielded by reflectance, its inherent relationship with scattering processes and contributions to the measured total reflectance.

  6. The Thickness Distribution of Oxidation Film on Tapered Pipe Surface in Dieless Drawing

    Directory of Open Access Journals (Sweden)

    Fang Qin

    2011-01-01

    Full Text Available The thickness distribution of oxidation film on the surface of AISI304 stainless steel tapered pipe, its influence factors, and the effect of metal matrix deformation on oxidation behavior during dieless drawing were studied in this paper. The results showed that oxidation rate was affected strongly by induction heating temperature and deformation degree. The thickness distribution of oxidation film was uneven and increased from the larger diameter end to the smaller diameter end along the axial direction of tapered pipe. When induction heating temperature raised or the distance between heat and cold sources was increased, or feed speed was decreased, oxidation rate was accelerated and oxidation film on the tapered pipe surface thickened significantly, due to massive cracks in oxidation film induced by deformation of metal matrix. The density and width of cracks in oxidation film were enlarged, and the thickness of oxidation film increased with the increase in deformation degree.

  7. MgB{sub 2} superconducting thin films sequentially fabricated using DC magnetron sputtering and thermionic vacuum arc method

    Energy Technology Data Exchange (ETDEWEB)

    Okur, S. [Physics Department, Izmir Institute of Technology (Turkey)], E-mail: salihokur@iyte.edu.tr; Kalkanci, M. [Material Science Program, Izmir Institute of Technology (Turkey); Pat, S.; Ekem, N.; Akan, T. [Physics Department, Osmangazi University (Turkey); Balbag, Z. [Department of Science and Mathematics Education, Osmangazi University (Turkey); Musa, G. [Plasma and Radiation, National Institute for Physics of Laser (Romania); Tanoglu, M. [Mechanical Engineering Department, Izmir Institute of Technology (Turkey)

    2007-11-01

    In this work, we discuss fabrication and characterization of MgB{sub 2} thin films obtained by sequential deposition and annealing of sandwich like Mg/B/Mg thin films on glass substrates. Mg and B films were prepared using DC magnetron sputtering and thermionic vacuum arc techniques, respectively. The MgB{sub 2} thin films showed superconducting critical transition at 33 K after annealing at 650 deg. C.

  8. Superconducting MgB2 Thin Films with Tc ≈ 39 K Grown by Pulsed Laser Deposition

    Institute of Scientific and Technical Information of China (English)

    王淑芳; 戴守愚; 周岳亮; 陈正豪; 崔大复; 许佳迪; 何萌; 吕惠宾; 杨国桢

    2001-01-01

    Superconducting MgB2 thin films were fabricated on Al2 O3 (0001) substrates under ex situ processing conditions.Boron thin films were deposited by pulsed laser deposition followed by a post-annealing process. Resistance measurements of the deposited MgB2 films show Tc of ~39 K, while scanning electron microscopy and x-ray vdiffraction analysis indicate that the films consist of well-crystallized grains with a highly c-axis-oriented structure.

  9. Abnormal Cutoff Thickness of Long-Range Surface Plasmon Polariton Modes Guided by Thin Metal Films

    Institute of Scientific and Technical Information of China (English)

    LIU Fang; RAO Yi; HUANG Yi-Dong; ZHANG Wei; PENG Jiang-De

    2007-01-01

    Long-range surface plasmon polariton(LRSPP) modes guided by a thin metal film surrounded by semi-infinite dielectrics with different refractive indices are studied.Our cMculation results show that the cutoff thickness of the metal film does not monotonically increase with refractive index difference △n between the SHbstrate and superstrate.Just because of this abnormal behaviour of cutoff thickness,the existence of LRSPP illustrates complicated situations in asymmetric configurations.For a certain metal film thickness,LRsPP may exist in one.two or three refractive index difference △n regions.

  10. Ultrasonic oil-film thickness measurement: An angular spectrum approach to assess performance limits

    OpenAIRE

    Zhang, J.; Drinkwater, B.W.; Dwyer-Joyce, R.S.

    2007-01-01

    The performance of ultrasonic oil-film thickness measurement in a ball bearing is quantified. A range of different viscosity oils (Shell T68, VG15, and VG5) are used to explore the lowest reflection coefficient and hence the thinnest oil-film thickness that the system can measure. The results show a minimum reflection coefficient of 0.07 for both oil VG15 and VG5 and 0.09 for oil T68 at 50 MHz. This corresponds to an oil-film thickness of 0.4 μm for T68 oil. An angular spectrum (or Fourier d...

  11. Enhanced superconductivity and superconductor to insulator transition in nano-crystalline molybdenum thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Shilpam; Amaladass, E.P. [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Sharma, Neha [Surface & Nanoscience Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Harimohan, V. [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Amirthapandian, S. [Materials Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Mani, Awadhesh, E-mail: mani@igcar.gov.in [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)

    2017-06-01

    Disorder driven superconductor to insulator transition via intermediate metallic regime is reported in nano-crystalline thin films of molybdenum. The nano-structured thin films have been deposited at room temperature using DC magnetron sputtering at different argon pressures. The grain size has been tuned using deposition pressure as the sole control parameter. A variation of particle sizes, room temperature resistivity and superconducting transition has been studied as a function of deposition pressure. The nano-crystalline molybdenum thin films are found to have large carrier concentration but very low mobility and electronic mean free path. Hall and conductivity measurements have been used to understand the effect of disorder on the carrier density and mobilities. Ioffe-Regel parameter is shown to correlate with the continuous metal-insulator transition in our samples. - Highlights: • Thin films of molybdenum using DC sputtering have been deposited on glass. • Argon background pressure during sputtering was used to tune the crystallite sizes of films. • Correlation in deposition pressure, disorder and particle sizes has been observed. • Disorder tuned superconductor to insulator transition along with an intermediate metallic phase has been observed. • Enhancement of superconducting transition temperature and a dome shaped T{sub C} vs. deposition pressure phase diagram has been observed.

  12. A New Method for Preparing Superconducting MgB2 Films from Diborane

    Institute of Scientific and Technical Information of China (English)

    王殿生; 傅兴华; 张正平; 杨健

    2002-01-01

    We report on a new preparation method for magnesium diboride (MgB2) films by chemical vapour deposition(CVD) from diborane (B2H6). It is a two-step ex situ approach, with the precursor boron films grown by CVD from B2H6 at 460°C, followed by a post-annealing process in magnesium (Mg) vapour at 830°C. The prepared MgB2 thin films on Al2O3 polycrystalline substrates have an onset transition temperature of 35K and a zeroresistance temperature of about 24K. Well-crystallized MgB2 grains have clearly been observed in the SEM images and confirmed by x-ray diffraction analysis. The advantages of the proposed method are the feasibility to prepare large-area superconducting films and the compatibility with semiconductor technology.

  13. Strain and High Temperature Superconductivity: Unexpected Results from Direct Electronic Structure Measurements in Thin Films

    Science.gov (United States)

    Abrecht, M.; Ariosa, D.; Cloetta, D.; Mitrovic, S.; Onellion, M.; Xi, X.; Margaritondo, G.; Pavuna, D.

    2003-07-01

    Angle-resolved photoemission spectroscopy reveals very surprising strain-induced effects on the electronic band dispersion of epitaxial La2-xSrxCuO4-δ thin films. In strained films we measure a band that crosses the Fermi level (EF) well before the Brillouin zone boundary. This is in contrast to the flat band reported in unstrained single crystals and in our unstrained films, as well as in contrast to the band flattening predicted by band structure calculations for in-plane compressive strain. In spite of the density of states reduction near EF, the critical temperature increases in strained films with respect to unstrained samples. These results require a radical departure from commonly accepted notions about strain effects on high temperature superconductors, with possible general repercussions on superconductivity theory.

  14. Ptychographic Imaging of Branched Colloidal Nanocrystals Embedded in Free-Standing Thick Polystyrene Films

    Science.gov (United States)

    de Caro, Liberato; Altamura, Davide; Arciniegas, Milena; Siliqi, Dritan; Kim, Mee R.; Sibillano, Teresa; Manna, Liberato; Giannini, Cinzia

    2016-01-01

    Research on composite materials is facing, among others, the challenging task of incorporating nanocrystals, and their superstructures, in polymer matrices. Electron microscopy can typically image nanometre-scale structures embedded in thin polymer films, but not in films that are micron size thick. Here, X-ray Ptychography was used to visualize, with a resolution of a few tens of nanometers, how CdSe/CdS octapod-shaped nanocrystals self-assemble in polystyrene films of 24 ± 4 μm, providing a unique means for non-destructive investigation of nanoparticles distribution and organization in thick polymer films.

  15. Phase thickness approach for determination of thin film refractive index dispersion from transmittance spectra

    Science.gov (United States)

    Nenkov, M. R.; Pencheva, T. G.

    2008-06-01

    A novel approach for determination of refractive index dispersion n(λ ) and thickness d of thin films of negligible absorption and weak dispersion is proposed. The calculation procedure is based on determination of the phase thickness of the film in the spectral region of measured transmittance data. All points of measured spectra are included in the calculations. Barium titanate and titanium oxide thin films are investigated and their n(λ ) and d are calculated. The approach is validated using Swanepoel's method and it is found to be applicable for relatively thinner films when measured transmittance spectra have one minimum and one maximum only.

  16. Impressive electromagnetic shielding effects exhibited by highly ordered, micrometer thick polyaniline films

    Science.gov (United States)

    Mohan, Ranjini R.; Varma, Sreekanth J.; Sankaran, Jayalekshmi

    2016-04-01

    The present work highlights the remarkably high shielding effectiveness of about 68 dB, exhibited by highly ordered and doped polyaniline films, in the microwave frequency range 4-12 GHz, obtained by self-stabilized dispersion polymerization as the synthesis route. The observed shielding effectiveness is found to depend quite sensitively on the electrical conducting properties, which are predominantly controlled by the nature and concentration of the dopants. The structural and morphological characterization of the films using XRD and TEM techniques reveals surprisingly high extent of crystallinity, which contributes significantly towards enhancing the electrical conductivity of the films. Most of the available reports on the microwave response of conducting polymer film samples deal with much thicker films, compared to the micrometer thick films of the present studies. The shielding effectiveness of acid doped, micrometer thick polyaniline films reported in the present work far exceeds most of the previously reported values and meets the commercial requirements.

  17. Gas Sensing Performance of Pure and Modified BST Thick Film Resistor

    Directory of Open Access Journals (Sweden)

    G. H. JAIN

    2008-04-01

    Full Text Available Barium Strontium Titanate (BST-(Ba0.87Sr0.13TiO3 ceramic powder was prepared by mechanochemical process. The thick films of different thicknesses of BST were prepared by screen-printing technique and gas-sensing performance of these films was tested for various gases. The films showed highest response and selectivity to ammonia gas. The pure BST film was surface modified by surfactant CrO3 by using dipping technique. The surface modified film suppresses the response to ammonia and enhances to H2S gas. The surface modification of films changes the adsorption-desorption relationship with the target gas and shifts its selectivity. The gas response, selectivity, response and recovery time of the pure and modified films were measured and presented.

  18. Josephson soliton oscillators in a superconducting thin film resonator

    DEFF Research Database (Denmark)

    Holm, J.; Mygind, Jesper; Pedersen, Niels Falsig

    1993-01-01

    . Different modes of half-wave resonances in the thin-film structure impose different magnetic field configurations at the boundaries of the junctions. The DC I-V characteristic shows zero-field steps with a number of resonator-induced steps. These structures are compared to RF-induced steps generated...

  19. Thickness measurement of organic films using Compton scattering of characteristic X-rays

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong-Yun, E-mail: kjy@kaeri.re.kr [Nuclear Chemistry Research Division, Korea Atomic Energy Research Institute, Daedeok-daero 1045, Dukjin-dong Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Choi, Yong Suk; Park, Yong Joon; Song, Kyuseok [Nuclear Chemistry Research Division, Korea Atomic Energy Research Institute, Daedeok-daero 1045, Dukjin-dong Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Jung, Sung-Hee [Division of Radioisotope R and D, Korea Atomic Energy Research Institute, Daedeok-daero 1045, Dukjin-dong Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Hussein, Esam M.A. [Laboratory for Threat Materials Detection, Department of Mechanical Engineering, University of New Brunswick, Fredericton, New Brunswick, Canada E3B 5A3 (Canada)

    2011-09-15

    An X-ray scattering method is presented for determining the thickness of an organic film placed on a steel substrate. The strong peaks of characteristic X-rays are taken as an advantage to measure the intensity of backscattered photons. It is shown that the intensity of Compton scattering of characteristic X-rays is proportional to film thickness, up to the thickness of 250 {mu}m of acrylic adhesive layers. In addition, the measurement time was 300 ms, providing a simple and convenient method for on-line for thickness monitoring.

  20. Miniaturized, Planar Ion-selective Electrodes Fabricated by Means of Thick-film Technology

    Directory of Open Access Journals (Sweden)

    Robert Koncki

    2006-04-01

    Full Text Available Various planar technologies are employed for developing solid-state sensorshaving low cost, small size and high reproducibility; thin- and thick-film technologies aremost suitable for such productions. Screen-printing is especially suitable due to itssimplicity, low-cost, high reproducibility and efficiency in large-scale production. Thistechnology enables the deposition of a thick layer and allows precise pattern control.Moreover, this is a highly economic technology, saving large amounts of the used inks. Inthe course of repetitions of the film-deposition procedure there is no waste of material dueto additivity of this thick-film technology. Finally, the thick films can be easily and quicklydeposited on inexpensive substrates. In this contribution, thick-film ion-selective electrodesbased on ionophores as well as crystalline ion-selective materials dedicated forpotentiometric measurements are demonstrated. Analytical parameters of these sensors arecomparable with those reported for conventional potentiometric electrodes. All mentionedthick-film strip electrodes have been totally fabricated in only one, fully automated thick-film technology, without any additional manual, chemical or electrochemical steps. In allcases simple, inexpensive, commercially available materials, i.e. flexible, plastic substratesand easily cured polymer-based pastes were used.

  1. Effect of thickness on structural and electrical properties of Al-doped ZnO films

    Energy Technology Data Exchange (ETDEWEB)

    Garcés, F.A., E-mail: felipe.garces@santafe-conicet.gov.ar [Instituto de Física del Litoral (CONICET-UNL), Güemes 3450, Santa Fe S3000GLN (Argentina); Budini, N. [Instituto de Física del Litoral (CONICET-UNL), Güemes 3450, Santa Fe S3000GLN (Argentina); Arce, R.D.; Schmidt, J.A. [Instituto de Física del Litoral (CONICET-UNL), Güemes 3450, Santa Fe S3000GLN (Argentina); Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santiago del Estero 2829, Santa Fe S3000AOM (Argentina)

    2015-01-01

    In this work, we have investigated the influence of thickness on structural and electrical properties of Al-doped ZnO films. Transparent conducting oxide films were grown by the spray pyrolysis technique from precursors prepared via the sol–gel method. We determined the structural properties of the films by performing X-ray diffraction and mosaicity measurements, which evidenced an increase of disorder and inhomogeneity between crystalline domains as the films thickened. This behavior was contrasted with results obtained from electrical measurements and was attributed to plastic deformation of the films as their thickness increased. As a result, the carrier mobility, the optical gap and the activation energy are affected due to emerging grain boundaries and a higher degree of disorder. - Highlights: • Al-doped ZnO thin films on glass with different thicknessesFilm thickness affects the morphological and electrical properties. • Increasing time deposition allows modification of resistivity and Hall mobility. • Mosaicity between crystalline domains increases with film thickness.

  2. Systematic experimental study of pure shear type dielectric elastomer membranes with different electrode and film thicknesses

    Science.gov (United States)

    Hodgins, M.; Seelecke, S.

    2016-09-01

    An approach to reduce the voltage required for dielectric elastomer actuators is to reduce film thickness. However, if the electrode thickness is not similarly reduced, the electrode’s mechanical behavior can increasingly and negatively impact the overall actuator behavior. This effect is yet to be studied and quantified for pure shear type specimens; a type recommended in a recent DE standardization journal publication. Therefore, in this work, using pure shear specimens, a comparative study of membrane actuators of different film thickness (20, 50 and 100 μm) is performed. Electrodes of different thicknesses are screen printed and tested in a uniaxial test device. The stiffening effect due to the solid-state electrodes is demonstrated by performing force-elongation tests for specimens with and without electrodes. Additionally the importance of thin electrodes (relative to film thickness) was demonstrated through a number of electromechanical tests. Isotonic tests revealed a lower electro-mechanical sensitivity for the 20 μm film when compared with the 50 and 100 μm films. This was attributed to the relatively thick electrodes. Best actuation results were achieved when the total electrode thickness was at least 15x thinner than the dielectric membrane thickness.

  3. Deposition by plasma-assisted laser ablation and maskless patterning of YBa[sub 2]Cu[sub 3]O[sub 7-x] superconducting thin films

    Energy Technology Data Exchange (ETDEWEB)

    Tejedor, P. (Centro Nacional de Microelectronica, CSIC, Madrid (Spain)); Cagigal, M. (Dept. de Fisica de Materiales, Univ. Complutense, Madrid (Spain)); Vicent, J.L. (Dept. de Fisica de Materiales, Univ. Complutense, Madrid (Spain)); Briones, F. (Centro Nacional de Microelectronica, CSIC, Madrid (Spain))

    1994-04-01

    YBa[sub 2]Cu[sub 3]O[sub 7-x] superconducting thin films were deposited in situ by plasma-assisted laser ablation onto polycrystalline yttria-stabilized-zirconia (YSZ) substrates at 700 C in a low pressure (200-400 mTorr) O[sub 2] discharge (-300 V). The laser operated at 5-50 Hz repetition rate and was focused onto a superconducting target with a typical energy density of 2.5-4 J cm[sup -2]. An in situ annealing step in 1 Torr O[sub 2] atmosphere at 425 C for 1-2 h was followed by slow cooling of the films to room temperature. The YBa[sub 2]Cu[sub 3]O[sub 7-x] films grew preferentially oriented with the c-axis normal to the substrate surface. They exhibited metallic behaviour in the normal state and superconducting transitions with typical onset of 91 K and zero resistance between 82 and 87 K. The transport critical current densities J[sub c] were 10[sup 2] A cm[sup -2] for 1 [mu]m thick films and two orders of magnitude higher, J[sub c] = 3 x 10[sup 4] A cm[sup -2], for 0.08 [mu]m thick films. Maskless patterning was achieved by utilizing the ArF laser beam to induce etching selectivity of the superconducting thin films. For this purpose, the central part of the beam was apertured by a slit and focused onto the sample by means of a 15 x Schwarzschild microscope objective to give an irradiated area on the sample of approximately 10 x 150 [mu]m[sup 2]. The laser energy density on the sample was typically 10[sup 3] J cm[sup -2], while the repetition rate was varied between 10 and 20 Hz. Microbridges of different geometries with a maximum resolution of 10 [mu]m and high edge definition were obtained at 20 [mu]m s[sup -1] scan rate using this technique. (orig.)

  4. Thickness dependent ferromagnetism in thermally decomposed NiO thin films

    Science.gov (United States)

    Ravikumar, Patta; Kisan, Bhagaban; Perumal, Alagarsamy

    2016-11-01

    We report the effects of film thickness, annealing temperature and annealing environments on thermal decomposition behavior and resulting magnetic properties of NiO (t=50-300 nm) thin films. All the NiO films were prepared directly on thermally oxidized Si at ambient temperature using magnetron sputtering technique and post annealed at different temperatures (TA) under vacuum and oxygen atmospheres. As-deposited films exhibit face centered cubic structure with large lattice constant due to strain induced during sputtering process. With increasing TA, the lattice constant decreases due to the release of strain and thickness dependent thermal decomposition reaction of NiO into Ni has been observed for the NiO films annealed at 500 °C under vacuum condition. As a result, the antiferromagnetic nature of the as-deposited NiO films transforms into ferromagnetic one with dominant thickness dependent ferromagnetic behavior at room temperature. In addition, the existence of both Ni and NiO phases in the annealed NiO films shows noticeable exchange bias under field cooling condition. The behavior of thermal decomposition was not observed for the NiO films annealed under oxygen condition which results in no detectable change in the magnetic properties. The observed results are discussed on the basis of thickness dependent thermal decomposition in NiO films with increasing TA and changing annealing conditions.

  5. Amorphous Indium Selenide Thin Films Prepared by RF Sputtering: Thickness-Induced Characteristics.

    Science.gov (United States)

    Han, Myoung Yoo; Park, Yong Seob; Kim, Nam-Hoon

    2016-05-01

    The influence of indium composition, controlled by changing the film thickness, on the optical and electrical properties of amorphous indium selenide thin films was studied for the application of these materials as Cd-free buffer layers in CI(G)S solar cells. Indium selenide thin films were prepared using RF magnetron sputtering method. The indium composition of the amorphous indium selenide thin films was varied from 94.56 to 49.72 at% by increasing the film thickness from 30 to 70 nm. With a decrease in film thickness, the optical transmittance increased from 87.63% to 96.03% and Eg decreased from 3.048 to 2.875 eV. Carrier concentration and resistivity showed excellent values of ≥1015 cm(-3) and ≤ 10(4) Ω x cm, respectively. The conductivity type of the amorphous indium selenide thin films could be controlled by changing the film-thickness-induced amount of In. These results indicate the possibility of tuning the properties of amorphous indium selenide thin films by changing their composition for use as an alternate buffer layer material in CI(G)S solar cells.

  6. Influence of film thickness and In-doping on physical properties of CdS thin films

    Energy Technology Data Exchange (ETDEWEB)

    Butt, Sajid, E-mail: sajidarif@hotmail.com [Department of Materials Science and Engineering, Institute of Space Technology (IST), Islamabad 44000 (Pakistan); Thermal Transport Laboratory, School of Chemical and Materials Engineering, National University of Sciences and Technology, Islamabad (Pakistan); Shah, Nazar Abbas [Department of Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan); Nazir, Adnan [Istituto Italiano di Tecnologia, Via Morego 30, I-16163 Genova (Italy); Ali, Zulfiqar [Optics Laboratories, P. O. Box 1021, Islamabad (Pakistan); Maqsood, Asghri [CESET, Center for Emerging Sciences, Engineering and Technology, Islamabad (Pakistan)

    2014-02-25

    Highlights: • Fabrication of polycrystalline CdS thin films by Close Spaced Sublimation technique. • The direct band gap of 2.44 eV and the electrical resistivity in the order of 10{sup 6}–10{sup 8} Ω cm was measured. • Resistivity was reduced to the order of 10{sup –2}–10{sup 1} Ω m by the thermally diffusion of indium into CdS films. -- Abstract: Polycrystalline CdS thin films were deposited on glass substrates by close spaced sublimation technique. Samples of various thicknesses, ranging from 250 to 940 nm were obtained. The optical and electrical properties of pure CdS thin films were studied as a function of film thickness. The resistivity of as-deposited CdS films was in the order of 10{sup 6}–10{sup 8} Ω cm, depending upon the film thickness. In the high temperature region, carriers are transported over the grain boundaries by thermionic emission. Resistivity was reduced to the order of 10{sup −2}–10{sup 1} Ω cm by the thermally diffusion of indium into CdS films, without changing the type of carriers. The annealing temperature dependence of structural, optical and electrical properties of In-doped CdS films showed that the samples annealed at 350 °C and 400 °C exhibited better results.

  7. Thickness dependence of temperature coefficient of resistivity of polycrystalline bismuth films

    Science.gov (United States)

    Kumar, Ajay; Katyal, O. P.

    1991-04-01

    Results for the temperature coefficient of resistivity (TCR) of polycrystalline bismuth films deposited on to glass substrate are reported for the thickness range 30 300 nm. The film TCR is found to be negative for all thicknesses studied and its absolute value exhibits a maximum of 3.70×10-3 K-1 near 72.5 nm. The variation of charge carrier density with film thickness has been estimated from the presence of surface states. To include the thickness dependence of charge carrier density, a modified theory has been used to explain the observed behaviour of the TCR. The experimental results for the TCR of Bi films are found to be consistent with the theoretical values. The existence of the extremum is theoretically verified. From the analysis, the specularity parameter p is about 0.44 and the reflection coefficient R is 0.1.

  8. Measurement of material thickness in the presence of a protective film

    Science.gov (United States)

    Ramamurthy, Rajesh; Harding, Kevin

    2017-05-01

    Many sheet products from plastic to structural composites are produce in tightly controlled thickness needed for functional applications. There are many methods that have been used to measure such sheeting from mechanical rollers to optical micrometers. However, many materials are produced with a thin protective film on either side that may not have critical dimensional controls. This paper addresses the challenge of measuring sheet products to critical thickness values in the presence of protective plastic films using high speed optical gaging methods. For this application, the protective films are assumed to be transparent though not necessarily scatter free, and have thickness variations that are comparable to the tolerances of the sheet product. We will examine the pros and cons of a number of different optical measurement methods in light of resolution, speed and robustness to the film thickness variation and present an approach able to address the desired sheet measurement tolerances.

  9. Determination of Thickness of an Inaccessible Thin Film under a Multilayered System from Natural Frequencies

    Institute of Scientific and Technical Information of China (English)

    ZHOU Chang-Zhi; LI Ming-Xuan; MAO Jie; WANG Xiao-Min

    2008-01-01

    @@ We investigate the relationship between natural frequencies of a multilayered system of different elastic materials and the thickness of the undermost thin film. The natural frequencies are numerically calculated from the reflection coefficient of a sample system of "steel-epoxy resin-aluminium-thin polymer' with normal incidence.Strain energy ratio is defined and calculated to give the physics explanation why some frequencies are sensitive to thickness of the thin film in certain range. Experiments of three specimens indicate that the measured natural frequencies agree well with the theoretical ones. It is found in our experiments that the ratio of the lowest film thickness to wavelength is about 1/5. The average relative errors for the inverted polymer film thicknesses are found to be 11.8%, -4.8% and -1.3%, respectively.

  10. Influences of non-uniformities and anisotropies on the flux avalanche behaviors of type-II superconducting films

    Science.gov (United States)

    Jing, Ze; Yong, Huadong; Zhou, Youhe

    2016-10-01

    In this paper, the anisotropic flux avalanche processes in thin square-shaped type-II superconducting films are numerically investigated by solving the coupled nonlinear Maxwell’s equations and the thermal diffusion equations. Influences of the non-uniformities and intrinsic critical current density anisotropies originate from the manufacturing process are considered in the simulation. In addition, we also studied the effect of the extrinsic anisotropy induced by the in-plane magnetic field. The results demonstrate that the non-uniformities and anisotropies of the critical current density play significant roles in the flux avalanche process of the thin film superconductors. Slight anisotropy (either intrinsic or extrinsic) can dramatically change the propagation direction of avalanches in the superconducting film, which is consistent with the experimental results. Simulations on the thin square-shaped isotropic superconducting films show that the threshold magnetic field for the flux avalanches increases with the angle between the applied field and the superconducting film-plane. In addition, the flux avalanche patterns change with the angular variation of the in-plane component of external magnetic field. When the in-plane magnetic field component is along the diagonal lines of the superconducting square, symmetric flux avalanche penetration patterns occur to the film.

  11. Superconductivity and superconductive electronics

    Science.gov (United States)

    Beasley, M. R.

    1990-12-01

    The Stanford Center for Research on Superconductivity and Superconductive Electronics is currently focused on developing techniques for producing increasingly improved films and multilayers of the high-temperature superconductors, studying their physical properties and using these films and multilayers in device physics studies. In general the thin film synthesis work leads the way. Once a given film or multilayer structure can be made reasonably routinely, the emphasis shifts to studying the physical properties and device physics of these structures and on to the next level of film quality or multilayer complexity. The most advanced thin films synthesis work in the past year has involved developing techniques to deposit a-axis and c-axis YBCO/PBCO superlattices and related structures. The in-situ feature is desirable because no solid state reactions with accompanying changes in volume, morphology, etc., that degrade the quality of the film involved.

  12. Effects of chromophore concentration and film thickness on thermo-optic properties of electro-optic fluorinated polyimide films

    Institute of Scientific and Technical Information of China (English)

    Hongxiang Song; Chengxun Wu

    2007-01-01

    Electro-optic (EO) effect and thermo-optic (TO) effect are jointly considered on the basis of field-induced and temperature-affected perturbations of the operating point in waveguide components. TO coefficients of EO fluorinated polyimide films with side-chain azobenzene chromophore were measured by attenuatedtotal-reflection (ATR) technique at different temperatures with TE- and TM-polarized lights, respectively.It is found that the absolute values of TO coefficients increase with the increments of both chromophore concentration and film thickness, but the polarization dependence of TO coefficients increases with the increment of chromophore concentration and decreases with the increment of film thickness.

  13. Thickness Influence on In Vitro Biocompatibility of Titanium Nitride Thin Films Synthesized by Pulsed Laser Deposition

    Directory of Open Access Journals (Sweden)

    Liviu Duta

    2016-01-01

    Full Text Available We report a study on the biocompatibility vs. thickness in the case of titanium nitride (TiN films synthesized on 410 medical grade stainless steel substrates by pulsed laser deposition. The films were grown in a nitrogen atmosphere, and their in vitro cytotoxicity was assessed according to ISO 10993-5 [1]. Extensive physical-chemical analyses have been carried out on the deposited structures with various thicknesses in order to explain the differences in biological behavior: profilometry, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy (XPS, X-ray diffraction and surface energy measurements. XPS revealed the presence of titanium oxynitride beside TiN in amounts that vary with the film thickness. The cytocompatibility of films seems to be influenced by their TiN surface content. The thinner films seem to be more suitable for medical applications, due to the combined high values of bonding strength and superior cytocompatibility.

  14. Influence of the thickness absorbing film on the PETN ignition threshold by a laser pulse

    Directory of Open Access Journals (Sweden)

    Dolgachev Vadim A.

    2015-01-01

    Full Text Available Numerical simulation of the PETN ignition by a film, which is heated by a laser pulse was conducted. There are shown that dependence of threshold energy of ignition of PETN by a laser pulse has a linear dependence from the thicknesses of the absorbing film. Calculations shown that critical the temperature on the boundary of two materials by the end of a laser pulse with threshold density doesn’t depend from the thickness of the absorbing film. The ignition delay time of PETN by the thick film less than the ignition delay time of PETN by the thin film. The reason is that the thicker contain more heat then in the thinner one.

  15. Structural, transport and microwave properties of 123/sapphire films: Thickness effect

    Energy Technology Data Exchange (ETDEWEB)

    Predtechensky, MR.; Smal, A.N.; Varlamov, Y.D. [Institute of Thermophysics, Novosibirsk (Russian Federation)] [and others

    1994-12-31

    The effect of thickness and growth conditions on the structure and microwave properties has been investigated for the 123/sapphire films. It has been shown that in the conditions of epitaxial growth and Al atoms do not diffuse from substrate into the film and the films with thickness up to 100nm exhibit the excellent DC properties. The increase of thickness of GdBaCuO films causes the formation of extended line-mesh defects and the increase of the surface resistance (R{sub S}). The low value of surface resistance R{sub S}(75GHz,77K)=20 mOhm has been obtained for the two layer YBaCuO/CdBaCuO/sapphire films.

  16. Photometric method of determining gold film thickness of nuclear radiation silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Nikitin, B.A.; Zakharchuk, D.V.; Kovalev, I.I.; Nikolaeva, T.V.; Serushkina, E.S.

    1987-07-01

    The authors examine a photometric method of assessing a nuclear radiation silicon detector's gold film thickness based on the photocurrent from a light passed through the sputtered metal layer. The surface-barrier detectors of nuclear radiations with a gold front contact are characterized by a high sensitivity to light in the 0.4-1.0 micrometer wavelength band. The relative error of determining the gold film thickness using the method examined here is of the 7% order.

  17. Investigation of thickness effects on the dielectric constant barium strontium titanate thin films

    CERN Document Server

    Grattan, L J

    2002-01-01

    The collapse in dielectric constant at small thickness commonly observed in ferroelectric thin films was measured and investigated in barium strontium titanate (Ba sub 0 sub . sub 5 Sr sub 0 sub . sub 5 TiO sub 3). The possible mechanisms responsible for this effect are reviewed. Functional measurements were performed on BST thin films, of 7.5 to 950 nm, by incorporating them into capacitor structures with bottom electrodes of strontium ruthenate (SRO) and thermally- evaporated Au top electrodes. A discussion on thin film growth considerations, optimal PLD conditions and the measurement techniques employed in the project is presented. The experimentally determined dielectric constant - thickness profile was fitted using the series capacitor model assuming low dielectric constant interfacial layers in series with the bulk. Consideration of the case where the combined 'dead layer' thickness was close to the total BST thickness revealed that, for this system, the total 'dead layer' thickness had to be less than ...

  18. High critical current density and enhanced irreversibility field in superconducting MgB2 thin films.

    Science.gov (United States)

    Eom, C B; Lee, M K; Choi, J H; Belenky, L J; Song, X; Cooley, L D; Naus, M T; Patnaik, S; Jiang, J; Rikel, M; Polyanskii, A; Gurevich, A; Cai, X Y; Bu, S D; Babcock, S E; Hellstrom, E E; Larbalestier, D C; Rogado, N; Regan, K A; Hayward, M A; He, T; Slusky, J S; Inumaru, K; Haas, M K; Cava, R J

    2001-05-31

    The discovery of superconductivity at 39 K in magnesium diboride offers the possibility of a new class of low-cost, high-performance superconducting materials for magnets and electronic applications. This compound has twice the transition temperature of Nb3Sn and four times that of Nb-Ti alloy, and the vital prerequisite of strongly linked current flow has already been demonstrated. One possible drawback, however, is that the magnetic field at which superconductivity is destroyed is modest. Furthermore, the field which limits the range of practical applications-the irreversibility field H*(T)-is approximately 7 T at liquid helium temperature (4.2 K), significantly lower than about 10 T for Nb-Ti (ref. 6) and approximately 20 T for Nb3Sn (ref. 7). Here we show that MgB2 thin films that are alloyed with oxygen can exhibit a much steeper temperature dependence of H*(T) than is observed in bulk materials, yielding an H* value at 4.2 K greater than 14 T. In addition, very high critical current densities at 4.2 K are achieved: 1 MA cm-2 at 1 T and 105 A cm-2 at 10 T. These results demonstrate that MgB2 has potential for high-field superconducting applications.

  19. Interplay of spin-orbit coupling and superconducting correlations in germanium telluride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Narayan, Vijay; Nguyen, Thuy-Anh; Mansell, Rhodri; Ritchie, David [Cavendish Laboratory, Department of Physics, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE (United Kingdom); Mussler, Gregor [Peter Gruenberg Institute (PGI-9), Forschungszentrum Juelich, 52425, Juelich (Germany)

    2016-03-15

    There is much current interest in combining superconductivity and spin-orbit coupling in order to induce the topological superconductor phase and associated Majorana-like quasiparticles which hold great promise towards fault-tolerant quantum computing. Experimentally these effects have been combined by the proximity-coupling of super-conducting leads and high spin-orbit materials such as InSb and InAs, or by controlled Cu-doping of topological insu-lators such as Bi{sub 2}Se{sub 3}. However, for practical purposes, a single-phase material which intrinsically displays both these effects is highly desirable. Here we demonstrate coexisting superconducting correlations and spin-orbit coupling in molecular-beam-epitaxy-grown thin films of GeTe. The former is evidenced by a precipitous low-temperature drop in the electrical resistivity which is quelled by a magnetic field, and the latter manifests as a weak antilocalisation (WAL) cusp in the magnetotransport. Our studies reveal several other intriguing features such as the presence of two-dimensional rather than bulk transport channels below 2 K, possible signatures of topological superconductivity, and unexpected hysteresis in the magnetotransport. Our work demonstrates GeTe to be a potential host of topological SC and Majorana-like excitations, and to be a versatile platform to develop quantum information device architectures. (copyright 2016 The Authors. Phys. Status Solidi RRL published by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Irradiation performance of rare earth and nanoparticle enhanced high temperature superconducting films based on YBCO

    Directory of Open Access Journals (Sweden)

    K.J. Leonard

    2016-12-01

    Full Text Available The new series of commercially produced high temperature superconducting (HTS tapes based on the YBa2Cu3O7 (YBCO structure have attracted renewed attention for their performance under applied magnetic fields without significant loss in supercurrent compared to the earlier generation of conductors. This adaptability is achieved through rare earth substitution and dopants resulting in the formation of nanoparticles and extended defects within the superconducting film matrix. The electrical performance of Zr-(Gdx,Y1−xBa2Cu3O7 and (Y1−x,DyxBa2Cu3O7 coated conductor tapes were tested prior to and after neutron exposures between 6.54×1017 and 7.00×1018 n/cm2 (E > 0.1MeV. Results showed a decrease in superconducting current with neutron irradiation for the range of fluences tested, with losses in the Zr-(Gdx,Y1−xBa2Cu3O7 conductor being more rapid. Post-irradiation testing was limited to evaluation at 77K and applied fields of up to 0.5Tesla, and therefore testing at lower temperatures and higher applied fields may result in improved superconducting properties as shown in previous ion irradiation work. Under the conditions tested, the doped conductors showed a loss in critical current at fluences lower than that of undoped YBa2Cu3O7 tapes reported on in literature.

  1. Planar Zeolite Film-Based Potentiometric Gas Sensors Manufactured by a Combined Thick-Film and Electroplating Technique

    Directory of Open Access Journals (Sweden)

    Gunter Hagen

    2011-08-01

    Full Text Available Zeolites are promising materials in the field of gas sensors. In this technology-oriented paper, a planar setup for potentiometric hydrocarbon and hydrogen gas sensors using zeolites as ionic sodium conductors is presented, in which the Pt-loaded Na-ZSM-5 zeolite is applied using a thick-film technique between two interdigitated gold electrodes and one of them is selectively covered for the first time by an electroplated chromium oxide film. The influence of the sensor temperature, the type of hydrocarbons, the zeolite film thickness, and the chromium oxide film thickness is investigated. The influence of the zeolite on the sensor response is briefly discussed in the light of studies dealing with zeolites as selectivity-enhancing cover layers.

  2. Thickness Effect on Properties of Sprayed In2S3 Films for Photovoltaic Applications

    Science.gov (United States)

    Bouguila, N.; Kraini, M.; Halidou, I.; Lacaze, E.; Bouchriha, H.; Bouzouita, H.

    2016-01-01

    Indium sulfide (In2S3) films have been deposited on soda-lime glass substrates using a spray technique (CSP). Indium chloride and thiourea were used as precursors at a molar ratio of S:In = 2. The substrate temperature was fixed at 340°C. The effect of film thickness on the structural, morphological and optical properties of the as-deposited films has been studied. These films were characterized by x-ray diffraction, scanning electron microscopy (SEM), atomic force microscopy (AFM) and optical absorption spectroscopy. As-prepared samples were polycrystalline with a cubic structure and (400) as preferential orientation. Their grain size increased from 35 nm to 41 nm with increasing thickness whereas the dislocation density and microstrain of the films decreased with the increase of thickness. Both SEM and AFM images showed that the films were homogenous with an increase of the surface roughness with the increase of thickness. The optical transmittance of the films decreased from 80% to 20% in the visible and infrared regions when the thickness was increased from 0.78 μm to 6.09 μm. The optical band gap E g was found to be in the range of 2.75-2.19 eV and showed a decrease with film thickness. Based on the measured optical constants (n and k), a Wemple-Didomenico model was used to determine the values of single oscillator energy ( E 0), dispersion energy ( E d), optical band gap ( E g) and high frequency dielectric constant ( \\varepsilon_{∞} ). In addition, these films exhibited n-type conductivity and were highly resistive. These results confirm that In2S3 thin films are a promising alternative as a buffer-layer material for CuInGa(S,Se)2-based solar cells.

  3. Temperature- and thickness-dependent elastic moduli of polymer thin films

    Directory of Open Access Journals (Sweden)

    Ao Zhimin

    2011-01-01

    Full Text Available Abstract The mechanical properties of polymer ultrathin films are usually different from those of their counterparts in bulk. Understanding the effect of thickness on the mechanical properties of these films is crucial for their applications. However, it is a great challenge to measure their elastic modulus experimentally with in situ heating. In this study, a thermodynamic model for temperature- (T and thickness (h-dependent elastic moduli of polymer thin films Ef(T,h is developed with verification by the reported experimental data on polystyrene (PS thin films. For the PS thin films on a passivated substrate, Ef(T,h decreases with the decreasing film thickness, when h is less than 60 nm at ambient temperature. However, the onset thickness (h*, at which thickness Ef(T,h deviates from the bulk value, can be modulated by T. h* becomes larger at higher T because of the depression of the quenching depth, which determines the thickness of the surface layer δ.

  4. Study of lead free ferroelectrics using overlay technique on thick film microstrip ring resonator

    Directory of Open Access Journals (Sweden)

    Shridhar N. Mathad

    2016-03-01

    Full Text Available The lead free ferroelectrics, strontium barium niobates, were synthesized via the low cost solid state reaction method and their fritless thick films were fabricated by screen printing technique on alumina substrate. The X band response (complex permittivity at very high frequencies of Ag thick film microstrip ring resonator perturbed with strontium barium niobates (SrxBa1-xNb2O6 in form of bulk and thick film was measured. A new approach for determination of complex permittivity (ε′ and ε′′ in the frequency range 8–12 GHz, using perturbation of Ag thick film microstrip ring resonator (MSRR, was applied for both bulk and thick film of strontium barium niobates (SrxBa1-xNb2O6. The microwave conductivity of the bulk and thick film lie in the range from 1.779 S/cm to 2.874 S/cm and 1.364 S/cm to 2.296 S/cm, respectively. The penetration depth of microwave in strontium barium niobates is also reported.

  5. Thickness dependence of magnetic properties in La–Co substituted strontium hexaferrite films with perpendicular anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Hui, Yajuan [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China); Cheng, Weiming, E-mail: wmcheng@mail.hust.edu.cn [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China); Yan, Peng [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China); Chen, Jincai [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China); Miao, Xiangshui [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China); Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2015-09-15

    The thickness dependence of magnetization reversal and coercivity behavior for La–Co substituted strontium hexaferrite (Sr-M) films was investigated. It is found that perpendicular anisotropy appears only when film thickness (t) is above 110 nm. With increasing t, perpendicular anisotropy energy (K{sub u⊥}) increases gradually to its maximum of 1.76×10{sup 6} erg/cm{sup 3} at t=300 nm, but turns to decrease when t>300 nm. Moreover, when t>110 nm, those films exhibit domains pinning or Stoner–Wohlfarth reversal model, present large K{sub u⊥} values and a rapid increase in H{sub c⊥}. However, while t≤110 nm, Sr-M films show nucleation model of magnetization reversal and perform low coercivity. The origin of the coercivity varying with thickness should be correlated with the grain size and preferred orientations in Sr-M films. - Highlights: • Thickness dependence in submicro-scale bulk system is investigated for La–Sr–Co–Fe–O films. • (0 0 1) preferred orientation gradually increases until t=300 nm and then declines. • The magnetization reversal presents different models with thickness. • Perpendicular anisotropy energy increases to maximum value of 1.76×10{sup 6} erg/cm{sup 3} at t=300 nm. • The coercivity varying with thickness is correlated with the grain size and preferred orientation.

  6. Magnetic properties of permalloy films with different thicknesses deposited onto obliquely sputtered Cu underlayers

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiaoyu; Sun, Xiaojun; Wang, Jianbo; Liu, Qingfang, E-mail: liuqf@lzu.edu.cn

    2015-03-01

    In this work, the influence of obliquely sputtered Cu underlayer of 10 nm on the magnetic properties of normally sputtered Permalloy thin films with different thicknesses from 10 nm to 150 nm has been investigated. It has been found that the samples with the Permalloy layer thickness ranging from 10 nm to 70 nm exhibit a good in-plane uniaxial magnetic anisotropy, and the increase of the film thickness leads to a decrease of the anisotropy field and the natural resonance frequency. The critical Permalloy layer thickness for stripe domain initiation of these films is about 80 nm, which is thinner than that of obliquely sputtered Permalloy thin films without an underlayer. The characteristic shapes of hysteresis loops which can be called ''transcritical'' are observed above the critical thickness. The condition and mechanism of appearing stripe domain structure were discussed and it has been found that the frequency response of permeability of the anisotropic films shows the characteristics of multi-peak resonance. - Highlights: • Py films were fabricated on obliquely sputtered Cu underlayers by RF magnetron sputtering. • Effects of Py layer thickness on anisotropy, ferromagnetic resonance frequency have been studied. • Samples with Py layer (<70 nm) show a good in-plane uniaxial magnetic anisotropy. • Samples with Py layer (>80 nm) show stripe domains and multi-peaks in permeability spectra.

  7. Thickness and microstructure effects in the optical and electrical properties of silver thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Guowen, E-mail: gding@intermolecular.com; Clavero, César; Schweigert, Daniel; Le, Minh [Intermolecular, Inc., 3011 North First Street, San Jose, CA 95134 (United States)

    2015-11-15

    The optical and electrical response of metal thin films approaching thicknesses in the range of the electron mean free path is highly affected by electronic scattering with the interfaces and defects. Here, we present a theoretical and experimental study on how thickness and microstructure affect the properties of Ag thin films. We are able to successfully model the electrical resistivity and IR optical response using a thickness dependent electronic scattering time. Remarkably, the product of electronic scattering time and resistivity remains constant regardless of the thickness (τx ρ = C), with a value of 59 ± 2 μΩ cm ⋅ fs for Ag films in the investigated range from 3 to 74 nm. Our findings enable us to develop a theoretically framework that allows calculating the optical response of metal thin films in the IR by using their measured thickness and resistivity. An excellent agreement is found between experimental measurements and predicted values. This study also shows the theoretical lower limit for emissivity in Ag thin films according to their microstructure and thickness. Application of the model presented here will allow rapid characterization of the IR optical response of metal thin films, with important application in a broad spectrum of fundamental and industrial applications, including optical coatings, low-emissivity windows and semiconductor industry.

  8. Thickness and microstructure effects in the optical and electrical properties of silver thin films

    Directory of Open Access Journals (Sweden)

    Guowen Ding

    2015-11-01

    Full Text Available The optical and electrical response of metal thin films approaching thicknesses in the range of the electron mean free path is highly affected by electronic scattering with the interfaces and defects. Here, we present a theoretical and experimental study on how thickness and microstructure affect the properties of Ag thin films. We are able to successfully model the electrical resistivity and IR optical response using a thickness dependent electronic scattering time. Remarkably, the product of electronic scattering time and resistivity remains constant regardless of the thickness (τx ρ = C, with a value of 59 ± 2 μΩ cm ⋅ fs for Ag films in the investigated range from 3 to 74 nm. Our findings enable us to develop a theoretically framework that allows calculating the optical response of metal thin films in the IR by using their measured thickness and resistivity. An excellent agreement is found between experimental measurements and predicted values. This study also shows the theoretical lower limit for emissivity in Ag thin films according to their microstructure and thickness. Application of the model presented here will allow rapid characterization of the IR optical response of metal thin films, with important application in a broad spectrum of fundamental and industrial applications, including optical coatings, low-emissivity windows and semiconductor industry.

  9. Quasiparticle state density on the surface of superconducting thin films of MgB{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Bobba, F [Groupe de Physique des Solides, UMR75-88 au CNRS, Universities Paris 6 et 7, Paris (France); Roditchev, D [Groupe de Physique des Solides, UMR75-88 au CNRS, Universities Paris 6 et 7, Paris (France); Lamy, R [Groupe de Physique des Solides, UMR75-88 au CNRS, Universities Paris 6 et 7, Paris (France); Choi, E-M [NCRICS, Department of Physics, Pohang University, Pohang (Korea, Republic of); Kim, H-J [NCRICS, Department of Physics, Pohang University, Pohang (Korea, Republic of); Kang, W N [NCRICS, Department of Physics, Pohang University, Pohang (Korea, Republic of); Ferrando, V [Department of Physics, University of Genoa, Genoa (Italy); Ferdeghini, C [Department of Physics, University of Genoa, Genoa (Italy); Giubileo, F [Department of Physics, University of Salerno, Salerno (Italy); Sacks, W [Groupe de Physique des Solides, UMR75-88 au CNRS, Universities Paris 6 et 7, Paris (France); Lee, S-I [NCRICS, Department of Physics, Pohang University, Pohang (Korea, Republic of); Klein, J [Groupe de Physique des Solides, UMR75-88 au CNRS, Universities Paris 6 et 7, Paris (France); Cucolo, A M [Department of Physics, University of Salerno, Salerno (Italy)

    2003-02-01

    High-speed scanning tunnelling spectroscopy (STS) was used at low temperature to study the quasiparticle excitation spectrum on the surface of c-axis-oriented superconducting thin films of MgB{sub 2}. The tunnelling spectra measured on as-grown films were compared with those acquired on chemically etched samples. In most cases the STS reveals only one small superconducting gap to be present in the tunnelling spectra, consistent with c-axis tunnelling and the particular electronic band structure of MgB{sub 2}. We found that the etching leads to the enhancement of the gap energy by 25% from 2.2 {+-} 0.3 meV to 2.8 {+-} 0.3 meV, and to the modification of the temperature dependence of the superconducting gap which, in both cases, has clearly a non-BCS shape. We argue that the modification of the electronic structure at the surface of the material due to the etching is responsible for these changes and discuss the possible origins of the effect.

  10. Hydrophobic switching nature of methylcellulose ultra-thin films: thickness and annealing effects

    Energy Technology Data Exchange (ETDEWEB)

    Innis-Samson, Vallerie Ann; Sakurai, Kenji, E-mail: sakurai@yuhgiri.nims.go.jp [University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577 (Japan)

    2011-11-02

    We have studied the thermosensitive property of methylcellulose (MC) thin films supported on Si substrate by static sessile drop contact angle measurements, and their surface properties and thin film structure by x-ray reflectivity (XRR) and atomic force microscopy (AFM) techniques. From the static sessile drop contact angle measurements, the MC thin films showed the characteristic hydrophilic-to-hydrophobic transition at {approx}70 {sup 0}C, which is the lower critical solution temperature of the bulk solution volume phase separation transition. For films with thickness d {<=} R{sub g}, the onset of such a transition is affected by the film thickness while very thick films, d >> R{sub g}, yielded higher contact angles. Annealing the MC thin films with thicknesses {approx}200 A (near the radius of gyration, R{sub g}, of the polymer) below the bulk glass transition temperature (T{sub g} {approx} 195 deg. C) would not change the hydrophobic switch nature of the film but annealing 'at' and above the bulk T{sub g} would change its surface property. From surface topography images by AFM, there were no significant changes in either the roughness or the film texture before and after annealing. With XRR data, we were able to determine that such changes in the surface properties are highly correlated to the film thickness changes after the annealing process. This study, we believe, is the first to examine the thermal annealing affects on the thermal response function of a thermoresponsive polymer and is important for researching how to tailor the hydrophobic switching property of MC thin films for future sensing applications. (paper)

  11. Hydrophobic switching nature of methylcellulose ultra-thin films: thickness and annealing effects.

    Science.gov (United States)

    Innis-Samson, Vallerie Ann; Sakurai, Kenji

    2011-11-02

    We have studied the thermosensitive property of methylcellulose (MC) thin films supported on Si substrate by static sessile drop contact angle measurements, and their surface properties and thin film structure by x-ray reflectivity (XRR) and atomic force microscopy (AFM) techniques. From the static sessile drop contact angle measurements, the MC thin films showed the characteristic hydrophilic-to-hydrophobic transition at ∼70 °C, which is the lower critical solution temperature of the bulk solution volume phase separation transition. For films with thickness d ≤ R(g), the onset of such a transition is affected by the film thickness while very thick films, d ≫ R(g), yielded higher contact angles. Annealing the MC thin films with thicknesses ∼200 Å (near the radius of gyration, R(g), of the polymer) below the bulk glass transition temperature (T(g) ∼ 195 ° C) would not change the hydrophobic switch nature of the film but annealing 'at' and above the bulk T(g) would change its surface property. From surface topography images by AFM, there were no significant changes in either the roughness or the film texture before and after annealing. With XRR data, we were able to determine that such changes in the surface properties are highly correlated to the film thickness changes after the annealing process. This study, we believe, is the first to examine the thermal annealing affects on the thermal response function of a thermoresponsive polymer and is important for researching how to tailor the hydrophobic switching property of MC thin films for future sensing applications.

  12. Hydrophobic switching nature of methylcellulose ultra-thin films: thickness and annealing effects

    Science.gov (United States)

    Innis-Samson, Vallerie Ann; Sakurai, Kenji

    2011-11-01

    We have studied the thermosensitive property of methylcellulose (MC) thin films supported on Si substrate by static sessile drop contact angle measurements, and their surface properties and thin film structure by x-ray reflectivity (XRR) and atomic force microscopy (AFM) techniques. From the static sessile drop contact angle measurements, the MC thin films showed the characteristic hydrophilic-to-hydrophobic transition at ˜70 °C, which is the lower critical solution temperature of the bulk solution volume phase separation transition. For films with thickness d ≤ Rg, the onset of such a transition is affected by the film thickness while very thick films, d ≫ Rg, yielded higher contact angles. Annealing the MC thin films with thicknesses ˜200 Å (near the radius of gyration, Rg, of the polymer) below the bulk glass transition temperature (Tg ˜ 195 ° C) would not change the hydrophobic switch nature of the film but annealing ‘at’ and above the bulk Tg would change its surface property. From surface topography images by AFM, there were no significant changes in either the roughness or the film texture before and after annealing. With XRR data, we were able to determine that such changes in the surface properties are highly correlated to the film thickness changes after the annealing process. This study, we believe, is the first to examine the thermal annealing affects on the thermal response function of a thermoresponsive polymer and is important for researching how to tailor the hydrophobic switching property of MC thin films for future sensing applications.

  13. Quantifying Local Thickness and Composition in Thin Films of Organic Photovoltaic Blends by Raman Scattering

    KAUST Repository

    Rodríguez-Martínez, Xabier

    2017-07-06

    We report a methodology based on Raman spectroscopy that enables the non-invasive and fast quantitative determination of local thickness and composition in thin films (from few monolayers to hundreds of nm) of one or more components. We apply our methodology to blends of organic conjugated materials relevant in the field of organic photovoltaics. As a first step, we exploit the transfer-matrix formalism to describe the Raman process in thin films including reabsorption and interference effects of the incoming and scattered electric fields. This allows determining the effective solid-state Raman cross-section of each material by studying the dependence of the Raman intensity on film thickness. These effective cross sections are then used to estimate the local thickness and composition in a series of polymer:fullerene blends. We find that the model is accurate within ±10 nm in thickness and ±5 vol% in composition provided that (i) the film thickness is kept below the thickness corresponding to the first maximum of the calculated Raman intensity oscillation; (ii) the materials making up the blend show close enough effective Raman cross-sections; and (iii) the degree of order attained by the conjugated polymer in the blend is similar to that achieved when cast alone. Our methodology opens the possibility to make quantitative maps of composition and thickness over large areas (from microns to centimetres squared) with diffraction-limited resolution and in any multi-component system based thin film technology.

  14. Gas sensing properties of Cu and Cr activated BST thick films

    Indian Academy of Sciences (India)

    G H Jain; L A Patil

    2006-08-01

    H2S gas sensing properties of BST ((Ba0.67Sr0.33)TiO3) thick films are reported here for the first time. BST ceramic powder was prepared by mechanochemical process. Thick films of BST were prepared by screen-printing technique. The sensing performance of the films was tested for various gases. The films were surface customized by dipping them into aqueous solutions of CuCl2 and CrO3 for various intervals of time. These surface modified BST films showed improved sensitivity to H2S gas (100 ppm) than pure BST film. Chromium oxide was observed to be a better activator than copper oxide in H2S gas sensing. The effect of microstructure and amount of activators on H2S gas sensing were discussed. The sensitivity, selectivity, stability, response and recovery time of the sensor were measured and presented.

  15. Superconductivity in transparent zinc-doped In2O3 films having low carrier density

    Directory of Open Access Journals (Sweden)

    Kazumasa Makise, Nobuhito Kokubo, Satoshi Takada, Takashi Yamaguti, Syunsuke Ogura, Kazumasa Yamada, Bunjyu Shinozaki, Koki Yano, Kazuyoshi Inoue and Hiroaki Nakamura

    2008-01-01

    Full Text Available Thin polycrystalline zinc-doped indium oxide (In2O3–ZnO films were prepared by post-annealing amorphous films with various weight concentrations x of ZnO in the range 0≤x ≤0.06. We have studied the dependences of the resistivity ρ and Hall coefficient on temperature T and magnetic field H in the range 0.5≤T ≤300 K, H≤6 Tfor 350 nm films annealed in air. Films with 0≤x≤0.03 show the superconducting resistive transition. The transition temperature Tc is below 3.3 K and the carrier density n is about 1025–1026 m−3. The annealed In2O3–ZnO films were examined by transmission electron microscopy and x-ray diffraction analysis revealing that the crystallinity of the films depends on the annealing time. We studied the upper critical magnetic field Hc2 (T for the film with x = 0.01. From the slope of dHc2 /dT, we obtain the coherence length ξ (0 ≈ 10 nm at T = 0 K and a coefficient of electronic heat capacity that is small compared with those of other oxide materials.

  16. Angular multiplexing holograms of four images recorded on photopolymer films with recording-film-thickness-dependent holographic characteristics

    Science.gov (United States)

    Osabe, Keiichi; Kawai, Kotaro

    2017-03-01

    In this study, angular multiplexing hologram recording photopolymer films were studied experimentally. The films contained acrylamide as a monomer, eosin Y as a sensitizer, and triethanolamine as a promoter in a polyvinyl alcohol matrix. In order to determine the appropriate thickness of the photopolymer films for angular multiplexing, photopolymer films with thicknesses of 29-503 μm were exposed to two intersecting beams of a YVO laser at a wavelength of 532 nm to form a holographic grating with a spatial frequency of 653 line/mm. The diffraction efficiencies as a function of the incident angle of reconstruction were measured. A narrow angular bandwidth and high diffraction efficiency are required for angular multiplexing; hence, we define the Q value, which is the diffraction efficiency divided by half the bandwidth. The Q value of the films depended on the thickness of the films, and was calculated based on the measured diffraction efficiencies. The Q value of a 297-μm-thick film was the highest of the all films. Therefore, the angular multiplexing experiments were conducted using 300-μm-thick films. In the angular multiplexing experiments, the object beam transmitted by a square aperture was focused by a Fourier transform lens and interfered with a reference beam. The maximum order of angular multiplexing was four. The signal intensity that corresponds to the squared-aperture transmission and the noise intensity that corresponds to transmission without the square aperture were measured. The signal intensities decreased as the order of angular multiplexing increased, and the noise intensities were not dependent on the order of angular multiplexing.

  17. Investigation of Top/bottom Electrode and Diffusion Barrier Layer for PZT thick film MEMS Sensors

    DEFF Research Database (Denmark)

    Pedersen, Thomas; Hindrichsen, Christian Carstensen; Lou-Møller, R.

    2007-01-01

    In this work screen printed piezoelectric Ferroperm PZ26 lead zirconate titanate (PZT) thick film is used for two MEMS devices. A test structure is used to investigate several aspects regarding bottom and top electrodes. 450 nm ZrO2 thin film is found to be an insufficient diffusion barrier layer...

  18. Effect of heat and film thickness on a photoinduced phase transition in azobenzene liquid crystalline polyesters

    DEFF Research Database (Denmark)

    Sanchez, C; Alcala, R; Hvilsted, Søren

    2003-01-01

    The liquid crystal to isotropic phase transition induced with 488 nm light in films of liquid crystalline azobenzene polyesters has been studied as a function of temperature, light intensity, and film thickness. That phase transition is associated with the photoinduced trans-cis-trans isomerizati...

  19. Plasmonic extinction in gold nanoparticle-polymer films as film thickness and nanoparticle separation decrease below resonant wavelength

    Science.gov (United States)

    Dunklin, Jeremy R.; Bodinger, Carter; Forcherio, Gregory T.; Keith Roper, D.

    2017-01-01

    Plasmonic nanoparticles embedded in polymer films enhance optoelectronic properties of photovoltaics, sensors, and interconnects. This work examined optical extinction of polymer films containing randomly dispersed gold nanoparticles (AuNP) with negligible Rayleigh scattering cross-sections at particle separations and film thicknesses less than (sub-) to greater than (super-) the localized surface plasmon resonant (LSPR) wavelength, λLSPR. Optical extinction followed opposite trends in sub- and superwavelength films on a per nanoparticle basis. In ˜70-nm-thick polyvinylpyrrolidone films containing 16 nm AuNP, measured resonant extinction per particle decreased as particle separation decreased from ˜130 to 76 nm, consistent with trends from Maxwell Garnett effective medium theory and coupled dipole approximation. In ˜1-mm-thick polydimethylsiloxane films containing 16-nm AuNP, resonant extinction per particle plateaued at particle separations ≥λLSPR, then increased as particle separation radius decreased from ˜514 to 408 nm. Contributions from isolated particles, interparticle interactions and heterogeneities in sub- and super-λLSPR films containing AuNP at sub-λLSPR separations were examined. Characterizing optoplasmonics of thin polymer films embedded with plasmonic NP supports rational development of optoelectronic, biomedical, and catalytic activity using these nanocomposites.

  20. The Effects of Two Thick Film Deposition Methods on Tin Dioxide Gas Sensor Performance

    OpenAIRE

    Bakrania, Smitesh D.; Margaret S. Wooldridge

    2009-01-01

    This work demonstrates the variability in performance between SnO2 thick film gas sensors prepared using two types of film deposition methods. SnO2 powders were deposited on sensor platforms with and without the use of binders. Three commonly utilized binder recipes were investigated, and a new binder-less deposition procedure was developed and characterized. The binder recipes yielded sensors with poor film uniformity and poor structural integrity, compared to the binder-less deposition meth...

  1. The Influence of Electrical Pulses on Thick Film (Du Pont 1421 Birox) Resistors

    OpenAIRE

    Tancula, M.; Kozlowski, J. M.

    1982-01-01

    This paper presents data on the effect of electric pulses on thick film resistors made using Du Pont 1421 Birox resistor pastes.Resistance changes during the application of the electric pulses were investigated. Two types of change were observed: reversible and irreversible (i.e. catastrophic).In order to illustrate the causes of these changes, observations of the film on a scanning electron microscope were made. Microcracks were observed in the film, which were mostly responsible for the per...

  2. Enhanced superconductivity and superconductor to insulator transition in nano-crystalline molybdenum thin films

    Science.gov (United States)

    Sharma, Shilpam; Amaladass, E. P.; Sharma, Neha; Harimohan, V.; Amirthapandian, S.; Mani, Awadhesh

    2017-06-01

    Disorder driven superconductor to insulator transition via intermediate metallic regime is reported in nano-crystalline thin films of molybdenum. The nano-structured thin films have been deposited at room temperature using DC magnetron sputtering at different argon pressures. The grain size has been tuned using deposition pressure as the sole control parameter. A variation of particle sizes, room temperature resistivity and superconducting transition has been studied as a function of deposition pressure. The nano-crystalline molybdenum thin films are found to have large carrier concentration but very low mobility and electronic mean free path. Hall and conductivity measurements have been used to understand the effect of disorder on the carrier density and mobilities. Ioffe-Regel parameter is shown to correlate with the continuous metal-insulator transition in our samples.

  3. Smooth surfaces in very thin GdBa{sub 2}Cu{sub 3}O{sub 7−δ} films for application in superconducting tunnel junctions

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, H., E-mail: henrynavarro@cab.cnea.gov.ar [Instituto Balseiro, Universidad Nacional de Cuyo & CNEA, 8400 Bariloche (Argentina); Centro Atómico Bariloche, Comisión Nacional de Energía Atómica. Av. Bustillo 9500, 8400 San Carlos de Bariloche (Argentina); Sirena, M. [Instituto Balseiro, Universidad Nacional de Cuyo & CNEA, 8400 Bariloche (Argentina); Centro Atómico Bariloche, Comisión Nacional de Energía Atómica. Av. Bustillo 9500, 8400 San Carlos de Bariloche (Argentina); Kim, Jeehoon [Department of Physics, Pohang University of Science and Technology, Pohang (Korea, Republic of); CALDES, Institute for Basic Science, Pohang (Korea, Republic of); Haberkorn, N. [Instituto Balseiro, Universidad Nacional de Cuyo & CNEA, 8400 Bariloche (Argentina); Centro Atómico Bariloche, Comisión Nacional de Energía Atómica. Av. Bustillo 9500, 8400 San Carlos de Bariloche (Argentina)

    2015-03-15

    Highlights: • A detailed study of the morphological properties of GdBa{sub 2}Cu{sub 3}O{sub 7−δ} thin films was realized. • The inclusion of a very thin SrTiO{sub 3} buffer layer modifies the surface of the SrTiO{sub 3} substrates. • The inclusion of the buffer layer suppress the three dimensional nucleation in the GdBa{sub 2}Cu{sub 3}O{sub 7−δ} film. • GdBa{sub 2}Cu{sub 3}O{sub 7−δ} films with large areas free of topological defects and T{sub c} close to liquid nitrogen can be obtained. - Abstract: This paper provides a systematic analysis of the morphology and the superconducting critical temperature obtained in very thin GdBa{sub 2}Cu{sub 3}O{sub 7−δ} films grown on (0 0 1) SrTiO{sub 3} substrates by DC sputtering. We find that the use of a very thin SrTiO{sub 3} buffer layer (≈2 nm) modify the nucleation of GdBa{sub 2}Cu{sub 3}O{sub 7−δ} on the surface of the substrate reducing the formation of 3 dimensional clusters. Our results demonstrate that 16 nm thick GdBa{sub 2}Cu{sub 3}O{sub 7−δ} films with an average root-mean-square (RMS) smaller than 1 nm and large surface areas (up 10 μm{sup 2}) free of 3 dimensional topological defects can be obtained. In films thinner than 24 nm the onset (zero resistance) of superconducting transition of the films is reduced, being close to liquid nitrogen. This fact can be associated with stress reducing the orthorhombicity and slightly drop in oxygen stoichiometry.

  4. Bibliography of high-T/sub c/ superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Talvacchio, J.

    1989-01-01

    This document represents an effort to make bibliographic information on high-T/sub c/ superconductor films available to those who cannot access the on-line database at the Westinghouse R and D Center. The database contains a growing list of references -- approaching 5000 -- each of which is identified by a set of two-letter keywords. The database is used the same way as as INSPEC's, but its fixed set of standard keywords enables the user to obtain a complete list of references on keyworded topics. Since a single keyword (or search term) such as ''sputtering'' creates a bibliography that is too long for practical use, the database is used most effectively by combining a series of keywords using Boolean algebra to identify a handful of relevant references. The structure of this document is intended to present the subset of papers concerning high-T/sub c/ films (725 papers) in a compact format as a substitute for on-line searches. Rather than listing separate bibliographies for each of the 185 keywords, a single list of all the references is contained in Section 6, and indices based on the keywords are contained in Sections 3--5. This report is a true bibliography and does not contain any informative text. 725 refs.

  5. Superconductivity in films of Pb/PbSe core/shell nanocrystals.

    Science.gov (United States)

    Zolotavin, Pavlo; Guyot-Sionnest, Philippe

    2012-09-25

    Superconductivity in films of electronically coupled colloidal lead nanocrystals is reported. The coupling between particles is in situ controlled through the conversion of the oxides present on the surface of the nanoparticles to chalcogenides. This transformation allows for a 10(9)-fold increase in the conductivity. The temperature of the onset of the superconductivity was found to depend upon the degree of coupling of the nanoparticles in the vicinity of the insulator-superconductor transition. The critical current density of the best sample of Pb/PbSe nanocrystals at zero magnetic field was determined to be 4 × 10(3) A/cm(2). In turn, the critical field of the sample shows 50-fold enhancement compared to bulk Pb.

  6. Epitaxial growth of hexagonal tungsten bronze Cs x WO3 films in superconducting phase region exceeding bulk limit

    Science.gov (United States)

    Soma, Takuto; Yoshimatsu, Kohei; Ohtomo, Akira

    2016-07-01

    We report epitaxial synthesis of superconducting Cs x WO3 (x = 0.11, 0.20, and 0.31) films on Y-stabilized ZrO2 (111) substrates. The hexagonal crystal structure was verified not only for the composition within the stable region of the bulk (x = 0.20 and 0.31), but also for the out-of-range composition (x = 0.11). The onset of the superconducting transition was recorded at 5.8 K for x = 0.11. We found a strong correlation between the superconducting transition temperature (T C) and the c-axis length, irrespective of the Cs content. These results indicated that the hidden superconducting phase region of hexagonal tungsten bronze is accessible using epitaxial synthesis of lightly doped films.

  7. Thickness dependency of sol-gel derived ZnO thin films on gas sensing behaviors

    Energy Technology Data Exchange (ETDEWEB)

    Kakati, Nitul; Jee, Seung Hyun; Kim, Su Hyun; Oh, Jun Young; Yoon, Young Soo, E-mail: yoonys@yonsei.ac.k

    2010-10-29

    ZnO thin films were fabricated by a sol-gel method using Zn(CH{sub 3}COO){sub 2}.2H{sub 2}O as starting material in order to prepare an acetone gas sensor. A homogeneous and stable solution was prepared by dissolving the zinc acetate in a solution of ethanol and monoethanolamine. The sol-gel solution is coated on alumina substrates with various thicknesses by spin coating technique and heat treated to grow crystalline ZnO thin films. The effect of thickness on physical and electrical properties of as deposited ZnO thin films has been studied. The as deposited ZnO thin films were characterized by X-ray diffraction spectroscopy, field emission scanning electron microscopy and atomic force microscopy. The root mean square surface roughness factors increase with thickness of the films and found 3.9, 6.6, 9.0, and 11.28 nm for 80-, 220-, 450- and 620-nm-thin films respectively. The activation energies of the films are calculated from the resistance temperature characteristics. The sensitivities of the ZnO films towards the acetone gas were determined at an operating temperature of 200 {sup o}C. The sensitivity towards acetone vapor is strongly depending on surface morphology of the ZnO thin films.

  8. Spacer Thickness-Dependent Electron Transport Performance of Titanium Dioxide Thick Film for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Reda E. El-Shater

    2015-01-01

    Full Text Available A titanium dioxide (P25 film was deposited by cast coating as conductive photoelectrode and subsequently immersed in dye solution (N719 to fabricate the photoanode of dye-sensitized solar cells (DSSCs. A plastic spacer was used as a separation and sealant layer between the photoanode and the counter electrode. The effect of the thickness of this spacer on the transfer of electrons in the liquid electrolyte of the DSSCs was studied by means of both IV curves and electrochemical impedance. Using a spacer thickness range of 20 μm to 50 μm, efficiency ranges from 3.73% to 7.22%. The highest efficiency of 7.22% was obtained with an optimal spacer thickness of 40 μm.

  9. Superconducting transitions in amorphous molybdenum-germanium ultrathin films and multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Missert, N.

    1989-01-01

    The primary goal of this work was to clarify the role of enhanced Coulomb interactions in the destruction of superconductivity in disordered systems of reduced dimensions. Through a systematic study of the critical temperatures in single film sandwich and multilayer structures, the author has examined the role of dimensionality in the reduction of {Tc} in disordered superconductors. The author has observed a continuous crossover from two to three dimensional behavior as electron diffusion between individual superconducting layers in the multilayer becomes possible. This demonstrates unambiguously that the reduction in {Tc} is an artistic 2D effect and is not simply due to interface or proximity effects, as has often been assumed in the past. Multilayers were fabricated by sequential cosputtering of alternate layers of superconducting and nonsuperconducting amorphous Mo-Ge alloys. The effects of screening at short length scales in these films are probed via a systematic variation of both the distance between superconducting layers and the conductivity of the nonsuperconducting layers in a multilayer structure. As the conductivity of the nonsuperconducting layer increases, electron diffusion becomes more three dimensional. However this increased conductivity also introduces a reduction in {Tc} due to the proximity effect. This has been accounted for by comparing the T, of the multilayers with a corresponding NISIN single layer sandwich structure, designed to have an identical proximity effect reduction of {Tc}, in addition to compensating for any effect of the SIN interface itself. X-ray diffraction measurements and cross-sectional TEM micrographs confirm that the layers are structurally well defined, uniform, and continuous.

  10. Nano-fabricated superconducting radio-frequency composites, method for producing nano-fabricated superconducting rf composites

    Science.gov (United States)

    Norem, James H.; Pellin, Michael J.

    2013-06-11

    Superconducting rf is limited by a wide range of failure mechanisms inherent in the typical manufacture methods. This invention provides a method for fabricating superconducting rf structures comprising coating the structures with single atomic-layer thick films of alternating chemical composition. Also provided is a cavity defining the invented laminate structure.

  11. Terahertz paintmeter for noncontact monitoring of thickness and drying progress in paint film

    Science.gov (United States)

    Yasui, Takeshi; Yasuda, Takashi; Sawanaka, Ken-Ichi; Araki, Tsutomu

    2005-11-01

    We propose a paintmeter for noncontact and remote monitoring of the thickness and drying progress of a paint film based on the time-of-flight measurement of the echo signal of a terahertz (THz) electromagnetic pulse. The proposed method is effectively applied to two-dimensional mapping of the painting thickness distribution for single-layer and multilayer paint films. Furthermore, adequate parameters for the drying progress are extracted from the THz pulse-echo signal and effectively applied to monitor the wet-to-dry transformation. The THz paintmeter can be a powerful tool for quality control of the paint film on the in-process monitoring of car body painting.

  12. Resistive switching in a few nanometers thick tantalum oxide film formed by a metal oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Ohno, Takeo, E-mail: t-ohno@wpi-aimr.tohoku.ac.jp [WPI - Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Japan Science and Technology Agency (JST), PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Samukawa, Seiji, E-mail: samukawa@ifs.tohoku.ac.jp [WPI - Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Institute of Fluid Science (IFS), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan)

    2015-04-27

    Resistive switching in a Cu/Ta{sub 2}O{sub 5}/Pt structure that consisted of a few nanometer-thick Ta{sub 2}O{sub 5} film was demonstrated. The Ta{sub 2}O{sub 5} film with thicknesses of 2–5 nm was formed with a combination of Ta metal film deposition and neutral oxygen particle irradiation at room temperature. The device exhibited a bipolar resistive switching with a threshold voltage of 0.2 V and multilevel switching operation.

  13. Investigation of the bulk pinning force in YBCO superconducting films with nano-engineered pinning centres

    Science.gov (United States)

    Crisan, A.; Dang, V. S.; Yearwood, G.; Mikheenko, P.; Huhtinen, H.; Paturi, P.

    2014-08-01

    For practical applications of superconducting materials in applied magnetic fields, artificial pinning centres in addition to natural ones are required to oppose the Lorentz force. These pinning centres are actually various types of defects in the superconductor matrix. The pinning centres can be categorised on their dimension (volume, surface, or point) and on their character (normal cores or Δκ cores). We have used the Dew Hughes approach to determine the types of pinning centres present in various samples, with various thicknesses, temperatures and nanostructured additions to the superconducting matrix. Results show that normal surface pinning centres are present throughout almost all the samples, as dominant pinning mechanism. Such 2D extended pinning centres are mainly due to dislocations, grain boundaries, nanorods. Strong normal point pinning centres were found to be common in BZO doped YBCO samples. Other types of pinning centres, in various (minor) concentrations were also found in some of the samples.

  14. Optimizing diode thickness for thin-film solid state thermal neutron detectors

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, John W.; Mejia, Israel; Quevedo-Lopez, Manuel A.; Gnade, Bruce [Department of Materials and Science, University of Texas at Dallas, Richardson, Texas 75080 (United States); Kunnen, George R.; Allee, David [Flexible Display Center at Arizona State University, Tempe, Arizona 85284 (United States)

    2012-10-01

    In this work, we investigate the optimal thickness of a semiconductor diode for thin-film solid state thermal neutron detectors. We evaluate several diode materials, Si, CdTe, GaAs, C (diamond), and ZnO, and two neutron converter materials, {sup 10}B and {sup 6}LiF. Investigating a coplanar diode/converter geometry, we determine the minimum semiconductor thickness needed to achieve maximum neutron detection efficiency. By keeping the semiconductor thickness to a minimum, gamma rejection is kept as high as possible. In this way, we optimize detector performance for different thin-film semiconductor materials.

  15. Ceramic thick film humidity sensor based on MgTiO{sub 3} + LiF

    Energy Technology Data Exchange (ETDEWEB)

    Kassas, Ahmad, E-mail: a.kassas.mcema@ul.edu.lb [Faculty of Agricultural Engineering and Veterinary Medicine, Laboratory of Materials, Catalysis, Environment and Analytical Methods (MCEMA), Faculty of Sciences and Doctoral School of Sciences and Technology (EDST), Lebanese University, Hariri Campus, Hadath, Beirut (Lebanon); Laboratoire Universitaire des Sciences Appliquées de Cherbourg (LUSAC), 50130 Cherbourg-Octeville (France); Bernard, Jérôme; Lelièvre, Céline; Besq, Anthony; Guhel, Yannick; Houivet, David; Boudart, Bertrand [Laboratoire Universitaire des Sciences Appliquées de Cherbourg (LUSAC), 50130 Cherbourg-Octeville (France); Lakiss, Hassan [Faculty of Agricultural Engineering and Veterinary Medicine, Laboratory of Materials, Catalysis, Environment and Analytical Methods (MCEMA), Faculty of Sciences and Doctoral School of Sciences and Technology (EDST), Lebanese University, Hariri Campus, Hadath, Beirut (Lebanon); Faculty of Engineering, Section III, Hariri Campus, Hadath, Beirut (Lebanon); Hamieh, Tayssir [Faculty of Agricultural Engineering and Veterinary Medicine, Laboratory of Materials, Catalysis, Environment and Analytical Methods (MCEMA), Faculty of Sciences and Doctoral School of Sciences and Technology (EDST), Lebanese University, Hariri Campus, Hadath, Beirut (Lebanon)

    2013-10-15

    Graphical abstract: - Highlights: • The fabricated sensor based on MgTiO{sub 3} + LiF materials used the spin coating technology. • The response time is 70 s to detect variation between 5 and 95% relative humidity. • The addition of Scleroglucan controls the viscosity and decreases the roughness of thick film surface. • This humidity sensor is a promising, low-cost, high-quality, reliable ceramic films, that is highly sensitive to humidity. - Abstract: The feasibility of humidity sensor, consisting of a thick layer of MgTiO{sub 3}/LiF materials on alumina substrate, was studied. The thermal analysis TGA-DTGA and dilatometric analysis worked out to confirm the sintering temperature. An experimental plan was applied to describe the effects of different parameters in the development of the thick film sensor. Structural and microstructural characterizations of the developed thick film were made. Rheological study with different amounts of a thickener (scleroglucan “sclg”), showing the behavior variation, as a function of sclg weight % was illustrated and rapprochement with the results of thickness variation as a function of angular velocity applied in the spin coater. The electrical and dielectric measurements confirmed the sensitivity of the elaborated thick film against moisture, along with low response time.

  16. Investigation of magnetic properties in thick CoFeB alloy films for controllable anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ke; Huang, Ya; Chen, Ruofei; Xu, Zhan [Huaqiao University, College of Information Science and Engineering, Xiamen City (China)

    2016-02-15

    CoFeB alloy material has attracted interest for its wide uses in magnetic memory devices and sensors. We investigate magnetic properties of thick Co{sub 40}Fe{sub 40}B{sub 20} films in the thickness range from 10 to 100 nm sandwiched by MgO and Ta layers. Strong in-plane uniaxial magnetic anisotropy is revealed in the as-deposited amorphous films by angular dependent magnetic measurements, and the growth-induced anisotropy is found to strongly depend on the film thickness. A fourfold cubic magnetic anisotropy develops with annealing, as a result of improved crystalline structure in films confirmed by X-ray diffraction measurements. The observed magnetic properties can be explained by the superposition of the uniaxial and additional cubic magnetic anisotropy, tuned by annealing temperature. (orig.)

  17. Investigation of magnetic properties in thick CoFeB alloy films for controllable anisotropy

    Science.gov (United States)

    Wang, Ke; Huang, Ya; Chen, Ruofei; Xu, Zhan

    2016-02-01

    CoFeB alloy material has attracted interest for its wide uses in magnetic memory devices and sensors. We investigate magnetic properties of thick Co40Fe40B20 films in the thickness range from 10 to 100 nm sandwiched by MgO and Ta layers. Strong in-plane uniaxial magnetic anisotropy is revealed in the as-deposited amorphous films by angular dependent magnetic measurements, and the growth-induced anisotropy is found to strongly depend on the film thickness. A fourfold cubic magnetic anisotropy develops with annealing, as a result of improved crystalline structure in films confirmed by X-ray diffraction measurements. The observed magnetic properties can be explained by the superposition of the uniaxial and additional cubic magnetic anisotropy, tuned by annealing temperature.

  18. Electromechanical Properties of Microcantilever Actuated by Enhanced Piezoelectric PZT Thick Film

    Institute of Scientific and Technical Information of China (English)

    LIU Hong-Mei; ZHAO Quan-Liang; CAO Mao-Sheng; YUAN Jie; DUAN Zhong-Xia; QIU Cheng-Jun

    2008-01-01

    Pb(Zro.53,Tio.47)O3 (PZT) films with thicknesses of 0.8μm, 2μm and 4μm are prepared by a sol-gel method and their longitudinal piezoelectric coefficients are analysed. The results show that the PZT thick films, whose density is closer to bulk PZT, has the better crystallization, with d33 and density much larger than those of PZT thin films. A piezoelectric microcantilever actuated by a 4-μm-thick PZT film is fabricated and its displacement is measured in different frequencies and voltages. The displacement increases linearly with the increasing bias,and the maximum displacement of 0.544 μm is observed at 30kHz for 5V bias. The resonant frequency obtained in the experiment matches quite well with the theoretical result, and it is shown that the resonant frequency of PZT microcantilever could be controlled and predicated.

  19. Lift-off PMN-PT Thick Film for High Frequency Ultrasonic Biomicroscopy.

    Science.gov (United States)

    Zhu, Benpeng; Han, Jiangxue; Shi, Jing; Shung, K Krik; Wei, Q; Huang, Yuhong; Kosec, M; Zhou, Qifa

    2010-10-01

    Piezoelectric 0.65Pb(Mg(1/3)Nb(2/3))O(3)-0.35PbTiO(3) (PMN-35PT) thick film with a thickness of approximately 12 µm has been deposited on the platinum buffered Si substrate via a sol-gel composite method. The separation of the film from the substrate was achieved using a wet chemical method. The lifted-off PMN-35PT thick film exhibited good dielectric and ferroelectric properties. At 1 kHz, the dielectric constant and the dielectric loss were 3,326 and 0.037, respectively, while the remnant polarization was 30.0 µC/cm(2). A high frequency single element acoustic transducer fabricated with this film showed a bandwidth at -6 dB of 63.6% at 110 MHz.

  20. Influence of Thickness on Field Emission Characteristics of Nanometre Boron Nitride Thin Films

    Institute of Scientific and Technical Information of China (English)

    顾广瑞; 李英爱; 陶艳春; 何志; 李俊杰; 殷红; 李卫青; 赵永年

    2003-01-01

    Nanometre boron nitride (BN) thin films with various thickness (54-135 nm) were prepared on Si(100) by rf magnetic sputtering physical vapour deposition. The field emission characteristics of the BN thin films were measured in an ultrahigh vacuum system. A threshold electric field of 11 V/μm and the highest emission current density of 240 μA/cm2 at an electric field of 23 V/μm were obtained for the about 54-nm-thick BN film. The threshold electric field increases with increasing the thickness in the nanometre range. The Fowler-Nordheim plots show that electrons were emitted from BN to vacuum by tunnelling through the potential barrier at the surface of BN thin films.

  1. Self-Poling of BiFeO3 Thick Films.

    Science.gov (United States)

    Khomyakova, Evgeniya; Sadl, Matej; Ursic, Hana; Daniels, John; Malic, Barbara; Bencan, Andreja; Damjanovic, Dragan; Rojac, Tadej

    2016-08-01

    Bismuth ferrite (BiFeO3) is difficult to pole because of the combination of its high coercive field and high electrical conductivity. This problem is particularly pronounced in thick films. The poling, however, must be performed to achieve a large macroscopic piezoelectric response. This study presents evidence of a prominent and reproducible self-poling effect in few-tens-of-micrometer-thick BiFeO3 films. Direct and converse piezoelectric measurements confirmed that the as-sintered BiFeO3 thick films yield d33 values of up to ∼20 pC/N. It was observed that a significant self-poling effect only appears in cases when the films are heated and cooled through the ferroelectric-paraelectric phase transition (Curie temperature TC ∼ 820 °C). These self-poled films exhibit a microstructure with randomly oriented columnar grains. The presence of a compressive strain gradient across the film thickness cooled from above the TC was experimentally confirmed and is suggested to be responsible for the self-poling effect. Finally, the macroscopic d33 response of the self-poled BiFeO3 film was characterized as a function of the driving-field frequency and amplitude.

  2. Reactive magnetron sputter deposition of superconducting niobium titanium nitride thin films with different target sizes

    CERN Document Server

    Bos, B G C; Haalebos, E A F; Gimbel, P M L; Klapwijk, T M; Baselmans, J J A; Endo, A

    2016-01-01

    The superconducting critical temperature (Tc>15 K) of niobium titanium nitride (NbTiN) thin films allows for low-loss circuits up to 1.1 THz, enabling on-chip spectroscopy and multi-pixel imaging with advanced detectors. The drive for large scale detector microchips is demanding NbTiN films with uniform properties over an increasingly larger area. This article provides an experimental comparison between two reactive d.c. sputter systems with different target sizes: a small target (100 mm diameter) system and a large target (127 mm x 444.5 mm) one, with the aim of improving the film uniformity using the large target system. We focus on the Tc of the films and I-V characteristics of the sputter plasma, and we find that both systems are capable of depositing films with Tc>15 K. We find that these films are deposited within the transition from metallic to compound sputtering, at the point where target nitridation most strongly depends on nitrogen flow. Key in the deposition optimization is to increase the system'...

  3. Fracture behaviors of thin superconducting films with field-dependent critical current density

    Energy Technology Data Exchange (ETDEWEB)

    He, An; Xue, Cun; Yong, Huadong; Zhou, Youhe, E-mail: zhouyh@lzu.edu.cn

    2013-09-15

    Highlights: • The fracture behaviors of superconducting films for the Kim model are studied. • The profile of stress intensity factor is generally the same as magnetostriction. • The crack problem of two collinear cracks is also researched for the Kim model. -- Abstract: The fracture behaviors under electromagnetic force with field-dependent critical current density in thin superconducting film are investigated. Applying finite element method, the energy release rates and stress intensity factors of one central crack versus applied field and crack length are obtained for the Bean model and Kim model. It is interesting that the profile of the stress intensity factor is generally the same as the magnetostrictive behavior during one full cycle applied field. Furthermore, the crack problem of two collinear cracks with respect to crack length and distance is also researched for the Kim model. The results show that the energy release rates and stress intensity factors of the two collinear cracks at left tip and right tip are remarkably different for relatively small crack distance and long crack length. This work can offer good estimations and provide a basis for interpretation of cracking and mechanical failure of HTS thin films in numerous real situations.

  4. Microstructure parameters and optical properties of cadmium ferrite thin films of variable thickness

    Science.gov (United States)

    Shaaban, E. R.

    2014-06-01

    CdFe2O4 thin films of different thicknesses were deposited onto glass substrates by the thermal evaporation technique. Their structural characteristics were studied by X-ray diffraction (XRD). The microstructure parameters, crystallite size, and microstrain were calculated. It is observed that both the crystallite size increases and microstrain increase with increasing with the film thickness. The fundamental optical parameters like absorption coefficient and optical band gap are calculated in the strong absorption region of transmittance and reflectance spectrum. The refractive indices have been evaluated in terms of the envelope method, which has been suggested by Swanepoel in the transparent region. The refractive index can be extrapolated by the Cauchy dispersion relationship over the whole spectra range, which extended from 400 to 2500 nm. The refractive index, n, increases on increasing the film thickness up to 733 nm and the variation of n with higher thickness lies within the experimental errors.

  5. Effect of withdrawal speed on film thickness and hexagonal pore-array dimensions of SBA-15 mesoporous silica thin film.

    Science.gov (United States)

    Hwang, Junho; Shoji, Naoko; Endo, Akira; Daiguji, Hirofumi

    2014-12-30

    Two-dimensional hexagonal mesoporous silica thin films of SBA-15 were synthesized on Si substrates via dip-coating using an evaporation-induced self-assembly process. The effect of the withdrawal speed on the thicknesses, one-dimensional pore alignments, and two-dimensional hexagonal pore arrays of the films was elucidated. Detailed analyses of FE-SEM and TEM images and XRD and XRR patterns of the synthesized thin films clarified that the pore sizes, interplanar spacings, and film thicknesses depend on the withdrawal speed. Furthermore, the same films were synthesized on Si substrates with microtrenches. The local flow of coating solutions around microtrenches affects the pore direction as well as the film thickness. In order to form well-ordered mesoporous silica thin films with large surface areas, it is important to control the synthetic conditions such as the local flow of the coating solutions as well as the physicochemical properties of the silica precursor solutions or template molecules.

  6. Fabrication and Characterization of PZT Thick Films for Sensing and Actuation

    Directory of Open Access Journals (Sweden)

    Kuo-Ching Kuo

    2007-04-01

    Full Text Available Lead Zirconate Titanate oxide (PZT thick films with thicknesses of up to 10 μmwere developed using a modified sol-gel technique. Usually, the film thickness is less than1 μm by conventional sol-gel processing, while the electrical charge accumulation whichreveals the direct effect of piezoelectricity is proportional to the film thickness and thereforerestricted. Two approaches were adopted to conventional sol-gel processing – precursorconcentration modulation and rapid thermal annealing. A 10 μm thick film was successfullyfabricated by coating 16 times via this technique. The thickness of each coating layer wasabout 0.6 μm and the morphology of the film was dense with a crack-free area as large as 16mm2. In addition, the structure, surface morphology and physical properties werecharacterized by X-ray diffraction (XRD, scanning electron microscopy (SEM and atomicforce microscopy (AFM and electrical performance. The dielectric constant and hysteresisloops were measured as electric characteristics. This study investigates the actuation andsensing performance of the vibrating structures with the piezoelectric thick film. Theactuation tests demonstrated that a 4 mm x 4 mm x 6.5 μm PZT film drove a 40 mm x 7 mmx 0.5 mm silicon beam as an actuator. Additionally, it generated an electrical signal of 60mVpp as a sensor, while vibration was input by a shaker. The frequencies of the first twomodes of the beam were compared with the theoretical values obtained by Euler-Bernoullibeam theory. The linearity of the actuation and sensing tests were also examined.

  7. An estimation method on failure stress of micro thickness Cu film-substrate structure

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The failure of thin film-substrate structure occurs mainly at the thin film or the interface. However, the characterizing and estimating methods of failure stress in thin film are neither uniform nor effective because there are some complex effects of such as size, interface and stress state on the failure behavior of thin film-substrate structure. Based on the scanning electron microscope (SEM) in-situ in- vestigation on the failure models of the Cu thin film-substrate structure and the nano scratched testing results, the failure stresses in different thicknesses of the Cu film-substrate were characterized, which were compared and confirmed by other methods, such as Stoney formula and other empiric equations. These results indicate that the novel estimating method of failure stress in thin film based on the critical wavelength of surface unstable analysis is better than other methods. The main reason is that the novel estimating method of failure stress in meso thickness film fully considered the effect factors of free surface unstable behavior and elastic anisotropy of thin film. Therefore, the novel estimating method of failure stress assists people to understand the critical interfacial strength and to set up the failure criterion of thin film-substrate structure.

  8. An estimation method on failure stress of micro thickness Cu film-substrate structure

    Institute of Scientific and Technical Information of China (English)

    WANG XiShu; LI Ying; MENG XiangKang

    2009-01-01

    The failure of thin film-substrate structure occurs mainly at the thin film or the interface.However,the characterizing and estimating methods of failure stress in thin film are neither uniform nor effective because there are some complex effects of such as size,interface and stress state on the failure behavior of thin film-substrate structure.Based on the scanning electron microscope(SEM)in-situ investigation on the failure models of the Cu thin film-substrata structure and the nano scratched testing results,the failure stresses in different thicknesses of the Cu film-substrate were characterized,which were compared and confirmed by other methods,such as Stoney formula and other empiric equations.These results indicate that the novel estimating method of failure stress in thin film based on the critical wavelength of surface unstable analysis is better than other methods.The main reason is that the novel estimating method of failure stress in meso thickness film fully considered the effect factors of free surface unstable behavior and elastic anisotropy of thin film.Therefore,the novel estimating method of failure stress assists people to understand the critical interracial strength and to set up the failure criterion of thin film-substrate structure.

  9. Surface functionalization by fine ultraviolet-patterning of nanometer-thick liquid lubricant films

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Renguo [Department of Complex Systems Science, Graduate School of Information Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Zhang, Hedong, E-mail: zhang@is.nagoya-u.ac.jp [Department of Complex Systems Science, Graduate School of Information Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Komada, Suguru [Department of Micro-Nano System Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Mitsuya, Yasunaga [Nagoya Industrial Science Research Institute, Noa Yotsuya Building 2F, 1-13, Yotsuya-Douri, Chikusa-ku, Nagoya 464-0819 (Japan); Fukuzawa, Kenji; Itoh, Shintaro [Department of Micro-Nano System Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2014-11-30

    Highlights: • We present fine UV-patterning of nm-thick liquid films for surface functionalization. • The patterned films exhibit both a morphological pattern and a functional pattern of different surface properties. • The finest pattern linewidth was 0.5 μm. • Fine patterning is crucial for improving surface and tribological properties. - Abstract: For micro/nanoscale devices, surface functionalization is essential to achieve function and performance superior to those that originate from the inherent bulk material properties. As a method of surface functionalization, we dip-coated nanometer-thick liquid lubricant films onto solid surfaces and then patterned the lubricant films with ultraviolet (UV) irradiation through a photomask. Surface topography, adhesion, and friction measurements demonstrated that the patterned films feature a concave–convex thickness distribution with thicker lubricant in the irradiated regions and a functional distribution with lower adhesion and friction in the irradiated convex regions. The pattern linewidth ranged from 100 to as fine as 0.5 μm. The surface functionalization effect of UV-patterning was investigated by measuring the water contact angles, surface energies, friction forces, and depletion of the patterned, as-dipped, and full UV-irradiated lubricant films. The full UV-irradiated lubricant film was hydrophobic with a water contact angle of 102.1°, and had lower surface energy, friction, and depletion than the as-dipped film, which was hydrophilic with a water contact angle of 80.7°. This demonstrates that UV irradiation substantially improves the surface and tribological properties of the nanometer-thick liquid lubricant films. The UV-patterned lubricant films exhibited superior surface and tribological properties than the as-dipped film. The water contact angle increased and the surface energy, friction, and depletion decreased as the pattern linewidth decreased. In particular, the 0.5-μm patterned lubricant

  10. Equivalent-Circuit Model for the Thickness-Shear Mode Resonator with a Viscoelastic Film Near Film Resonance

    Energy Technology Data Exchange (ETDEWEB)

    BANDEY, HELEN L.; BROWN, MARK J.; CERNOSEK, RICHARD W.; HILLMAN, A. ROBERT; MARTIN, STEPHEN J.

    1999-09-16

    We derive a lumped-element, equivalent-circuit model for the thickness shear mode (TSM) resonator with a viscoelastic film. This modified Butterworth-Van Dyke model includes in the motional branch a series LCR resonator, representing the quartz resonance, and a parallel LCR resonator, representing the film resonance. This model is valid in the vicinity of film resonance, which occurs when the acoustic phase shift across the film is an odd multiple of {pi}/2 radians. This model predicts accurately the frequency changes and damping that arise at resonance and is a reasonable approximation away from resonance. The elements of the model are explicitly related to film properties and can be interpreted in terms of elastic energy storage and viscous power dissipation. The model leads to a simple graphical interpretation of the coupling between the quartz and film resonances and facilitates understanding of the resulting responses. These responses are compared with predictions from the transmission-line and the Sauerbrey models.

  11. Impact of film thickness on the morphology of mesoporous carbon films using organic-organic self-assembly.

    Science.gov (United States)

    Vogt, Bryan D; Chavez, Vicki L; Dai, Mingzhi; Arreola, M Regina Croda; Song, Lingyan; Feng, Dan; Zhao, Dongyuan; Perera, Ginusha M; Stein, Gila E

    2011-05-03

    Mesoporous polymer and carbon thin films are prepared by the organic-organic self-assembly of an oligomeric phenolic resin with an amphiphilic triblock copolymer template, Pluronic F127. The ratio of resin to template is selected such that a body-centered cubic (Im3m) mesostructure is formed in the bulk. However, well-ordered mesoporous films are not always obtained for thin films (body-centered cubic symmetry with a preferential orientation of the closest-packed (110) plane parallel to the substrate. Film thickness and initial composition of the carbonizable precursors in the template are critical factors in determining the morphology of mesoporous carbon films. These results provide insight into why difficulties have been reported in producing ultrathin ordered mesoporous carbon films using cooperative organic-organic self-assembly.

  12. Humidity sensing properties of WO{sub 3} thick film resistor prepared by screen printing technique

    Energy Technology Data Exchange (ETDEWEB)

    Garde, Arun S, E-mail: arungarde@yahoo.co.in

    2014-12-25

    Highlights: • Polycrystalline WO{sub 3} Thick films are fabricated by screen printing technique. • Monoclinic phases were the majority in formation of films. • The peak at 1643 cm{sup −1} shows stretching vibrations attributed to W-OH of adsorbed H{sub 2}O. • Absorption peaks in the range 879–650 cm{sup −1} are attributed to the stretching W-O-W bonds. • Increase in resistance with decrease in RH when exposed to 20–100% RH. - Abstract: Thick films of tungsten oxide based were prepared using standard screen printing technique. To study the effect of temperature on the thick films were fired at different temperature for 30 min in air atmosphere. The WO{sub 3} thick films were characterized with X-ray diffraction, scanning electron microscopy and EDAX for elemental analysis. The formation of mixed phases of the film together with majority of monoclinic phase was observed. IR spectra confirm the peak at 1643 cm{sup −1} clearly shows stretching vibrations attributed to the W-OH bending vibration mode of the adsorbed water molecules. The absorption peaks in the range 879–650 cm{sup −1} are attributed to the stretching W-O-W bonds (i.e. ν [W-O{sub inter}-W]). The peak located at 983 cm{sup −1} belong to W=O terminal of cluster boundaries. A change in the resistance was observed with respect to the relative humidity when the WO{sub 3} thick films were exposed to a wide humidity range of 20–100%. An increasing firing temperature of WO{sub 3} film increases with the sensitivity. The parameters such as sensitivity and hysteresis of the WO{sub 3} film sensors have been evaluated.

  13. Improved gas sensing and dielectric properties of Fe doped hydroxyapatite thick films: Effect of molar concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Mene, Ravindra U. [PDEA' s, Annasaheb Waghire College of Science, Arts and Commerce, Otur 412409, M.S. (India); School of Physical Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431606, M.S. (India); Mahabole, Megha P. [School of Physical Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431606, M.S. (India); Mohite, K.C. [Haribhai. V. Desai College, Pune 411002, M.S. (India); Khairnar, Rajendra S., E-mail: rskhairnarsps@gmail.com [School of Physical Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431606, M.S. (India)

    2014-02-01

    Highlights: • We report improved gas sensing and dielectric characteristics of Fe ion exchanged HAp films. • Fe doped HAp film shows maximum gas response at relatively lower temperature. • Response and gas uptake capacity of sensors is improved for appropriate amount of Fe ions in HAp matrix. • Fe-HAp films exhibit remarkable improvement in dielectric properties compared to pure HAp. • Fe doped HAp films show significant improvement in gas sensing as well as in dielectric properties. - Abstract: In the present work Fe doped hydroxyapatite (Fe-HAp) thick films has been successfully utilized to improve the gas sensing as well as its dielectric properties. Initially, HAp nano powder is synthesized by chemical precipitation process and later on Fe ions are doped in HAp by ion exchange process. Structural and morphological modifications are observed by means of X-ray diffraction and scanning electron microscopy analysis. The sensing parameters such as operating temperature, response/recovery time and gas uptake capacity are experimentally determined. The Fe-HAp (0.05 M) film shows improved CO and CO{sub 2} gas sensing capacity at lower operating temperature compared to pure HAp. Moreover, variation of dielectric constant and dielectric loss for pure and Fe-HAp thick films are studied as a function of frequency in the range of 10 Hz–1 MHz. The study reveals that Fe doped HAp thick films improve the sensing and dielectric characteristics as compared to pure HAp.

  14. Effect of Nanoscale Ag Film Thickness on the Electrical and Optical Properties of Transparent IZTO/Ag/IZTO Multilayer Films Deposited on Glass Substrates.

    Science.gov (United States)

    Oh, Dohyun; Lee, Nam Hyun; Cho, Woon-Jo; Kim, Tae Whan

    2015-07-01

    The effect of nanoscale Ag film thickness on the electrical and optical properties in transparent conducting oxide films consisting of an IZTO/Ag/IZTO multilayer were investigated. The homoge- neous morphologies of the Ag films sandwiched between the IZTO films affected the optical and electrical properties of the IZTO/Ag/IZTO multilayer films. The transmittance and resistivity of the IZTO/Ag/IZTO multilayer films decreased with increasing Ag film thickness. The resistivities of the IZTO/Ag/IZTO multilayer films grown on glass substrates were decreased by using an Ag thin inter- layer in comparison with that of the IZTO single layer.

  15. Transport critical-current density of superconducting films with hysteretic ferromagnetic dots

    Directory of Open Access Journals (Sweden)

    Nuria Del-Valle

    2012-06-01

    Full Text Available Superconductor-ferromagnet hybrids present a rich and complex phenomenology. Particularly, a hysteretic behavior on the transport critical-current density, as a function of a uniform perpendicular applied field, has been experimentally found in superconducting films with some embedded ferromagnets. Here we analyze the interaction superconductor-ferromagnets by means of an iterative model based on the critical-state model with field-dependent internal critical-current density and compare the results with actual transport measurements. By using arguments of field compensation, we show how the change in the magnetization of the ferromagnetic inclusions is responsible for the observed hysteresis on the transport critical current.

  16. Effect of boron doping on first-order Raman scattering in superconducting boron doped diamond films

    Science.gov (United States)

    Kumar, Dinesh; Chandran, Maneesh; Ramachandra Rao, M. S.

    2017-05-01

    Aggregation of impurity levels into an impurity band in heavily boron doped diamond results in a background continuum and discrete zone centre phonon interference during the inelastic light scattering process. In order to understand the Raman scattering effect in granular BDD films, systematically heavily doped samples in the semiconducting and superconducting regimes have been studied using the excitation wavelengths in the UV and visible regions. A comprehensive analysis of the Fano resonance effect as a function of the impurity concentrations and the excitation frequencies is presented. Various Raman modes available in BDD including signals from the grain boundaries are discussed.

  17. The I{sub c}(H)-T{sub c}(H) phase boundary of superconducting Nb thin films with periodic and quasiperiodic antidot arrays

    Energy Technology Data Exchange (ETDEWEB)

    Bothner, D.; Kemmler, M.; Cozma, R.; Kleiner, R.; Koelle, D. [Physikalisches Institut and Center for Collective Quantum Phenomena, Universitaet Tuebingen (Germany); Misko, V.; Peeters, F. [Departement Fysica, Universiteit Antwerpen (Belgium); Nori, F. [Advanced Science Institute, RIKEN (Japan)

    2011-07-01

    The magnetic field dependent critical current I{sub c}(H) of superconducting thin films with artificial defects strongly depends on the symmetry of the defect arrangement. Likewise the critical temperature T{sub c}(H) of superconducting wire networks is heavily influenced by the symmetry of the system. Here we present experimental data on the I{sub c}(H)-T{sub c}(H) phase boundary of Nb thin films with artificial defect lattices of different symmetries. For this purpose we fabricated 60 nm thick Nb films with antidots in periodic (triangular) and five different quasiperiodic arrangements. The parameters of the antidot arrays were varied to investigate the influence of antidot diameter and array density. Experiments were performed with high temperature stability ({delta}T<1 mK) at 0.5{<=}T/T{sub c}{<=}1. From the I-V-characteristics at variable H and T we extract I{sub c}(H) and T{sub c}(H) for different voltage and resistance criteria. The experimental data for the critical current density are compared with results from numerical molecular dynamics simulations.

  18. Effect of Nanotube Film Thickness on the Performance of Nanotube-Silicon Hybrid Solar Cells

    Directory of Open Access Journals (Sweden)

    Daniel D. Tune

    2013-12-01

    Full Text Available The results of measurements on solar cells made from randomly aligned thin films of single walled carbon nanotubes (SWCNTs on n-type monocrystalline silicon are presented. The films are made by vacuum filtration from aqueous TritonX-100 suspensions of large diameter arc-discharge SWCNTs. The dependence of the solar cell performance on the thickness of the SWCNT film is shown in detail, as is the variation in performance due to doping of the SWCNT film with SOCl2.

  19. Thickness dependence of structural, electrical and optical behaviour of undoped ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bouderbala, M.; Hamzaoui, S. [Laboratoire de Microscopie Electronique et des Sciences des Materiaux, Departement de Physique, USTO, B.P. 1505, El-Mnaouer, 31000 Oran (Algeria); Amrani, B. [Department of Physics, Centre Universitaire de Mascara, Mascara 29000 (Algeria)], E-mail: abouhalouane@yahoo.fr; Reshak, Ali H. [Institute of Physical Biology-South Bohemia University, Institute of System Biology and Ecology-Academy of Sciences, Nove Hrady 37333 (Czech Republic); Adnane, M.; Sahraoui, T.; Zerdali, M. [Laboratoire de Microscopie Electronique et des Sciences des Materiaux, Departement de Physique, USTO, B.P. 1505, El-Mnaouer, 31000 Oran (Algeria)

    2008-09-01

    Undoped ZnO thin films of different thicknesses were prepared by r.f. sputtering in order to study the thickness effect upon their structural, morphological, electrical and optical properties. The results suggest that the film thickness seems to have no clear effect upon the orientation of the grains growth. Indeed, the analysis with X-ray diffraction show that the grains were always oriented according to the c(0 0 2)-axis perpendicular to substrate surface whatever the thickness is. However, the grain size was influenced enough by this parameter. An increase in the grain size versus the thickness was noted. For the electrical properties, measurements revealed behaviour very dependent upon thickness. The resistivity decreased from 25 to 1.5x10{sup -3} {omega} cm and the mobility increased from 2 to 37 cm{sup 2} V{sup -1} s{sup -1} when the thickness increased from 70 to 1800 nm while the carrier concentration seems to be less affected by the film thickness and varied slightly remaining around 10{sup 20} cm{sup -3}. Nevertheless, a tendency to a decrease was noticed. This behaviour in electrical properties was explained by the crystallinity and the grain size evolution. The optical measurements showed that all the samples have a strong transmission higher than 80% in the visible range. A slight shift of the absorption edge towards the large wavelengths was observed as the thickness increased. This result shows that the band gap is slightly decreases from 3.37 to 3.32 eV with the film thickness vary from 0.32 to 0.88 {mu}m.

  20. Thick barium ferrite films use for passive isolators

    Energy Technology Data Exchange (ETDEWEB)

    Capraro, Stephane; Chatelon, Jean Pierre; Rouiller, Thomas; Rousseau, Jean Jacques [DIOM, University of Saint-Etienne, 23 rue Michelon, 42023 Saint-Etienne cedex (France); Berre, Martine Le; Barbier, Daniel [LPM, UMR 5511, INSA Lyon, 7 av. Jean Capelle, 69621 Villeurbanne cedex (France); Joisten, Helene [CEA-LETI, 17 rue des martyrs, 38041 Grenoble cedex (France)

    2004-12-01

    Ferrites have magnetic properties suitable for electronic applications, especially in the microwave range (circulators and isolators). Hexagonal ferrite, such as barium ferrite, are of great interest for microwave device applications because of their large resistivity and high permeability at high frequencies. BaM films are deposited under optimized conditions by RF magnetron sputtering on alumina substrates. In order to crystallize the films that are amorphous after deposition, a post deposition annealing at 800 C is implemented. All samples present a good crystallization, a smooth surface and a good in-depth uniformity. The magnetic properties of BaM films show an optimized coercive force and saturation magnetization of 330 kA/m and 500 mT respectively. These values are close to that of the bulk BaM. Isolators are then realized and measured by a vector network analyzer and a probing system. Results on transmission coefficients show a non reciprocal effect, which reaches 8.3 dB/cm at 50 GHz. This proves that such a component behaves like an isolator in the 50 GHz band. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Unusual Contact-Line Dynamics of Thick Films and Drops

    Science.gov (United States)

    Veretennikov, Igor; Agarwal, Abhishek; Indeikina, Alexandra; Chang, Hsueh-Chia

    1999-01-01

    We report several novel phenomena In contact-line and fingering dynamics of macroscopic spinning drops and gravity-driven films with dimensions larger than the capillary length. It is shown through experimental and theoretical analysis that such macroscopic films can exhibit various interfacial shapes, including multi valued ones, near the contact line due to a balance between the external body forces with capillarity. This rich variety of front shapes couples with the usual capillary, viscous, and intermolecular forces at the contact line to produce a rich and unexpected spectrum of contact-line dynamics. A single finger develops when part of the front becomes multivalued on a partially wetting macroscopic spinning drop in contrast to a different mechanism for microscopic drops of completely wetting fluids. Contrary to general expectation, we observe that, at high viscosity and low frequencies of rotation, the speed of a glycerine finger increases with increasing viscosity. Completely wetting Dow Corning 200 Fluid spreads faster over a dry inclined plane than a prewetted one. The presence of a thin prewetted film suppresses fingering both for gravity-driven flow and for spin coating. We analyze some of these unique phenomena in detail and offer qualitative physical explanations for the others.

  2. Characterization of 3-dimensional superconductive thin film components for gravitational experiments in space

    Energy Technology Data Exchange (ETDEWEB)

    Hechler, S.; Nawrodt, R.; Nietzsche, S.; Vodel, W.; Seidel, P. [Friedrich-Schiller-Univ. Jena (Germany). Inst. fuer Festkoerperphysik; Dittus, H. [ZARM, Univ. Bremen (Germany); Loeffler, F. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)

    2007-07-01

    Superconducting quantum interference devices (SQUIDs) are used for high precise gravitational experiments. One of the most impressive experiments is the satellite test of the equivalence principle (STEP) of NASA/ESA. The STEP mission aims to prove a possible violation of Einstein's equivalence principle at an extreme level of accuracy of 1 part in 10{sup 18} in space. In this contribution we present an automatically working measurement equipment to characterize 3-dimensional superconducting thin film components like i.e. pick-up coils and test masses for STEP. The characterization is done by measurements of the transition temperature between the normal and the superconducting state using a special built anti-cryostat. Above all the setup was designed for use in normal LHe transport Dewars. The sample chamber has a volume of 150 cm{sup 3} and can be fully temperature controlled over a range from 4.2 K to 300 K with a resolution of better then 100 mK. (orig.)

  3. Modelling and optimization of film thickness variation for plasma enhanced chemical vapour deposition processes

    Science.gov (United States)

    Waddell, Ewan; Gibson, Des; Lin, Li; Fu, Xiuhua

    2011-09-01

    This paper describes a method for modelling film thickness variation across the deposition area within plasma enhanced chemical vapour deposition (PECVD) processes. The model enables identification and optimization of film thickness uniformity sensitivities to electrode configuration, temperature, deposition system design and gas flow distribution. PECVD deposition utilizes a co-planar 300mm diameter electrodes with separate RF power matching to each electrode. The system has capability to adjust electrode separation and electrode temperature as parameters to optimize uniformity. Vacuum is achieved using dry pumping with real time control of butterfly valve position for active pressure control. Comparison between theory and experiment is provided for PECVD of diamond-like-carbon (DLC) deposition onto flat and curved substrate geometries. The process utilizes butane reactive feedstock with an argon carrier gas. Radiofrequency plasma is used. Deposited film thickness sensitivities to electrode geometry, plasma power density, pressure and gas flow distribution are demonstrated. Use of modelling to optimise film thickness uniformity is demonstrated. Results show DLC uniformity of 0.30% over a 200 mm flat zone diameter within overall electrode diameter of 300mm. Thickness uniformity of 0.75% is demonstrated over a 200mm diameter for a non-conformal substrate geometry. Use of the modelling method for PECVD using metal-organic chemical vapour deposition (MOCVD) feedstock is demonstrated, specifically for deposition of silica films using metal-organic tetraethoxy-silane. Excellent agreement between experimental and theory is demonstrated for conformal and non-conformal geometries. The model is used to explore scalability of PECVD processes and trade-off against film thickness uniformity. Application to MEMS, optical coatings and thin film photovoltaics is discussed.

  4. Measurement setup for the magnetic penetration depth and superfluid stiffness in thin superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, Lorenz; Brunner, Markus Christopher Paul; Schneider, Ina; Kronfeldner, Klaus; Strunk, Christoph [Institute for exp. and appl. Physics, University of Regensburg (Germany); Bousquet, Jessica; Bustarret, Etienne [Institut NEEL, Grenoble (France)

    2015-07-01

    A mutual inductance measurement setup has been established in order to determine the magnetic penetration depths of thin film superconductors. By measuring the variation of the mutual inductance M, the temperature dependent penetration depth can be evaluated. The setup has been characterized using thin aluminum and niobium films as a reference. Temperature dependence of λ of B-doped diamond films is determined down to 0.3 K and compared with theoretical expectations. The impact of the doping ratio B/C and film thickness on λ and T{sub c} is investigated. Correlation between the film impedance σ = σ{sub 1} - i σ{sub 2} and λ is examined.

  5. Thickness, morphology, and optoelectronic characteristics of pristine and surfactant-modified DNA thin films

    Science.gov (United States)

    Arasu, Velu; Reddy Dugasani, Sreekantha; Son, Junyoung; Gnapareddy, Bramaramba; Jeon, Sohee; Jeong, Jun-Ho; Park, Sung Ha

    2017-10-01

    Although the preparation of DNA thin films with well-defined thicknesses controlled by simple physical parameters is crucial for constructing efficient, stable, and reliable DNA-based optoelectronic devices and sensors, it has not been comprehensively studied yet. Here, we construct DNA and surfactant-modified DNA thin films by drop-casting and spin-coating techniques. The DNA thin films formed with different control parameters, such as drop-volume and spin-speed at given DNA concentrations, exhibit characteristic thickness, surface roughness, surface potential, and absorbance, which are measured by a field emission scanning electron microscope, a surface profilometer, an ellipsometer, an atomic force microscope, a Kelvin probe force microscope, and an UV–visible spectroscope. From the observations, we realized that thickness significantly affects the physical properties of DNA thin films. This comprehensive study of thickness-dependent characteristics of DNA and surfactant-modified DNA thin films provides insight into the choice of fabrication techniques in order for the DNA thin films to have desired physical characteristics in further applications, such as optoelectronic devices and sensors.

  6. X-ray Photoelectron Spectroscopy on Superconducting Tl2CaBa2Cu2O8 Thin Film

    Science.gov (United States)

    Zeng, Wensheng; Qiu, Ping; Yan, Shaolin; Li, Zengfa; Zhang, Guangyin

    1991-06-01

    We have prepared single-phase superconducting Tl2CaBa2Cu2O8 thin film by dc magnetron sputtering process and measured x-ray photoelectron spectra of the film at room and liquid nitrogen temperatures. From the relative intensities of the Ba3d, Tl4f. O1s and Cu2p spectra taken at different take-off angles, we have concluded that there is an adventitious contamination (nonsuperconducting phase) surface layer. After excluding contributions from these spurious phases, we have tentatively assigned which core-level shifts should be caused by the superconducting phase transition.

  7. WS{sub 2} nanotube formation by sulphurization: Effect of precursor tungsten film thickness and stress

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Sheung Mei; Wong, Hon Fai; Wong, Wang Cheung; Tan, Choon Kiat; Choi, Sin Yuk; Mak, Chee Leung; Li, Gui Jun [Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Dong, Qing Chen [MOE Key Laboratory for Interface Science and Engineering in Advanced Materials and Research Center of Advanced Materials Science and Technology, Taiyuan University of Technology, 79 Yingze West Street, Taiyuan 030024 (China); Leung, Chi Wah, E-mail: dennis.leung@polyu.edu.hk [Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)

    2016-09-15

    Transition metal dichalcogenides can exhibit as 2-dimensional layers, 1-dimensional nanotubes or 0-dimensional quantum dot structures. In general, dichalcogenide nanotubes are grown under stringent conditions, using high growth temperatures with tedious processes. Here, we report the controlled formation of tungsten disulphide (WS{sub 2}) nanostructures by manipulating the precursor film thickness, followed by a direct sulphurization process. WS{sub 2} nanotubes were formed by ultra-thin tungsten precursor films, while particle-like WS{sub 2} were obtained from thicker tungsten films under identical sulphurization conditions. To elucidate the origin of WS{sub 2} nanostructure formation, micron-sized tungsten film tracks were prepared, and such patterned films were found to suppress the growth of WS{sub 2} nanotubes. We attribute the suppression of nanotube formation to the relieving of film stress in patterned precursor films. - Highlights: • WS{sub 2} were obtained by sulphurization of sputtered tungsten films on Si substrates. • Resultant WS{sub 2} nanostructure morphology was dependent on precursor film thickness. • Patterning into micro-size W tracks suppressed the formation of nanotubes. • Stress relaxation was attributed as controlling factor for WS{sub 2} structure formation.

  8. Construction of sputtering system and preparation of high temperature superconducting thin films

    CERN Document Server

    Kaynak, E

    2000-01-01

    The preparation of high T sub c superconducting thin film is important both for the understanding of fundamental behaviours of these materials and for the investigations on the usefulness of technological applications. High quality thin films can be prepared by various kinds of techniques being used today. Among these, sputtering is the most preferred one. The primary aim of this work is the construction of a r. f. and c. magnetron sputtering system. For this goal, a magnetron sputtering system was designed and constructed having powers up to 500W (r.f.) and 1KW (d.c.) that enables to deposit thin films of various kinds of materials: metals, ceramics and magnetic materials. The temperature dependence of the electrical resistance of the films was investigated by using four-point probe method. The zero resistance and the transition with of the films were measured as 80-85 K, and 2-9 K, respectively. The A.C. susceptibility experiments were done by utilising the system that was designed and constructed. The appl...

  9. Preparation of YBCO-BYTO and YBCO-BZO nanostructured superconducting films by chemical method

    Science.gov (United States)

    Garcés, P.; Coll, M.; Castro, H.; Puig, T.; Obradors, X.

    2017-01-01

    YBCO-BYTO6% and YBCO-BZO10% YBa2Cu3O7-d-Ba2YTaO6 6% (YBCO-BYTO6%) and YBa2Cu3O7--BaZrO3 10% (YBCO-BZO 10%) nanostructured films were grown by the Chemical Solution Deposition method, and compared with YBCO pure films. Films were deposited on YSZ substrates, with Ce0.9Zr0.1O2 and Ce0.6Zr0.4O2 buffer layers. They were characterized by GADDS X-ray diffraction, scanning electron microscopy (SEM) and inductive (SQUID) measurements of the critical temperature (Tc) and critical current density (Jc). It was found that YBCO-BZO10% films presented better superconducting properties (Tc=89.2K and Jc=1.3MA/cm2), probably due to an enhanced pinning force, originated by BZO nanoparticles. Additionally, it was found that these films have lower reactivity with the buffer layer.

  10. Microdomain orientation dependence on thickness in thin films of cylinder-forming PS-b-PMMA.

    Science.gov (United States)

    Zucchi, I A; Poliani, E; Perego, M

    2010-05-07

    The self-assembly of block-copolymer thin films in periodic nanostructures has received considerable attention during the last decade due to their potential applications in nanofabrication and nanolithography. We followed the morphologies developed in thin films of a cylinder-forming diblock copolymer polystyrene-b-poly(methylmethacrylate) ((PS-b-PMMA), PS 46.1 kg mol( - 1), PMMA 21.0 kg mol( - 1), lattice spacing L(0) = 36 nm), as a function of the film thickness (t), analyzing the effect of thickness commensurability on domain orientation in respect to the substrate. The study was circumscribed to the unexplored range of thickness below L(0). Two thickness windows with perpendicular orientation of the PMMA domains were identified: a well-known window at t approximately L(0) and a new window at t approximately L(0)/2. A half-parallel cylinder morphology was observed for [Formula: see text] with a progressive change in morphology [Formula: see text] when thickness increases from L(0)/2 to L(0). This experimental evidence provides new insights on the mechanism of block copolymers self-organization and indicates the possibility to tune the thickness of the nanostructured polymeric film below L(0), allowing the fabrication of ultrathin soft masks for advanced lithographic processes.

  11. Imaging of current distributions in superconducting thin film structures; Abbildung von Stromverteilungen in supraleitenden Duennfilmstrukturen

    Energy Technology Data Exchange (ETDEWEB)

    Doenitz, D.

    2006-10-31

    Local analysis plays an important role in many fields of scientific research. However, imaging methods are not very common in the investigation of superconductors. For more than 20 years, Low Temperature Scanning Electron Microscopy (LTSEM) has been successfully used at the University of Tuebingen for studying of condensed matter phenomena, especially of superconductivity. In this thesis LTSEM was used for imaging current distributions in different superconducting thin film structures: - Imaging of current distributions in Josephson junctions with ferromagnetic interlayer, also known as SIFS junctions, showed inhomogeneous current transport over the junctions which directly led to an improvement in the fabrication process. An investigation of improved samples showed a very homogeneous current distribution without any trace of magnetic domains. Either such domains were not present or too small for imaging with the LTSEM. - An investigation of Nb/YBCO zigzag Josephson junctions yielded important information on signal formation in the LTSEM both for Josephson junctions in the short and in the long limit. Using a reference junction our signal formation model could be verified, thus confirming earlier results on short zigzag junctions. These results, which could be reproduced in this work, support the theory of d-wave symmetry in the superconducting order parameter of YBCO. Furthermore, investigations of the quasiparticle tunneling in the zigzag junctions showed the existence of Andreev bound states, which is another indication of the d-wave symmetry in YBCO. - The LTSEM study of Hot Electron Bolometers (HEB) allowed the first successful imaging of a stable 'Hot Spot', a self-heating region in HEB structures. Moreover, the electron beam was used to induce an - otherwise unstable - hot spot. Both investigations yielded information on the homogeneity of the samples. - An entirely new method of imaging the current distribution in superconducting interference

  12. Optical properties of c-axis oriented superconducting MgB2 films.

    Science.gov (United States)

    Tu, J J; Carr, G L; Perebeinos, V; Homes, C C; Strongin, M; Allen, P B; Kang, W N; Choi, E M; Kim, H J; Lee, S I

    2001-12-31

    Temperature dependent optical conductivities and dc resistivity of c-axis oriented superconducting (T(c) = 39.6 K) MgB2 films (approximately 450 nm) have been measured. The normal state ab-plane optical conductivities can be described by the Drude model with a temperature independent Drude plasma frequency of omega(p,D) = 13 600+/-100 cm(-1) or 1.68+/-0.01 eV. The normal state resistivity is fitted by the Bloch-Grüneisen formula with an electron-phonon coupling constant lambda(tr) = 0.13+/-0.02. The optical conductivity spectra below T(c) of these films suggest that MgB2 is a multigap superconductor.

  13. Fracture behaviors of thin superconducting films with field-dependent critical current density

    Science.gov (United States)

    He, An; Xue, Cun; Yong, Huadong; Zhou, Youhe

    2013-09-01

    The fracture behaviors under electromagnetic force with field-dependent critical current density in thin superconducting film are investigated. Applying finite element method, the energy release rates and stress intensity factors of one central crack versus applied field and crack length are obtained for the Bean model and Kim model. It is interesting that the profile of the stress intensity factor is generally the same as the magnetostrictive behavior during one full cycle applied field. Furthermore, the crack problem of two collinear cracks with respect to crack length and distance is also researched for the Kim model. The results show that the energy release rates and stress intensity factors of the two collinear cracks at left tip and right tip are remarkably different for relatively small crack distance and long crack length. This work can offer good estimations and provide a basis for interpretation of cracking and mechanical failure of HTS thin films in numerous real situations.

  14. Growth and superconductivity characteristics of MgB sub 2 thin films

    CERN Document Server

    Chen, K; Nie Rui Juan; Yang, T; Xie, F X; Liu, L Y; Wang, S Z; Dai, Y D; Wang, F

    2002-01-01

    We attempt to make MgB sub 2 thin films by using a pulsed-laser-deposition (PLD) and a magnetron sputtering method. We have deposited metal magnesium and boron on various substrates under different vacuum conditions. The PLD method has been employed to fabricate layers of magnesium and boron sandwiches under room temperature and the multi-layer system was then annealed in-situ under different temperatures. We also attempted to co-deposit magnesium and boron under high vacuum (5 x 10 sup - sup 5 Pa) on heated substrates with PLD. We have successfully grown superconducting MgB sub 2 thin films on an STO (100) substrate by magnetron sputtering. The onset transition temperature was 37 K and zero resistance temperature was 34 K.

  15. Formulation and Characterization of Cu Doped ZnO Thick Films as LPG Gas Sensor

    Directory of Open Access Journals (Sweden)

    A. V. PATIL

    2010-12-01

    Full Text Available Thick films of pure and various concentrations (1 wt. %, 3 wt. %, 5 wt. %, 7 wt. % and 10 wt. % of Cu-doped ZnO were prepared on alumina substrates using a screen printing technique. These films were fired at a temperature of 700ºC for two hours in an air atmosphere. Morphological, compositional and structural properties of the samples were obtained using the scanning electron microscopy (SEM, Energy dispersive spectroscopy (EDAX and X-ray diffraction techniques respectively. The LPG gas sensing properties of these thick films were investigated at different operating temperatures and LPG gas concentrations. The surface resistance of thick films decreases when exposed to LPG gas. The Cu doped films show significant sensitivity to LPG gas than pure ZnO film. 5 wt. % Cu-doped ZnO film was found to be more sensitive (87.3 % to LPG gas exposed at 300 oC than other doping concentrations with fast response and recovery time.

  16. Terahertz ultrathin film thickness sensor below λ/90 based on metamaterial.

    Science.gov (United States)

    Chen, Meng; Fan, Fei; Shen, Si; Wang, Xianghui; Chang, Shengjiang

    2016-08-10

    The film thickness sensing based on metamaterial is investigated in the terahertz (THz) region. We fabricated the metamaterial sensor, and demonstrated its resonance by using the THz time-domain spectroscopy system. The results show that the resonant dip redshifts as the film thickness increases, which achieves reliable film sensing in the THz band. Its sensitivity is larger than 9.4 GHz/μm with a film thinner than λ/90. Meanwhile, the sensing mechanism is revealed by the simulation of near-field resonance distribution, which shows that the resonant intensity is stronger when the field is closer to the interface between the metamaterial surface and polyvinyl alcohol film. Therefore, the nonlinear type of the sensing sensitivity in our experiment can be well explained, and a higher sensitive sensing can be obtained when the film thickness is smaller. This simple and flexible method can realize the ultrathin film sensing in the THz region, and has application potential in the real-time monitoring of sample quality.

  17. Improvement of the critical temperature of superconducting NbTiN and NbN thin films using the AlN buffer layer

    Energy Technology Data Exchange (ETDEWEB)

    Shiino, Tatsuya; Shiba, Shoichi; Sakai, Nami; Yamamoto, Satoshi [Department of Physics, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Yamakura, Tetsuya [Institute of Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, Ten-nodai, Tsukuba, Ibaraki 305-8577 (Japan); Jiang, Ling [College of Information Science and Technology, Nanjing Forestry University, Nanjing 210037, Jiangsu (China); Uzawa, Yoshinori [National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan); Maezawa, Hiroyuki, E-mail: shiino@taurus.phys.s.u-tokyo.ac.j [Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chigusa-ku, Nagoya 464-8602 (Japan)

    2010-04-15

    Thin superconducting NbTiN and NbN films with a few nm thickness are used in various device applications including in hot electron bolometer mixers. Such thin films have lower critical temperature (T{sub c}) and higher resistivity than corresponding bulk materials. In an effort to improve them, we have investigated an effect of the AlN buffer layer between the film and the substrate (quartz or soda lime glass). The AlN film is deposited by DC magnetron sputtering, and the process condition is optimized so that the x-ray diffraction intensity from the 002 surface of wurtzite AlN becomes the highest. By use of this well-characterized buffer layer, T{sub c} and the resistivity of the NbTiN film with a few nm thickness are remarkably increased and decreased, respectively, in comparison with those without the buffer layer. More importantly, the AlN buffer layer is found to be effective for NbN. With the AlN buffer layer, T{sub c} is increased from 7.3 to 10.5 K for the 8 nm NbN film. The improvement of T{sub c} and the resistivity originates from the good lattice matching between the 002 surface of AlN and the 111 surface of NbTiN or NbN, which results in better crystallization of the NbTiN or NbN film. This is further confirmed by the x-ray diffraction measurement.

  18. Study of $\\beta$-phase development in spin-coated PVDF thick films

    Indian Academy of Sciences (India)

    BHOOPESH MAHALE; DHANANJAY BODAS; S A GANGAL

    2017-06-01

    A study was conducted to ascertain the effect of variation in spin speed and baking temperature on $\\beta$-phase content in the spin-coated poly(vinylidene fluoride) (PVDF) thick films ($\\sim$4−25 $\\mu$m). Development of $\\beta$-phase is dependent on film stretching and crystallization temperature. Therefore, to study the development of $\\beta$-phase in films, stretching is achieved by spinning and crystallization temperature is adjusted by means of baking. PVDF films are characterized using Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, and scanning electronmicroscopy. It is observed that crystallization temperature lower than 60$^{\\circ}$C and increase in spin speed increases the $\\beta$-phasecontent in PVDF films. Crystallization temperature above 60$^{\\circ}$C reduces $\\beta$-phase content and increases α-phase content. It was also observed that viscosity of the PVDF solution affects the β-phase development in films at a particular spin speed.

  19. Bio-interfaces--interaction of PLL/HA thick films with nanoparticles and microcapsules.

    Science.gov (United States)

    Skirtach, Andre G; Volodkin, Dmitry V; Möhwald, Helmuth

    2010-03-15

    The interaction of biocompatible, exponentially grown films composed of poly-L-lysine (PLL) and hyaluronic acid (HA) polymers with gold nanoparticles and microcapsules is studied. Both aggregated and non-aggregated nanoparticle states are achieved; desorption of PLL accounts for aggregation of nanoparticles. The presence of aggregates of gold nanoparticles on films enables remote activation by near-infrared irradiation due to local, nanometer confined heating. Thermally shrunk microcapsules, which are remarkably monodisperse upon preparation but gain polydispersity after months of storage, are also adsorbed onto films. PLL polymers desorbed from films interact with microcapsules introducing a charge imbalance which leads to an increase of the microcapsule size, thus films amplify this effect. Multifunctional, biocompatible, thick gel films with remote activation and release capabilities are targeted for cell cultures in biology and tissue engineering in medicine.

  20. Adsorbed films of three-patch colloids: Continuous and discontinuous transitions between thick and thin films

    Science.gov (United States)

    Dias, C. S.; Araújo, N. A. M.; Telo da Gama, M. M.

    2014-09-01

    We investigate numerically the role of spatial arrangement of the patches on the irreversible adsorption of patchy colloids on a substrate. We consider spherical three-patch colloids and study the dependence of the kinetics on the opening angle between patches. We show that growth is suppressed below and above minimum and maximum opening angles, revealing two absorbing phase transitions between thick and thin film regimes. While the transition at the minimum angle is continuous, in the directed percolation class, that at the maximum angle is clearly discontinuous. For intermediate values of the opening angle, a rough colloidal network in the Kardar-Parisi-Zhang universality class grows indefinitely. The nature of the transitions was analyzed in detail by considering bond flexibility, defined as the dispersion of the angle between the bond and the center of the patch. For the range of flexibilities considered we always observe two phase transitions. However, the range of opening angles where growth is sustained increases with flexibility. At a tricritical flexibility, the discontinuous transition becomes continuous. The practical implications of our findings and the relation to other nonequilibrium transitions are discussed.

  1. Influence of preparation conditions on superconducting properties of Bi-2223 thin films

    Indian Academy of Sciences (India)

    N T Mua; A Sundaresan; N K Man; D D Dung

    2014-02-01

    We report electrical transport properties of Bi2Sr2Ca2Cu3O10+ (Bi-2223) superconducting thin films fabricated by pulsed-laser deposition on SrTiO3 substrate. The aim of the study was to investigate the influence of preparation conditions such as deposition temperature (S), annealing time (A) and deposition rate (). A critical temperature (c) as high as 110 K and critical current density (c) of 6.2 × 106 A/cm2 at 20 K were obtained for S = 760° C, A = 4h and = 1.5 Å/s. We also investigated the effect of Li doping on Bi-2223 thin films. Li intercalation results in high resistive onset transition temperature and the resistivity shows broadening in magnetic field that increases with field. The large broadening of resistivity curve in magnetic field suggests that this phenomenon is directly related to the intrinsic superconducting properties of the copper oxide superconductors. The sudden drop in c at relatively low magnetic field ( < 0.5 tesla) is due to the effect of Josephson weak-links at the grain boundaries.

  2. Pinning effects on hot-electron vortex flow instability in superconducting films

    Science.gov (United States)

    Shklovskij, Valerij A.

    2017-07-01

    The hot-electron vortex flow instability in superconducting films in magnetic field B at substrate temperature T0 ≪ Tc is theoretically considered in the presence of pinning. The magnetic field dependences of the instability critical parameters (electric field E*, current density j*, resistivity ρ*, power density P* and vortex velocity v*) are derived for a cosine and a saw-tooth washboard pinning potential and compared with the results obtained earlier by M. Kunchur [Phys. Rev. Lett. 89 (2002) 137005] in absence of pinning. It is shown that the B-behavior of E*, j* and ρ* is monotonic, whereas the B-dependence of v* is quite different, namely dv*/dB may change its sign twice, as sometimes observed in experiments. The simplest heat balance equation for electrons in low-Tc superconducting films is considered within the framework of the two-fluid model. A theoretical analysis reveals that the instability critical temperature T* ≈ 5Tc/6 at T0 < T*/2 with T* being independent of B.

  3. High-performance piezoelectric thick film based energy harvesting micro-generators for MEMS

    DEFF Research Database (Denmark)

    Zawada, Tomasz; Hansen, Karsten; Lou-Moeller, Rasmus

    2010-01-01

    Energy harvesting, known also as energy scavenging, covers a great body of technologies and devices that transform low grade energy sources such as solar energy, environmental vibrations, thermal energy, human motion into usable electrical energy. In this paper vibrations are used as energy source...... and are transformed by the energy harvesting micro-generator into usable electrical signal. The micro-generator comprises a silicon cantilever with integrated InSensor® TF2100 PZT thick film deposited using screen-printing. The output power versus frequency and electrical load has been investigated. Furthermore......, devices based on modified, pressure treated thick film materials have been tested and compared with the commercial InSensor® TF2100 PZT thick films. It has been found that the structures based on the pressure treated materials exhibit superior properties in terms of energy output....

  4. Mems-based pzt/pzt bimorph thick film vibration energy harvester

    DEFF Research Database (Denmark)

    Xu, Ruichao; Lei, Anders; Dahl-Petersen, Christian

    2011-01-01

    We describe fabrication and characterization of a significantly improved version of a MEMS-based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass. The main advantage of bimorph vibration energy harvesters is that strain energy is not lost in mechanical...... support materials since only PZT is strained, and thus it has a potential for significantly higher output power. An improved process scheme for the energy harvester resulted in a robust fabrication process with a record high fabrication yield of 98.6%. Moreover, the robust fabrication process allowed...... a high pressure treatment of the screen printed PZT thick films prior to sintering, improving the PZT thick film performance and harvester power output reaches 37.1 μW at 1 g....

  5. Critical heat flux enhancement regarding to the thickness of graphene films under pool boiling

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Man; Park, Hyun Sun [Pohang Univ. of Science and Technology, Pohang (Korea, Republic of); Park, Youngjae; Kim, Hyungdae [Kyung Hee Univ., Yongin (Korea, Republic of); Kim, Dong Eok [Kyungpook Nat. Univ., Sangju (Korea, Republic of); Kim, Moo Hwan [Korea Inst. of Nuclear Safety, Daejeon (Korea, Republic of); Ahn, Ho Seon [Incheon Nat. Univ., Incheon (Korea, Republic of)

    2014-05-15

    The large thermal conductivity of the graphene films inhibits the formation of hot spots, thereby increasing the CHF. An infrared high-speed visualization showed graphene effect on boiling characteristics during operation. The graphene-coated heater showed an increase in BHT and CHF. As the thickness of the graphene films increased, the CHF also increased up to an asymptotic limit when the graphene layer was approximately 150 nm thick. The increased BHT was explained by the slight decrease in the wettability and the folded edges of the RGO flakes, which led to a decrease in the diameter of the departing bubbles, a larger bubble generation frequency, and an increase in the areal density of the bubble nucleation sites. The increase in the CHF was explained by considering the thermal activity of the graphene films, and the dependence thereof on the thickness and thermal properties of the layer, which was calculated based on high-speed IR visualization data.

  6. (100)-Textured KNN-based thick film with enhanced piezoelectric property for intravascular ultrasound imaging

    Science.gov (United States)

    Zhu, Benpeng; Zhang, Zhiqiang; Ma, Teng; Yang, Xiaofei; Li, Yongxiang; Shung, K. Kirk; Zhou, Qifa

    2015-04-01

    Using tape-casting technology, 35 μm free-standing (100)-textured Li doped KNN (KNLN) thick film was prepared by employing NaNbO3 (NN) as template. It exhibited similar piezoelectric behavior to lead containing materials: a longitudinal piezoelectric coefficient (d33) of ˜150 pm/V and an electromechanical coupling coefficient (kt) of 0.44. Based on this thick film, a 52 MHz side-looking miniature transducer with a bandwidth of 61.5% at -6 dB was built for Intravascular ultrasound (IVUS) imaging. In comparison with 40 MHz PMN-PT single crystal transducer, the rabbit aorta image had better resolution and higher noise-to-signal ratio, indicating that lead-free (100)-textured KNLN thick film may be suitable for IVUS (>50 MHz) imaging.

  7. Thickness-dependent magnetic properties of Ce{sub 9}Fe{sub 91} films

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xueyun; Wang, Dianyuan; Yu, Jianmin [Faculty of Science, Jiujiang University, Jiujiang City, Jiangxi Province (China); Wang, Zhenkun; Ge, Shihui [Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University (China); Yao, Dongsheng [Tianjin Key Laboratory of Low-Dimensional Materials Physics and Preparing Technology, Faculty of Science, Tianjin University (China)

    2014-12-01

    Ce{sub 9}Fe{sub 91} films with different thickness were fabricated by a rf magnetron sputtering method. The critical thickness t{sub c} for spin reorientation transition has been determined to be approximately 90 nm using the stripe domain model and magnetic force microscope. Above t{sub c}, the films exhibit Bloch stripe domain structure and a superhigh resonance frequency at 6 GHz is found for the parallel stripe configuration. However, below t{sub c}, the films possess an in-plane uniaxial anisotropy caused by order interface tension between the film and substrate, and the resonance frequency breaks through the Snoek limit. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Thick growing multilayer nanobrick wall thin films: super gas barrier with very few layers.

    Science.gov (United States)

    Guin, Tyler; Krecker, Michelle; Hagen, David Austin; Grunlan, Jaime C

    2014-06-24

    Recent work with multilayer nanocoatings composed of polyelectrolytes and clay has demonstrated the ability to prepare super gas barrier layers from water that rival inorganic CVD-based films (e.g., SiOx). In an effort to reduce the number of layers required to achieve a very low oxygen transmission rate (OTR (layer-by-layer (LbL) assembly. Buffering the chitosan solution and its rinse with 50 mM Trizma base increased the thickness of these films by an order of magnitude. The OTR of a 1.6-μm-thick, six-bilayer film was 0.009 cc/m(2)·day·atm, making this the best gas barrier reported for such a small number of layers. This simple modification to the LbL process could likely be applied more universally to produce films with the desired properties much more quickly.

  9. Multifunctional thick-film structures based on spinel ceramics for environment sensors

    Energy Technology Data Exchange (ETDEWEB)

    Vakiv, M; Hadzaman, I; Klym, H; Shpotyuk, O [Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, 79031 (Ukraine); Brunner, M, E-mail: shpotyuk@novas.lviv.ua, E-mail: klymha@yahoo.com [Fachhochschule Koeln/University of Applied Sciences, 2 Betzdorfer str., Koeln, 50679 (Germany)

    2011-04-01

    Temperature sensitive thick films based on spinel-type NiMn{sub 2}O{sub 4}-CuMn{sub 2}O{sub 4}-MnCo{sub 2}O{sub 4} manganites with p- and p{sup +}-types of electrical conductivity and their multilayer p{sup +}-p structures were studied. These thick-film elements possess good electrophysical characteristics before and after long-term ageing test at 170 deg. C. It is shown that degradation processes connected with diffusion of metallic Ag into film grain boundaries occur in one-layer p-and p{sup +}-conductive films. Some part of the p{sup +}-p structures were of high stability, the relative electrical drift being no more than 1 %.

  10. Thick and hard anodized aluminum film with large pores for surface composites

    Institute of Scientific and Technical Information of China (English)

    WANG Hui; WANG Hao-wei

    2004-01-01

    Al-base surface self-lubricating composites need thick and hard alumina membranes with large pores to add lubricants easily. This kind of porous alumina layer was fabricated in additive-containing, phosphoric acid-based solution. The effects of additive containing organic carboxylic acid and Ce salt on the properties of the oxide film and mechanism were investigated in detail with SEM and EDAX analyses. The results show that the pore diameter is about 100 nm, the film thickness increases by 4 -5 times, and the Vickers hardness improves by about 50% through adding some amount of organic carboxylic acid and Ce salt. Such an improvement in properties is explained in terms of a lower film dissolving velocity and better film quality in compound solution.

  11. Interference-aided spectrum fitting method for accurately film thickness determination

    CERN Document Server

    Liu, Xingxing; Xia, Hui; Zhang, Xutao; Ji, Ruonan; Li, Tianxin; Lu, Wei

    2016-01-01

    A new approach was proposed to accurately determine the thickness of film, especially for ultra-thin film, through spectrum fitting with the assistance of interference layer. The determination limit can reach even less than 1 nm. Its accuracy is far better than traditional methods. This determination method is verified by experiments and the determination limit is at least 3.5 nm compared with the results of AFM. Furthermore, double-interference-aided spectra fitting method is proposed to reduce the requirements of determination instruments, which allow one to determine the film thickness with a low precision common spectrometer and largely lower the cost. It is a very high precision determination method for on-site and in-situ applications, especially for ultra-thin films.

  12. Preparation and Properties of High-T(sub c) Bi-Pb-Sr-Ca-Cu-O Thick Film Superconductors on YSZ Substrates

    Science.gov (United States)

    Hooker, Matthew W.

    1996-01-01

    An evaluation of four firing profiles was performed to determine the optimum processing conditions for producing high-T(sub c) Bi-Pb-Sr-Ca-Cu-O thick films on yttria-stabilized zirconia substrates. Using these four profiles, the effects of sintering temperatures of 830-850 C and soak times of 0.5 to 12 hours were examined. In this study, T-c, zero values of 100 K were obtained using a firing profile in which the films were sintered for 1.5 to 2 hours at 840 to 845 C and then quenched to room temperature. X-ray diffraction analyses of these specimens confirmed the presence of the high-T(sub c) phase. Films which were similarly fired and furnace cooled from the peak processing temperature exhibited a two-step superconductive transition to zero resistance, with T-c,zero values ranging from 85 to 92 K. The other firing profiles evaluated in this investigation yielded specimens which either exhibited critical transition temperatures below 90 K or did not exhibit a superconductive transition above 77 K.

  13. Cap effect of (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub y} thick films during post-annealing process

    Energy Technology Data Exchange (ETDEWEB)

    Tokuda, T. [Department of Electrical and Electronic Engineering, Tottori University, 4-101, Koyama-Minami, Tottori 680-8552 (Japan); Honda, S., E-mail: b03t3052@faradayele.tottori-u.ac.j [Department of Electrical and Electronic Engineering, Tottori University, 4-101, Koyama-Minami, Tottori 680-8552 (Japan); Kinoshita, K.; Kishida, S. [Department of Electrical and Electronic Engineering, Tottori University, 4-101, Koyama-Minami, Tottori 680-8552 (Japan)

    2009-10-15

    We prepared (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub y} (BiPb-2223) thick films on MgO substrates by a spin coating method and investigated their superconducting property. The surface of BiPb-2223 thick films was capped with MgO, Ag or BiPb-2223/MgO during sintering process. From the results of X-ray diffraction patterns and resistance-temperature characteristics, we found that the caps of MgO and Ag were useful for obtaining the 30 mum-BiPb-2223 thick films with the T{sub c} above 100 K. Although the T{sub c} of the thick films with the thickness less than 5 mum decreased, the T{sub c} of the BiPb-2223 films with the thickness less than 5 mum was improved by use of the BiPb-2223/MgO cap.

  14. The development of Tl-2212 based superconducting thin films for microwave applications

    CERN Document Server

    Hyland, D M C

    2001-01-01

    This thesis attempts to develop the understanding of the two-stage ex-situ processing of Tl sub 2 Ba sub 2 CaCu sub 2 O (Tl-2212) thin films on LaAlO sub 3 substrates. Initially a thallium-free precursor film is deposited by sputtering, this is then annealed in a sealed crucible containing a thallium source to produce the final crystalline film. An investigation into the correlation of physical characteristics of the films with their microwave properties is presented. High reproducibility of processing was achieved for 1cm sup 2 size films with measured R sub s < 0.5m OMEGA. Strong dependence of the microwave properties was found with film thickness and growth morphology of the crystalline film. A good correlation of R sub s was seen with defect density, greater numbers of defects giving higher R sub s values. Problems were encountered in scaling up the process to fabricate 2-inch diameter films, initially limited by the increased defect density associated with a larger surface area. Additionally when usin...

  15. Some limitations in applying classical EHD film-thickness formulae to a high-speed bearing

    Science.gov (United States)

    Coy, J. J.; Zaretsky, E. V.

    1980-01-01

    Elastohydrodynamic film thickness was measured for a 20 mm ball bearing using the capacitance technique. The bearing was thrust loaded to 90, 448, and 778 N. The corresponding maximum stresses on the inner race were 1.28, 2.09, and 2.45 GPa. Test speeds ranged from 400 to 14,000 rpm. Film thickness measurements were taken with four different lubricants: (1) synthetic paraffinic; (2) synthetic paraffinic with additives; (3) neopentylpolyol (tetra) ester; and (4) synthetic cycloaliphatic hydrocarbon traction fluid. The test bearing was mist lubricated. Test temperatures were 300, 338, and 393 K. The measured results were compared to theoretical predictions and are presented.

  16. Laser drilling of vias in dielectric for high density multilayer LSHI thick film circuits

    Science.gov (United States)

    Cocca, T.; Dakesian, S.

    1977-01-01

    A design analysis of a high density multilevel thick film digital microcircuit used for large scale integration is presented. The circuit employs 4 mil lines, 4 mil spaces and requires 4 mil diameter vias. Present screened and fired thick film technology is limited on a production basis to 16 mil square vias. A process whereby 4 mil diameter vias can be fabricated in production using laser technology was described along with a process to produce 4 mil diameter vias for conductor patterns which have 4 mil lines and 4 mil spacings.

  17. Thickness dependent exchange bias in martensitic epitaxial Ni-Mn-Sn thin films

    Directory of Open Access Journals (Sweden)

    Anna Behler

    2013-12-01

    Full Text Available A thickness dependent exchange bias in the low temperature martensitic state of epitaxial Ni-Mn-Sn thin films is found. The effect can be retained down to very small thicknesses. For a Ni50Mn32Sn18 thin film, which does not undergo a martensitic transformation, no exchange bias is observed. Our results suggest that a significant interplay between ferromagnetic and antiferromagnetic regions, which is the origin for exchange bias, is only present in the martensite. The finding is supported by ab initio calculations showing that the antiferromagnetic order is stabilized in the phase.

  18. Thickness and structure of the water film deposited from vapour on calcite surfaces

    DEFF Research Database (Denmark)

    Bohr, Jakob; Wogelius, Roy A.; Morris, Peter M.

    2010-01-01

    Synchrotron X-ray reflectivity (SXR) was used to measure the thickness of the water film that adsorbs on a {10¯14} cleavage surface of calcite (CaCO3) in a sample chamber where relative humidity could be controlled within the range from......Synchrotron X-ray reflectivity (SXR) was used to measure the thickness of the water film that adsorbs on a {10¯14} cleavage surface of calcite (CaCO3) in a sample chamber where relative humidity could be controlled within the range from...

  19. Piezoelectric sensors to monitor lubricant film thickness at piston-cylinder contacts in a fired engine

    OpenAIRE

    2013-01-01

    The contact between the piston ring and cylinder liner is the most important sealing interface in an automotive engine. Understanding the contact interactions and lubricant film formation at this interface is crucial for the development of fuel-efficient and low emission engines. This article outlines the development of an ultrasonic approach to enable non-invasive measurement of the lubricant film thickness formed between piston and cylinder wall of a fired engine. The sensor system consiste...

  20. A novel multi-degree-of-freedom thick-film ultrasonic motor.

    Science.gov (United States)

    Aoyagi, Manaba; Beeby, Steve P; White, Neil M

    2002-02-01

    This paper describes a new multi-degree-of-freedom (MDOF) ultrasonic motor that comprises few parts and is based on low-cost thick-film technology. Conventional ultrasonic motors using bulk lead zirconate titanate (PZT) or thin-film PZT layers are relatively expensive at the present time. Thick-film printed PZT technology provides the opportunity to reduce the costs of ultrasonic motors. To demonstrate the feasibility of this approach, an ultrasonic motor was fabricated from alumina using thick-film printed PZT actuators. The thick-film PZT and electrode layers were printed on a thin alumina plate, and a tiny cylinder was mounted at its center. This cylinder magnifies the lateral displacement of the stator, holds the spherical rotor, and transmits the driving force to the sphere. Three bending vibrations, B22, B30, B03, of the plate were applied to rotate the sphere. Sufficient displacements for rotating the sphere were obtained near the resonance of B22 by applying an excitation voltage of 200 V peak-to-peak via a three-phase drive circuit. Rotations in three orthogonal directions have been observed by controlling the phase of the driving signal to the PZT electrodes, and a MDOF ultrasonic motor was successfully realized.

  1. Thickness dependence of structural and optical properties of cadmium iodide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Yahia, I.S. [Department of Physics, Faculty of Science, King Khalid University, P.O. Box 9004, Abha (Saudi Arabia); Centre of Nanotechnology, King AbdulAziz University, Jeddah (Saudi Arabia); Shapaan, M. [Department of Physics, Faculty of Science, Al-Azahar University, Cairo (Egypt); Ismail, Yasser A.M.; Aboraia, A.M. [Department of Physics, Faculty of Science, Al-Azahar University, Assiut 71542 (Egypt); Shaaban, E.R., E-mail: esamramadan2008@yahoo.com [Department of Physics, Faculty of Science, Al-Azahar University, Assiut 71542 (Egypt)

    2015-07-05

    Highlights: • Different thicknesses of CdI{sub 2} films were prepared. • Both crystallite size and microstrain of the films has been determined. • The room temperature reflectance and transmittance data are analyzed. • The refractive index and energy gap are determined. - Abstract: Structural and optical properties as a function of film thickness have been studied for the thermally evaporated cadmium iodide (CdI{sub 2}) films. According to XRD structure, the thickness of investigated films extends from 272 to 696 nm, showing hexagonal structure and good c-axis alignment normal to glass substrate plane. Both of crystallite size and lattice strain have been determined in terms of Voight method of the main peak. The optical constants, refractive index (n), and extinction coefficient (k) have been determined using envelope method. The optical absorption data indicates an allowed direct inter – band transition near the absorption edge with an optical energy gap that decreases continuously from 3.572 to 3.767 eV. Both of optical constants and energy gap show thickness dependence that can be explained in terms of structure parameters, crystallite size, and lattice strain.

  2. Ultrasonic oil-film thickness measurement: an angular spectrum approach to assess performance limits.

    Science.gov (United States)

    Zhang, Jie; Drinkwater, Bruce W; Dwyer-Joyce, Rob S

    2007-05-01

    The performance of ultrasonic oil-film thickness measurement in a ball bearing is quantified. A range of different viscosity oils (Shell T68, VG15, and VG5) are used to explore the lowest reflection coefficient and hence the thinnest oil-film thickness that the system can measure. The results show a minimum reflection coefficient of 0.07 for both oil VG15 and VG5 and 0.09 for oil T68 at 50 MHz. This corresponds to an oil-film thickness of 0.4 microm for T68 oil. An angular spectrum (or Fourier decomposition) approach is used to analyze the performance of this configuration. This models the interaction of component plane waves with the measurement system and quantifies the effect of the key parameters (transducer aperture, focal length, and center frequency). The simulation shows that for a focused transducer the reflection coefficient tends to a limiting value at small oil-film thickness. For the transducer used in this paper it is shown that the limiting reflection coefficient is 0.05 and the oil-film measurement errors increase as the reflection coefficient approaches this value. The implications for improved measurement systems are then discussed.

  3. Measurements of liquid film thickness, concentration, and temperature of aqueous urea solution by NIR absorption spectroscopy

    Science.gov (United States)

    Pan, R.; Jeffries, J. B.; Dreier, T.; Schulz, C.

    2016-01-01

    A multi-wavelength near-infrared (NIR) diode laser absorption sensor has been developed and demonstrated for real-time monitoring of the thickness, solute concentration, and temperature of thin films of urea-water solutions. The sensor monitors the transmittance of three near-infrared diode lasers through the thin liquid film. Film thickness, urea mass fraction, and liquid temperature were determined from measured transmittance ratios of suitable combinations of lasers. Available laser wavelengths were selected depending on the variation of the NIR absorption spectrum of the solution with temperature and solute concentration. The spectral database was measured by a Fourier transform infrared spectrometer in the range 5500-8000 cm-1 for urea solutions between 5 and 40 wt% and temperatures between 298 and 338 K. A prototype sensor was constructed, and the sensor concept was first validated with measurements using a calibration cell providing liquid layers of variable thickness (200-1500 µm), urea mass fraction (5-40 wt%) and temperature (298-318 K). Temporal variations of film thickness and urea concentration were captured during the constant-temperature evaporation of a liquid film deposited on an optically polished heated quartz flat.

  4. Effect of film thickness on NO2 gas sensing properties of sprayed orthorhombic nanocrystalline V2O5 thin films

    Science.gov (United States)

    Mane, A. A.; Moholkar, A. V.

    2017-09-01

    The nanocrystalline V2O5 thin films with different thicknesses have been grown onto the glass substrates using chemical spray pyrolysis (CSP) deposition method. The XRD study shows that the films exhibit an orthorhombic crystal structure. The narrow scan X-ray photoelectron spectrum of V-2p core level doublet gives the binding energy difference of 7.3 eV, indicating that the V5+ oxidation state of vanadium. The FE-SEM micrographs show the formation of nanorods-like morphology. The AFM micrographs show the high surface area to volume ratio of nanocrystalline V2O5 thin films. The optical study gives the band gap energy values of 2.41 eV, 2.44 eV, 2.47 eV and 2.38 eV for V2O5 thin films deposited with the thicknesses of 423 nm, 559 nm, 694 nm and 730 nm, respectively. The V2O5 film of thickness 559 nm shows the NO2 gas response of 41% for 100 ppm concentration at operating temperature of 200 °C with response and recovery times of 20 s and 150 s, respectively. Further, it shows the rapid response and reproducibility towards 10 ppm NO2 gas concentration at 200 °C. Finally, NO2 gas sensing mechanism based on chemisorption process is discussed.

  5. Synthesis of thick diamond films by direct current hot-cathode plasma chemical vapour deposition

    CERN Document Server

    Jin Zeng Sun; Bai Yi Zhen; Lu Xian Yi

    2002-01-01

    The method of direct current hot-cathode plasma chemical vapour deposition has been established. A long-time stable glow discharge at large discharge current and high gas pressure has been achieved by using a hot cathode in the temperature range from 1100 degree C to 1500 degree C and non-symmetrical configuration of the poles, in which the diameter of the cathode is larger than that of anode. High-quality thick diamond films, with a diameter of 40-50 mm and thickness of 0.5-4.2 mm, have been synthesized by this method. Transparent thick diamond films were grown over a range of growth rates between 5-10 mu m/h. Most of the thick diamond films have thermal conductivities of 10-12 W/K centre dot cm. The thick diamond films with high thermal conductivity can be used as a heat sink of semiconducting laser diode array and as a heat spreading and isolation substrate of multichip modules. The performance can be obviously improved

  6. Investigating the Materials Limits on Coherence in Superconducting Charge Qubits

    Science.gov (United States)

    2014-12-04

    mesoscopic effects in superconductors on the coherence of qubits and on losses in superconducting films , and comparing these to experiment. This...on the superconducting films themselves, or at the metal-substrate interfaces) was the main limitation on qubit lifetimes, which were then in the...quality. We also developed and tested the “vertical transmon” design, where the transmon capacitors are formed through the bulk thickness of the

  7. Maximum allowable currents in YBa2Cu3O7 superconducting tapes as a function of the coating thickness, external magnetic field induction, and cooling conditions

    Science.gov (United States)

    Arkharov, A. M.; Dontsova, E. S.; Lavrov, N. A.; Romanovskii, V. R.

    2014-04-01

    Maximum allowable (ultimate) currents stably passing through an YBa2Cu3O7 superconducting current-carrying element are determined as a function of a silver (or copper) coating thickness, external magnetic field induction, and cooling conditions. It is found that if a magnetic system based on yttrium ceramics is cooled by a cryogenic coolant, currents causing instabilities (instability onset currents) are almost independent of the coating thickness. If, however, liquid helium is used as a cooling agent, the ultimate current monotonically grows with the thickness of the stabilizing copper coating. It is shown that depending on cooling conditions, the stable values of the current and electric field strength preceding the occurrence of instability may be both higher and lower than the a priori chosen critical parameters of the superconductor. These features should be taken into account in selecting the stable value of the operating current of YBa2Cu3O7 superconducting windings.

  8. Smoothness improvement of micrometer- and submicrometer-thick nanocrystalline diamond films produced by MWPECVD

    Science.gov (United States)

    Cicala, G.; Magaletti, V.; Senesi, G. S.; Tamborra, M.

    2013-04-01

    Thick (around 3 μm) and thin (48-310 nm) nanocrystalline diamond (NCD) films have been produced from Ar-rich CH4/Ar/H2 (1/89/10 %) and H2-rich CH4/H2 (1/99 %) microwave plasmas, respectively. The deposition rate and the nucleation enhancement have been monitored in situ and in real time by pyrometric and laser reflectance interferometry for micrometer- and nanometer-thick films. For thick films, an improvement of the NCD films' smoothness has been obtained by a buffer layer between the films and the treated Si substrate. For thin films, a combinatorial approach, i.e., a treatment of the Si substrate in a suspension of mixed diamond powders of 250 nm and 40-60 μm, has been utilized. The present experimental results show that the buffer layer procedure allows good preservation of the surface of the treated Si substrate and the combinatorial approach promotes effectively the seeding of the Si surface.

  9. Image processing techniques for measuring non-uniform film thickness profiles

    Energy Technology Data Exchange (ETDEWEB)

    Nitta, S.V.; Liu, An-Hong; Plawsky, J.L.; Wayner, P.C. Jr. [Rensselaer Polytechnique Institute, Troy, NY (United States)

    1996-12-31

    The long term objective of this research program is to determine the fluid flow and drying characteristics of thin liquid/solid films using image processing techniques such as Image Analyzing Interferometry (IAI) and Image Scanning Ellipsometry (ISE). The primary purpose of this paper is to present experimental data on the effectiveness of IAI and ISE to measure nonuniform film thickness profiles. Steady-state, non-isothermal profiles of evaporating films were measured using IAI. Transient thickness profiles of a draining film were measured using ISE. The two techniques are then compared and contrasted. The ISE can be used to measure transient as well as steady-state profiles of films with thickness ranging from 1 nm to > 20 {mu}m, whereas IAI can be used to directly measure Steady-state and transient profiles of only films thicker than about 100 nm. An evaluation of the reflected intensity can be used to extend the use of the IAI below 100 nm.

  10. Thickness dependent phase transformation of magnetron-sputtered Ni-Mn-Sn ferromagnetic shape memory alloy thin films

    Energy Technology Data Exchange (ETDEWEB)

    Vishnoi, Ritu; Singhal, Rahul; Kaur, Davinder, E-mail: dkaurfph@iitr.ernet.in [Indian Institute of Technology Roorkee, Functional Nanomaterials Research Laboratory, Department of Physics and Center of Nanotechnology (India)

    2011-09-15

    In this study, the influence of film thickness on the first-order martensite-austenite phase transformation of Ni-Mn-Sn ferromagnetic shape memory alloy thin films has been systematically investigated. Different thicknesses of the Ni-Mn-Sn films (from {approx}100 to 2,500 nm) were deposited by DC magnetron sputtering on Si (100) substrates at 550 Degree-Sign C. X-ray analysis reveals that all the films exhibit austenitic phase with the L2{sub 1} cubic crystal structure at room temperature. The grain size and crystallization extent increase with the increase in film thickness, but the films with thickness above {approx}1,400 nm show structural deterioration due to the formation of MnSn{sub 2} and Ni{sub 3}Sn{sub 4} precipitates. The improvement in the crystallinity of the film with thickness is attributed to the decrease in film-substrate interfacial strain resulting in preferred oriented growth of the films. Temperature-dependent magnetization measurements as well as electrical measurements demonstrate the complete absence of phase transformation for the film of thickness of {approx}120 nm. For thickness greater than 400 nm, film exhibits the structural transformation, and it occurs at higher temperature with better hysteresis as film thickness is increased up to {approx}1,400 nm, after which degradation of phase transformation phenomenon is observed. This degradation is attributed to the disorders present in the films at higher thicknesses. Film with thickness {approx}1,400 nm possesses the highest magnetization with the smallest thermal hysteresis among all the films and therefore best suited for the actuators based on first-order structural phase transformation. Nanoindentation measurements reveal that the higher values of hardness and elastic modulus of about 5.5 and 215.0 GPa obtained in film of 1,014 nm thickness can considerably improve the ductility of ferromagnetic shape memory alloys (FSMA) and their applicability for MEMS applications. The exchange bias

  11. Variation of structure and magnetic properties with thickness of thin Co59Fe26Ni15 films

    OpenAIRE

    Chechenin, NG; van Voorthuysen, EHD; De Hosson, JTM; Boerma, DO

    2005-01-01

    Variations of phase composition and magnetic properties of electrodeposited nanocrystalline Co-Fe-Ni films with film thickness in the range of 50-500 nm were analyzed. The samples were magnetically soft with coercivity in the range H-c = 2-20 Oe and uni axial magnetic anisotropy up to H-k = 20 Oe. It was found that H-c decreases and H-k increases with increasing film thickness. The BCC phase dominates at small film thickness up to about 80 nm and the FCC phase increases when the film growths ...

  12. In-situ deposition of YBCO high-Tc superconducting thin films by MOCVD and PE-MOCVD

    Science.gov (United States)

    Zhao, J.; Noh, D. W.; Chern, C.; Li, Y. Q.; Norris, P. E.; Kear, B.; Gallois, B.

    1991-01-01

    Metal-Organic Chemical Vapor Deposition (MOCVD) offers the advantages of a high degree of compositional control, adaptability for large scale production, and the potential for low temperature fabrication. The capability of operating at high oxygen partial pressure is particularly suitable for in situ formation of high temperature superconducting (HTSC) films. Yttrium barium copper oxide (YBCO) thin films having a sharp zero-resistance transition with T(sub c) greater than 90 K and J(sub c) of approximately 10(exp 4) A on YSZ have been prepared, in situ, at a substrate temperature of about 800 C. Moreover, the ability to form oxide films at low temperature is very desirable for device applications of HTSC materials. Such a process would permit the deposition of high quality HTSC films with a smooth surface on a variety of substrates. Highly c-axis oriented, dense, scratch resistant, superconducting YBCO thin films with mirror-like surfaces have been prepared, in situ, at a reduced substrate temperature as low as 570 C by a remote microwave-plasma enhanced metal-organic chemical vapor deposition (PE-MOCVD) process. Nitrous oxide was used as a reactant gas to generate active oxidizing species. This process, for the first time, allows the formation of YBCO thin films with the orthorhombic superconducting phase in the as-deposited state. The as-deposited films grown by PE-MOCVD show attainment of zero resistance at 72 K with a transition width of about 5 K. MOCVD was carried out in a commercial production scale reactor with the capability of uniform deposition over 100 sq cm per growth run. Preliminary results indicate that PE-MOCVD is a very attractive thin film deposition process for superconducting device technology.

  13. In Situ deposition of YBCO high-T(sub c) superconducting thin films by MOCVD and PE-MOCVD

    Science.gov (United States)

    Zhao, J.; Noh, D. W.; Chern, C.; Li, Y. Q.; Norris, P.; Gallois, B.; Kear, B.

    1990-01-01

    Metalorganic Chemical Vapor Deposition (MOCVD) offers the advantages of a high degree of compositional control, adaptability for large scale production, and the potential for low temperature fabrication. The capability of operating at high oxygen partial pressure is particularly suitable for in situ formation of high temperature superconducting (HTSC) films. Yttrium barium copper oxide (YBCO) thin films having a sharp zero-resistance transition with T( sub c) greater than 90 K and Jc approx. 10 to the 4th power A on YSZ have been prepared, in situ, at a substrate temperature of about 800 C. Moreover, the ability to form oxide films at low temperature is very desirable for device applications of HTSC materials. Such a process would permit the deposition of high quality HTSC films with a smooth surface on a variety of substrates. Highly c-axis oriented, dense, scratch resistant, superconducting YBCO thin films with mirror-like surfaces have been prepared, in situ, at a reduced substrate temperature as low as 570 C by a remote microwave-plasma enhanced metalorganic chemical vapor deposition (PE-MOCVD) process. Nitrous oxide was used as a reactant gas to generate active oxidizing species. This process, for the first time, allows the formation of YBCO thin films with the orthorhombic superconducting phase in the as-deposited state. The as-deposited films grown by PE-MOCVD show attainment of zero resistance at 72 K with a transition width of about 5 K. MOCVD was carried out in a commercial production scale reactor with the capability of uniform deposition over 100 sq cm per growth run. Preliminary results indicate that PE-MOCVD is a very attractive thin film deposition process for superconducting device technology.

  14. Effect of Layer and Film Thickness and Temperature on the Mechanical Property of Micro- and Nano-Layered PC/PMMA Films Subjected to Thermal Aging

    Directory of Open Access Journals (Sweden)

    Ahmed Abdel-Mohti

    2015-04-01

    Full Text Available Multilayered polymer films with biomimicking, layered structures have unique microstructures and many potential applications. However, a major limitation of polymer films is the deterioration of mechanical properties in working environments. To facilitate the design and development of multilayered polymer films, the impact of thermal aging on the mechanical behavior of micro- and nano-layered polymer films has been investigated experimentally. The composition of the polymer films that have been studied is 50 vol% polycarbonate (PC and 50 vol% poly(methyl methacrylate (PMMA. The current study focuses on the effect of film and layer thickness and temperature on the mechanical properties of the materials subjected to thermal aging. To study the effect of film and layer thickness, films with the same thickness, but various layer thicknesses, and films with the same layer thickness, but various film thicknesses, were thermally aged at 100 °C in a constant temperature oven for up to six weeks. The results show that as the layer thickness decreases to 31 nm, the film has a higher stiffness and strength, and the trend of the mechanical properties is relatively stable over aging. The ductility of all of the films decreases with aging time. To study the effect of temperature, the films with 4,096 layers (31 nm thick for each layer were aged at 100 °C, 115 °C and 125 °C for up to four weeks. While the 100 °C aging results in a slight increase of the stiffness and strength of the films, the higher aging temperature caused a decrease of the stiffness and strength of the films. The ductility decreases with the aging time for all of the temperatures. The films become more brittle for higher aging temperatures.

  15. Effect of film thickness on the magneto-structural properties of ion beam sputtered transition metal-metalloid FeCoNbB/Si (100) alloy thin films

    Science.gov (United States)

    Gupta, Pooja; Tripathi, Yagyanidhi; Kumar, Dileep; Rai, S. K.; Gupta, Mukul; Reddy, V. R.; Svec, Peter

    2016-08-01

    The structure and magnetic properties of ion beam sputtered transition metal-metalloid FeCoNbB/Si(100) alloy thin film have been studied as a function of film thickness using complementary techniques of x-ray reflectivity (XRR), grazing incidence x-ray diffraction, and magneto optical Kerr effect. Thicknesses of the films range from ˜200 to 1500 Å. The coercivity of all the films ranges between 4 and 14 Oe, which suggests soft magnetic nature of FeCoNbB/Si thin films. Films with thickness up to 800 Å are amorphous in nature and are found to possess uniaxial magnetic anisotropy in the film plane, although no magnetic field was applied during deposition. The presence of the two fold symmetry in such amorphous thin films may be attributed to quenched-in stresses developed during deposition. Upon increasing the film thickness to ˜1200 Å and above, the structure of FeCoNbB films transforms from amorphous to partially nanocrystalline structure and has bcc-FeCo nanocrystalline phase dispersed in remaining amorphous matrix. The crystalline volume fraction (cvf) of the films is found to be proportional to the film thickness. Azimuthal angle dependence of remanence confirms the presence of in-plane four-fold anisotropy (FFA) in the crystalline film with cvf ˜75%. Synchrotron x-ray diffraction measurement using area detector suggests random orientation of crystallites and thus clearly establishes that FFA is not related to texture/cubic symmetry in such polycrystalline thin films. As supported by asymmetric Bragg diffraction measurements, the origin of FFA in such partially crystalline thin film is ascribed to the additional compressive stresses developed in the film upon crystallization. Results indicate that promising soft magnetic properties in such films can be optimized by controlling the film thickness. The revelation of controllable and tunable anisotropy suggests that FeCoNbB thin films can have potential application in electromagnetic applications.

  16. Thickness-Dependent Structural and Optoelectronic Properties of In2O3 Films Prepared by Spray Pyrolysis Technique

    Science.gov (United States)

    Khan, M. A. Majeed; Khan, Wasi

    2016-08-01

    In this work, nanostructured In2O3 thin films with thickness in the range of 40-160 nm were deposited on glass substrates by the chemical spray pyrolysis technique. The microstructural, surface morphology and optical properties were investigated as a function of film thickness through x-ray diffraction, scanning electron microscopy equipped with energy dispersive spectroscopy, atomic force microscopy, Raman spectroscopy, UV-visible spectroscopy and photoluminescence measurements. The x-ray diffraction analysis showed that the deposited films were polycrystalline in nature with a cubic structure having (222) as preferred orientation. The morphological analyses of the samples exhibited uniform and smooth surface of the films with systematical increments in the surface roughness with increasing film thickness. The grain size increased from 9 nm to 13 nm with increasing film thickness. Raman spectroscopy has been employed to study the crystalline quality and the structural disorder of the films. A blue-shift in the energy band gap ( E g) from 3.74 eV to 3.98 eV was observed with the increase of film thickness. Moreover, photoluminescence peaks of the In2O3 films appeared at 443 nm and 527 nm for all films. The thickness had a substantial influence on the microstructural and optical properties as well as on the luminescence intensity of the films. The strategy presented here indicates that the prepared films could be suitable candidates for optoelectronic device applications.

  17. Three dimensional phase field study on the thickness effect of ferroelectric polymer thin film

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The electromechanical behavior of poly(vinylidene fluoride-trifluoroethylene)[P(VDF -TrFE)]ferroelectric thin film was investigated using the three dimensional(3D) phase-field method. Various energetic contributions,including elastic,electrostatic,and domain wall energy were taken into account in the variational functional of the phase field model.Evolution of the microscopic domain structures of P(VDF-TrFE) polymer film was simulated.Effects of the in-plane residual stress,the film thickness and externa...

  18. Influence of Fe Buffer Layer on Co-Doped BaFe2As2 Superconducting Thin Films

    Directory of Open Access Journals (Sweden)

    C. Bonavolontà

    2015-01-01

    Full Text Available A systematic characterization of Co-doped BaFe2As2 (Ba-122 thin films has been carried out. Two samples were available, one grown on CaF2 substrate and the other on MgO with an Fe buffer layer. The goal was to investigate films’ magnetic and superconducting properties, their reciprocal interplay, and the role played by the Fe buffer layer in modifying them. Morphological characterization and Energy Dispersive X-ray analyses on the Fe-buffered sample demonstrate the presence of diffused Fe close to the Co-doped Ba-122 outer surface as well as irregular holes in the overlying superconducting film. These results account for hysteresis loops obtained with magneto-optic Kerr effect measurements and observed at both room and low temperatures. The magnetic pattern was visualized by magneto-optical imaging with an indicator film. Moreover, we investigated the onset of superconductivity through a measure of the superconducting energy gap. The latter is strictly related to the decay time of the excitation produced by an ultrashort laser pulse and has been determined in a pump-probe transient reflectivity experiment. A comparison of results relative to Co-doped Ba-122 thin films with and without Fe buffer layer is finally reported.

  19. Y1Ba2Cu3O(7-delta) thin film dc SQUIDs (superconducting quantum interference device)

    Science.gov (United States)

    Racah, Daniel

    1991-03-01

    Direct current superconducting quantum interferometers (SQUIDs) based on HTSC thin films have been measured and characterized. The thin films used were of different quality: (1) Granular films on Sapphire substrates, prepared either by e-gun evaporation, by laser ablation or by MOCVD (metal oxide chemical vapor deposition), (2) Epitaxial films on MgO substrates. Modulations of the voltage on the SQUIDs as a function of the applied flux have been observed in a wide range of temperatures. The nature of the modulation was found to be strongly dependent on the morphology of the film and on its critical current. The SQUIDs based on granular films were relatively noisy, hysteretic and with a complicated V-phi shape. Those devices based on low quality (lowIc) granular films could be measured only at low temperatures (much lower than 77 K). While those of higher quality (granular films with high Ic) could be measured near to the superconductive transition. The SQUID based on high quality epitaxial film was measured near Tc and showed an anomalous, time dependent behavior.

  20. Performances of screen-printing silver thick films: Rheology, morphology, mechanical and electronic properties

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Jung-Shiun; Liang, Jau-En; Yi, Han-Liou [Department of Chemical Engineering, National Chung Cheng University, Chia Yi 621, Taiwan, ROC (China); Chen, Shu-Hua [China Steel Corporation, Kaohsiung City 806, Taiwan, ROC (China); Hua, Chi-Chung, E-mail: chmcch@ccu.edu.tw [Department of Chemical Engineering, National Chung Cheng University, Chia Yi 621, Taiwan, ROC (China)

    2016-06-15

    Numerous recent applications with inorganic solar cells and energy storage electrodes make use of silver pastes through processes like screen-printing to fabricate fine conductive lines for electron conducting purpose. To date, however, there have been few studies that systematically revealed the properties of the silver paste in relation to the mechanical and electronic performances of screen-printing thick films. In this work, the rheological properties of a series of model silver pastes made of silver powders of varying size (0.9, 1.3, and 1.5 μm) and shape (irregular and spherical) were explored, and the results were systematically correlated with the morphological feature (scanning electron microscopy, SEM) and mechanical (peeling test) and electronic (transmission line method, TLM) performances of screen-printing dried or sintered thick films. We provided evidence of generally intimate correlations between the powder dispersion state in silver pastes—which is shown to be well captured by the rheological protocols employed herein—and the performances of screen-printing thick films. Overall, this study suggests the powder dispersion state and the associated phase behavior of a paste sample can significantly impact not only the morphological and electronic but also mechanical performances of screen-printing thick films, and, in future perspectives, a proper combination of silver powders of different sizes and even shapes could help reconcile quality and stability of an optimum silver paste. - Highlights: • Powder dispersion correlates well with screen-printing thick film performances. • Rheological fingerprints can be utilized to fathom the powder dispersion state. • Good polymer-powder interactions in the paste ensure good powder dispersion. • Time-dependent gel-like viscoelastic features are found with optimum silver pastes. • The size and shape of functional powder affect the dispersion and film performances.

  1. Analysis of water film thickness on contact lens by reflectometry technique

    Science.gov (United States)

    Wang, Michael R.; Lu, Hui; Wang, Jianhua; Shen, Meixiao

    2011-03-01

    We report the use of optical reflectometry technique for evaluation of water film on contact lens. The water film can be measured through the spectral dependent reflectance evaluation, which is carried out by illuminating the contact lens with a white light and collecting the returning light with an optical fiber coupled to a spectrometer. Water film thinning process has been observed on different soft contact lenses and minimum measurable thickness is about 0.85 μm. The measurement is fast and accurate. The water film measurement can be valuable for contact lens design to improve its hydrophilic properties. The technique can be extended for the study of tear film dynamics in an eye.

  2. Temperature and Thickness Effects on Electrical Properties of InP Films Deposited by Spray Pyrolysis

    Institute of Scientific and Technical Information of China (English)

    Rcfik Kayah; Mehmet Ari; Mustafa Oztas; Metin Bedir; Funda Aksoy

    2009-01-01

    InP film samples are prepared by spray pyrolysis technique using aqueous solutions of InCl3 and Na2HPO4, which are atomized with compressed air as carrier gas onto glass substrates at 500 ℃ with different thicknesses of the films. The structural properties of the samples are determined by x-ray diffraction (XRD). It is found that the crystal structure of the InP films is polycrystailine hexagonal. The orientations of all the obtained films are along the c-axis perpendicular to the substrate. The electrical measurements of the samples are obtained by dc four-probe technique on rectangular-shape samples. The effects of temperature on the electrical properties of the InP films are studied in detail.

  3. Thickness and optical constants calculation for chalcogenide-alkali metal Se80Te8(NaCl)12 thin film

    Science.gov (United States)

    Abd-Elrahman, M. I.; Abu-Sehly, A. A.; Bakier, Y. M.; Hafiz, M. M.

    2017-09-01

    Chalcogenide-alkali metal semiconducting thin films of four different thicknesses of Se80Te8(NaCl)12 are deposited from bulk by thermal evaporation technique. The crystallinity of the film improves with increasing of thickness as indicated by the recorded X-ray diffraction patterns. The transmission and reflection spectra are measured in the wavelength range of the incident photons from 250 to 2500 nm. The thickness and optical constants of the films are calculated based on Swanepeol method using the interference patterns appeared in the transmission spectra. It is found that the films have absorption mechanism which is an indirect allowed transition. The effect of the film thickness on the refractive index and the high-frequency dielectric constant are studied. With increasing the film thickness, both the absorption coefficient and high-frequency dielectric constant increase while the single-oscillator energy, optical band gap and extinction coefficient decrease.

  4. An experimental investigation of piezoelectric P(VDF-TrFE) thick film on flexible substrate as energy harvester

    Science.gov (United States)

    Khoon Keat, Chow; Swee Leong, Kok; Kok Tee, Lau

    2017-06-01

    This paper proposes an experimental inves tigation of energy harvester using poly(vinylidene fluoride-trifluoroethylene) or P(VDF-TrFE) thick-film on flexible substrate by using print screen and rod method. Polyester film being used as the substrate where a sandwiched layer of electrode-piezopolymer-electrode thick film is deposited on. The thick-film is then annealed at 100°C and polarized at 100 V for the film with a thickness of about 18µm, being inspected under EDX, FESEM and XRD. The fabricated energy harvester piezoelectric is able to generate a maximum output power of 4.36 µW at an externa l electrical load of 1 kΩ with a maximum peak-to-peak of about 3.0V when an impact free-fall force of 0.2N was applied on the thick-film.

  5. Predicting the Mean Liquid Film Thickness and Profile along the Annular Length of a Uniformly Heated Channel at Dryout

    Directory of Open Access Journals (Sweden)

    V.Y. Agbodemegbe

    2011-03-01

    Full Text Available The objective of this study was to predict the mean liquid film thickness and profile at high shear stress using a mechanistic approach. Knowledge of the liquid film thickness and its variation with two-phase flow parameters is critical for the estimation of safety parameters in the annular flow regime. The mean liquid film thickness and profile were predicted by the PLIFT code designed in Fortran 95 programming language using the PLATO FTN95 compiler. The film thickness was predicted within the annular flow regime for a flow boiling quality ranging from 40 to 80 % at high interfacial shear stress. Results obtained for a laminar liquid film flow were dumped into an excel file when the ratio of the actual predicted film thickness to the critical liquid film thickness lied within the range of 0.9 to unity. The film thickness was observed to decrease towards the exit of the annular regime at high flow boiling qualities and void fractions. The observation confirmed the effect of evaporation in decreasing the film thickness as quality is increased towards the exit of the annular regime.

  6. Characteristics of a thick film ethanol gas sensor made of mechanically treated LaFeO3 powder

    Science.gov (United States)

    Suhendi, Endi; Witra, Hasanah, Lilik; Syarif, Dani Gustaman

    2017-05-01

    In this work, fabrication of LaFeO3 thick film ceramics for ethanol gas sensor made of mechanically treated (milling) powder was studied. The thick films were fabricated using screen printing technique from LaFeO3 powder treated by HEM (High Energy Milling). The films were baked at 800°C for one hour and analyzed using XRD and SEM. Sensitivity of the films was studied by measuring resistance of them at various temperatures in a chamber containing air with and without ethanol gas. Data of XRD showed that the thick film crystalizes in orthorombic structure with space group of Pn*a. SEM data showed that the films consisted of small grains with grain size of about 225 nm. According to the electrical data, the LaFeO3 thick films that produced in this work could be applied as ethanol gas with operating temperature of about 275°C.

  7. Force measurements of a superconducting-film actuator for a cryogenic interferometric gravitational-wave detector

    CERN Document Server

    Sato, N; Kanda, N; Kuroda, K; Miyoki, S; Ohashi, M; Saitô, Y; Shintomi, T; Suzuki, T; Tatsumi, D; Taylor, C; Tomaru, T; Uchiyama, T; Yamamoto, A

    2002-01-01

    We measured forces applied by an actuator with a YBCO film at near 77 K for the Large-scale Cryogenic Gravitational-wave Telescope (LCGT) project. An actuator consisting of both a YBCO film of 1.6 micrometers thickness and 0.81 square centimeters area and a solenoid coil exerted a force of up to 0.2 mN on a test mass. The presented actuator system can be used to displace the mirror of LCGT for fringe lock of the interferometer.

  8. Full-field optical thickness profilometry of semitransparent thin films with transmission densitometry

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Jay; Harris, Tequila

    2010-05-20

    A novel bidirectional thickness profilometer based on transmission densitometry was designed to measure the localized thickness of semitransparent films on a dynamic manufacturing line. The densitometer model shows that, for materials with extinction coefficients between 0.3 and 2.9 D/mm, 100-500 {mu}m measurements can be recorded with less than {+-}5% error at more than 10,000 locations in real time. As a demonstration application, the thickness profiles of 75 mmx100 mm regions of polymer electrolyte membrane (PEM) were determined by converting the optical density of the sample to thickness with the Beer-Lambert law. The PEM extinction coefficient was determined to be 1.4 D/mm, with an average thickness error of 4.7%.

  9. Sputtering of thin and intermediately thick films of solid deuterium by keV electrons

    DEFF Research Database (Denmark)

    Svendsen, Winnie Edith; Thestrup Nielsen, Birgitte; Schou, Jørgen

    1995-01-01

    Sputtering of films of solid deuterium by keV electrons was studied in a cryogenic set-up. The sputtering yield shows a minimum yield of about 4 D2/electron for 1.5 and 2 keV electrons at a thickness slightly larger than the average projected range of the electrons. We suggest that the yield around...

  10. Boron film thickness determination to develop a low cost neutron using Monte Carlo method

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Priscila; Raele, Marcus P.; Yoriyaz, Helio; Siqueira, Paulo de T.D.; Zahn, Guilherme S.; Genezini, Frederico A., E-mail: fredzini@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Neutron measurement is important for safety and security of workers at nuclear facilities. As neutron is an uncharged particle, for its detection is necessary to use a converter material that interacts with the neutron and produce a charged particle, which is easy to detect. One of the converter candidates is natural boron composed by about 20% of Boron-10, which capture a low energy neutron ejecting an energetic alpha particle and a lithium ion. A neutron detector can be developed applying a boron thin film over a silicon photodiode, which is charged particle sensitive. For this reason is important to determine the optimal film thickness. We have used an empirical solution for the boron film thickness evaluation; furthermore we developed, using Monte Carlo method (MCNP6), a model to simulate the alpha particles propagation through the detector. Our goal was to ensure the best production and transference of alpha particles to silicon region. The film thickness ranged between 0 to 5.5 μm, the neutron energy was also varied. The optimal thickness value will be used to develop a prototype of a low cost neutron detector. (author)

  11. Thick-Film and LTCC Passive Components for High-Temperature Electronics

    Directory of Open Access Journals (Sweden)

    A. Dziedzic

    2013-04-01

    Full Text Available At this very moment an increasing interest in the field of high-temperature electronics is observed. This is a result of development in the area of wide-band semiconductors’ engineering but this also generates needs for passives with appropriate characteristics. This paper presents fabrication as well as electrical and stability properties of passive components (resistors, capacitors, inductors made in thick-film or Low-Temperature Co-fired Ceramics (LTCC technologies fulfilling demands of high-temperature electronics. Passives with standard dimensions usually are prepared by screen-printing whereas combination of standard screen-printing with photolithography or laser shaping are recommenced for fabrication of micropassives. Attainment of proper characteristics versus temperature as well as satisfactory long-term high-temperature stability of micropassives is more difficult than for structures with typical dimensions for thick-film and LTCC technologies because of increase of interfacial processes’ importance. However it is shown that proper selection of thick-film inks together with proper deposition method permit to prepare thick-film micropassives (microresistors, air-cored microinductors and interdigital microcapacitors suitable for the temperature range between 150°C and 400°C.

  12. Screen printed PZT/PZT thick film bimorph MEMS cantilever device for vibration energy harvesting

    DEFF Research Database (Denmark)

    Xu, Ruichao; Lei, Anders; Dahl-Petersen, Christian

    2012-01-01

    We present a microelectromechanical system (MEMS) based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass. Most piezoelectric energy harvesting devices use a cantilever beam of a non piezoelectric material as support beneath or in-between the piezoelectri...

  13. Film Thickness Model for Grease-Lubricated Bearing Seals with an Axial Contacting Lip

    NARCIS (Netherlands)

    Baart, P.; van Zoelen, M.T.; Lugt, Pieter Martin

    2013-01-01

    A theoretical model is presented to predict the oil film thickness in an axial sealing contact based on grease properties and operating conditions. It is assumed that a small amount of grease will form an oil reservoir on the rotating part and slowly supply oil to the sealing contact. The oil bleed

  14. Effects of load system dynamics on the film thickness in EHL contacts during start up

    NARCIS (Netherlands)

    Popovici, G.; Venner, Cornelis H.; Lugt, P.M.; Lugt, Pieter Martin

    2004-01-01

    By means of numerical simulations the effects of the loading system on the contact dynamics of an EHL contact during start up have been studied. The work was initiated by experimental results obtained for the start up situation on a ball on disk apparatus in which strong film thickness oscillations

  15. Microstructural Studies of Ni-P Thick Film Resistor Temperature Sensors

    Directory of Open Access Journals (Sweden)

    Barbara Holodnik

    1986-01-01

    Full Text Available Thick Ni-P films have been widely investigated at our Institute. This article tends to visualize by use of various microscopic methods how the growth and sintering of individual conducting grains, results in the formation of nickel dendrites responsible for the metallic character of electrical conduction.

  16. CO responses of sensors based on cerium oxide thick films prepared from clustered spherical nanoparticles.

    Science.gov (United States)

    Izu, Noriya; Matsubara, Ichiro; Itoh, Toshio; Akamatsu, Takafumi; Shin, Woosuck

    2013-03-08

    Various types of CO sensors based on cerium oxide (ceria) have been reported recently. It has also been reported that the response speed of CO sensors fabricated from porous ceria thick films comprising nanoparticles is extremely high. However, the response value of such sensors is not suitably high. In this study, we investigated methods of improving the response values of CO sensors based on ceria and prepared gas sensors from core-shell ceria polymer hybrid nanoparticles. These hybrid nanoparticles have been reported to have a unique structure: The core consists of a cluster of ceria crystallites several nanometers in size. We compared the characteristics of the sensors based on thick films prepared from core-shell nanoparticles with those of sensors based on thick films prepared from conventionally used precipitated nanoparticles. The sensors prepared from the core-shell nanoparticles exhibited a resistance that was ten times greater than that of the sensors prepared from the precipitated nanoparticles. The response values of the gas sensors based on the core-shell nanoparticles also was higher than that of the sensors based on the precipitated nanoparticles. Finally, improvements in sensor response were also noticed after the addition of Au nanoparticles to the thick films used to fabricate the two types of sensors.

  17. Thickness Dependence of the Quantum Anomalous Hall Effect in Magnetic Topological Insulator Films.

    Science.gov (United States)

    Feng, Xiao; Feng, Yang; Wang, Jing; Ou, Yunbo; Hao, Zhenqi; Liu, Chang; Zhang, Zuocheng; Zhang, Liguo; Lin, Chaojing; Liao, Jian; Li, Yongqing; Wang, Li-Li; Ji, Shuai-Hua; Chen, Xi; Ma, Xucun; Zhang, Shou-Cheng; Wang, Yayu; He, Ke; Xue, Qi-Kun

    2016-08-01

    The evolution of the quantum anomalous Hall effect with the thickness of Cr-doped (Bi,Sb)2 Te3 magnetic topological insulator films is studied, revealing how the effect is caused by the interplay of the surface states, band-bending, and ferromagnetic exchange energy. Homogeneity in ferromagnetism is found to be the key to high-temperature quantum anomalous Hall material.

  18. Investigation of top electrode for PZT thick films based MEMS sensors

    DEFF Research Database (Denmark)

    Hindrichsen, Christian Carstensen; Pedersen, Thomas; Kristiansen, Paw T.;

    2010-01-01

    In this work processing of screen printed piezoelectric PZT thick films on silicon substrates is investigated for use in future MEMS devices. E-beam evaporated Al and Pt are patterned on PZT as a top electrode using a lift-off process with a line width down to 3 mu m. Three test structures are used...

  19. Measurement of oil film thickness and friction force on a guide shoe bearing

    DEFF Research Database (Denmark)

    Vølund, Anders

    2002-01-01

    An experimental program was carried out in order to reveal oil film thickness, and friction force of the guide shoe bearing of a large two stroke marine diesel engine. The experiment was conducted on a full size engine located at the research facility at MAN B&W Diesel A/S. The experiment was con...

  20. Thickness dependence of the L{sub 2,3} branching ratio of Cr thin films

    Energy Technology Data Exchange (ETDEWEB)

    Aksoy, F. [Physics Department, University of Cukurova, 01330 Adana (Turkey); Physics Department, University of Nigde, 51100 Nigde (Turkey); Akguel, G. [Physics Department, University of Cukurova, 01330 Adana (Turkey); Ufuktepe, Y., E-mail: ufuk@cu.edu.t [Physics Department, University of Cukurova, 01330 Adana (Turkey); Nordlund, D. [Stanford Synchrotron Radiation Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)

    2010-10-22

    We report the electronic structure of chromium (Cr) thin films depending on its thickness using two measures, total electron yield (TEY) and transmission yield mode. The Cr L edge X-ray absorption spectroscopy (XAS) spectrum shows strong thickness dependence with broader line widths observed for L{sub 2,3} edge peaks for thinner films. The white line ratio (L{sub 3}/L{sub 2}) was found to be 1.25 from the integrated area under each L{sub 3} and L{sub 2} peak and 1.36 from the ratio of the amplitudes of each L{sub 3} and L{sub 2} peak after the deconvolution. Additionally, we show that full-width at half-maximum (FWHM) at the L{sub 2} and L{sub 3} edges and the branching ratio of Cr change as a function of film thickness and these are discussed in detail. Using L{sub 2,3} resonance intensity variation as a function of film thickness we calculated the electron escape depth and X-ray attenuation length in Cr. Comparing our results with the literature, there was good agreement for the L{sub 3}-L{sub 2} ratio although the detailed shape can show additional solid state and atomic effects.