Synthesis, properties and space applications of chemically precipitated YBa/sub 2/Cu/sub 3/O/sub 7-x/ superconducting powders

International Nuclear Information System (INIS)

Trivedi, A.; Sundahl, R.C.; Olson, W.L.; Welsh, L.B.; Polak, A.J.; Dolgin, B.P.; Barder, T.J.; Karasek, K.R.; Parker, C.A.

1988-01-01

Processing properties of and chemically precipitated YBa/sub 2/Cu/sub 3/O/sub 7-x/ powders were evaluated. The authors have successfully developed a method for precipitating stoichiometric oxalate precursors for YBa/sub 2/Cu/sub 3/O/sub 7-x/ powders. Precipitation and calcination conditions were found to dramatically impact upon key powder characteristics such as particle size, morphology, phase composition and microscopic homogeneity. Four space applications were identified: a superconducting motor/generator, a magnetic bearing, an electromagnetic coupling, and a motor commutator. The primary device, a motor, would make use of superconducting windings and a superconducting flux bottle to improve efficiency

Electron stimulated desorption of positive and negative oxygen ions from YBa{sub 2}Cu{sub 3}O{sub 7} surfaces

Energy Technology Data Exchange (ETDEWEB)

Hoffman, A. [Technion-Israel Inst. of Tech., Haifa (Israel). Solid State Inst.; Moss, S.D.; Paterson, P.J.K. [Royal Melbourne Inst. of Tech., VIC (Australia); McCubbery, D. [La Trobe Univ., Bundoora, VIC (Australia); Petravic, M. [Australian National Univ., Canberra, ACT (Australia)

1996-12-31

The electron stimulated desorption (ESD) of positive and negative oxygen ion from superconducting YBa{sub 2}Cu{sub 3}O{sub 7} surfaces was studied. Based on ion desorption yield measurements as function of electron kinetic energy, primary excitations leading to positive and negative oxygen ion desorption are suggested. To the best of the authors` knowledge this is the first study on electron energy dependent ESD from YBa{sub 2}Cu{sub 3}O{sub 7} surfaces. The YBa{sub 2}Cu{sub 3}O{sub 7} samples were prepared from BaCO{sub 3}, Y{sub 2}O{sub 3} and CuO using standard high temperature sintering and annealing procedures. Slices 2 mm thick were cut and further annealed at 400 C in flowing oxygen for 24 hours prior to insertion into the ultrahigh vacuum (UHV) chamber for ESD. The near surface composition and chemical state of the annealed sample after exposure to air was examined by Auger and XPS analysis. These measurements suggest that the ESD experiments were performed on samples of similar near surface and bulk composition with some OH- chemisorbed groups and Cl surface contaminations and that negative and positive oxygen ion desorption may be initiated via a primary core level ionization. 10 refs., 3 figs.

Electron stimulated desorption of positive and negative oxygen ions from YBa{sub 2}Cu{sub 3}O{sub 7} surfaces

Energy Technology Data Exchange (ETDEWEB)

Hoffman, A [Technion-Israel Inst. of Tech., Haifa (Israel). Solid State Inst.; Moss, S D; Paterson, P J.K. [Royal Melbourne Inst. of Tech., VIC (Australia); McCubbery, D [La Trobe Univ., Bundoora, VIC (Australia); Petravic, M [Australian National Univ., Canberra, ACT (Australia)

1997-12-31

The electron stimulated desorption (ESD) of positive and negative oxygen ion from superconducting YBa{sub 2}Cu{sub 3}O{sub 7} surfaces was studied. Based on ion desorption yield measurements as function of electron kinetic energy, primary excitations leading to positive and negative oxygen ion desorption are suggested. To the best of the authors` knowledge this is the first study on electron energy dependent ESD from YBa{sub 2}Cu{sub 3}O{sub 7} surfaces. The YBa{sub 2}Cu{sub 3}O{sub 7} samples were prepared from BaCO{sub 3}, Y{sub 2}O{sub 3} and CuO using standard high temperature sintering and annealing procedures. Slices 2 mm thick were cut and further annealed at 400 C in flowing oxygen for 24 hours prior to insertion into the ultrahigh vacuum (UHV) chamber for ESD. The near surface composition and chemical state of the annealed sample after exposure to air was examined by Auger and XPS analysis. These measurements suggest that the ESD experiments were performed on samples of similar near surface and bulk composition with some OH- chemisorbed groups and Cl surface contaminations and that negative and positive oxygen ion desorption may be initiated via a primary core level ionization. 10 refs., 3 figs.

Comparison in the electronic structure of YBa{sub 2}Fe{sub 3}O{sub 8} insulator with YBa{sub 2}Cu{sub 3}O{sub 7} and SmFeAsO{sub 0.8}F{sub 0.2} superconductors

Energy Technology Data Exchange (ETDEWEB)

Zhang, Y.; Guan, X.Y. [Key Laboratory of Magnetic Suspension Technology and Maglev Vehicle, Ministry of Education, Superconductivity R and D Center, Southwest Jiaotong University, Chengdu 610031 (China); Cheng, C.H. [School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia); Pan, M. [Key Laboratory of Magnetic Suspension Technology and Maglev Vehicle, Ministry of Education, Superconductivity R and D Center, Southwest Jiaotong University, Chengdu 610031 (China); Zhang, H. [Department of Physics, Peking University, Beijing 100871 (China); Zhao, Y., E-mail: yzhao@home.swjtu.edu.cn [Key Laboratory of Magnetic Suspension Technology and Maglev Vehicle, Ministry of Education, Superconductivity R and D Center, Southwest Jiaotong University, Chengdu 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia)

2013-10-15

Highlights: • The electronic structure of YBa{sub 2}Fe{sub 3}O{sub 8}, YBa{sub 2}Cu{sub 3}O{sub 7} and SmFeAsO{sub 0.8}F{sub 0.2} were investigated by XPS. • The core-level and valence-band structures of these systems are different. • The density of states at Fermi level is related to the superconductivity. -- Abstract: The electronic structure and chemical states of relevant elements of YBa{sub 2}Fe{sub 3}O{sub 8} are investigated using X-ray photoemission spectroscopy (XPS), compared with those of YBa{sub 2}Cu{sub 3}O{sub 7} and SmFeAsO{sub 0.8}F{sub 0.2} superconductors. The typical differences and similarities in core-level and valence-band structures of these systems have been detected, strongly suggesting that the superconductivity have the finite density of states around Fermi level. Several features of O1s, Y3d, Ba3d, and Fe2p core lines in XPS spectra are also carefully compared and analyzed.

Y{sub 2}BaCuO{sub 5} particle distribution in YBa{sub 2}Cu{sub 3}O{sub 7-y} grains of melt growth processed YBCO oxides; Y{sub 2}BaCuO{sub 5}-Partikelverteilung in YBa{sub 2}Cu{sub 3}O{sub 7-y}-Koernern durch das Melt-Growth-Verfahren verarbeiteter YBCO-Oxide

Energy Technology Data Exchange (ETDEWEB)

Kim, Chan-Joong; Park, Soon-Dong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of). Neutron Science Div.; Park, Hai-Woong [Korea Univ. of Technology and Education, Chungnam (Korea, Republic of). College of Energy, Materials and Chemical Engineering

2013-02-01

Y{sub 2}BaCuO{sub 5} (Y211) particle distribution within YBa{sub 2}Cu{sub 3}O{sub 7-y} (Y123) grains of YBCO samples melt growth (MG) processed was examined. To understand the processing variables on the Y211 distribution, a cooling rate (R{sub C}=1 K/h to R{sub C}=20 K/h) through a peritectic temperature (T{sub p} = 1010 C), a precursor powder size and composition were changed. Two different Y211 distributions (a linear x-like track and planar butterfly-like pattern) were observed, depending on the processing variables. The linear x-like Y211 tracks were observed in the Y123 samples prepared using a stoichiometric Y123 precursor, whereas the planar butterfly-like Y211 patterns were observed in the Y{sub 1.8}Ba{sub 2.4}Cu{sub 3.4}O{sub 7-d} (Y1.8) samples prepared using an Y211-excess composition precursor. The track and planar Y211 patterns were clearer at lower R{sub C} (slower growth rate of Y123 grains) and for the smaller Y211 particles. In contrast, the random Y211 distribution was dominant at the higher R{sub C} and for the larger Y211 particles. The Y211 distribution patterns in the Y123 grains were explained in terms of the interfacial energy difference among growing Y123 fronts. (orig.)

Microstructure and critical current of superconducting YBa/sub 2/Cu/sub 3/Osub(7-x)

Energy Technology Data Exchange (ETDEWEB)

Camps, R A; Evetts, J E; Glowacki, B A; Newcomb, S B; Somekh, R E; Stobbs, W M

1987-09-17

The authors present the main results of a detailed electron microscopical study of sintered YBa/sub 2/Cu/sub 3/0sub(7-x), and discuss their relevance to observed critical current and its modification by increased silicon impurity levels. In the light of these results, the prospects are assessed for controlling microstructure development so as to optimize the critical current for technological application.

Out-of-substrate plane orientation control of thin YBa{sub 2}Cu{sub 3}O {sub x} films on NdGaO{sub 3} tilted-axes substrates

Energy Technology Data Exchange (ETDEWEB)

Mozhaev, Peter B. [Institute of Physics and Technology RAS, Moscow 117218 (Russian Federation) and Department of Physics, Technical University of Denmark, Lyngby, DK-2800 (Denmark)]. E-mail: pbmozh@nm.ru; Mozhaeva, Julia E. [Institute of Physics and Technology RAS, Moscow 117218 (Russian Federation); Department of Physics, Technical University of Denmark, Lyngby, DK-2800 (Denmark); Bdikin, Igor K. [Institute of Solid State Physics RAS, Chernogolovka, Moscow distr., 142432 (Russian Federation); CICECO, University of Aveiro, Aveiro 3810-193 (Portugal); Kotelyanskii, Iosif M. [Institute of Radio Engineering and Electronics RAS, Moscow 125009 (Russian Federation); Lusanov, Valery A. [Institute of Radio Engineering and Electronics RAS, Moscow 125009 (Russian Federation); Hansen, Jorn Bindslev [Department of Physics, Technical University of Denmark, Lyngby, DK-2800 (Denmark); Jacobsen, Claus S. [Department of Physics, Technical University of Denmark, Lyngby, DK-2800 (Denmark); Kholkin, Andrey L. [CICECO, University of Aveiro, Aveiro 3810-193 (Portugal)

2006-02-01

Epitaxial heterostructures YBa{sub 2}Cu{sub 3}O {sub x}(YBCO)/CeO{sub 2}/NdGaO{sub 3} were prepared on tilted-axes NdGaO{sub 3} substrates using laser ablation technique. Morphology, crystal structure and electrical properties of the obtained films were characterized. The seeding mechanisms are affected by the tilt angle, resulting in superior YBCO films on NdGaO{sub 3} substrates in an intermediate range of tilt angles of 6-14{sup o}. The introduction of CeO{sub 2} layer leads to change of the YBCO film orientation: at low deposition rate c-oriented films are formed, while at high deposition rates the film grows with c-axis tilted along the [1 1 0] NdGaO{sub 3} direction. Bi-epitaxial films and structures were prepared by removal of part of the CeO{sub 2} layer using ion-beam milling.

Integration of gas phase condensed nanoparticles in YBa{sub 2}Cu{sub 3}O{sub 7-δ} multilayers; Integration von gasphasenkondensierten Nanopartikeln in YBa{sub 2}Cu{sub 3}O{sub 7-δ}-Multilagen

Energy Technology Data Exchange (ETDEWEB)

Sparing, Maria

2012-07-01

The control and targeted variation of nanoparticles properties is a central challenge in research on particle induced defects in YBa{sub 2}Cu{sub 3}O{sub 7-δ}. Using a combined Sputter-PLD system with inert gas condensation particle size and density integrated into the YBCO multilayers were varied independently. The cooling process influences the electrical properties of the multilayers. The effect of HfO2 and FePt nanoparticles on the structural and electrical properties was studied.

Analysis of process parameters in the laser deposition of YBa{sub 2}Cu{sub 3}O{sub 7} superconducting films by using SVR

Energy Technology Data Exchange (ETDEWEB)

Cai, C.Z., E-mail: caiczh@gmail.com [Department of Applied Physics, Chongqing University, Chongqing 401331 (China); Xiao, T.T. [Department of Applied Physics, Chongqing University, Chongqing 401331 (China); Science and Technology on Plasma Physics Laboratory, Research Center of Laser Fusion, CAEP, P.O. Box 919-988, Mianyang 621900 (China); Tang, J.L.; Huang, S.J. [Department of Applied Physics, Chongqing University, Chongqing 401331 (China)

2013-10-15

Highlights: • Proposed new ideas and strategies to improve energy storage density for SMES system. • One is to increase the effective current density in the superconducting coils. • Another is to optimize the configuration of the SMES coil. • A new conceive of energy compression is also proposed. -- Abstract: There are several process parameters in the growth of YBa{sub 2}Cu{sub 3}O{sub 7} superconducting films by using pulsed laser deposition (PLD). The relationship between the response and process parameters is highly nonlinear and quite complicated. It is very valuable to quantitatively estimate the response under different deposition parameters. In this study, according to an experimental data set on the superconducting transition temperature (T{sub c}) and relative resistance ratio (r{sub R}) of 17 samples of YBa{sub 2}Cu{sub 3}O{sub 7} films deposited under various parameters, the support vector regression (SVR) combined with particle swarm optimization (PSO), was proposed to predict the T{sub c} and r{sub R} for YBa{sub 2}Cu{sub 3}O{sub 7} films. The prediction performance of SVR was compared with that of multiple regression analysis (MRA) models. The results strongly support that the generalization ability of SVR model consistently surpasses that of MRA via leave-one-out cross validation (LOOCV). The mean absolute percentage errors for T{sub c} and r{sub R} are 0.37% and 1.51% respectively via LOOCV test of SVR. Sensitivity analysis discovered the most sensitive parameters affecting the T{sub c} and r{sub R}. This study suggests that the established SVR model can be used to accurately foresee the T{sub c} and r{sub R}. And it can be used to optimizing the deposition parameters in the development of YBa{sub 2}Cu{sub 3}O{sub 7} films via PLD.

Tc enhancement and superconducting properties of a YBa[sub 2]Cu[sub 3]O[proportional to]6. 5 thin film after fluorine insertion

Energy Technology Data Exchange (ETDEWEB)

Pena, O.; Mokhtari, M.; Perrin, C.; Thivet, C.; Guilloux-Viry, M.; Perrin, A.; Sergent, M. (Lab. de Chimie du Solide et Inorganique Moleculaire, Univ. de Rennes 1, 35 (France))

1993-02-10

An oxygen-deficient YBa[sub 2]Cu[sub 3]O[sub x] thin film (Tc=54 K, [Delta]Tc>8K) was treated under a diluted (3% in N[sub 2]) NF[sub 3] gas flow at temperatures not exceeding 280degC. AC induction measurements show a substantial increase of Tc up to about 86 K and a clear improvement of the [chi]''[sub AC] dissipation component (FWHM=1.2 K), as a function of the reaction time. The film was further studied at the end of the reaction by the AC-field dependence and by DC magnetization measurements, including ZFC/FC and magnetization cycles. It was found that granular effects are not important, meaning that the crystalline properties of the film are not degraded by the fluorination process, in good agreement with the X-ray diffraction data. The sharpness of the [chi]''[sub AC] peak, the low M[sub FC]/M[sub ZFC] ratio and the large hysteresis of the magnetization cycle indicate that the critical current densities are high (of the order of 10[sup 6] A/cm[sup 2] at 5 K) and comparable to reasonably good YBa[sub 2]Cu[sub 3]O[sub 7] thin films. The usefulness of the fluorination method and a comparison with halogenated YBa[sub 2]Cu[sub 3]O[sub x] ceramics are also presented. (orig.).

Gadolinium substitution for yttrium and chemical preparation effects in YBa{sub 2}Cu{sub 3}O{sub 7}: an EPR study; Effets de la substitution de l`yttrium par le gadolinium et de la preparation chimique dans YBa{sub 2}Cu{sub 3}O{sub 7}: etude par RPE

Energy Technology Data Exchange (ETDEWEB)

Bejjit, L.; Haddad, M. [Faculte des Sciences, Meknes (Morocco); Bejjit, L. [Faculte des Sciences, Errachidia (Morocco); Deville, A.; Gaillard, B.; Noel, H. [Universite de Provence, 13 - Marseille (France); Monnereau, O. [Universite de Rennes, 35 - Rennes (France)

1998-01-01

Compounds with yttrium totally or partially substituted by gadolinium in High-T{sub c} superconductor YBa{sub 2}Cu{sub 3}O{sub 7} were prepared. The superconductivity is not affected by this substitution. An orthorhombic structure has been observed in GdBa{sub 2}Cu{sub 3}O{sub 7} sintered and single crystals. The EPR measurements show linewidth dependence on chemical preparation in GdBa{sub 2}Cu{sub 3}O{sub 7}. In Gd-low concentration compounds (x{<=}0.02), a narrow parasite signal, due to the Y{sub 2}BaCuO{sub 5} green phase, appears superimposed to the principal Gd{sup 3+} ions Electron Spin Resonance (EPR) line. (authors) 12 refs.

Influence of calcium on transport properties, band spectrum and superconductivity of YBa{sub 2}Cu{sub 3}O{sub y} and YBa{sub 1.5}La{sub 0.5}Cu{sub 3}O{sub y}{sup {center_dot}}

Energy Technology Data Exchange (ETDEWEB)

Gasumyants, V.E.; Vladimirskaya, E.V. [State Technical Univ., St. Petersburg (Russian Federation); Patrina, I.B. [Institute of Silicate Chemistry, St. Petersburg (Russian Federation)

1994-12-31

The comparative investigation of transport phenomena in Y{sub 1-x}Ca{sub x}Ba{sub 2}Cu{sub 3}O{sub y} (0y>6.87 and 6.73Cu{sub 3}O{sub y} (0y>6.96) and YBa{sub 2-x}La{sub x}Cu{sub 3}O{sub y} (0YBa{sub 2}Cu{sub 3}O{sub y}{sup {center_dot}}. The results obtained suggest that Ca gives rise to some peculiarities in band spectrum of this compound.

Raman Spectroscopic Studies of YBa{sub 2}Cu{sub 3}O{sub 7} Coated Conductors

Energy Technology Data Exchange (ETDEWEB)

Choi, Mi Kyeung; Mnh, Nguyen Van; Bae, J. S.; Jo, William; Yang, In Sang [Ewha Womans University, Seoul (Korea, Republic of); Ko, Rock Kil; Ha, Hong Soo; Park, Chan [Korea Electrotecnology Research Institute, Changwon (Korea, Republic of)

2005-04-15

We present results of Raman spectroscopic studies of superconducting YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) coated conductors. Raman scattering is used to characterize optical phonon modes, oxygen content, c-axis misalignment, and second phases of the YBCO coated conductors at a micro scale. A two-dimensional mapping of Raman spectra with transport properties has been performed to elucidate the effect of local propertied on current path and superconducting phase. The information taken from the local measurement will be useful for optimizing the process condition.

Interface structure and electronic properties of SrTiO{sub 3} and YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} crystals and thin films

Energy Technology Data Exchange (ETDEWEB)

Thiess, S.

2007-07-01

Two new extensions of the X-ray standing wave (XSW) technique, made possible by the intense highly collimated X-ray beams from undulators at the ESRF, are described in this thesis. First, the XSW method was applied in a structural study to solve the nucleation mechanism of the high temperature superconductor YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} on the (001) surface of SrTiO{sub 3}. Second, the valence electronic structures of SrTiO{sub 3} and YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} were investigated. Finally, recent developments in the field of photoelectron spectroscopy in the hard X-ray region are described. The X-ray standing wave method is used in combination with fluorescence, Auger or photoelectron spectroscopy and lends very high spatial resolution power to these analytical techniques. Previously, the XSW method has been used for structure determination of surfaces and interfaces. The currently available X-ray intensities permit extensions to the XSW technique. Two recently established applications, described in this thesis, are XSW real space imaging and XSW valence electronic structure analysis. XSW real space imaging was employed to analyse the atomic structure of 0.5 and 1.0 layers of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} deposited on SrTiO{sub 3}(001). Three-dimensional images of the atomic distributions were reconstructed for each of the elements from experimentally determined Fourier components of the atomic distribution functions. The images confirmed the formation of a perovskite precursor phase prior to the formation of the YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} phase during the growth of the first monolayer of the film. XSW valence electronic structure analysis applied to SrTiO{sub 3} identified the valence band contributions arising from the strontium, titanium, and oxygen sites of the crystal lattice. Relations between the site-specific valence electronic structure and the lattice structure were established. The experimental results agree very well with

Structure of the non-superconducting phase La/sub 3/Ba/sub 3/Cu/sub 6/Osub(14+ x) and its relation to the high - Tc superconductor YBa/sub 2/Cu/sub 3/Osub(7 -delta)

Energy Technology Data Exchange (ETDEWEB)

David, W.I.F.; Harrison, W.T.A.; Ibberson, R.M.; Grasmeder, J.R.; Lanchester, P.

1987-07-23

The authors report time-of-flight neutron powder diffraction results, which confirm that the structure of La/sub 3/Ba/sub 3/Cu/sub 6/Osub(14 + x) is isomorphous with the tetragonal variant of YBa/sub 2/Cu/sub 3/Osub(7-delta); in particular, the copper coordination and calculated valencies of both compounds agree closely. The apparent contradiction of stoichiometries between these two phases is resolved by ordering of the large cations consistent with a formulation La(Lasub(0.25)Basub(0.75))/sub 2/Cu/sub 3/Osub(7 + 1/2x). The present results indicate that there is a remarkable structural stability from RA/sub 2/Cu/sub 3/O/sub 6/ to RA/sub 2/Cu/sub 3/Osub(7.2), although superconductivity appears to be confined to the range RA/sub 2/Cu/sub 3/Osub(6.5) to Ra/sub 2/Cu/sub 3/O/sub 7/.

10 GHz R[sub s] measurements of YBa[sub 2]Cu[sub 3]O[sub 7]. Influence of a magnetic field

Energy Technology Data Exchange (ETDEWEB)

Deville, A. (Electronique des Milieux Condenses, Univ. de Provence, 13 Marseille (France)); Fawaz, H. (Electronique des Milieux Condenses, Univ. de Provence, 13 Marseille (France)); Gaillard, B. (Electronique des Milieux Condenses, Univ. de Provence, 13 Marseille (France)); Noel, H. (Chimie du Solide et Inorganique Moleculaire, Univ. de Rennes, 35 Rennes (France)); Potel, M. (Chimie du Solide et Inorganique Moleculaire, Univ. de Rennes, 35 Rennes (France)); Monnereau, O. (Chimie des Materiaux, Univ. de Provence, 13 Marseille (France))

1994-02-01

We examine the 10 GHz surface resistance of YBa[sub 2]Cu[sub 3]O[sub 7] single crystals, without and with a continuous magnetic field up to 2T, in both cases without modulation of the magnetic field. We compare the results in a continuous field with those we obtain using a modulation. The results are briefly discussed. (orig.)

A study on the superconducting properties of YBa{sub 2}Cu{sub 9-x}Nb{sub x}O{sup y} thin films

Energy Technology Data Exchange (ETDEWEB)

Srinivas, S.; Bhatnagar, A.K. [Univ. of Hyderabad (India); Pinto, R. [Solid State Electronics Group, Bombay (India)] [and others

1994-12-31

Effect of niobium substitution at the copper site in YBa{sub 2}Cu{sub 9}O{sub 7-x} was studied in thin film form. The films were deposited by laser ablation technique using the targets of the YBa{sub 2}Cu{sub 3-x}Nb{sub x}O{sub y} where x = 0.0, 0.025, 0.05, 0.1, 0.2, 0.4, 0.8 and 1.0 under identical deposition conditions on SrTiO{sub 9} <100> substrates. Films were characterized by XRD, resistivity, I-V and J{sub c} measurements. Films made from x = 0.025 and 0.05 concentrations of Nb substituted targets showed relatively improved superconducting properties compared to that of undoped films. The best 7 realized for x = 0.025 Nb concentration was 1.8 x 10{sup {sigma}} A/cm{sup 2} and for 0.05 Nb concentration it was 3.2x10{sup {sigma}} A/cm{sup 2} at 77K. However, degradation of the superconducting properties, with the increase of x {ge} 0.1 Nb concentration and drastic suppression and complete loss of superconductivity was noticed for x {ge} 0.4. The growth of impurity phase YBa{sub 2}NbO{sub 6} for x = 0.1 and above of Nb concentration was noticed from XRD patterns. However, the site occupancy of Nb could not be confirmed from these studies.

High resolution electron microscopy and electron diffraction of YBa/sub 2/Cu/sub 3/O/sub 7-x/

International Nuclear Information System (INIS)

Krakow, W.; Shaw, T.M.

1988-01-01

Experimental high resolution electron micrographs and computer simulation experiments have been used to evaluate the visibility of the atomic constituents of YBa/sub 2/Cu/sub 3/O/sub 7-x/. In practice, the detection of oxygen has not been possible in contradiction to that predicted by modelling of perfect crystalline material. Preliminary computer experiments of the electron diffraction patterns when oxygen vacancies are introduced on the Cu-O sheets separating Ba layers show the diffuse streaks characteristic of short range ordering

Bi-epitaxial YBa{sub 2}Cu{sub 3}O{sub x} Thin Films on Tilted-axes NdGaO{sub 3} Substrates with CeO{sub 2} Seeding Layer

Energy Technology Data Exchange (ETDEWEB)

Mozhaev, P B [Institute of Physics and Technology RAS, 117218, Moscow (Russian Federation); Mozhaeva, J E [Institute of Physics and Technology RAS, 117218, Moscow (Russian Federation); Jacobsen, C S [Technical University of Denmark, Physics Department, Lyngby, DK-2800, Denmark (Denmark); Hansen, J Bindslev [Technical University of Denmark, Physics Department, Lyngby, DK-2800, Denmark (Denmark); Bdikin, I K [CICECO, University of Aveiro, Aveiro, 3810-193 (Portugal); Luzanov, V A [Institute of Radio Engineering and Electronics, Moscow, 125009 (Russian Federation); Kotelyanskii, I M [Institute of Radio Engineering and Electronics, Moscow, 125009 (Russian Federation); Zybtsev, S G [Institute of Radio Engineering and Electronics, Moscow, 125009 (Russian Federation)

2006-06-01

Bi-epitaxial YBa{sub 2}Cu{sub 3}O{sub x} (YBCO) thin films with out-of-plane tilt angle in the range 18 - 27{sup 0} were manufactured using pulsed laser deposition on NdGaO{sub 3} tilted-axes substrates with CeO{sub 2} seeding layers. The YBCO thin film orientation over the seeding layer depended on deposition conditions. Removal of the seeding layer from part of the substrate surface by ionbeam etching resulted in formation of a bi-epitaxial thin film with different c-axis orientation of two parts of the film. The bi-epitaxial film orientation and structure were studied using X-ray diffraction techniques, and surface morphology was observed with atomic force microscope (AFM). Photolithography and ion-beam etching techniques were used for patterning bi-epitaxial thin films. Electrical characterization of the obtained structures was performed.

The role of Ca substitution on the nature of the superconducting transition of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}

Energy Technology Data Exchange (ETDEWEB)

Jaeckel, S.T.; Lopes, L.F.; Nunes, S.E.; Mendonca, A.P.A.; Lopes, R.F.; Vieira, V.N. [Universidade Federal de Pelotas, RS (Brazil). Inst. de Fisica e Matematica; Pureur, P.; Pimentel Junior, J.L.; Rosa, F.M. [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Inst. de Fisica; Ferreira, L.M. [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil). Centro de Ciencias Naturais e Humanas

2012-07-01

Full text: In this work we report the results of an experimental study about the superconducting transition of Ca- doped YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}samples. Temperature dependent in-plane resistivity measurements were carried out on Y{sub 1-x}Ca{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-{delta}} single crystals with Ca content x = 0, 0.01, 0.05, 0.10. The samples were studied under hydrostatic pressure conditions (P {<=}15 kbar) and applied magnetic fields (H {<=} 2500 Oe) with H parallel to the c-axis. From the analysis of the contribution of superconducting fluctuations to the electrical conductivity we identified a fluctuation regime described by the small exponent {lambda}{sub cr} = 0.20 in a narrow temperature range immediately above the critical temperature. The origin of this fluctuation regime is still unclear. A possibility is that it may be a precursor to a weakly first-order pairing transition. The evolution of this super-critical regime with pressure and magnetic field for our Ca-doped samples is distinct from results reported in the literature for pure and other divalent substituted YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}samples. Our results indicate that Ca doping favors the stabilization of the super-critical regime. (author)

Thermal capacity of ternary oxide YBa[sub 2]Cu[sub 3]O[sub 7-y] in 300-1100 K interval. Teploemkost' trojnogo oksida YBa[sub 2]Cu[sub 3]O[sub 7-y] v intervale 300-1100 K

Energy Technology Data Exchange (ETDEWEB)

Sharpataya, G A; Ozerova, Z P; Kolnovalova, I A; Lazarev, V B; Shaplygin, I S [AN SSSR, Moscow (Russian Federation). Inst. Obshchej i Neorganicheskoj Khimii

1991-08-01

Thermal capacity of YBa[sub 2]Cu[sub 3]O[sub 7-y] samples with different thermal prehistory is measured using a differential scanning calorimeter within 300-1100 K interval. It is shown that the combination of thermal capacity temperature dependence curves in these samples demonstrates reversibility and temperature limits of oxygen absorption and release processes with the corresponding changes of the formular index by oxygen from 6.85-6.90 to 6.35 and vice versa. Thermal capacity anomaly, corresponding to the reversible structural transition from orthorhombic to tetragonal phase with the simultaneous oxygen loss is observed within 630-1000 K interval.

Investigation of the effect of Zn impurities and magnetic field on the spin dynamics in underdoped YBa{sub 2}(Cu{sub 1-y}Zn{sub y}){sub 3}O{sub x}

Energy Technology Data Exchange (ETDEWEB)

Suchaneck, Anton

2009-04-20

This work employs neutron scattering to examine the changes in the spin excitation spectrum of the underdoped high-temperature superconductor YBa{sub 2}Cu{sub 3}O{sub x} which is doped with zinc or subject to a strong magnetic field. Doping levels of x=6.6 and x=6.45 are used with an optional zinc substitution of 2% zinc per copper atom. A detwinning procedure is an important factor in order to reorient all twinning domains of the orthorhombic crystal cell in the same direction. Numerous single crystals were oriented and assembled to create a sample of total mass 2 g neccessary for neutron scattering experiments. The experiments were performed on triple axis neutron scattering spectrometers to measure spin excitations around the antiferromagnetic wave vector at energies up to 50 meV. Zinc substitution and magnetic field influence the spin excitations, which in the pure compound feature the resonance mode, a spin gap and an hour-glass dispersion. Upon zinc substitution the spectrum of YBa{sub 2}(Cu{sub 0.98}Zn{sub 0.02}){sub 3}O{sub 6.6} is quantitatively unchanged around the resonance energy, however its marked temperature onset disappears. At lower energies new induced quasi-static excitations emerge. Similar finding have been observed in other cuprate compounds. The induced excitation exhibit a strong anisotropy in the copper planes. All these results are compared to other experimental techniques which provide comparable experimental evidence. Another compounds examined in this work is the more strongly oxygen underdoped YBa{sub 2}(Cu{sub 0.98}Zn{sub 0.02}){sub 3}O{sub 6.45}. The common bilayer related signal remains unchanged with zinc substitution, however a new inter-plane correlated signal is induced indicating ordering between copper planes. A comparison with other experimental techniques indicated that the superconducting critical temperature is the sole determining factor of the qualitative spin excitation spectrum, no matter what factor are responsible

Resonant behavior of the barrier of YBa{sub 2}Cu{sub 3}O{sub 7} grain boundary Josephson junctions fabricated on bicrystalline substrates with different geometries

Energy Technology Data Exchange (ETDEWEB)

Navacerrada, M.A., E-mail: mdelosangeles.navacerrada@upm.es [Grupo de Acustica Arquitectonica, Escuela Tecnica Superior de Arquitectura, Universidad Politecnica de Madrid, Avenida Juan de Herrera 4, 28040 Madrid (Spain); Lucia, M.L.; Sanchez-Quesada, F. [Departamento Fisica Aplicada III (Electricidad y Electronica), Facultad de Cc. Fisicas, Universidad Complutense, Avenida Complutense s/n, 28040 Madrid (Spain)

2012-12-14

We have analyzed a resonant behavior in the dielectric constant associated to the barrier of YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) grain boundary Josephson junctions (GBJJs) fabricated on a wide variety of bicrystalline substrates: 12 Degree-Sign [0 0 1] tilt asymmetric, 24 Degree-Sign [0 0 1] tilt asymmetric, 24 Degree-Sign [0 0 1] tilt symmetric, 24 Degree-Sign [1 0 0] tilt asymmetric, 45 Degree-Sign [1 0 0] tilt asymmetric and 24 Degree-Sign [0 0 1] tilt symmetric +45 Degree-Sign [1 0 0] tilt asymmetric bicrystals. The resonance analysis allows us to estimate a more appropriate value of the relative dielectric constant, and so a more adequate value for the length L of the normal N region assuming a SNINS model for the barrier. In this work, the L dependence on the critical current density Jc has been investigated. This analysis makes possible a single representation for all the substrate geometries independently on around which axes the rotation is produced to generate the grain boundary. On the other hand, no clear evidences exist on the origin of the resonance. The resonance frequency is in the order of 10{sup 11} Hz, pointing to a phonon dynamic influence on the resonance mechanism. Besides, its position is affected by the oxygen content of the barrier: a shift at low frequencies is observed when the misorientation angle increases.

Light induced superconductivity in underdoped YBa{sub 2}Cu{sub 3}O{sub x}

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Kaiser, Stefan [Max-Planck-Institut fuer die Struktur und Dynamik der Materie, Hamburg (Germany); Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany); 4. Physikalisches Institut und Research Center SCoPE, Uni Stuttgart (Germany); Nicoletti, Daniele; Hunt, Cassi; Hu, Wanzheng; Mankowsky, Roman; Foerst, Michael; Gierz, Isabella; Cavalleri, Andrea [Max-Planck-Institut fuer die Struktur und Dynamik der Materie, Hamburg (Germany); Loew, Toshinao; LeTacon, Mathieu; Keimer, Bernhard [Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany)

2015-07-01

Photo-stimulation with femtosecond mid-infrared pulses allows us to induce an inhomogeneous non-equilibrium superconducting state in YBa{sub 2}Cu{sub 3}O{sub x} at temperatures as high as 300 K. Its transient response is probed via THz time-domain spectroscopy. We measure and characterize its complex optical response above and below the superconducting transition temperature T{sub c}: Below T{sub c}, we find an enhancement of the optical signatures of superconducting coherence. Above T{sub c} we find that the incoherent optical properties at equilibrium become highly coherent with optical signatures very similar to the ones for superconductors below T{sub c}. In the course of understanding these observations, ultrafast x-ray experiments at LCLS allow us observing reconstructed crystal structure in the transient superconducting state and the influence of competing CDW-order to the phonon-excitation.

Consolidation of powders of the superconductor YBa/sub 2/Cu/sub 3/O/sub 7-. delta. / by high energy-high rate processing

Energy Technology Data Exchange (ETDEWEB)

Lee, J.Y.; Persad, C.; Swinnea, J.S.; Marcus, H.L.; Steinfink, H. (Texas Univ., Austin, TX (USA). Center for Materials Science and Engineering)

1988-01-01

The consolidation response of powders of the superconducting compound YBa/sub 2/Cu/sub 3/O/sub 7-{delta}/ by itself and admixed with metal powders is reported. The processing approach relies on short duration (2/), pulse resistive heating of powders under applied pressures of 200 MPa to 400 MPa. Powders and fabricated disk concepts were characterized by X-ray diffraction, optical and scanning electron microscopy.

Synthesis of Y{sub 1-x}Al{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-δ} via combustion route: Effects of Al{sub 2}O{sub 3} nanoparticles on superconducting properties

Energy Technology Data Exchange (ETDEWEB)

Mohd Suan, Mohd Shahadan, E-mail: mohdshahadan@utem.edu.my [Department of Engineering Materials, Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, 76100 Durian Tunggal, Melaka (Malaysia); Johan, Mohd Rafie [Nanomaterial Engineering Research Group, Advanced Materials Research Laboratory, Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2017-02-01

Combustion reaction was used to synthesis Al{sub 2}O{sub 3} nanoparticles embedded Y{sub 1-x}Al{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-δ} simultaneously. The effects of Al{sub 2}O{sub 3} nanoparticles with nominal molar mass (x{sub mol}) of 0.02, 0.04, 0.06, 0.08 and 0.10 towards the critical current density J{sub C} of Y{sub 1-x}Al{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-δ} were verified by magnetic measurement. Resulted XRD patterns revealed that the calcined samples consist of pure Al{sub 2}O{sub 3} and Y{sub 1-x}Al{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-δ} phases which had been confirmed by EDX results. The SEM images showed that Al{sub 2}O{sub 3} nanoparticles (~10 nm) were distributed in polycrystalline YBa{sub 2}Cu{sub 3}O{sub 7-δ} grains and grain boundaries. The presence of higher concentration of Al{sub 2}O{sub 3} nanoparticles has developed Al{sup 3+} rich spots which diffused within the YBa{sub 2}Cu{sub 3}O{sub 7-δ} superconducting matrix to form Y{sub 1-x}Al{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-δ} and was confirmed by EDX analysis. The samples were electrically superconducting at temperature above 85 K as measured by using standard four-probe technique. The magnetic field (H) dependent magnetization (M), M-H hysteresis loops measured at 77 K for x{sub mol}≤0.06 samples are significantly improved attributed to the increase of trapped fluxes in the samples. Remarkable increase of magnetic J{sub C} (H) in Al{sub 2}O{sub 3} nanoparticles added samples compared to the as prepared polycrystalline YBa{sub 2}Cu{sub 3}O{sub 7-δ} sample indicating strong pinning effect. It is suggested that well-distributed Al{sub 2}O{sub 3} nanoparticles in the polycrystalline YBa{sub 2}Cu{sub 3}O{sub 7-δ} matrix achieved via auto-combustion reaction has efficiently pin the magnetic vortex. The magnetic J{sub C} was optimized to ~6 kAcm{sup -2} in x{sub mol}=0.06 sample. On the other hand, insignificant magnetic J{sub C} improvement in x{sub mol}≥0.08 samples is probably resulted from the

Electrical, magnetic and physical properties of YBa/sub 2/Cu/sub 3/O/sub 7-x/ superconductor/polymer composites

International Nuclear Information System (INIS)

Fuierer, P.A.; Srinivasan, T.T.; Newnham, R.E.

1988-01-01

A polymer matrix provides a composite with flexibility and improved impact strength as well as protection against humidity and chemical attack. Superconductor/polymer 0-3 composites have been prepared by mixing YBa/sub 2/Cu/sub 3/O/sub 7-x/ powder with silicone rubber, pressing and curing. The resistivities of these composites do not go to zero, however, the magnetic flux exclusion is maintained in the temperature range, T< T/sub c/(--91K). The composite resistivities show percolation behavior and diamagnetism increases with increasing volume fraction of the superconductor filler. The composites exhibit levitation and large diamagnetic susceptibilities

Enhanced flux pinning properties in superconducting YBa{sub 2}Cu{sub 3}O{sub 7−z} films by a novel chemical doping approach

Energy Technology Data Exchange (ETDEWEB)

Wang, W.T., E-mail: wtwang@swjtu.edu.cn [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Southwest Jiaotong University, Mail Stop 165, Chengdu, Sichuan 610031 (China); Pu, M.H.; Lei, M.; Zhang, H.; Wang, Z. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Southwest Jiaotong University, Mail Stop 165, Chengdu, Sichuan 610031 (China); Zhang, H. [Department of Physics, Peking University, Beijing 100871 (China); Cheng, C.H. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Southwest Jiaotong University, Mail Stop 165, Chengdu, Sichuan 610031 (China); Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wale, Sydney, 2052 NSW (Australia); Zhao, Y., E-mail: yzhao@swjtu.edu.cn [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Southwest Jiaotong University, Mail Stop 165, Chengdu, Sichuan 610031 (China); Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wale, Sydney, 2052 NSW (Australia)

2013-10-15

Highlights: • Pure and Co-doped YBCO films were prepared by newly-developed chemical method. • The doped films have much denser and smoother surface microstructures. • Significantly enhanced fux-pinning properties have been obtained for dilute Co-doped flm. -- Abstract: Pure and cobalt-doped superconducting YBa{sub 2}Cu{sub 3}O{sub 7−z} (YBCO) films were prepared on (0 0 l) LaAlO{sub 3} substrate by a newly developed polymer-assisted metal organic deposition method. The cobalt-doped YBCO films display much denser and smoother surface microstructures and the superconducting transition temperature T{sub c} spans a small range of 1.7 K with the doping levels. Significantly enhanced flux-pinning properties have been obtained for dilute cobalt-doped film. This may be attributed to the good grain connections and the effective flux pinning centers introduced by cobalt doping.

Secondary phase formation in YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} thin films and YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}/SrTiO{sub 3} superlattices

Energy Technology Data Exchange (ETDEWEB)

Johnson, C.N.L.

1996-06-01

Studies of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) thin films and YBCO/STO superlattices has been performed. The dc magnetron sputtered YBCO single layer investigation concerned the dependence of the secondary phase formation and superconducting transport properties on sputtering target and ambient gas composition. YBCO/STO superlattices, grown by dc and rf magnetron sputtering, respectively, were analyzed with respect to microstructure and formation of secondary phases. The main characterization techniques used in this study have been x-ray diffraction to identify phases and to obtain orientational relationships, scanning electron microscopy to study surface morphology, transmission electron microscopy for microstructural characterization, and energy-dispersive x-ray spectroscopy for chemical characterization. With the aim to reduce or avoid the formation of copper-rich surface particles and still maintain satisfactory superconducting transport properties, YBCO films were deposited using copper-poor or yttrium-rich sputtering targets in an Ar:O{sub 2} or Ar:O{sub 2}:N{sub 2}O sputtering gas mixture. It was found that the use of yttrium-rich targets and N{sub 2}O in the sputtering gas is a reliable way to achieve smooth films without surface particles and with satisfactory superconducting properties, while the use of copper-poor targets and N{sub 2}O deteriorates those properties. Based on the previous results, YBCO/STO superlattices were grown using yttrium-rich YBCO targets and stoichiometric STO targets, respectively, in a Ar:O{sub 2}:N{sub 2}O sputtering gas mixture. The superlattices were found to have sharp interfaces and no indications of interface reactions were detected. 61 refs, 18 figs, 3 tabs

Out-of-plane tilted Josephson junctions of bi-epitaxial YBa{sub 2}Cu{sub 3}O {sub x} thin films on tilted-axes NdGaO{sub 3} substrates with CeO{sub 2} seeding layer

Energy Technology Data Exchange (ETDEWEB)

Mozhaev, Peter B. [Institute of Physics and Technology RAS, Moscow 117218 (Russian Federation) and Department of Physics, Technical University of Denmark, Lyngby DK-2800 (Denmark)]. E-mail: pbmozh@nm.ru; Mozhaeva, Julia E. [Institute of Physics and Technology RAS, Moscow 117218 (Russian Federation); Department of Physics, Technical University of Denmark, Lyngby DK-2800 (Denmark); Bdikin, Igor K. [CICECO, University of Aveiro, Aveiro 3810-193 (Portugal); Kotelyanskii, Iosif M. [Institute of Radio Engineering and Electronics RAS, Moscow 125009 (Russian Federation); Luzanov, Valery A. [Institute of Radio Engineering and Electronics RAS, Moscow 125009 (Russian Federation); Zybtsev, Sergey G. [Institute of Radio Engineering and Electronics RAS, Moscow 125009 (Russian Federation); Hansen, Jorn Bindslev [Department of Physics, Technical University of Denmark, Lyngby DK-2800 (Denmark); Jacobsen, Claus S. [Department of Physics, Technical University of Denmark, Lyngby DK-2800 (Denmark)

2006-03-15

Bi-epitaxial heterostructures YBa{sub 2}Cu{sub 3}O {sub x}(YBCO)/CeO{sub 2}/NdGaO{sub 3} were prepared on tilted-axes NdGaO{sub 3} substrates using laser ablation technique. The heterostructures were patterned for electrical measurements using photolithography and ion-beam milling. Electrical anisotropy of the YBCO film was tested on the ion-beam etched surface. Bi-epitaxial junctions with four different orientations of the bi-epitaxial border were fabricated and studied. The measured I V curves showed flux-flow behavior with critical current density 2.5 x 10{sup 4} A/cm{sup 2} for the twist-type junctions and 1.5 x 10{sup 3} A/cm{sup 2} for [1 0 0]-tilt type junctions.

Effects of junction resistance and counterelectrode material on point-contact tunneling into single- and polycrystalline YBa/sub 2/Cu/sub 3/O/sub 7-y/

Energy Technology Data Exchange (ETDEWEB)

Moog, E.R.; Hawley, M.E.; Gray, K.E.; Liu, J.Z.; Hinks, D.G.; Capone, D.W. II; Downey, J.

1988-06-01

The effects of junction resistance and counterelectrode material on the results of point-contact tunneling studies into single- and polycrystalline YBa/sub 2/Cu/sub 3/O/sub 7-y/ are illustrated. Although reasonably symmetric I(V) curves predominantly indicate energy gap values /Delta/ /approx/ 20 meV, large asymmetries are often found for high-resistance junctions. Very low-resistance junctions show the expected behavior of pure metallic bridge and indicate /Delta/ /approx/ 25-30 meV.

Formation of nanoparticles and defects in YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} prepared by the metal organic deposition process

Energy Technology Data Exchange (ETDEWEB)

Goswami, R. [Naval Research Laboratory, Washington, DC 20375 (United States); SAIC, Washington, DC 20003 (United States)], E-mail: goswami@anvil.nrl.navy.mil; Holtz, R.L. [Naval Research Laboratory, Washington, DC 20375 (United States); Rupich, M.W. [American Superconductors Inc., Westborough, MA 01581 (United States); Spanos, G. [Naval Research Laboratory, Washington, DC 20375 (United States)

2007-11-15

Nanoparticles and defects have been investigated using transmission electron microscopy in fully reacted YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO), prepared by the metal-organic deposition (MOD) process. Two types of particles, Y{sub 2}O{sub 3} and CuY{sub 2}O{sub 5}, ranging from 10 to 100 nm, have been observed in the YBCO matrix. The YBCO contains a large number of planar defects and a considerable number of (1 1 0) rotational twins. Details of the nanoparticles and defects in the MOD-processed YBCO films are presented in this paper.

Yttrium-enriched YBa{sub 2}Cu{sub 3}O{sub x} thin films for coated conductors fabricated by pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Khoryushin, Alexey V., E-mail: khoryushin@ya.ru [Department of Physics, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); Mozhaev, Peter B.; Mozhaeva, Julia E.; Andersen, Niels H. [Department of Physics, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); Grivel, Jean-Claude [Department of Energy Conversion and Storage, Technical University of Denmark, DK-4000 Roskilde (Denmark); Hansen, Jørn Bindslev; Jacobsen, Claus S. [Department of Physics, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark)

2013-02-14

Highlights: ► YBCO films were fabricated by PLD from targets of various elemental compositions. ► The Y-enriched films contain yttria nanoparticles which provide efficient pinning. ► The best film has 5.5× higher j{sub c}(5 T,50 K) = 2.6MA/cm{sup 2} comparing with a reference film. ► The Y-enriched films remain c-oriented up to 500 nm. ► Films demonstrate no j{sub c} suppression with thickness and remarkable stability with time. -- Abstract: The effects of excess yttria on the structural and electrical properties of the YBa{sub 2}Cu{sub 3}O{sub x} (YBCO) thin films are studied. The films were deposited on (LaAlO{sub 3}){sub 0.3}–(Sr{sub 2}AlTaO{sub 8}){sub 0.7} substrates by pulsed laser ablation from targets with different elemental composition. An increase of yttrium content of the target leads to formation of porous films with significantly improved current-carrying capabilities. Structural studies of these films reveal presence of yttria nanoparticles embedded into the YBCO matrix. The highest obtained critical current density in an external magnetic field of 5 T was 2.6 MA/cm{sup 2} at 50 K and 9.4 MA/cm{sup 2} at 20 K. The fabricated Y-enriched YBCO films remain c-oriented at least up to 600 nm thickness with no significant suppression of the critical current density.

On the origin of the double superconducting transition in overdoped YBa{sub 2}Cu{sub 3}O {sub x}

Energy Technology Data Exchange (ETDEWEB)

Lortz, R. [Department of Condensed Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, CH-1211 Geneva 4 (Switzerland)]. E-mail: Rolf.Lortz@physics.unige.ch; Tomita, T. [Department of Physics, Washington University, CB 1105, One Brookings Dr., St. Louis, MO 63130 (United States); Wang, Y. [Department of Condensed Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, CH-1211 Geneva 4 (Switzerland); Junod, A. [Department of Condensed Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, CH-1211 Geneva 4 (Switzerland); Schilling, J.S. [Department of Physics, Washington University, CB 1105, One Brookings Dr., St. Louis, MO 63130 (United States); Masui, T. [Department of Physics, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Tajima, S. [Department of Physics, Osaka University, Toyonaka, Osaka 560-0043 (Japan)

2006-02-15

The superconducting transition in a single overdoped, detwinned YBa{sub 2}Cu{sub 3}O {sub x} (YBCO) crystal is studied using four different probes. Whereas the AC and DC magnetic susceptibilities find a dominant transition at 88 K with a smaller effect near 92 K, the specific heat and electrical resistivity reveal only a single transition at 88 K and 92 K, respectively. Under hydrostatic pressures to 0.60 GPa these two transitions shift in opposite directions, their separation increasing. The present experiments clearly show that the bulk transition lies at 88 K and originates from fully oxygenated YBCO; the 92 K transition likely arises from filamentary superconductivity in a minority optimally doped phase (<1%) of YBCO located at or near the crystal surface.

Evidence of oxygen content heterogeneity in TSMTG YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}/Y{sub 2}BaCuO{sub 5} composites by micro-Raman spectrometry

Energy Technology Data Exchange (ETDEWEB)

Delorme, F. [Laboratoire CRISMAT, UMR CNRS 6508, ISMRA, Boulevard du Marechal Juin, 14050 Caen Cedex (France)], E-mail: f.delorme@brgm.fr; Bardeau, J.-F. [Laboratoire de Physique de l' Etat Condense, Faculte des Sciences, Universite du Maine, Avenue Olivier Messiaen, 72085 Le Mans Cedex 09 (France); Harnois, C. [Laboratoire CRISMAT, UMR CNRS 6508, ISMRA, Boulevard du Marechal Juin, 14050 Caen Cedex (France); Monot-Laffez, I. [Laboratoire LEMA, CNRS FRE-2077- CEA-LRC M01 - IUT de Blois, 3 Place Jean Jaures, CS2903, 41029 Blois (France)

2008-03-01

The homogeneity of the oxygen content of TSMTG-YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}/Y{sub 2}BaCuO{sub 5} composites has been investigated by micro-Raman spectrometry. The Y123 compound has been found to be very sensitive to the laser power, but a laser power of 0.04 mW has been shown to not to be harmful for the samples, even after 2 h of irradiation. Raman spectra have shown that the oxygen content of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}/Y{sub 2}BaCuO{sub 5} ceramics is not homogeneous at the micrometer scale. In addition, no monotonic decrease of the oxygen content is observed from the periphery to the core of the sample, confirming that the oxygen uptake is not strictly controlled by a diffusion process.

Time-resolved X-ray diffraction study on superconducting YBa{sub 2}Cu{sub 3}O{sub 7} epitaxially grown on SrTiO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Luebcke, A.

2007-07-01

In this PhD thesis time-resolved X-ray diffraction in optical pump - X-ray probe scheme was applied for the first time to a High-Temperature Superconductor in the superconducting state. The aim was to study the possible lattice response to optical Cooper pair breaking. As sample a thin YBa{sub 2}Cu{sub 3}O{sub 7} film with a superconducting transition temperature of T{sub c}=90 K, epitaxially grown on a SrTiO{sub 3} single crystal was used. (orig.)

High J{sub c} YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} Films via Rapid, Low pO{sub 2} Pyrolysis

Energy Technology Data Exchange (ETDEWEB)

DAWLEY,JEFFREY T.; CLEM,PAUL G.; SIEGAL,MICHAEL P.; OVERMYER,DONALD L.

2000-09-21

In this investigation, YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} (YBCO) films were fabricated via a metal acetate, trifluoroacetic acid based sol-gel route, and spin-coat deposited on (100) LaAlO{sub 3} with a focus on maximizing J{sub c}, while minimizing processing time. We demonstrate that the use of a low pO{sub 2} atmosphere during the pyrolysis stage can lead to at least a tetiold reduction in pyrolysis time, compared to a 1 atm. O{sub 2} ambient. High-quality YBCO films on LaAlO{sub 3}, with J{sub c} values up to 3 MA/cm{sup 2} at 77 K, can be routinely crystallized from these rapidly pyrolyzed films.

Correlation of tunneling spectra with surface nanomorphology and doping in thin YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} films

Energy Technology Data Exchange (ETDEWEB)

Sharoni, A.; Millo, O. [Hebrew Univ., Jerusalem (Israel). Racah Inst. of Physics; Koren, G. [Technion-Israel Inst. of Tech., Haifa (Israel). Dept. of Physics

2001-06-01

Tunneling spectra measured on thin epitaxial YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} films are found to exhibit strong spatial variations, showing U- and V-shaped gaps as well as zero-bias conductance peaks typical of a d-wave superconductor. A full correspondence is found between the tunneling spectra and the surface morphology down to a level of a unit-cell step. Splitting of the zero-bias conductance peak is seen in optimally-doped and overdoped films, but not in the underdoped ones, suggesting that there is no transition to a state of broken time-reversal symmetry in the underdoped regime. (orig.)

Interaction of plasma-sprayed YBa/sub y/Cu/sub 3/0/sub x/ coatings with alumina substrates

Energy Technology Data Exchange (ETDEWEB)

Moreau, C; Parent, L; Dallaire, S; Champagne, B

1989-01-01

Superconducting YBa/sub 2/Cu/sub 3/O/sub x/ coatings can be obtained by plasma spraying. Since the as-sprayed coatings do not have an appropriate crystalline structure and are not superconducting, a thermal treatment must be done for crystallizing them in the appropriate YBa/sub 2/Cu/sub 3/O/sub x/ phase. During heat treatment, reactions between the substrate and coating occur and in some cases, may prevent superconducting properties to be obtained. In the present study, YBa/sub 2/Cu/sub 3/O sub/x/ coatings have been deposited on alumina substrates by plasma spraying and heat treated under flowing oxygen at 950/sup 0/C for different periods of time. The modification in coating microstructure has been investigated after different heat treatments. A degradation mechanism of superconducting coatings is proposed. 14 refs., 7 figs., 2 tabs.

Scanning micro-Hall probe mapping of magnetic flux distributions and current densities in YBa{sub 2}Cu{sub 3}O{sub 7}

Energy Technology Data Exchange (ETDEWEB)

Xing, W.; Heinrich, B. [Simon Fraser Univ., British Columbia (Canada); Zhou, H. [CTF Systems, Inc., British Columbia (Canada)] [and others

1994-12-31

Mapping of the magnetic flux density B{sub z} (perpendicular to the film plane) for a YBa{sub 2}Cu{sub 3}O{sub 7} thin-film sample was carried out using a scanning micro-Hall probe. The sheet magnetization and sheet current densities were calculated from the B{sub z} distributions. From the known sheet magnetization, the tangential (B{sub x,y}) and normal components of the flux density B were calculated in the vicinity of the film. It was found that the sheet current density was mostly determined by 2B{sub x,y}/d, where d is the film thickness. The evolution of flux penetration as a function of applied field will be shown.

Ag screen contacts to sintered YBa/sub 2/Cu/sub 3/O/sub x/ powder for rapid superconductor characterization

International Nuclear Information System (INIS)

Moreland, J.; Goodrich, L.F.

1989-01-01

The authors have developed a new method for making current contacts and voltage taps to YBa/sub 2/Cu/sub 3/O/sub x/ sintered pellets for rapid superconductor characterization. Ag wire screens are interleaved between calcined powder sections and then fired at 930 0 C to form a composite pellet for resistivity and critical current measurements. The Ag diffuses into the powder during the sintering process forming a proximity contact that is permeable to O/sub 2/. Contact surface resistivities (area-resistance product) range from 1 to 10μΩ-cm/sup 2/ at 77 K for the Ag-powder interface. In this configuration, current can be uniformly injected into the ends of the pellet through the bonded Ag screen electrodes. Also, Ag screen voltage contacts, which span a cross section of the pellet, may provide an ideal geometry for detecting voltage drops along the pellet, minimizing current transfer effects

Magnetic and transport properties of YBa{sub 2}Cu{sub 3}O{sub 7} - La{sub 0.7}Ca{sub 0.3}MnO{sub 3} heterostructures

Energy Technology Data Exchange (ETDEWEB)

Mustafa, Luqman

2016-11-25

The exploration of interface properties in complex oxide heterostructures and superlattices is one of the new exciting fields in condensed matter sciences. This is particularly originating from the technological advances in synthesizing heterostructures with atomic scale precision by advanced thin film deposition techniques. There is a plethora of novel achievements culminating in unexpected results, such as generating artificial multifunctional materials with the prominent example of the appearance of interface electrical conductivity and even superconductivity in between insulating films (SrTiO{sub 3} - LaAlO{sub 3}). In this thesis a special case of heterostructures is treated. Here, heterostructures composed of superconducting YBa{sub 2}Cu{sub 3}O{sub 7} and half-metallic ferromagnetic La{sub 2/3}Ca{sub 1/3}MnO{sub 3} are investigated and the interplay of the two long-range antagonistic ordering principles - superconductivity and ferromagnetism - is intended to be studied. Whereas the physics of such structures with the CuO{sub 2} planes of the superconducting YBa{sub 2}Cu{sub 3}O{sub 7} oriented parallel to the substrate plane (i.e. the short coherence length of the superconductor, ξ{sub c} ∝ 0.1 nm is facing the interface perpendicular) has been explored in great detail, little is known in the case of the CuO{sub 2} planes oriented perpendicular to the substrate plane and thus ξ{sub ab} ∝ 1.6 nm is pointing perpendicular to the interface. In the former case, the properties of the heterostructures and superlattices are determined by an interplay of charge transfer and orbital reconstruction, but the mechanisms occurring in the latter case are unknown so far. Prior to elaborated experiments to study the interface properties at an atomistic scale, the technology of fabricating such structures has to be accomplished and their macroscopic properties (structure, transport and magnetic properties) have to be investigated. It is the goal of this thesis to

Critical current through grain boundary of metal oxide superconductors YBa sub 2 Cu sub 3 O sub 7-. delta. Kriticheskij tok cherez granitsu zeren metallooksidnykh sverkhprovodnikov YBa sub 2 Cu3O sub 7-. delta

Energy Technology Data Exchange (ETDEWEB)

Ermolov, S N; Kislov, N A; Marchenko, V A [and others

1989-06-01

Josephson junction with characteristics, corresponding to sandwich type structure is produced at 78 K at the link of large YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} crystallite with fine-grain structure. J{sub c}(H) dependence on the thermomagnetic prehistory is explained with regard to scattering fields of magnetic flux captured by grains.

LaNiO{sub 3} buffer layers for high critical current density YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} and Tl{sub 2}Ba{sub 2}CaCu{sub 2}O{sub 8{minus}{delta}} films

Energy Technology Data Exchange (ETDEWEB)

Carlson, C.M.; Parilla, P.A.; Siegal, M.P.; Ginley, D.S.; Wang, Y.; Blaugher, R.D.; Price, J.C.; Overmyer, D.L.; Venturini, E.L.

1999-10-01

We demonstrate high critical current density superconducting films of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} (YBCO) and Tl{sub 2}Ba{sub 2}CaCu{sub 2}O{sub 8{minus}{delta}} (Tl-2212) using LaNiO{sub 3} (LNO) buffer layers. YBCO films grown on an LNO buffer layer have only a slightly lower J{sub c} (5 K, H=0) than films grown directly on a bare LaAlO{sub 3} substrate. YBCO films grown on LNO buffer layers exhibit minor microstructural disorder and enhanced flux pinning. LNO-buffered Tl-2212 samples show large reductions in J{sub c} at all temperatures and fields compared to those grown on bare LaAlO{sub 3}, correlating to both {ital a}-axis grain and nonsuperconducting phase formation. LNO could be a promising buffer layer for both YBCO and Tl-based superconducting films in coated conductor applications. {copyright} {ital 1999 American Institute of Physics.}

Defect structures in YBa/sub 2/Cu/sub 3/O/sub 7-x/ produced by electron irradiation

International Nuclear Information System (INIS)

Kirk, M.A.; Baker, M.C.; Liu, J.Z.; Lam, D.J.; Weber, H.W.

1988-01-01

Defect structures in YBa/sub 2/Cu/sub 3/O/sub 7-x/ produced by electron irradiation at 300 K were investigated by transmission electron microscopy. Threshold energies for the production of visible defects were determined to be 152 keV and 131 keV (+- 7 keV) in directions near the a and b (b>a) axes (both perpendicular to c, the long axis in the orthorhombic structure), respectively. During above threshold irradiations in an electron flux of 3x10/sup 18/ cm/sup -2/ s/sup -1/, extended defects were observed to form and grow to sizes of 10-50 nm over 1000 s in material thickness 20-200 nm. Such low electron threshold energies suggest oxygen atom displacements with recoil energies near 20 eV. The observation of movement of twin boundaries during irradiation just above threshold suggests movement of the basal plane oxygen atoms by direct displacement or defect migration processes. Crystals irradiated above threshold were observed after about 24 hours to have transformed to a structure heavily faulted on planes perpendicular to the c axis

Substrate decoration for improvement of current-carrying capabilities of YBa{sub 2}Cu{sub 3}O{sub x} thin films

Energy Technology Data Exchange (ETDEWEB)

Khoryushin, Alexey V., E-mail: khoryushin@ya.ru [Department of Physics, Technical University of Denmark, DTU Building 309, Kgs. Lyngby DK-2800 (Denmark); Mozhaev, Peter B.; Mozhaeva, Julia E. [Department of Physics, Technical University of Denmark, DTU Building 309, Kgs. Lyngby DK-2800 (Denmark); Bdikin, Igor K. [Department of Mechanical Engineering, Centre for Mechanical Technology and Automation, University of Aveiro, 3810-193 Aveiro (Portugal); Zhao, Yue [Department of Energy Conversion and Storage, Technical University of Denmark, DK-4000 Roskilde (Denmark); Andersen, Niels H.; Jacobsen, Claus S.; Hansen, Jørn Bindslev [Department of Physics, Technical University of Denmark, DTU Building 309, Kgs. Lyngby DK-2800 (Denmark)

2013-03-15

Highlights: ► Effects of substrate decoration on properties of YBCO thin films were studied. ► Y{sub 2}O{sub 3} nanoparticles, ultra-thin Y{sub 2}O{sub 3} and Y:ZrO{sub 2} layers were used as decoration layer. ► Decoration improves j{sub C} (5 T and 50 K) up to 0.97 MA/cm{sup 2} vs. 0.76 MA/cm{sup 2} for a reference film. ► Ultra-thin layer of yttria and yttria nanoparticles have a similar effect on YBCO. ► Y{sub 2}O{sub 3} decoration results in power law coefficient α = 0.3 vs. α = 0.4 for a reference film. -- Abstract: The effects of substrate decoration with yttria and Y:ZrO{sub 2} on the structural and electrical properties of the YBa{sub 2}Cu{sub 3}O{sub x} (YBCO) thin films are studied. The films were deposited on (LaAlO{sub 3}){sub 3}–(Sr{sub 2}AlTaO{sub 8}){sub 7} substrates by pulsed laser deposition. Two different structures of decoration layer were applied, a template layer of nanoparticles and an uniform ultra-thin layer. Significant improvement of current-carrying capabilities was observed, especially at high external magnetic fields. Structural studies of these films reveal the presence of extended linear defects in the YBCO matrix. The formation of these structures is attributed to seeding of randomly oriented YBCO grains due to suppression of epitaxy in the very beginning of the deposition. The films of both kinds of decoration layers show nearly the same improvement of j{sub C} over the reference film at 77 and 50 K: j{sub C} (5T and 50 K) reaches 0.92 and 0.97 MA/cm{sup 2} for uniform and template decoration layers. At 5 and 20 K the effect of template decoration layers is more beneficial: j{sub C} (5T and 20 K) values are 3.5 and 4.1 MA/cm{sup 2}, j{sub C} (5T and 5 K) values are 6.4 and 7.9 MA/cm{sup 2}, for uniform and template decoration layers, respectively.

Paramagnetic moments in YBa{sub 2}Cu{sub 3}O{sub 7−δ} nanocomposite films

Energy Technology Data Exchange (ETDEWEB)

Dias, F.T.; Vieira, V.N.; Silva, D.L. [Instituto de Física e Matemática, Universidade Federal de Pelotas, C.P. 354, 96010-900 Pelotas, RS (Brazil); Albino Aguiar, J. [Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil); Programa de Pós-Graduação em Ciência de Materiais, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil); Valadão, D.R.B., E-mail: danielavaladao.ufpe@gmail.com [Programa de Pós-Graduação em Ciência de Materiais, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil); Obradors, X.; Puig, T. [Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, Campus U.A. Barcelona, 08193 Bellaterra (Spain); Wolff-Fabris, F.; Kampert, E. [Dresden High Magnetic Field Laboratory, HZ Dresden-Rossendorf , 01314 Dresden (Germany)

2014-08-15

Highlights: • The paramagnetic Meissner effect was observed in a nanocomposite YBaCuO thin film. • The paramagnetic moments in FC experiments were observed up to 10 T. • The paramagnetic Meissner effect increases when the magnetic field is increased. • Results may be explained based on the flux compression scenario and vortex pinning. • An apparent saturation tendency of the paramagnetic moments could be observed. - Abstract: We report on magnetization studies in YBa{sub 2}Cu{sub 3}O{sub 7−δ} thin films with dispersed Ba{sub 2}YTaO{sub 6} nanoparticles. The magnetization measurements were made using a superconducting quantum interference device (SQUID) and a vibrating sample magnetometer (VSM). Magnetic moments were measured as functions temperature using zero-field cooling (ZFC) and field-cooled (FC) prescriptions for magnetic fields up to 10 T applied parallel and perpendicular to the ab planes. A paramagnetic response related to the superconducting state was observed during the FC experiments. This effect, known as paramagnetic Meissner effect (PME), apparently increases when the magnetic field is increased. We discuss our PME results in terms of the strong pinning scenario modulated by Ba{sub 2}YTaO{sub 6} nanoparticles dispersed into the superconducting matrix.

Studies of YBa{sub 2}Cu{sub 3}O{sub 6+x} degradation and surface conductivity properties by Scanning Spreading Resistance Microscopy

Energy Technology Data Exchange (ETDEWEB)

Truchly, Martin, E-mail: martin.truchly@fmph.uniba.sk [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, 84248 Bratislava (Slovakia); Plecenik, Tomas; Krsko, Ondrej; Gregor, Maros; Satrapinskyy, Leonid; Roch, Tomas; Grancic, Branislav; Mikula, Marian [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, 84248 Bratislava (Slovakia); Dujavova, Agata; Chromik, Stefan [Institute of Electrical Engineering, Slovak Academy of Sciences, 84104 Bratislava (Slovakia); Kus, Peter; Plecenik, Andrej [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, 84248 Bratislava (Slovakia)

2012-12-14

Local surface conductivity properties and surface degradation of c-axis oriented YBa{sub 2}Cu{sub 3}O{sub 6+x} (YBCO) thin films were studied by Scanning Spreading Resistance Microscopy (SSRM). For the surface degradation studies, the YBCO surface was cleaned by ion beam etching and the SSRM surface conductivity map has been subsequently repeatedly measured over several hours in air and pure nitrogen. Average surface conductivity of the scanned area was gradually decreasing over time in both cases, faster in air. This was explained by oxygen out-diffusion in both cases and chemical reactions with water vapor in air. The obtained surface conductivity images also revealed its high inhomogenity on micrometer and nanometer scale with numerous regions of highly enhanced conductivity compared to the surroundings. Furthermore, it has been shown that the size of these conductive regions considerably depends on the applied voltage. We propose that such inhomogeneous surface conductivity is most likely caused by varying thickness of degraded YBCO surface layer as well as varying oxygen concentration (x parameter) within this layer, what was confirmed by scanning Auger electron microscopy (SAM). In our opinion the presented findings might be important for analysis of current-voltage and differential characteristics measured on classical planar junctions on YBCO as well as other perovskites.

Microstructural and compositional analysis of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} films grown by MOCVD before and after GCIB smoothing

Energy Technology Data Exchange (ETDEWEB)

Hatzistergos, M.S.; Efstathiadis, H.; Reeves, J.L.; Selvamanickam, V.; Allen, L.P.; Lifshin, E.; Haldar, P

2004-06-15

The microstructural and compositional evolution of thick (>1 {mu}m) high temperature superconducting YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) films grown on single crystal SrTiO{sub 3} substrates by the metal organic chemical vapor deposition (MOCVD) process was investigated by focused ion beam microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and atomic force microscopy. This study showed that as the MOCVD YBCO film thickness increased above 0.5 {mu}m, defects such as second phase particles, pores, and misaligned grains preferentially nucleated and grew at the YBCO surface. A portion of this defective top layer was eliminated from all the samples using a gas cluster ion beam (GCIB) process that first removed material with a focused argon cluster beam. Next, an oxygen cluster beam was used to smooth the surface and re-oxygenate the YBCO. Comparing the critical current (I{sub c}) measured before and after GCIB processing showed that the I{sub c} remained the same, and even improved, when part of the defective top layer was removed. This microstructural and electromagnetic 'dead layer' is believed to be responsible for the overall I{sub c} decrease of MOCVD YBCO films thicker than 0.5 {mu}m.

Thin film YBa{sub 2}Cu{sub 3}O{sub 7} junctions with La{sub 2/3}Ca{sub 1/3}MnO{sub 3} barrier

Energy Technology Data Exchange (ETDEWEB)

Hepting, Matthias; Stoehr, Andreas; Werner, Robert; Kleiner, Reinhold; Koelle, Dieter [Physikalisches Institut - Experimentalphysik II and Center for Collective Quantum Phenomena in LISAplus, Universitaet Tuebingen, Auf der Morgenstelle 14, 72076 Tuebingen (Germany)

2012-07-01

We report on the fabrication and electric transport properties of thin film YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) junctions with La{sub 2/3}Ca{sub 1/3}MnO{sub 3} (LCMO) barrier. Heteroepitaxial YBCO/LCMO/YBCO multilayers were grown in-situ by pulsed laser deposition and subsequently patterned by photolithography and Ar ion milling to form rectangular junctions with typical area 5 {mu}m x 30 {mu}m. A self-alignment process was used for electrical contact via an Au wiring layer to the upper YBCO electrode, similarly as described. Samples were characterized at temperature T=4.2 K either in magnetically shielded environment or in in-plane magnetic fields B up to the Tesla range. We present and discuss current-voltage-characteristics and measurements of critical current vs B.

Growth of simplified buffer template on flexible metallic substrates for YBa{sub 2}Cu{sub 3}O{sub 7-δ} coated conductors

Energy Technology Data Exchange (ETDEWEB)

Xue, Yan; Zhang, Ya-Hui; Zhang, Fei; Zhao, Rui-Peng [State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054 (China); Wang, Hui [Applied Research Laboratory of Superconduction and New Material, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, 100190 (China); Xiong, Jie, E-mail: jiexiong@uestc.edu.cn [State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054 (China); Tao, Bo-Wan [State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054 (China)

2016-07-15

A much simplified buffer structure, including a three-layer stack of LaMnO{sub 3}/MgO/composite Y{sub 2}O{sub 3}–Al{sub 2}O{sub 3}, was proposed for high performance YBa{sub 2}Cu{sub 3}O{sub 7-δ} (YBCO) coated conductors. In this structure, biaxially textured MgO films were prepared on solution deposition planarized amorphous substrate through ion-beam-assisted deposition (IBAD) technology. By the use of in situ reflection high-energy electron diffraction monitor, X-ray diffraction and atomic force microscope, the influence of deposition parameters, such as film deposition rate, ion penetrate energy and ion beam flux, on crystalline orientation, texture, lattice parameter and surface morphology was systematically investigated. Moreover, stopping and range of ion in mater simulation was performed to study the effects of ion bombardment on MgO films. By optimizing IBAD process parameters, the best biaxial texture showed ω-scan of (002) MgO and Φ-scan of (220) MgO yield full width at half maximum values of 2.4° and 3.7°, indicating excellent biaxial texture. Subsequently, LaMnO{sub 3} films were directly deposited on the IBAD-MgO template to improve the lattice mismatch between MgO and YBCO. Finally, YBCO films grown on this simplified buffer template exhibited a critical current density of 2.4 MA/cm{sup 2} at 77 K and self-field, demonstrating the feasibility of this buffer structure. - Highlights: • Simplified buffer structure for YBCO coated conductors. • Growth of biaxially textured MgO films on flexible amorphous substrates. • Studying the influence of film deposition rate, ion energy and ion beam flux on the development of biaxial texture. • Demonstrating highly oriented YBCO films with a critical current density of 2.4 MA/cm{sup 2} at self-field and 77 K.

YBa{sub 2}Cu{sub 3}O{sub 7} microwave resonators for strong collective coupling with spin ensembles

Energy Technology Data Exchange (ETDEWEB)

Ghirri, A., E-mail: alberto.ghirri@nano.cnr.it [Istituto Nanoscienze - CNR, Centro S3, via Campi 213/a, 41125 Modena (Italy); Bonizzoni, C.; Affronte, M. [Dipartimento Fisica, Informatica e Matematica, Università di Modena e Reggio Emilia and Istituto Nanoscienze - CNR, Centro S3, via Campi 213/a, 41125 Modena (Italy); Gerace, D.; Sanna, S. [Dipartimento di Fisica, Università di Pavia, via Bassi 6, 27100 Pavia (Italy); Cassinese, A. [CNR-SPIN and Dipartimento di Fisica, Università di Napoli Federico II, 80138 Napoli (Italy)

2015-05-04

Coplanar microwave resonators made of 330 nm-thick superconducting YBa{sub 2}Cu{sub 3}O{sub 7} have been realized and characterized in a wide temperature (T, 2–100 K) and magnetic field (B, 0–7 T) range. The quality factor (Q{sub L}) exceeds 10{sup 4} below 55 K and it slightly decreases for increasing fields, remaining 90% of Q{sub L}(B=0) for B = 7 T and T = 2 K. These features allow the coherent coupling of resonant photons with a spin ensemble at finite temperature and magnetic field. To demonstrate this, collective strong coupling was achieved by using di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium organic radical placed at the magnetic antinode of the fundamental mode: the in-plane magnetic field is used to tune the spin frequency gap splitting across the single-mode cavity resonance at 7.75 GHz, where clear anticrossings are observed with a splitting as large as ∼82 MHz at T = 2 K. The spin-cavity collective coupling rate is shown to scale as the square root of the number of active spins in the ensemble.

Rapid processing method for solution deposited YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} thin films

Energy Technology Data Exchange (ETDEWEB)

Dawley, J.T.; Clem, P.G.; Boyle, T.J.; Ottley, L.M.; Overmyer, D.L.; Siegal, M.P

2004-02-01

YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) films, deposited on buffered metal substrates, are the primary candidate for second-generation superconducting (SC) wires, with applications including expanded power grid transmission capability, compact motors, and enhanced sensitivity magnetic resonance imaging. Feasibility of manufacturing such superconducting wires is dependent on high processing speed, often a limitation of vapor and solution-based YBCO deposition processes. In this work, YBCO films were fabricated via a new diethanolamine-modified trifluoroacetic film solution deposition method. Modifying the copper chemistry of the YBCO precursor solution with diethanolamine enables a hundredfold decrease in the organic pyrolysis time required for MA/cm{sup 2} current density (J{sub c}) YBCO films, from multiple hours to {approx}20 s in atmospheric pressure air. High quality, {approx}0.2 {mu}m thick YBCO films with J{sub c} (77 K) values {>=}2 MA/cm{sup 2} at 77 K are routinely crystallized from these rapidly pyrolyzed films deposited on LaAlO{sub 3}. This process has also enabled J{sub c} (77 K)=1.1 MA/cm{sup 2} YBCO films via 90 m/h dip-coating on Oak Ridge National Laboratory RABiTS textured metal tape substrates. This new YBCO solution deposition method suggests a route toward inexpensive and commercializable {approx}$10/kA m solution deposited YBCO coated conductor wires.

Mesoscopic conductance fluctuations in high-T{sub c} grain boundary Josephson junctions: Coherent quasiparticle transport

Energy Technology Data Exchange (ETDEWEB)

Tafuri, F. [Dip. Ingegneria dell' Informazione, Seconda Universita di Napoli, 81031 Aversa (Italy); CNR-INFM Coherentia, Dip. Scienze Fisiche, Universita di Napoli Federico II, 80125 Naples (Italy)], E-mail: tafuri@na.infn.it; Tagliacozzo, A.; Born, D.; Stornaiuolo, D. [CNR-INFM Coherentia, Dip. Scienze Fisiche, Universita di Napoli Federico II, 80125 Naples (Italy); Gambale, E.; Dalena, D. [Dip. Ingegneria dell' Informazione, Seconda Universita di Napoli, 81031 Aversa (Italy); Lombardi, F. [Department of Microelectronics and Nanoscience, MINA, Chalmers University of Technology, 41296 Goeteborg (Sweden)

2007-09-01

Magneto-fluctuations of the normal resistance R{sub N} have been reproducibly observed in YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (HTS) biepitaxial grain boundary junctions at low temperatures. We attribute them to mesoscopic transport in narrow channels across the grain boundary line. The Thouless energy appears to be the relevant energy scale. Possible implications on the understanding of coherent transport of quasiparticles in HTS and of the dissipation mechanisms are discussed.

Shielded high-T{sub c} (Bi, Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub y} (Bi-2223) superconducting tapes

Energy Technology Data Exchange (ETDEWEB)

Lelovic, M.; Eror, N.G. [Department of Materials Science, University of Pittsburgh, Pittsburgh, PA (United States); Balachandran, U.; Prorok, B. [Energy Technology Division, Argonne National Laboratory, Argonne, IL (United States); Selvamanickam, V.; Haldar, P. [Intermagnetics General Corporations, Latham, NY (United States); Talvacchio, J.; Young, R. [Science and Technology Center, Northrop Grumman, Pittsburgh, PA (United States)

1998-11-01

A new composite tape was fabricated in which the primary function of the central Ag-sheathed (Bi, Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub y} (Bi-2223) filaments was to conduct transport current. A YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (Y-123) thin film was deposited on the top of the Ag-sheathed Bi-2223 tape to shield the applied magnetic field and to protect the central Bi-2223 filaments. The critical current densities of the Y-123-coated, Ag-sheathed Bi-2223 tapes were better than those of an uncoated tape. However, the Y-123 thin film exhibited T{sub c} approx.= 72 K and a broad transition region that shifted the effect to lower temperatures. Furthermore, pole figure measurements showed widely spread a,b planes along the rolling direction, indicating high-angle grain boundaries that diminished the magnitude of the effect. Microstructural observations showed platelike grains of Y-123 with fine growth ledges in the thin film that was heat treated, in contrast with the microstructure of an as-coated thin film that showed large twinned grains. From the processing point of view, the results showed that heat treating Y-123 thin film according to the Bi-2223 tape schedule was compatible with and beneficial for Y-123. These preliminary results may provide a basis for further improvements in processing of long-length Bi-2223 tapes for high-field applications. (author)

Morphology, structure, and electrical properties of YBa{sub 2}Cu{sub 3}O{sub x} thin films on tilted NdGaO{sub 3} substrates, deposited by DC-sputtering

Energy Technology Data Exchange (ETDEWEB)

Mozhaev, Peter B. [Institute of Radio Engineering and Electronics RAS, Moscow 125009 (Russian Federation)]. E-mail: pbmozh@nm.ru; Kotelyanskii, Iosif M. [Institute of Radio Engineering and Electronics RAS, Moscow 125009 (Russian Federation); Luzanov, Valery A. [Institute of Radio Engineering and Electronics RAS, Moscow 125009 (Russian Federation); Mozhaeva, Julia E. [Institute of Radio Engineering and Electronics RAS, Moscow 125009 (Russian Federation); Donchev, Todor [Institute of Electronics BAS, Sofia (Bulgaria); Mateev, Emil [Institute of Electronics BAS, Sofia (Bulgaria); Nurgaliev, Timur [Institute of Electronics BAS, Sofia (Bulgaria); Bdikin, Igor K. [Institute of Solid State Physics RAS, Chernogolovka, Moscow 142432 (Russian Federation); Department of Ceramic and Glass Engineering, CICECO, University of Aveiro, Aveiro 3810-193 (Portugal); Narymbetov, Bakhyt Zh. [Complex Institute of Natural Sciences UzAS, Nukus (Uzbekistan)

2005-02-15

Thin YBa{sub 2}Cu{sub 3}O{sub x} (YBCO) films were deposited using DC-sputtering technique on NdGaO{sub 3} substrates, tilted from (1 1 0) orientation by 0-26 deg . The structure and surface quality of the substrates were carefully characterized to obtain reliable results of thin films deposition. Structural, morphological and electrical properties of the YBCO thin films show three different ranges of inclination angle: vicinal, intermediate and high. In the vicinal range the properties of the film are generally the same as of the standard films deposited on (1 1 0) NdGaO{sub 3} substrate. An increase of the inclination angle to the intermediate range results in a significant improvement of morphology and structural quality of the film. Best electrical parameters are measured for the films of the intermediate range also. Probable reason for such behavior is simultaneous and regular seeding of the film in the joints of facets on the substrate surface. Further increase of inclination angle leads to step bunching and oxygen out-diffusion, destroying both structural and electrical perfection of the tilted-axes YBCO film.

Raman study of the effect of water vapor during low-temperature annealing on the structure and electrophysical properties of YBa{sub 2}Cu{sub 3}O{sub y}

Energy Technology Data Exchange (ETDEWEB)

Bobylev, I.B., E-mail: bobylev@imp.uran.ru; Ponosov, Yu.S.; Zyuzeva, N.A.

2015-11-01

The effects of an interaction of YBa{sub 2}Cu{sub 3}O{sub y} (123) with water vapors at a temperature 200 °C on the structure and electrophysical properties of the compound have been examined by Raman spectroscopy. It has been found that the penetration of water into the 123-type causes the transition of the compound from an oxide to a hydride-oxide-hydroxide, which is accompanied with transformation to the 124 pseudotype phase. Direct evidence has been obtained for the incorporation of OH{sup −}-groups in the 123-structure. After the interaction with water, the materials with high oxygen content (y ≥ 6.5) retain their superconductivity and exhibit two-magnon scattering in Raman spectra, which is not typical for them. Short-term recovery annealing followed by oxidation removes the water from the compound structure, which leads to the disappearance of the spin fluctuation spectra. At the same time, the structural defects are partially preserved. These manifest themselves through some peculiarities in the Raman spectra and are apparently pinning centers of magnetic vortices. A model of a splitting of the Cu–O chains and a formation of the 124-like phase in water-intercalated 123-structure has been proposed. This mechanism supposes the dissociation of the OH{sup −}-groups and the filling in the copper vacancies by protons. - Highlights: • Absorbing water at 200 °C, the Y-123 ceramics transforms to H{sub x}YBa{sub 2}Cu{sub 3}O{sub y}(OH){sub z}. • The incorporation of water in the Y-123 (y ≥ 6.5) leads to the well magnetic peak. • For the Y-123 with y < 6.5 the OH{sup −}-groups occupy the vacancies of several types. • The OH{sup −}-groups are oriented along the c-axis.

Optical characterization of YBa{sub 2}Cu{sub 3}O{sub 7−δ} thin film modified gold nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Naujok, P.; Katzer, C. [Friedrich Schiller University Jena, Institute of Solid State Physics, Helmholtzweg 5, 07743 Jena (Germany); Schmidl, G., E-mail: gabriele.schmidl@ipht-jena.de [Leibniz Institute of Photonic Technology (IPHT), Albert-Einstein-Straße 9, 07745 Jena (Germany); Jatschka, J.; Fritzsche, W. [Leibniz Institute of Photonic Technology (IPHT), Albert-Einstein-Straße 9, 07745 Jena (Germany); Schmidl, F. [Friedrich Schiller University Jena, Institute of Solid State Physics, Helmholtzweg 5, 07743 Jena (Germany)

2015-12-01

Highlights: • Different thick YBCO layers allow an active control of particle sizes and density distributions on film surfaces. • The gold volume on the YBCO film surface decreases with increasing YBCO layer thickness. • Combining SEM and dark-field microscopy via image processing. • Clear correlation of scattering spectrum and addressed particles supporting by a new Ti-marker technology. - Abstract: We report on the influence of YBa{sub 2}Cu{sub 3}O{sub 7−δ} (YBCO) thin films on the self-organized formation of gold nanoparticles. A thickness variation of the YBCO film allows one to actively control the size of the particles and their density distribution. In this context, the particle forming process is discussed. The YBCO matrix can be removed in order to reduce the particle density on the substrate. The remaining modified particles can be used in plasmonic applications. Combining scanning electron microscopy and dark-field microscopy permits one to identify a correlation of the measured scattering spectra with the physical properties of each studied particle. A clear assignment of spectrum and particle is supported by a new Ti-marker technology and image processing. Growth parameters allow the scientist to tune the spectral peak position of the plasmon resonance and the spectral bandwidth.

Microstructure and properties of in-situ rf sputtered YBa{sub 2}Cu{sub 3}O{sub 7} thin films for microwave applications

Energy Technology Data Exchange (ETDEWEB)

Reagor, D.W.; Houlton, R.J.; Garzon, F.H.; Hawley, M.; Raistrick, I.D. [Los Alamos National Lab., NM (United States); Piza, M.E. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science

1992-06-01

The residual surface resistance of a number of films of YBa{sub 2}Cu{sub 3}O{sub 7}, prepared by off-axis sputtering onto MgO substrates, has been measured using parallel-plate resonator technique. Deposition conditions were kept constant, apart from the substrate temperature. There is no correlation between surface resistance and other important microscopic parameters, such as T{sub c} and c-axis lattice parameter. There is, however, a trend to higher R{sub s} with increasing volume fraction of in-plane misoriented material, although the correlation is not perfect. Furthermore, we have found that most of the misoriented material is localized at the film substrate interface and therefore is probably not responsible for most of the RF losses. The data suggest that at higher deposition temperatures, there is an increasing tendency for 45{degrees}-misoriented material to appear in the films, and it may be that a significant fraction of this material is present closer to the free film surface. STM qualitatively supports this conclusion.

High field magneto-transport study of YBa{sub 2}Cu{sub 3}O{sub 7}:Ag{sub x} (x = 0.00–0.20)

Energy Technology Data Exchange (ETDEWEB)

Rani, Poonam; Pal, Anand; Awana, V.P.S, E-mail: awana@mail.npindia.org

2014-02-15

Highlights: •YBCO: Ag{sub x} composites. •High field magneto-transport. •The upper critical field. -- Abstract: We report high field (up to 13 T) magneto transport [ρ(T)H] of YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO):Ag{sub x} (x = 0.0, 0.1 and 0.2) composites. The transport properties are significantly improved by Ag doping on the insulating grain boundaries of YBCO. Pure and Ag diffused YBCO superconducting samples are synthesised through solid state reaction route. Both pure and Ag doped YBCO are superconducting at below 90 K. Though, the T{sub c} (ρ = 0) of YBCO:Ag samples under applied field of 13 T is around 65 K, the same is 45 K for pure YBCO under same applied field. The upper critical field [H{sub c2}(0)], being estimated from ρ(T)H is around 70 T for pristine sample, and is above 190 T for Ag doped samples. The boarding of the resistive transition under applied magnetic field is comparatively less and nearly single step for Ag doped samples, while the same is clearly two step and relatively much larger for the pristine YBCO. The resistive broadening is explained on the basis of changed inter-granular coupling and thermally activated flux flow (TAFF). The TAFF activation energy (U{sub 0}) is found to be linear with applied magnetic field for all the samples, but with nearly an order of magnitude less value for the Ag doped samples. Summarily, it is shown that inclusion of Ag significantly improves the superconducting performance of YBCO:Ag composites, in particular under applied field.

Thermally activated phase slippage in high- T sub c grain-boundary Josephson junctions

Energy Technology Data Exchange (ETDEWEB)

Gross, R.; Chaudhari, P.; Dimos, D.; Gupta, A.; Koren, G. (IBM Thomas J. Watson Research Center, P.O. Box 218, Yorktown Heights, New York 10598 (USA))

1990-01-08

The effect of thermally activated phase slippage (TAPS) in YBa{sub 2}Cu{sub 3}O{sub 7} grain-boundary Josephson junctions has been studied. TAPS has been found to be responsible for the dc noise voltage superimposed on the dc Josephson current near the transition temperature. Because of the reduced Josephson coupling energy of the grain-boundary junctions, which is caused by a reduced superconducting order parameter at the grain-boundary interface, TAPS is present over a considerable temperature range. The implications of TAPS on the applicability of high-{ital T}{sub {ital c}} Josephson junctions are outlined.

Study of the halogenation of EuBa[sub 2]Cu[sub 3]O[sub 6]. Etude de l'halogenation de EuBa[sub 2]Cu[sub 3]O[sub 6

Energy Technology Data Exchange (ETDEWEB)

Kabeya, D.T. (Rennes-1 Univ., 35 (France). Lab. de Chimie du Solide et Inorganique Moleculaire); Mokhtari, M. (Rennes-1 Univ., 35 (France). Lab. de Chimie du Solide et Inorganique Moleculaire); Perrin, C. (Rennes-1 Univ., 35 (France). Lab. de Chimie du Solide et Inorganique Moleculaire); Sergent, M. (Rennes-1 Univ., 35 (France). Lab. de Chimie du Solide et Inorganique Moleculaire); Grushko, Yu. (Russian Academy of Sciences, Gatchina (Russian Federation). Nuclear Physics Inst.); Kokovina, L. (Russian Academy of Sciences, Gatchina (Russian Federation). Nuclear Physics Inst.); Rozhniakova, N. (Russian Academy of Sciences, Gatchina (Russian Federation). Nuclear Physics Inst.)

1994-11-01

Sintered samples of EuBa[sub 2]Cu[sub 3]O[sub 6] have been halogenated at low temperature (t<300 C) by treatments under NF[sub 3] or CCl[sub 4] flow diluted in nitrogen, or by reaction with iodine in sealed tubes. Such mild conditions of synthesis allowed to avoid the decomposition of the material during the reactions. The incorporation of the halogen in the sample has been evidenced by the weight gain, by the evolution of the unit-cell parameters and by SEM and EDS analyses. After fluorination and chlorination, the samples become superconducting, but no superconducting behaviour is observed after iodination. These results are compared to the ones previously obtained during the halogenation of YBa[sub 2]Cu[sub 3]O[sub 6]. (orig.).

One-step chemical bath deposition and photocatalytic activity of Cu{sub 2}O thin films with orientation and size controlled by a chelating agent

Energy Technology Data Exchange (ETDEWEB)

Xu, HaiYan, E-mail: xuhaiyan@ahjzu.edu.cn; Dong, JinKuang, E-mail: dongjinkuang1988@126.com; Chen, Chen, E-mail: 13865901653@139.com

2014-01-15

Nanocrystalline cuprous oxide (Cu{sub 2}O) thin films were prepared via a one-step chemical bath deposition (CBD) method. The effects of a chelating agent on the orientation, morphology, crystallite size, and photocatalytic activity of the thin films were carefully examined using X-ray diffractometry, scanning electron microscopy, and UV–vis spectrophotometry. The results confirmed that the crystallite size as well as the orientation of the films was dependent on the volume of trisodium citrate (TSC), demonstrating that the band gap ranged from 2.71 eV to 2.49 eV. The morphology and number density of the thin films also depended on the volume of TSC. In addition, the obtained Cu{sub 2}O thin films could degrade methyl orange (MO) efficiently in the presence of H{sub 2}O{sub 2} under visible-light irradiation, and the mechanism for the enhanced photocatalytic activity of the Cu{sub 2}O thin films with the assistance of H{sub 2}O{sub 2} was also explored in detail. - Graphical abstract: Nano-structured Cu{sub 2}O thin films have been prepared by a one-step chemical bath deposition method. The number density, crystallite size, surface morphology and orientation of these thin films could be tailored by chelating agent. The results confirmed that the crystallite size as well as the orientation of the thin films was dependent on the volume of TSC, showed that the band gap ranged from 2.71 eV to 2.49 eV. The formation mechanism of the Cu{sub 2}O particles could be illuminated by an oriented attachment mode. In addition, the obtained Cu{sub 2}O thin films degraded methyl orange efficiently in the presence of H{sub 2}O{sub 2} under the irradiation of visible light, and the mechanism for photocatalytic reaction was also discussed in detail. - Highlights: • Oriented Cu{sub 2}O thin films were prepared by one-step chemical bath deposition. • Orientation and crystallite size were dependent on trisodium citrate volume. • The enhanced visible light degradation mechanism

3d-metal doping (Fe,Co,Ni,Zn) of the high T/sub c/ perovskite YBa/sub 2/Cu/sub 3/O/sub 7-y/

International Nuclear Information System (INIS)

Tarascon, J.M.; Barboux, P.; Greene, L.H.; Hull, G.W.; Bagley, B.G.

1988-01-01

The structural, magnetic and superconducting properties of the mixed compounds YBa/sub 2/Cu/sub 3-x/M/sub x/O/sub 7-y/ (M = Ni, Zn, Fe and Co) are reported. Values of y, determined by titration, are found to be dependent on the nature and amount of the doping. The range of solubility is greater for the Fe and Co compounds (chi = 1) than for those with Ni or Zn (chi = 0.3). The undoped material is orthorhombic and remains orthorhombic after substitution for Cu by Ni or Zn, whereas a tetragonal phase is observed when Fe, Co are substituted for Cu. DC resistance and AC susceptibility measurements show that T/sub c/ is depressed from 90K (chi = 0) to 45K (chi = 0.2) for both the Ni and Zn doped compounds and T/sub c/ is destroyed in the Fe and Co doped compounds when chi reaches 0.4. The authors suggest that a valance of 2 be assigned to the Ni and Zn and 3 to the Fe and Co ions

Evolution of the specific-heat anomaly of the high-temperature superconductor YBa{sub 2}Cu{sub 3}O{sub 7} under the influence of doping through application of pressure up to 10 GPa

Energy Technology Data Exchange (ETDEWEB)

Lortz, Rolf [Department of Condensed Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, CH-1211 Geneva 4 (Switzerland); Junod, Alain [Department of Condensed Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, CH-1211 Geneva 4 (Switzerland); Jaccard, Didier [Department of Condensed Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, CH-1211 Geneva 4 (Switzerland); Wang, Yuxing [Department of Condensed Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, CH-1211 Geneva 4 (Switzerland); Meingast, Christoph [Forschungszentrum Karlsruhe, Institut fuer Festkoerperphysik, 76021 Karlsruhe (Germany); Masui, Takahiko [Superconductivity Research Laboratory-ISTEC, 10-13 Shinonome I-Chome, Koto-ku, Tokyo 135 (Japan); Tajima, Setsuko [Superconductivity Research Laboratory-ISTEC, 10-13 Shinonome I-Chome, Koto-ku, Tokyo 135 (Japan)

2005-07-06

The evolution of the specific-heat anomaly in the overdoped range of a single crystal of the high-temperature superconductor YBa{sub 2}Cu{sub 3}O{sub 7} has been studied under the influence of pressure up to 10 GPa, using AC calorimetry in a Bridgman-type pressure cell. We show that the specific-heat jump as well as the bulk T{sub c} are reduced with increasing pressure in accordance with a simple charge-transfer model. This new method enables us through pressure-induced charge transfer to study the doping dependence of the superconducting transition, as well as the evolution of the superconducting condensation energy on a single stoichiometric sample without adding atomic disorder.

Record critical current densities in IG processed bulk YBa{sub 2}Cu{sub 3}O{sub y} fabricated using ball-milled Y{sub 2}Ba{sub 1}Cu{sub 1}O{sub 5} phase

Energy Technology Data Exchange (ETDEWEB)

Muralidhar, Miryala; Kenta, Nakazato; Murakami, Masato [Department of Materials Science and Engineering, Superconducting Materials Laboratory, Shibaura Institute of Technology, Tokyo (Japan); Zeng, XianLin; Koblischka, Michael R. [Institute of Experimental Physics, Saarland University, Saarbruecken (Germany); Diko, Pavel [Institute of Experimental Physics, Material Physics Laboratory, Slovak Academy of Sciences, Kosice (Slovakia)

2016-02-15

The infiltration-growth (IG) technique enables the uniform and controllable Y{sub 2}BaCuO{sub 5} (Y211) secondary phase particles formation within the YBa{sub 2}Cu{sub 3}O{sub y} (Y123) matrix. Recent results clarified that the flux pinning performance of the Y123 material was dramatically improved by optimizing the processing conditions during the IG process. In this paper, we adapted the IG technique and produced several samples with addition of nanometer-sized Y211 secondary phase particles, which were produced by a ball milling technique. We found that the performance of the IG processed Y123 material dramatically improved in the low field region for a ball milling time of 12 h as compared to the samples without a ball milling step. Magnetization measurements showed a sharp superconducting transition with an onset T{sub c} at around 92 K. The critical current density (J{sub c}) at 77 K and zero field was determined to be 224 022 Acm{sup -2}, which is higher than the not ball-milled sample. Furthermore, microstructural observations exhibited a uniform microstructure with homogenous distribution of nanosized Y-211 inclusions within the Y-123 matrix. The improved performance of the Y-123 material can be understood in terms of fine distribution of the secondary phases. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Weakening of thickness dependence of J{sub C} in YBa{sub 2}Cu{sub 3}O{sub 7-δ} films using a titanium-added MOD precursor solution

Energy Technology Data Exchange (ETDEWEB)

Zhang, H.L., E-mail: zhanghuiliang@mail.iee.ac.cn [Key Laboratory of Applied Superconductivity, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); School of Science, Hebei University of Engineering, Handan 056038 (China); Ding, F.Z., E-mail: dingfazhu@mail.iee.ac.cn [Key Laboratory of Applied Superconductivity, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Gu, H.W., E-mail: guhw@mail.iee.ac.cn [Key Laboratory of Applied Superconductivity, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Dong, Z.B. [Key Laboratory of Applied Superconductivity, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Qu, F.; Zhang, H.; Shang, H.J. [Key Laboratory of Applied Superconductivity, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China)

2017-04-15

Highlights: • The thickness dependence of J{sub C} in YBCO film was weakened by introducing BaTiO{sub 3} nanoparticles into YBCO matrix. • The high I{sub C} value of 430 MA/cm-width was obtained in the BaTiO{sub 3}-doped YBCO film prepared by the MOD method. • The YBCO composite thick film prepared by using the precursor solution with polyethyleneglycol shows a compact and smooth surface. - Abstract: BaTiO{sub 3} (BTO)-doped YBa{sub 2}Cu{sub 3}O{sub 7-δ} (YBCO) films were prepared by the metal-organic deposition method using a precursor solution with titanium ion. These YBCO films were deposited on (00l)-oriented LaAlO{sub 3} single-crystal substrates using an automated dip coater. The thickness dependence of critical current density (J{sub C}) in the BTO-doped YBCO films was investigated. The J{sub C} value of the YBCO composite film was reduced from 6.3 to 4.6 MA/cm{sup 2} with increasing film thickness from 450 to 930 nm in self-filed at 77 K, which arose mainly from degradation of texture and roughening of the film. However, relative to undoped YBCO thick films, J{sub C} values of the YBCO composite thick films were greatly improved, and more importantly, the reduction in J{sub C} with increasing film thickness was hindered, especially in a high magnetic field. This result indicated that the introduction of BTO nanoparticles as pinning centers into YBCO matrix weakened the thickness dependence of J{sub C}.

Progress towards all-chemical superconducting YBa{sub 2}Cu{sub 3}O{sub 7}-coated conductors

Energy Technology Data Exchange (ETDEWEB)

Obradors, X [Institut de Ciencia de Materials de Barcelona, CSIC Campus de la UAB, 08193 Bellaterra (Spain); Puig, T [Institut de Ciencia de Materials de Barcelona, CSIC Campus de la UAB, 08193 Bellaterra (Spain); Pomar, A [Institut de Ciencia de Materials de Barcelona, CSIC Campus de la UAB, 08193 Bellaterra (Spain)

2006-03-15

Chemical solution deposition (CSD) has recently emerged as a very competitive technique for obtaining epitaxial films of high quality with controlled nanostructure. In particular, the all-CSD approach is considered to be one of the most promising approaches for cost-effective production of second-generation superconducting wires. The trifluoroacetate (TFA) route is a very versatile route for achieving epitaxial YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) layers with high critical currents. In this work, recent advances towards improvement of the performance of several conductor architectures based on the YBCO TFA process will be presented. We show that new improved anhydrous TFA precursors allow a significant shortening of the pyrolysis time ({approx}1.5 h), and we have increased the total film thickness in a single deposition using polymeric additives. On the other hand, further understanding of the YBCO nucleation and growth process has allowed us to obtain a controlled microstructure and high critical currents (J{sub c}{approx}4-5 MA cm{sup -2} and I{sub c}{approx}300 A cm{sup -1} width at 77 K). The growth conditions (CSD) and post-processing conditions (sputtering and CSD) for the underlying oxide cap and buffer layers (CeO{sub 2}, BaZrO{sub 3}, SrTiO{sub 3}, La{sub 2}Zr{sub 2}O{sub 7} (La,Sr)MnO{sub 3}) and of self-organized nanostructures (CeO{sub 2}, BaZrO{sub 3}) deposited by CSD have been investigated to obtain high-quality interfaces in multilayered systems. Different single-crystal or metallic substrates (YSZ-IBAD (yttrium stabilized zirconia-ion beam assisted deposition) and Ni-RABiT (rolling assisted biaxial texturing)) have been investigated and long ({approx}10 m) CSD biaxially textured buffers (CeO{sub 2}, La{sub 2}Zr{sub 2}O{sub 7}) have been grown on Ni-RABiT substrates using a reel-to-reel system. High-performance TFA-YBCO-coated conductors have been obtained on vacuum-based buffer layers (I{sub c}{approx}140 A cm{sup -1} width) and on CSD buffer layers

Why the compound Yba sub 2 Cu sub 3 O sub 6 is not a superconductor. Pourquoi le compose YBa sub 2 Cu sub 3 O sub 6 n'est-il pas un supraconducteur

Energy Technology Data Exchange (ETDEWEB)

Gupta, M [Paris-11, Univ., 91 - Orsay (FR); Gupta, R P [CEA Centre d' Etudes Nucleaire de Saclay, 91 - Gif-sur-Yvette (FR). Dept. de Technologie

1989-01-01

A comparative study of the electronic structure of superconducting YBa{sub 2}Cu{sub 3}O{sub 7} and non superconducting YBa{sub 2}Cu{sub 3}O{sub 6} is presented. Our calculation shows that the densities of states at the Cu sites with pyramidal coordination and at its four oxygen neighboring sites in the horizontal planes are very similar in the superconducting and non-superconducting phases. Thus, the bidimensional character is unaltered in the two compounds. However, unlike for YBa{sub 2}Cu{sub 3}O{sub 7}, we find that in YBa{sub 2}Cu{sub 3}O{sub 6}, the Cu atoms of the linear chain sites and the oxygen atoms with which it interacts along the c axis are respectively in the charged state Cu{sup +} and O{sup 2-}; these sites are insulating since the densities of states at the Fermi energy is almost nil. These results suggest the importance of the linear Cu-O chains in the superconducting properties.

Microstructure of edge-type Josephson junctions with PrBa[sub 2]Cu[sub 3]O[sub 7-x] barrier layer

Energy Technology Data Exchange (ETDEWEB)

Lebedev, O I; Vasiliev, A L; Kiselev, N A [Inst. of Crystallography, Russian Academy of Sciences, Moscow (Russia); Mazo, L A; Gaponov, S V; Paveliev, D G; Strikovsky, M D [Inst. of Applied Physics, Russian Academy of Sciences, Novgorod (Russia)

1992-08-01

HREM investigations of edge Josephson junctions (EJJ) with PrBa[sub 2]Cu[sub 3]O[sub 7-x] barrier layer (PB) were performed. All layers (superconducting YBa[sub 2]Cu[sub 3]O[sub 7-x]) (Y1) and (Y2), insulating PrBa[sub 2]Cu[sub 3]O[sub 7-x] (PI) and barrier (PB) were obtained by laser ablation. The edges were formed by ion sputtering using a fotoresist mask. EJJ shows Josephson conductivity at Tc=77 K, giving j[sub c]=10[sup 4] A/cm[sup 2] at U[sub c]=50 [mu]V. Cross-sectional images show that Y1, PI and PB layers are single crystalline with the c-axis normal to the substrate surface. The Y2 layer in the regions of a multilayered structure is polycrystalline. The PB/Y1 interface is characterised by APB line boundaries; it is inclined to the substrate by 20-35deg. (orig.).

Improved flux-pinning properties of REBa{sub 2}Cu{sub 3}O{sub 7-z} films by low-level Co doping

Energy Technology Data Exchange (ETDEWEB)

Wang, Wentao; Pu, Minghua; Wang, Weiwei; Lei, Ming [Key Laboratory of Magnetic Levitation and Maglev Trains, Ministry of Education of China, Superconductivity R and D Centre (SRDC), Southwest Jiaotong University, Erhuanlu Beiyiduan 111, 610031 Chengdu (China); Cheng, Cuihua [Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wales, 2052 NSW, Sydney (Australia); Zhao, Yong [Key Laboratory of Magnetic Levitation and Maglev Trains, Ministry of Education of China, Superconductivity R and D Centre (SRDC), Southwest Jiaotong University, Erhuanlu Beiyiduan 111, 610031 Chengdu (China); Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wales, 2052 NSW, Sydney (Australia)

2011-09-15

Biaxially textured REBa{sub 2}Cu{sub 3-x}Co{sub x}O{sub 7-z} (RE = Gd,Y) films were prepared on (00l) LaAlO{sub 3} substrate using self-developed fluorine-free chemical solution deposition (CSD) approach. The in-field J{sub c} values are significantly improved for REBa{sub 2}Cu{sub 3-x}Co{sub x}O{sub 7-z} films through low-level Co doping. Co-doped GdBa{sub 2}Cu{sub 3}O{sub 7-z} film shows the highest J{sub c} values at higher temperatures and fields, whereas the J{sub c} values of Co-doped YBa{sub 2}Cu{sub 3}O{sub 7-z} film surpass that of other films at lower temperatures and fields. In addition, the volume pinning force densities of films with Co doping have been distinctly enhanced in the applied fields, indicating improved flux-pinning properties. The possible reasons are discussed in detail. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Conductivity fluctuation and superconducting parameters of the YBa{sub 2}Cu{sub 3-} {sub x} (PO{sub 4}) {sub x} O{sub 7-} {sub {delta}} material

Energy Technology Data Exchange (ETDEWEB)

Rojas Sarmiento, M.P. [Grupo de Fisica de Nuevos Materiales, Departamento de Fisica, Universidad Nacional de Colombia, AA 14490, Bogota DC (Colombia); Uribe Laverde, M.A. [Grupo de Fisica de Nuevos Materiales, Departamento de Fisica, Universidad Nacional de Colombia, AA 14490, Bogota DC (Colombia); Vera Lopez, E. [Grupo de Superficies, Electroquimica y Corrosion, UPTC, Tunja (Colombia); Landinez Tellez, D.A. [Grupo de Fisica de Nuevos Materiales, Departamento de Fisica, Universidad Nacional de Colombia, AA 14490, Bogota DC (Colombia); Roa-Rojas, J. [Grupo de Fisica de Nuevos Materiales, Departamento de Fisica, Universidad Nacional de Colombia, AA 14490, Bogota DC (Colombia)]. E-mail: jroar@unal.edu.co

2007-09-01

Synthesis of the YBa{sub 2}Cu{sub 3-} {sub x} (PO{sub 4}) {sub x} O{sub 7-} {sub {delta}} superconducting material by the standard solid-state reaction is reported. DC resistivity measurements reveal the improvement of the critical temperature (T {sub C}) when substitution of phosphate in the Cu sites is performed. A bulk T {sub C}=97 K was determined by the criterion of the maximum in the temperature derivative of electrical resistivity. Structure characterization by means the X-ray diffraction technique shows the crystalline appropriated distribution of PO{sub 4} into the CuO{sub 2} superconducting planes. In order to examine the effect of phosphates on the pairing mechanism close to T {sub C}, conductivity fluctuation analysis was performed by the method of logarithmic temperature derivative of the conductivity excess. We found the occurrence of Gaussian-like fluctuations. The correlations of the critical exponents with the dimensionality of the fluctuation system for each Gaussian regime were performed by using the Aslamazov-Larkin theory. The Ginzburg number for this superconducting material is predicted and the critical magnetic fields, critical current density and the jump in the specific heat at the critical temperature are theoretically determined.

Impedance measurements on YB/sub 2/Cu/sub 3/O/sub 7-delta) interpretation and trapping parameters

International Nuclear Information System (INIS)

Yasmeen, S.; Mohammad, M.; Khan, A.Y.; Subhani, M.S.

1997-01-01

Two probe impedance spectroscopic studies were carried out on YBa/sub 2/Cu/sub 3/ O/sub 7-delta/ two different sintering conditions i.e. at before final sintering and at after final sintering. In both condition ac impedance studies were done in the frequency range of 1Hz to 100kHz and at different temperatures from room temperature down to 78K. Measurements were done with contacts opposite side (i.e., ceramic behaves as a resister) as well as on opposite sides (i.e., ceramic behaves as a capacitor). Results were obtained in the form of Nyquist plot. Log, Yi/omega Vs log f plot and Yr/omega Vs log f plot. These plots were explained through equivalent circuits. The bulk resistance Rb, the grain boundary resistance R/sub b/ and grain boundary capacitance C/sub gb/ were obtained through these plots. The ac conductivities were also obtained at all temperatures. The log sigma g Vs log omega (frequency) plots were interpreted invoking the theory of ac conductivity in polycrystalline solids. The trapping parameters (binding energy, the hopping distance etc.) were calculated and interpreted. (author)

A revision of the fishtail effect in YBa{sub 2}Cu{sub 3}O{sub 7−δ} crystals and its connection with vortex dynamics

Energy Technology Data Exchange (ETDEWEB)

Pérez Daroca, D. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica and CONICET, Av. General Paz 1499, 1650 San Martín, Buenos Aires (Argentina); Pasquini, G., E-mail: pasquini@df.uba.ar [Departamento de Física, FCEyN, Universidad de Buenos Aires and IFIBA, CONICET, Pabellon 1, Ciudad Universitaria, 1428 Buenos Aires (Argentina)

2015-01-15

Highlights: • A critical revision of the accepted fishtail magnetization picture in YBCO crystals. • In slightly underdoped YBCO crystals the fishtail has a dynamic origin. • We show correlation between fishtail magnetization, Peak Effect and history effects. • We propose that the fishtail indicates a crossover between two plastic creep regimes. - Abstract: The fishtail magnetization observed in many type II superconductors has been investigated since the earliest nineties and associated with different phase transitions and dynamic crossovers in complex vortex matter. In systems without a sharp order–disorder phase transition, the fishtail has been related with a crossover from elastic to plastic vortex creep regimes. In this paper we perform a critical revision of this accepted picture. We show that, in slightly underdoped YBa{sub 2}Cu{sub 3}O{sub 7−δ} single crystals, there is a clear correlation between the fishtail magnetization and the Peak Effect observed in ac experiments with the associated history effects. We propose that both features are originated in the same dynamic crossover, between two plastic creep regimes. The proposed picture can also apply to other system, as those belonging to same families of iron-based pnictides.

High-field paramagnetic Meissner effect up to 14 T in melt-textured YBa{sub 2}Cu{sub 3}O{sub 7–δ}

Energy Technology Data Exchange (ETDEWEB)

Dias, F.T., E-mail: fabio.dias@ufpel.edu.br [Instituto de Física e Matemática, Universidade Federal de Pelotas, Caixa Postal 354, 96010-900, Pelotas, Rio Grande do Sul (Brazil); Vieira, V.N. [Instituto de Física e Matemática, Universidade Federal de Pelotas, Caixa Postal 354, 96010-900, Pelotas, Rio Grande do Sul (Brazil); Wolff-Fabris, F.; Kampert, E. [Dresden High Magnetic Field Laboratory, Helmholtz-Zentrum Dresden-Rossendorf, 01314, Dresden (Germany); Gouvêa, C.P.; Campos, A.P.C.; Archanjo, B.S. [National Institute of Metrology, Quality and Technology (Inmetro), Material Metrology Division, 25250-020, Duque de Caxias, Rio de Janeiro (Brazil); Schaf, J. [Instituto de Física, Universidade Federal do Rio Grande do Sul, 91501-970, Porto Alegre, Rio Grande do Sul (Brazil); Obradors, X.; Puig, T. [Institut de Ciència de Materials de Barcelona, CSIC, Universitat Autònoma de Barcelona, 08193, Bellaterra (Spain); Roa, J.J. [Departamento de Ciencia de Materiales e Ingeniería Metalúrgica, Universitat Politècnica de Catalunya, 08028, Barcelona (Spain); Sahoo, B.K. [Goverment College (Autonomous), Angul, 759143 Odisha (India)

2016-06-15

Highlights: • A persistent paramagnetic Meissner effect up to 14 T. • The PME with a slight tendency to saturate in high magnetic fields. • Strong time effects causing a paramagnetic relaxation dependent on the cooling rate. - Abstract: We have performed magnetization experiments in a melt-textured YBa{sub 2}Cu{sub 3}O{sub 7-δ} (Y123) sample with Y{sub 2}BaCuO{sub 5} (Y211) inclusions, under magnetic fields up to 14 T applied parallel or perpendicular to the ab plane. Magnetic anisotropy and paramagnetic moments were observed in both FC (field-cooling) and FCW (field-cooled warming) procedures and these features correspond to the so-called High-Field Paramagnetic Meissner Effect (HFPME). The HFPME effect increases monotonically as the magnetic field rises and a strong paramagnetic relaxation, toward increasing paramagnetic moment was additionally observed as a function of time. Microscopy analysis revealed a complex and correlated microstructure of the Y211 particles. These correlated defects are well known to cause strong flux pinning. Our results suggest a scenario of strong flux compression within weak or non-superconducting regions of the samples, developed as a consequence of the Meissner effect and assisted by strong flux pinning by the Y211 particles. This scenario is observed up to 14 T and clearly persists beyond.

Functional behavior of the anomalous magnetic relaxation observed in melt-textured YBa{sub 2}Cu{sub 3}O{sub 7-δ} samples showing the paramagnetic Meissner effect

Energy Technology Data Exchange (ETDEWEB)

Dias, F.T., E-mail: fabio.dias@ufpel.edu.br [Instituto de Física e Matemática, Universidade Federal de Pelotas, Caixa Postal 354, 96010-900, Pelotas, Rio Grande do Sul (Brazil); Vieira, V.N.; Garcia, E.L. [Instituto de Física e Matemática, Universidade Federal de Pelotas, Caixa Postal 354, 96010-900, Pelotas, Rio Grande do Sul (Brazil); Wolff-Fabris, F.; Kampert, E. [Dresden High Magnetic Field Laboratory, Helmholtz-Zentrum Dresden-Rossendorf, 01314, Dresden (Germany); Gouvêa, C.P. [National Institute of Metrology, Quality and Technology (Inmetro), Material Metrology Division, 25250-020, Duque de Caxias, Rio de Janeiro (Brazil); Schaf, J. [Instituto de Física, Universidade Federal do Rio Grande do Sul, 91501-970, Porto Alegre, Rio Grande do Sul (Brazil); Obradors, X.; Puig, T. [Institut de Ciència de Materials de Barcelona, CSIC, Universitat Autònoma de Barcelona, 08193, Bellaterra (Spain); Roa, J.J. [Departamento de Ciencia de Materiales e Ingeniería Metalúrgica, Universitat Politècnica de Catalunya, 08028, Barcelona (Spain)

2016-10-15

Highlights: • Paramagnetic Meissner effect observed up to 5T in FCC and FCW measurements. • Time effects evidenced by irreversibilities between FCC and FCW measurements. • Strong time effects causing an anomalous paramagnetic relaxation. • Paramagnetic relaxation governed by different flux dynamics in different intervals. • An interpretative analysis to identify the flux dynamics in the relaxation process. - Abstract: We have studied the functional behavior of the field-cooled (FC) magnetic relaxation observed in melt-textured YBa{sub 2}Cu{sub 3}O{sub 7-δ} (Y123) samples with 30 wt% of Y{sub 2}Ba{sub 1}Cu{sub 1}O{sub 5} (Y211) phase, in order to investigate anomalous paramagnetic moments observed during the experiments. FC magnetic relaxation experiments were performed under controlled conditions, such as cooling rate and temperature. Magnetic fields up to 5T were applied parallel to the ab plane and along the c-axis. Our results are associated with the paramagnetic Meissner effect (PME), characterized by positive moments during FC experiments, and related to the magnetic flux compression into the samples. After different attempts our experimental data could be adequately fitted by an exponential decay function with different relaxation times. We discuss our results suggesting the existence of different and preferential flux dynamics governing the anomalous FC paramagnetic relaxation in different time intervals. This work is one of the first attempts to interpret this controversial effect in a simple analysis of the pinning mechanisms and flux dynamics acting during the time evolution of the magnetic moment. However, the results may be useful to develop models to explain this interesting and still misunderstood feature of the paramagnetic Meissner effect.

YBa{sub 2}Cu{sub 3}O{sub 7-x} thin films prepared by chemical solution deposition

Energy Technology Data Exchange (ETDEWEB)

Apetrii, Claudia

2009-11-25

The discovery of superconductivity in ceramic materials by Bednorz and Mueller in early 1987, immediately followed by Wu et al., who showed that YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) becomes superconducting (92 K) well above the boiling point of nitrogen (77 K) created a great excitement in superconductivity research. Potential applications of high T{sub c}-superconductors require large critical currents and high-applied magnetic fields. Effective ways to increase the critical current density at high magnetic fields in YBCO are the introduction of nanoparticles and chemical substitution of yttrium by other rare earth elements. Since low costs and environmental compatibility are essential conditions for the preparation of long length YBCO films, the cost effective chemical solution deposition (CSD) procedure was selected, given that no vacuum technology is required. To reveal the flexibility and the good optimization possibilities of the CSD approach two main processes were chosen for comparison: a fluorine-free method, namely the polymer-metal precursor technique, and a fluorine-based method, the metalorganic deposition (MOD) using the trifluoroacetates (TFA) technique. Sharp transition temperature widths {delta}T{sub c} of 1.1 K for the polymer metal method, 0.8 K for TFA method and critical current densities J{sub c} of {approx}3.5 MA/cm{sup 2} shows that high quality YBCO thin films can be produced using both techniques. Especially interesting is the magnetic field dependence of the critical current density J{sub c}(B) of the Y(Dy)BCO (80 %) films showing that for the lower magnetic fields the critical current density J{sub c}(B) is higher for a standard YBCO film, but at fields higher than 4.5 T the critical current density J{sub c}(B) of Y(Dy)BCO is larger than that for the YBCO. Above 8 T, J{sub c}(B) of the Y(Dy)BCO film is more than one order of magnitude higher than in pure YBCO film. (orig.)

Calcination and solid state reaction of ceramic-forming components to provide single-phase superconducting materials having fine particle size

Science.gov (United States)

Balachandran, Uthamalingam; Poeppel, Roger B.; Emerson, James E.; Johnson, Stanley A.

1992-01-01

An improved method for the preparation of single phase, fine grained ceramic materials from precursor powder mixtures where at least one of the components of the mixture is an alkali earth carbonate. The process consists of heating the precursor powders in a partial vacuum under flowing oxygen and under conditions where the partial pressure of CO.sub.2 evolved during the calcination is kept to a very low level relative to the oxygen. The process has been found particularly suitable for the preparation of high temperature copper oxide superconducting materials such as YBa.sub.2 Cu.sub.3 O.sub.x "123" and YBa.sub.2 Cu.sub.4 O.sub.8 "124".

Study of the local induction in the superconductor YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} by Moessbauer spectroscopy using the probe {sup 170}Yb{sup 3+}: methodology and results; Etude de l`induction locale dans le compose supraconducteur YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} par spectroscopie mossbauer sur la sonde {sup 170}Yb{sup 3+}: methodologie et resultats

Energy Technology Data Exchange (ETDEWEB)

Vaast-Paci, Ch

1997-12-09

This thesis is concerned with the measurement of the local induction in the anisotropic type II superconductor YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} in presence of an applied field. In this compound, the field penetrates in the form of vortices whose characteristics are governed by both intrinsic (critical fields, anisotropy, penetration lengths,...) and extrinsic parameters (such as pinning centers). We have developed a new microscopic technique to measure the local fields using Moessbauer probes {sup 170}Yb{sup 3+} dilutes for Y{sup 3+}. The measurements are based on the field dependence (size and direction) of the Moessbauer transitions between the electronuclear levels of the probe. These probes are distributed randomly over the sample so the measurements provide both the size and the direction of the internal field distribution over the whole sample. The possible measurement range extends from below 50 Oe to about 4000 Oe, for temperatures up to 60 deg.K. Measurements were made at T4.2 deg. K, for sintered pellets with different oxygen amount and for optimally doped ci-axis oriented single crystals. The penetration length measurements showed that the density of the superconducting condensate increases progressively with carrier doping. Field penetration measurements furnished the microscopic lower penetration field H{sub cl}, and enabled us to propose a model describing the profile of the flux distribution which is controlled by the pinning centers. The measurements also evidenced an anomalous penetration in small sized single crystals. In additions, we obtained the average direction of the vortices when the applied field is titled from the c axis and we showed that the vortex direction depends on the way the field is applied (ZFC or FC configuration) and that there exists a competition between the pinning forces and the intrinsic anisotropy. (author) 94 refs.

YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} coated conductor deposited onto non-magnetic ternary alloy NiCrW RABiTS tape by in situ pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Tomov, R I; Kursumovic, A; Majoros, M; Glowacki, B A; Evetts, J E; Tuissi, A; Villa, E; Zamboni, M; Sun, Y; Toenies, S; Weber, H W

2003-01-01

Pulsed laser deposition of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO)/buffer (Y{sub 2}O{sub 3}, YSZ, CeO{sub 2}) heterostructures have been performed in situ onto recently developed non-magnetic oxygenation resistant NiCrW tape. The influence of the critical processing parameters on texture development are investigated and the issues involved in NiO formation and relation to the substrate surface quality are discussed. The roles of Ni poisoning YBCO as well as local cation disorder are considered as possible current limiting factors. X-ray diffraction has been used for macro-texture evaluation. Both buffers and YBCO layers show good biaxial alignment with {omega} and {phi} scans having best YBCO FWHM values of 4.0 deg. and 6.5 deg. respectively. A comparison is made with results achieved on industrial Ni{sub 50}Fe{sub 50} tape. The film morphology has been characterized using atomic force microscopy and scanning electron microscopy. The cation disorder has been studied by Raman spectroscopy. Critical temperatures of 90 K ({delta}T{sub c}=5 K) have been measured. Direct transport as well as magnetic measurements shows the critical current density J{sub c} is 0.2 MA/cm{sup 2} in self-field at liquid nitrogen temperatures.

Femtosecond optical detection of quasiparticle dynamics in high- T sub c YBa sub 2 Cu sub 3 O sub 7 minus. delta. superconducting thin films

Energy Technology Data Exchange (ETDEWEB)

Han, S.G.; Vardeny, Z.V.; Wong, K.S.; Symko, O.G. (Department of Physics, University of Utah, Salt Lake City, UT (USA)); Koren, G. (Department of Physics, Technion, 32000 Haifa (Israel))

1990-11-19

Femtosecond dynamics of photogenerated quasiparticles in YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} superconducting thin films shows, at {ital T}{le}{ital T}{sub {ital c}}, two main electronic processes: (i) quasiparticle avalanche production during hot-carrier thermalization, which takes about 300 fsec; (ii) recombination of quasiparticles to form Cooper pairs, which is completed within 5 psec. In contrastr, nonsuperconducting epitaxial films such as PrBa{sub 2}Cu{sub 2}O{sub 7} and YBa{sub 2}Cu{sub 3}O{sub 6} show regular picosecond electronic response.

Orientation and thickness dependence of magnetic levitation force and trapped magnetic field of single grain YBa{sub 2}Cu{sub 3}O{sub 7-y} bulk superconductors

Energy Technology Data Exchange (ETDEWEB)

Jung, Y.; Go, S. J.; Joo, H. T. [Korea Science Academy of Korea Advanced Institute of Science and Technology, Pusan (Korea, Republic of); Lee, Y. J.; Park, S. D.; Jun, B. H.; KIm, C. J. [Neutron Utilization Technology Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2017-03-15

The effects of the crystallographic orientation and sample thickness on the magnetic levitation forces (F) and trapped magnetic field (B) of single grain YBCO bulk superconductors were examined. Single grain YBCO samples with a (001), (110) or (100) surface were used as the test samples. The samples used for the force-distance (F-d) measurement were cooled at 77 K without a magnetic field (zero field cooling, ZFC), whereas the samples used for the B measurement were cooled under the external magnetic field of a Nd-B-Fe permanent magnet (field cooling, FC). It was found that F and B of the (001) surface were higher than those of the (110) or (100) surface, which is attributed to the higher critical current density (J{sub c}) of the (001) surface. For the (001) samples with t=5–18 mm, the maximum magnetic levitation forces (F{sub max}s) of the ZFC samples were larger than 40 N. About 80% of the applied magnetic field was trapped in the FC samples. However, the F and B decreased rapidly as t decreased below 5 mm. There exists a critical sample thickness (t=5 mm for the experimental condition of this study) for maintaining the large levitation/trapping properties, which is dependent on the material properties and magnitude of the external magnetic fields.

Magneto-transport properties of La{sub 0.75}Ca{sub 0.15}Sr{sub 0.1}MnO{sub 3} with YBa{sub 2}Cu{sub 3}O{sub 7–δ} addition

Energy Technology Data Exchange (ETDEWEB)

Zghal, E. [Laboratoire de Physique des Matériaux, Université de Sfax, Faculté des Sciences de Sfax, B. P. 1171, 3000 Sfax (Tunisia); Koubaa, M., E-mail: mohamedkoubaa@yahoo.fr [Laboratoire de Physique des Matériaux, Université de Sfax, Faculté des Sciences de Sfax, B. P. 1171, 3000 Sfax (Tunisia); Berthet, P. [Institut de Chimie Moléculaire et Matériaux d’Orsay, Bâtiment 410 Université Paris-Sud XI, 15 rue Georges Clémenceau, 91405 Orsay Cedex (France); Sicard, L. [ITODYS, Université Paris Diderot, CNRS UMR 7086, 15 rue Jean Antoine de Baïf, 75205 Paris (France); Cheikhrouhou-Koubaa, W. [Laboratoire de Physique des Matériaux, Université de Sfax, Faculté des Sciences de Sfax, B. P. 1171, 3000 Sfax (Tunisia); Decorse-Pascanut, C. [Institut de Chimie Moléculaire et Matériaux d’Orsay, Bâtiment 410 Université Paris-Sud XI, 15 rue Georges Clémenceau, 91405 Orsay Cedex (France); Cheikhrouhou, A. [Laboratoire de Physique des Matériaux, Université de Sfax, Faculté des Sciences de Sfax, B. P. 1171, 3000 Sfax (Tunisia); and others

2016-09-15

We report the structural, magnetic, electrical and magentoresistance properties of (La{sub 0.75}Ca{sub 0.15}Sr{sub 0.1}MnO{sub 3}){sub 1−x}(YBa{sub 2}Cu{sub 3}O{sub 7−δ}){sub x} (with x=0, 0.025, 0.05, 0.075, 0.1, 0.2, and 0.3) composites synthesized through sol–gel method. The powder X-ray diffraction patterns indicate no evidence of reaction between La{sub 0.75}Ca{sub 0.15}Sr{sub 0.1}MnO{sub 3} (LCSMO) and YBa{sub 2}Cu{sub 3}O{sub 7−δ} (YBCO). The addition of YBCO induces a reduction of the total magnetization while the Curie temperature remains almost constant (∼312 K). The behavior of the electrical resistivity evolves differently depending on the doping level. Above the paramagnetic–insulating transition temperature the resistivity data were best-fitted by using the adiabatic small polaron and variable range hopping models. Ferromagnetic–metallic regime in the composites seems to emanate from the electron–phonon or/and electron–magnon scattering processes. With increasing the YBCO doping content (until x=0.1), the positive magnetoresistance (MR) of YBCO phase dominates the negative MR of LCSMO one, which gives rise to the decreasing of MR of the composites. - Highlights: • LCSMO compound possess an orthorhombic-distorted structure (Pbnm space group). • YBCO crystallizes in orthorhombic structure (Pmmm space group). • Resistivity increases with increasing YBCO content in LCSMO/YBCO composites. • A detailed analysis of the transport mechanisms. • Coexistence of positive and negative MR in the composites.

Pulsed laser deposition of epitaxial YBa{sub 2}Cu{sub 3}O{sub 7-y}/oxide multilayers onto textured NiFe substrates for coated conductor applications

Energy Technology Data Exchange (ETDEWEB)

Tomov, R I [Department of Materials Science and IRC in Superconductivity, University of Cambridge, Cambridge (United Kingdom); Kursumovic, A; Kang, D -J; Glowacki, B A; Evetts, J E [Department of Materials Science and IRC in Superconductivity, University of Cambridge, Cambridge (United Kingdom); Majoros, M [IRC in Superconductivity, University of Cambridge, Cambridge (United Kingdom)

2002-04-01

Pulsed laser depositions of double-buffer and triple-buffer YBa{sub 2}Cu{sub 3}O{sub 7-y} (YBCO)/Y{sub 2}O{sub 3}(YSZ)/CeO{sub 2} heterostructures have been performed in situ onto commercially available biaxially textured NiFe 50%/50% tape. The deposition in the forming gas (4% H{sub 2}/Ar) from a CeO{sub 2} target and the deposition in vacuum from a CeO{sub 2}:Pd composite target have been explored as two possible routes for cube-on-cube growth of the first buffer layer. The influence of the critical processing parameters on the texture is investigated and some of the issues involved in the reduction of NiO (111) and the formation of cube-on-cube NiO (200) growth are discussed. X-ray diffraction has been used for texture evaluation of the substrate and subsequent deposited layers. The substrate-buffer interface region has been studied by focused ion beam cross section electron microscopy. Both the buffers and YBCO layers show biaxial alignment with {omega} and {phi} scans having optimum YBCO full width at half maximum (FWHM) values of 4.3 deg. and 8.8 deg., respectively. The morphology has been characterized using atomic force microscopy and scanning electron microscopy. The value of T{sub c} (onset) has been measured at 90 K ({delta}T{sub c}=10 K). The critical current density, J{sub c}, has been measured by transport measurements and magnetic measurements performed in a dc SQUID magnetometer. (author)

Microstructural and superconducting properties of high current metal-organic chemical vapor deposition YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} coated conductor wires

Energy Technology Data Exchange (ETDEWEB)

Holesinger, T G; Maiorov, B; Ugurlu, O; Civale, L [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Chen, Y; Xiong, X; Xie, Y; Selvamanickam, V [SuperPower, Inc., Schenectady, NY 12304 (United States)

2009-04-15

Metal-organic chemical vapor deposition (MOCVD) on flexible, ion beam assisted deposition MgO templates has been used to produce high critical current density (J{sub c}) (Y,Sm){sub 1}Ba{sub 2}Cu{sub 3}O{sub y} (REBCO) films suitable for use in producing practical high temperature superconducting (HTS) coated conductor wires. Thick films on tape were produced with sequential additions of 0.7 {mu}m of REBCO via a reel-to-reel progression through a custom-designed MOCVD reactor. Multi-pass processing for thick film deposition is critically dependent upon minimizing surface secondary phase formation. Critical currents (I{sub c}s) of up to 600 A/cm width (t = 2.8 {mu}m, J{sub c} = 2.6 MA cm{sup -2}, 77 K, self-field) were obtained in short lengths of HTS wires. These high performance MOCVD films are characterized by closely spaced (Y,Sm){sub 2}O{sub 3} nanoparticle layers that may be tilted relative to the film normal and REBCO orientation. Small shifts in the angular dependence of J{sub c} in low and intermediate applied magnetic fields can be associated with the tilted nanoparticle layers. Also present in these films were YCuO{sub 2} nanoplates aligned with the YBCO matrix (short dimension perpendicular to the film normal), threading dislocations, and oriented composite defects (OCDs). The latter structures consist of single or multiple a-axis oriented grains coated on each side with insulating (Y,Sm){sub 2}O{sub 3} or CuO. The OCDs formed a connected network of insulating phases by the end of the fourth pass. Subsequent attempts at adding additional layers did not increase I{sub c}. There is an inconsistency between the measured J{sub c} and the observed microstructural degradation that occurs with each additional layer, suggesting that previously deposited layers are improving with each repeated reactor pass. These dynamic changes suggest a role for post-processing to optimize superconducting properties of as-deposited films, addressing issues associated with

Muon-spin rotation (. mu. SR) study of the temperature dependence of the London penetration depth in copper oxide superconductors

Energy Technology Data Exchange (ETDEWEB)

Keller, H.; Kuendig, W.; Savic, I.M.; Simmler, H.; Staeuble-Puempin, B.; Warden, M.; Zech, D.; Zimmermann, P. (Physik-Inst., Univ. Zurich (Germany)); Kaldis, E.; Karpinski, J.; Rusiecki, S. (Lab. fuer Festkoerperphysik, ETH Zurich (Switzerland)); Brewer, J.H.; Riseman, T.M.; Schneider, J.W. (TRIUMF and Dept. of Physics, Univ. of British Columbia, Vancouver (Canada)); Maeno, Y.; Rossel, C. (IBM Research Div., Zurich Research Lab., Rueschlikon (Switzerland))

1991-12-01

A {mu}SR study of the temperature dependence of the London penetration depth {lambda} in sintered samples of YBa{sub 2}Cu{sub 3}O{sub x} (with various oxygen contents x), YBa{sub 2}Cu{sub 4}O{sub 8} and Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} is presented. It is found that the temperature behavior of {lambda} of all these cuprate superconductors is consistent with conventional s-wave pairing. However, there are significant differences concerning the exact temperature dependence of {lambda} in these materials. In YBa{sub 2}Cu{sub 3}O{sub x} with high x, the behavior of {lambda}(T) is well described by the two-fluid model (strong coupling), whereas {lambda}(T) in YBa{sub 2}Cu{sub 3}O{sub x} with low x, YBa{sub 2}Cu{sub 4}O{sub 8} and Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} is in better agreement with weak-coupling BCS theory. Possible reasons for the different temperature behavior of {lambda} in these materials are discussed. (orig.).

High performance GdBa{sub 2}Cu{sub 3}O{sub 7-z} film preparation by non-fluorine chemical solution deposition approach

Energy Technology Data Exchange (ETDEWEB)

Wang, W.T.; Pu, M.H.; Wang, W.W. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhang, H. [Department of Physics, Peking University, Beijing 100871 (China); Cheng, C.H. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China)] [Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wale, Sydney, 2052 NSW (Australia); Zhao, Y., E-mail: yzhao@swjtu.edu.cn [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China)] [Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wale, Sydney, 2052 NSW (Australia)

2011-11-15

Biaxially textured GdBa{sub 2}Cu{sub 3}O{sub 7}-z films with Tc above 93 K have been prepared on (0 0 l) by non-fluorine CSD approach. Nanoparticles with homogeneous distribution are introduced into the GdBCO films as effective pinning centers. A high Jc (77 K, 0 T) of 2.28 MA/cm{sup 2} with slow decreasing Jc-B behavior is observed in the films. Biaxially textured GdBa{sub 2}Cu{sub 3}O{sub 7-z} (GdBCO) films with T{sub c} above 93 K have been prepared on (0 0 l) LaAlO{sub 3} substrate by self-developed non-fluorine polymer-assisted chemical solution deposition (PA-CSD) approach. The GdBCO films show smooth and crack-free morphology. Many nanoscale particles with homogeneous distribution are observed in the GdBCO films, which have not been observed yet in the YBa{sub 2}Cu{sub 3}O{sub 7-z} (YBCO) films prepared by the same processing technique. Besides a high J{sub c} (77 K, 0 T) of 2.28 MA/cm{sup 2}, the optimized GdBCO films show a better J{sub c}-B behavior and an improved high-field J{sub c}, compared to the YBCO films.

Three-dimensional vortex pinning by nano-precipitates in a Sm-doped YBa{sub 2}Cu{sub 3}O{sub 7-x} coated conductor

Energy Technology Data Exchange (ETDEWEB)

Chen, Z [University of Wisconsin-Madison, Madison, WI 53706 (United States); Feldmann, D M [University of Wisconsin-Madison, Madison, WI 53706 (United States); Song, X [University of Wisconsin-Madison, Madison, WI 53706 (United States); Kim, S I [University of Wisconsin-Madison, Madison, WI 53706 (United States); Gurevich, A [University of Wisconsin-Madison, Madison, WI 53706 (United States); Reeves, J L [SuperPower Incorporated, 450 Duane Avenue, Schenectady, NY 12304 (United States); Xie, Y Y [SuperPower Incorporated, 450 Duane Avenue, Schenectady, NY 12304 (United States); Selvamanickam, V [SuperPower Incorporated, 450 Duane Avenue, Schenectady, NY 12304 (United States); Larbalestier, D C [University of Wisconsin-Madison, Madison, WI 53706 (United States)

2007-09-15

We report on the thickness and angular dependence of the critical current density J{sub c}(H,{theta}), the irreversibility field H{sup irr}, and the bulk pinning force F{sub p}(H) of a metal-organic chemical vapour deposition (MOCVD) grown YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) coated conductor, which contains {approx}17 vol% of {approx}10 nm sized (Y,Sm){sub 2}O{sub 3} precipitates with an average spacing of {approx}10-15 nm. Some surface porosity and amorphous second-phase particles on the scale of {approx}0.5-1 {mu}m appear to reduce the current-carrying cross-section, which controls the magnitude of J{sub c} but not the vortex pinning. We observed an enhanced H{sup irr}{approx}9 T at 77 K along the c-axis which, like the shape of J{sub c}(H) and F{sub p}(H), was independent of thickness as the sample was milled down to {approx}0.16 {mu}m. Angular-dependent measurements of J{sub c} showed the usual excess vortex pinning along the c-axis and along the ab-plane, but with a background that could only be fitted with an unusually small anisotropy parameter of 3, which, like the high H{sup irr} and the thickness-independent shape of F{sub p}(H), we ascribe to strong vortex pinning centre interactions. Together, these measurements show very different behaviour from most pulsed-laser-deposited films, which exhibit strong thickness-dependent properties. We ascribe the present different results to the dense array of small, insulating precipitates, which act as strong pinning centres and produce strong three-dimensional (3D) vortex pinning, because their separation of 10-15 nm is always much smaller than the film thickness.

Investigation and optimization of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} grain boundaries and coated conductors; Untersuchung und Optimierung von YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}-Korngrenzen und Bandsupraleitern

Energy Technology Data Exchange (ETDEWEB)

Held, Rainer Robert Martin

2010-01-29

With increasing misorientation angle grain boundaries strongly reduce the critical current density of high temperature superconductors. For this reason costly techniques are used in production of modern Coated Conductors to induce sharp textures in the polycrystalline superconductor layers. In this dissertation measurements of the critical current density of different grain boundary types are presented showing that out-of-plane grain boundaries exhibit, also in applied magnetic fields, much higher critical current densities than expected. In further analysis of the grain boundaries indications for a microstructural reason of the high critical current densities were found. The high critical current densities of the out-of-plane grain boundaries should in fabrication of Coated Conductors allow for a relaxation of the out-of-plane grain alignment requirements and a concomitant cost reduction. In this work also results of a industrial cooperation with Nexans are presented demonstrating that the critical current density of metal-organic deposited grain boundaries and Coated Conductor layers can be increased by selective Calcium-doping. In the experiments selective Calcium-doping most effectively increased the critical current density of weak spots. (orig.)

Critical current density of strained multilayer thin films of Nd sub 1. 83 Ce sub 0. 17 CuO sub x /YBa sub 2 Cu sub 3 O sub 7 minus. delta

Energy Technology Data Exchange (ETDEWEB)

Gross, R.; Gupta, A.; Olsson, E.; Segmueller, A.; Koren, G. (IBM T. J. Watson Research Center, P.O. Box 218, Yorktown Heights, New York 10598 (USA))

1990-07-09

The superconducting transport properties of strained multilayer thin films of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}/ Nd{sub 1.83}Ce{sub 0.17}CuO{sub {ital x}}, grown heteroepitaxially by laser ablation deposition, are reported. For individual layer thicknesses below a critical layer thickness of about 250 A, coherency strain removes the orthorhombic distortion in the YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} layers and makes them twin-free. Zero-field critical current densities as high as 1.1{times}10{sup 7} A/cm{sup 2} at 77 K have been measured for the YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} layers. Flux pinning energies at zero temperature and zero magnetic field in the range of 80--140 meV have been found.

YBCO/manganite layered structures on NdGaO{sub 3} substrates

Energy Technology Data Exchange (ETDEWEB)

Nurgaliev, T [Institute of Electronics BAS, 72 Tsarigradsko Chaussee, 1784 Sofia (Bulgaria); Blagoev, B [Institute of Electronics BAS, 72 Tsarigradsko Chaussee, 1784 Sofia (Bulgaria); Donchev, T [Institute of Electronics BAS, 72 Tsarigradsko Chaussee, 1784 Sofia (Bulgaria); Miteva, S [Institute of Electronics BAS, 72 Tsarigradsko Chaussee, 1784 Sofia (Bulgaria); Mozhaev, P B [Institute of Physics and Technology RAS, Nakhimovsky ave. 36, 117218 Moscow (Russian Federation); Mozhaeva, J E [Institute of Physics and Technology RAS, Nakhimovsky ave. 36, 117218 Moscow (Russian Federation); Ovsyannikov, G A [Institute of Radio Engineering and Electronics RAS, Mokhovaya st.11, 103907 Moscow (Russian Federation); Kotelyanskii, I M [Institute of Radio Engineering and Electronics RAS, Mokhovaya st.11, 103907 Moscow (Russian Federation); Jacobsen, C [Technical University of Denmark, Building 307-309, DK-2800, Kgs.Lyngby, Denmark (Denmark)

2006-06-01

Results of deposition of YBa{sub 2}Cu{sub 3}O{sub 7-x}/CeO{sub 2}/(La{sub 0.7}Ca{sub 0.3}MnO{sub 3} or La{sub 0.7}Sr{sub 0.3}MnO{sub 3}) structures on the standard oriented and tilted ( 8{sup 0}) NdGaO{sub 3} substrates and results of investigation of electrical parameters of YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) films in such structures are presented. The YBCO component of the structure exhibits lower value of the critical parameters in comparison with those of single YBCO films. The contribution of the magnetic layer to the microwave losses of the YBCO film in the layered structure is evaluated.

Influence of iodine insertion on the YBaCuO superconducting properties

Energy Technology Data Exchange (ETDEWEB)

Mokhtari, M.; Perrin, C.; Pena, O.; Sergent, M. (Lab. de Chimie du Solide et Inorganique Moleculaire, Univ. de Rennes 1, 35 (France))

1992-11-01

YBa[sub 2]Cu[sub 3]O[sub x] (x=6, 6.7 and 7) have been treated under iodine vapours, in evacuated silica tubes. After iodination, YBa[sub 2]Cu[sub 3]O[sub 6] exhibits a tetragonal/orthorhombic structural transition and becomes superconducting with T[sub c] increasing up to 70 K; the T[sub c] of YBa[sub 2]Cu[sub 3]O[sub 6.7] increases progressively from 63 K up to 80 K while the inductive amplitude decreases correlatively; for YBa[sub 2]Cu[sub 3]O[sub 7] only a slight quantity of iodine is inserted in the sample, which does not change the T[sub c] of 91 K, but provokes an important decrease of the inductive amplitude. EDS and SEM observations are used to test the homogeneity of the bromine insertion in the pellets and in the microcrystals. (orig.).

Selective Rutherford backscattering techniques in the study of transition-metal implanted YBa{sub 2}C{sub 3}O{sub 7-{delta}}

Energy Technology Data Exchange (ETDEWEB)

Martin, J.W.; Russell, G.J. [New South Wales Univ., Kensington, NSW (Australia). School of Physics; Cohen, D.D.; Evans, P.J. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1993-12-31

Using a metal-vapor vacuum arc ion source, several as-grown, large single crystal YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} were implanted with a dose of 1x10{sup 17} zinc, nickel and iron ions. After implantation the crystal was subjected to two anneal cycles that has allowed to examine crystal structure, superconducting transitions and composition, through X-ray diffraction, rutherford backscattering spectroscopy (RBS) and AC susceptibility measurements respectively. Although RBS discriminates strongly against light elements, such as oxygen, the use of resonant reaction {sup 16}O ({alpha}, {alpha}){sup 16}O at 3.4 MeV was beneficial, as its cross section is nearly 23 times that of the rutherford cross section. 4 figs.

Selective Rutherford backscattering techniques in the study of transition-metal implanted YBa{sub 2}C{sub 3}O{sub 7-{delta}}

Energy Technology Data Exchange (ETDEWEB)

Martin, J W; Russell, G J [New South Wales Univ., Kensington, NSW (Australia). School of Physics; Cohen, D D; Evans, P J [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1994-12-31

Using a metal-vapor vacuum arc ion source, several as-grown, large single crystal YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} were implanted with a dose of 1x10{sup 17} zinc, nickel and iron ions. After implantation the crystal was subjected to two anneal cycles that has allowed to examine crystal structure, superconducting transitions and composition, through X-ray diffraction, rutherford backscattering spectroscopy (RBS) and AC susceptibility measurements respectively. Although RBS discriminates strongly against light elements, such as oxygen, the use of resonant reaction {sup 16}O ({alpha}, {alpha}){sup 16}O at 3.4 MeV was beneficial, as its cross section is nearly 23 times that of the rutherford cross section. 4 figs.

Zinc-induced modification of the dynamical magnetic susceptibility in the superconducting state of YBa{sub 2}Cu{sub 3}O{sub 6+}{sub {ital x}} as revealed by inelastic neutron scattering

Energy Technology Data Exchange (ETDEWEB)

Sidis, Y.; Bourges, P.; Hennion, B. [Laboratoire Leon Brillouin, CEA-CNRS, Centre dEtudes de Saclay, 91191 Gif-sur-Yvette (France); Regnault, L.P. [Centre dEtudes Nucleaires de Grenoble, Departement de Recherche Fondamentale sur la Matiere Condensee, Service de Physique Statistique, Magnetisme et Supraconductivite, Groupe Magnetisme et Diffraction Neutronique, 85 X, 38041 Grenoble cedex (France); Villeneuve, R.; Collin, G. [Laboratoire Leon Brillouin, CEA-CNRS, Centre dEtudes de Saclay, 91191 Gif-sur-Yvette (France); Marucco, J.F. [Laboratoire des Composes Non-Stoechiometriques, CNRS URA 446, Batiment 415, Universite Paris Sud centre dOrsay, Orsay (France)

1996-03-01

Inelastic-neutron-scattering measurements have been performed to determine the imaginary part of the dynamical susceptibility, {chi}{double_prime}({ital Q},{omega}), of a YBa{sub 2}(Cu{sub 1{minus}{ital y}}Zn{sub {ital y}}){sub 3}O{sub 6.97} sample exhibiting a superconducting transition at {ital T}{sub {ital c}}=69 K. Zinc substitution induces striking modifications of the energy dependence of {chi}{double_prime}({ital Q},{omega}) but magnetic fluctuations remain peaked at the antiferromagnetic wave vector, {ital Q}{sub AF}, at all investigated energies. In the superconducting state of the zinc-free compound, {chi}{double_prime}({ital Q},{omega}) is restricted to a narrow energy range, {h_bar}{omega}=33{endash}47 meV, displaying a {ital spin} {ital gap} at {ital E}{sub {ital G}}=33 meV and a resonant enhancement at {ital E}{sub {tau}}=39 meV, both features vanishing upon heating up above {ital T}{sub {ital c}}. In the {ital y}=0.02 substituted sample in the superconducting state, there is still an energy band in the range 32{endash}47 meV but no clear resonance, and a signal is now observed in the low energy range, though the line shape of {chi}{double_prime}({ital Q},{omega}) indicates some reminiscence of the spin gap of the pure compound. {copyright} {ital 1996 The American Physical Society.}

Interplane redistribution of oxygen in fine-grained HTSC

Energy Technology Data Exchange (ETDEWEB)

Makarov, E.F. [Semenov Institute of Chemical Physics, Russian Academy of Sciences, ul. Kosygina 4, Moscow 119991 (Russian Federation); Mamsurova, L.G. [Semenov Institute of Chemical Physics, Russian Academy of Sciences, ul. Kosygina 4, Moscow 119991 (Russian Federation)]. E-mail: mamsurova@chph.ras.ru; Permyakov, Yu.V. [National Institute for Physical, Radio and Technical Measurements (VNIIFTRI), Mendeleevo, Moscow Region 141570 (Russian Federation); Pigalskiy, K.S. [Semenov Institute of Chemical Physics, Russian Academy of Sciences, ul. Kosygina 4, Moscow 119991 (Russian Federation); Vishnev, A.A. [Semenov Institute of Chemical Physics, Russian Academy of Sciences, ul. Kosygina 4, Moscow 119991 (Russian Federation)

2004-10-01

Moessbauer spectra (T = 78 and 293 K) and X-ray (T = 293 K) studies of fine-grained high-temperature superconductors (HTSC) YBa{sub 2}Cu{sub 2.985}{sup 57}Fe{sub 0.015}O{sub y} (y = 6.92-6.93, T{sub c} = 91-91.5 K) with the average grain sizes equal to 0.4, 1, and 2 {mu}m are carried out. The redistribution in the intensities of Moessbauer spectra components with the decrease in the average grain size is found. The latter evidences the oxygen content to increase in (CuO{sub {delta}}) basal planes at the expense of its decrease in (CuO{sub 2}) and (BaO) planes. The redistribution of the oxygen between the different planes of the unit cell is accompanied by the decrease in the lattice parameter c. These effects are caused likely by nonequilibrium conditions which are commonly used in preparation of fine-grained HTSC. The assumption about the existence of partial disorder between Y{sup 3+} and Ba{sup 2+} sites in the samples explains the observed changes in the values of {delta} and c parameters. An efficiency of Moessbauer spectra studies for the compounds of YBaCuO type in the case of the enhanced oxygen parameter {delta} and the possibility of its quantitative estimation from the analysis of the intensities of Moessbauer spectrum components is demonstrated.

Reversible and irreversible magnetocaloric effect in the NdBa{sub 2}Cu{sub 3}O{sub 7} superconductor in relation to specific heat and magnetization

Energy Technology Data Exchange (ETDEWEB)

Plackowski, T [Departement de Physique de la Matiere Condensee, Universite de Geneve, CH-1211 Geneva 4 (Switzerland); Institute of Low Temperature and Structure Research, ulica Okolna 2, 50-422 Wroclaw (Poland); Wang, Y [Departement de Physique de la Matiere Condensee, Universite de Geneve, CH-1211 Geneva 4 (Switzerland); Lortz, R [Departement de Physique de la Matiere Condensee, Universite de Geneve, CH-1211 Geneva 4 (Switzerland); Junod, A [Departement de Physique de la Matiere Condensee, Universite de Geneve, CH-1211 Geneva 4 (Switzerland); Wolf, Th [Forschungszentrum Karlsruhe, Institut fuer Technische Physik, Postfach 3640, D-76021Karlsruhe (Germany)

2005-11-02

A recently developed technique for measuring the isothermal magnetocaloric coefficient (M{sub T}) is applied to the study of a superconducting NdBa{sub 2}Cu{sub 3}O{sub 7} single crystal. Results are compared with magnetization (M) and specific heat (C). In the reversible region both C and M{sub T} follow the scaling law of the 3D-xy universality class. The anomalies connected with flux-line lattice melting are visible on M{sub T}(B) curves as peaks and steps, similar to C(T) curves yet with much smaller background. At lower temperature, in the irreversible region the M{sub T}(B) behaviour resembles more that of M(B), exhibiting the 'fishtail' effect. Our results confirm that the peculiarities of the phase diagram known from the high-temperature superconductor YBa{sub 2}Cu{sub 3}O{sub 7}, e.g. vortex melting, dominance of critical fluctuations and absence of a B{sub c2} critical field line, are a common property of RE-123 systems.

Ambient growth of highly oriented Cu{sub 2}S dendrites of superior thermoelectric behaviour

Energy Technology Data Exchange (ETDEWEB)

Mulla, Rafiq; Rabinal, M.K., E-mail: mkrabinal@yahoo.com

2017-03-01

Highlights: • A simple and ambient route to synthesize highly oriented dendrites of copper sulfide is proposed. • Remarkable enhancement is observed in Seebeck coefficient by room temperature, solution phase doping. • High thermoelectric power factor is observed at room temperature, indicating promising behaviour. - Abstract: Low-cost, non-toxic and efficient material is an urgent need for the thermoelectric energy conversion. Here, a rapid and ambient chemical route has been developed to grow dense and highly oriented dendrites of copper sulfide (Cu{sub 2}S) on copper substrate in a very simple approach, these films are uniform and covered with dense nanosheets. Room temperature solution doping of copper ions is carried out to improve thermoelectric performance. The Seebeck coefficient increased from ∼100 to 415 μV K{sup −1} with a slight decrease in electrical conductivity, this gives a high power factor (S{sup 2}σ) of about ∼400 μW m{sup −1} K{sup −2}. The improved thermoelectric properties in these films are accounted for resonant energy level doping and high phonon scattering. Such films with improved thermoelectric behaviour can be promising materials for energy conversion. The earth abundant, low cost, non toxic with a good thermoelectric property makes copper sulfide as a promising thermoelectric material for future applications.

Effect of rare-earth composition on microstructure and pinning properties of Zr-doped (Gd, Y)Ba{sub 2}Cu{sub 3}O{subx} superconducting tapes.

Energy Technology Data Exchange (ETDEWEB)

Selvamanickam, V.; Chen, Y.; Zhang, Y.; Guevara, A.; Shi, T.; Yao, Y.; Majkic, G.; Lei, C.; Galtsyan, E.; Miller, D. J. (Materials Science Division); (Univ. Houston); (SuperPower Inc.)

2012-01-01

The effect of changing Gd + Y content from 1.2 to 1.6 in the precursor of (Gd,Y)Ba{sub 2}Cu{sub 3}O{sub 7} superconducting thin film tapes made by metal organic chemical vapor deposition (MOCVD) at a constant Gd:Y ratio and a fixed Zr content of 7.5% has been studied. The influence of changing the Gd:Y ratio from Gd = 0 to Y= 0 in 0.2 mol steps at a constant Gd + Y content of 1.2 in the precursor has also been investigated at a fixed Zr content of 7.5%. The critical current of these films is found to vary significantly as a function of rare-earth content as well as a function of rare-earth type. Even for a fixed Zr content, it is found that the critical current in the orientation of magnetic field parallel to the a-b plane and that in the orientation of field perpendicular to the a-b plane can be systematically varied with changing Gd + Y content as well as with changing Gd:Y ratio. The nanoscale defect structures along the a-b plane and along the c-axis are found to be sensitive to these changes in rare-earth content and type.

Growth and properties of La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/YBa{sub 2}Cu{sub 3}O{sub 7−δ}/La{sub 0.7}Sr{sub 0.3}MnO{sub 3} epitaxial trilayer films

Energy Technology Data Exchange (ETDEWEB)

Sharma, Minaxi, E-mail: meenanith@gmail.com; Kumar, Arvind; Sharma, K. K. [Department of Physics, National Institute of Technology, Hamirpur -177005 (India); Kumar, Ravi [Centre for Materials Science and Engineering, National Institute of Technology, Hamirpur -177005 (India); Beant College of Engineering and Technology, Gurdaspur Punjab-143521 (India); Choudhary, R. J. [UGC-DAE-Consortium for Scientific Research, Khandwa Road, Indore-452001 (India)

2015-08-28

We report the growth and properties of La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/YBa{sub 2}Cu{sub 3}O{sub 7−δ}/La{sub 0.7}Sr{sub 0.3}MnO{sub 3} LSMO/YBCO/LSMO epitaxial trilayer films, fabricated on SrTiO{sub 3} substrate using pulsed laser deposition technique. From x-ray diffraction and high resolution x-ray diffraction measurements, it is confirmed that the grown trilayered films are single phase and epitaxial in nature. Magneto-transport and magnetic properties are found to be dependent on the thickness of YBCO spacer layer. We infer that for fixed thickness of top and bottom LSMO layers, superconductivity is completely suppressed. At 100 K, the hysteresis loops reveal the ferromagnetic signature of trilayered film. At room temperature, we obtain a butterfly type scenario, signifies the co-existence of ferromagnetic and antiferromagnetic interaction. In addition, at room temperature, the YBCO spacer layer allowing the top and bottom LSMO layers to interact antiferromagnetically.

Structural and superconducting properties of oxygen-deficient NdBa sub 2 Cu sub 3 O sub 7 minus. delta

Energy Technology Data Exchange (ETDEWEB)

Shaked, H. (Nuclear Research Center-Negev, Post Office Box 9001, Beer Sheva, Israel (IL) Ben Gurion University of the Negev, Post Office Box 653, Beer Sheva, Israel (IL)); Veal, B.W.; Faber, J. Jr.; Hitterman, R.L.; Balachandran, U.; Tomlins, G.; Shi, H.; Morss, L.; Paulikas, A.P. (Argonne National Laboratory, Argonne, Illinois 60439 (USA))

1990-03-01

Neutron diffraction was used to determine the structural properties of oxygen deficient NdBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} for 0.09{lt}{delta}{lt}0.74. It was found that superconductivity disappears at the orthorhombic-to-tetragonal phase transition which occurs at {delta}{sub {ital O}{ital T}}=0.45. Structural parameters vary smoothly with {delta} but exhibit a change in slope at the orthorhombic-to-tetragonal transition. The structural properties exhibit the same features found in YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} where {delta}{sub {ital O}{ital T}}=0.65. It is shown that the repulsion energy of oxygen atoms in the O(1) and O(5) sites in NdBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} is smaller than in YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}. This lower repulsion energy stabilizes the orthorhombic phase at lower values of {delta}. It is argued that the disappearance of superconductivity at the orthorhombic-to-tetragonal transition is an inherent property of the {ital R}Ba{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} ({ital R} denotes rare earth) system.

Interaction of RBa sub 2 Cu sub 3 O sub x (R = Y or Nd) coatings with alumina and zirconia substrates. [YBaCuO; NdBaCuO

Energy Technology Data Exchange (ETDEWEB)

Moreau, C; Parent, L; Champagne, B; Dallaire, S [National Research Council of Canada, Industrial Materials Research Inst., Boucherville, PQ (Canada)

1989-12-10

As-deposited YBa{sub 2}Cu{sub 3}O{sub x} coatings by plasma spraying are not superconducting because of their inadequate crystalline structure and low oxygen content. A post-deposition heat treatment in oxygen is required to restore the appropriate superconducting YBa{sub 2}Cu{sub 3}O{sub x} structure. During heat treatment, deterimental reactions between coatings and substrates may occur and lead to the degradation or destruction of the coating superconducting properties. In the present paper, interactions of RBa{sub 2}Cu{sub 3}O{sub x} (R = Y, Nd) coatings with alumina and zirconia substrates are examined. The modifications of the coating electrical properties and microstructure are studied using X-ray diffraction, energy dispersive X-ray analysis and resistivity measurements. Coating degradation is shown to occur by diffusion of the barium atoms out of the coating leading to the formation of Y{sub 2}BaCuO{sub 5} and CuO in yttrium-based coatings, and to the formation of nonstoichiometric Nd{sub 1+y}Ba{sub 2-y}Cu{sub 3}O{sub x} and CuO in neodymium-based coatings. The coating degradation is more important on alumina substrates that on zirconia substrates for both yttrium- and neodymium-based coatings. (orig.).

Phase relations in the quasi-binary Cu{sub 2}GeS{sub 3}-ZnS and quasi-ternary Cu{sub 2}S-Zn(Cd)S-GeS{sub 2} systems and crystal structure of Cu{sub 2}ZnGeS{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Parasyuk, O.V. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine)]. E-mail: oleg@lab.univer.lutsk.ua; Piskach, L.V. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine); Romanyuk, Y.E. [Advanced Photonics Laboratory, Institute of Imaging and Applied Optics, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Olekseyuk, I.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine); Zaremba, V.I. [Department of Inorganic Chemistry, Ivan Franko National University of Lviv, 6 Kyryla and Mefodiya Str., 79005 L' viv (Ukraine); Pekhnyo, V.I. [V.I. Vernadskii Institute of General and Inorganic Chemistry, Ukrainian National Academy of Sciences, Palladina Ave 32-34, 03680 Kiev (Ukraine)

2005-07-19

The isothermal section of the Cu{sub 2}S-Zn(Cd)S-GeS{sub 2} systems at 670K was constructed using X-ray diffraction analysis. At this temperature, two quaternary intermediate phases, Cu{sub 2}CdGeS{sub 4} and {approx}Cu{sub 8}CdGeS{sub 7}, exist in the Cu{sub 2}S-CdS-GeS{sub 2} system, and only one phase, Cu{sub 2}ZnGeS{sub 4}, exists in the Cu{sub 2}S-ZnS-GeS{sub 2} system. The phase diagram of the Cu{sub 2}GeS{sub 3}-ZnS system was constructed using differential-thermal analysis and X-ray diffraction, and the existence of Cu{sub 2}ZnGeS{sub 4} has been confirmed. It forms incongruently at 1359K. Powder X-ray diffraction was used to refine the crystal structure of Cu{sub 2}ZnGeS{sub 4}, which crystallizes in the tetragonal stannite-type structure at 670K (space group I4-bar 2m, a=0.534127(9)nm, c=1.05090(2)nm, R{sub I}=0.0477). The possibility of the formation of quaternary compounds in the quasi-ternary systems A{sup I}{sub 2}X-B{sup II}X-C{sup IV}X{sub 2}, where A{sup I}-Cu, Ag; B{sup II}-Zn, Cd, Hg; C{sup IV}-Si, Ge, Sn and X-S, Se, Te is discussed.

Magnetic and electronic properties of YBa sub 2 Cu sub 3 O sub x (6. 5

Energy Technology Data Exchange (ETDEWEB)

Puempin, B.; Keller, H.; Kuendig, W.; Savic, I.M.; Schneider, J.W.; Simmler, H.; Zimmermann, P. (Physik-Inst., Univ. Zurich (Switzerland)); Kaldis, E.; Rusiecki, S. (Lab. fuer Festkoerperphysik, ETH Zurich (Switzerland)); Rossel, C. (IBM Research Div., Zurich Research Lab., Rueschlikon (Switzerland)); Forgan, E.M. (School of Physics and Space Research, Univ. of Birmingham (UK))

1990-10-15

A systematic study of the local magnetic field distribution p(B) in the perovskite-type superconductor YBa{sub 2}Cu{sub 3}O{sub x} is presented. Special attention is given to the second moment <{Delta}B{sup 2}> of p(B) which is closely related to the superconducting carrier density n{sub s} and the effective mass m{sup *} of the superconducting carriers. The influence of temperature, anisotropy and hole doping are investigated in detail. It is found that the temperature dependence of the magnetic penetration depth in YBa{sub 2}Cu{sub 3}O{sub x} is in agreement with conventional s-wave pairing and suggests strong coupling. The anisotropic behavior of p(B) is well described by a theory for uniaxial type II superconductors, with an anisotropy ratio {gamma}{approx equal}5(1). Moreover, the zero-temperature values {lambda}{sub ab}(0)=130(10) nm and {lambda}{sub c}(0){approx equal}500-800 nm (penetration depth for screening currents flowing in the ab-planes and along the c-axis, respectively) were extracted from our data. {mu}SR experiments performed on oxygen deficient samples indicate that the structural and electronic properties of YBa{sub 2}Cu{sub 3}O{sub x} are strongly correlated via the oxygen content x. (orig.).

Substrate type < 111 >-Cu{sub 2}O/<0001 >-ZnO photovoltaic device prepared by photo-assisted electrodeposition

Energy Technology Data Exchange (ETDEWEB)

Zamzuri, Mohd, E-mail: zamzuri@tf.me.tut.ac.jp [Department of Mechanical Eng., Toyohashi University of Technology, 1-1 Hibari Gaoka, Tempaku, Toyohashi, Aichi 441-8580 (Japan); School of Manufacturing Eng., Universiti Malaysia Perlis, Kampus Tetap Pauh Putra, Jln Arau-Changlun, 02600 Arau, Perlis (Malaysia); Sasano, Junji [Department of Mechanical Eng., Toyohashi University of Technology, 1-1 Hibari Gaoka, Tempaku, Toyohashi, Aichi 441-8580 (Japan); Mohamad, Fariza Binti [Faculty of Electrical & Electronic Eng., University Tun Hussein Onn Malaysia, 86400, Parit Raja, Batu Pahat, Johor (Malaysia); Izaki, Masanobu [Department of Mechanical Eng., Toyohashi University of Technology, 1-1 Hibari Gaoka, Tempaku, Toyohashi, Aichi 441-8580 (Japan)

2015-11-30

The substrate-type < 0001 > ZnO/<111 > Cu{sub 2}O photovoltaic (PV) device has been constructed by electrodeposition of a < 111 >-p-Cu{sub 2}O layer on an Au(111)/Si wafer substrate followed by stacking the n-ZnO layer by electrodeposition during light irradiation in aqueous solutions. The PV device was fabricated by stacking the Al:ZnO-window by sputtering and the top Al electrode by vacuum evaporation. The < 0001 >-ZnO layer was composed of aggregates of hexagonal columnar grains grown in the direction normal to the surface, and pores could be observed between the ZnO grains at the deposition time last 1800 s. The < 0001 >-ZnO/<111 >-Cu{sub 2}O PV device showed a photovoltaic performance under AM1.5 illumination, and showed the improved short-circuit current density of 5.87 mA cm{sup −2} by stacking the AZO-TCO due to the increase in the diffusion length of the carrier. - Highlights: • Substrate type ZnO/Cu{sub 2}O photovoltaic devices only by electrodeposition • ZnO layer was stacked on the Cu{sub 2}O layer by photo-assisted electrodeposition. • AZO/ZnO/Cu{sub 2}O photovoltaic devices with a short-circuit current density of 5.87 mA cm{sup −2}.

Preparation and properties of Y{sub 1-x}Ho{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-{delta}} thin films by TFA-MOD method

Energy Technology Data Exchange (ETDEWEB)

Jian Hongbin [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Li Qi; Shi Dongqi [Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong 2522 (Australia); Zhang Li [Department of Mathematic and Physics, Anhui University of Architecture, Hefei 230022 (China); Yang Zhaorong [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Dou Shixue [Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong 2522 (Australia); Zhu Xuebin, E-mail: xbzhu@issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Sun Yuping [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China)

2011-12-15

Y{sub 1-x}Ho{sub x}BCO thin films were prepared by TFA-MOD. The best performances were obtained for the Y{sub 0.6}Ho{sub 0.4}BCO thin film. The pinning mechanism was {delta}l-type for all derived thin films. Y{sub 1-x}Ho{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-{delta}} (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) thin films were prepared on LaAlO{sub 3} (0 0 1) substrates by trifluoroacetate metal organic deposition (TFA-MOD) without change of the processing parameters. The highest J{sub c} was attributed to the sample of Y{sub 0.6}Ho{sub 0.4}Ba{sub 2}Cu{sub 3}O{sub 7-{delta}} thin film, whose critical current density is about 1.6 times as compared to that of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} thin film at 77 K and self field. The flux pinning type was not varied with Ho substitution and can be attributed to {delta}l pinning model, which is attributed to the close ionic radius between the Y{sup 3+} and Ho{sup 3+} ions. The improvement of J{sub c} by Ho substitution without change of the processing parameters will provide an effective route to enhance the J{sub c} of YBCO-based thin films using TFA-MOD method.

Observation of changing crystal orientations during grain coarsening

International Nuclear Information System (INIS)

Sharma, Hemant; Huizenga, Richard M.; Bytchkov, Aleksei; Sietsma, Jilt; Offerman, S. Erik

2012-01-01

Understanding the underlying mechanisms of grain coarsening is important in controlling the properties of metals, which strongly depend on the microstructure that forms during the production process or during use at high temperature. Grain coarsening of austenite at 1273 K in a binary Fe–2 wt.% Mn alloy was studied using synchrotron radiation. Evolution of the volume, average crystallographic orientation and mosaicity of more than 2000 individual austenite grains was tracked during annealing. It was found that an approximately linear relationship exists between grain size and mosaicity, which means that orientation gradients are present in the grains. The orientation gradients remain constant during coarsening and consequently the character of grain boundaries changes during coarsening, affecting the coarsening rate. Furthermore, changes in the average orientation of grains during coarsening were observed. The changes could be understood by taking the observed orientation gradients and anisotropic movement of grain boundaries into account. Five basic modes of grain coarsening were deduced from the measurements, which include: anisotropic (I) and isotropic (II) growth (or shrinkage); movement of grain boundaries resulting in no change in volume but a change in shape (III); movement of grain boundaries resulting in no change in volume and mosaicity, but a change in crystallographic orientation (IV); no movement of grain boundaries (V).

Fabrication and sulfurization of Cu{sub 2}SnS{sub 3} thin films with tuning the concentration of Cu-Sn-S precursor ink

Energy Technology Data Exchange (ETDEWEB)

Wang, Chi-Jie [Institute of Microelectronics & Department of Electrical Engineering, National Cheng Kung University, Taiwan (China); Shei, Shih-Chang, E-mail: scshei@mail.nutn.edu.tw [Department of Electrical Engineering, Nation University of Tainan, Taiwan (China); Chang, Shih-Chang [Department of Electrical Engineering, Nation University of Tainan, Taiwan (China); Chang, Shoou-Jinn [Institute of Microelectronics & Department of Electrical Engineering, National Cheng Kung University, Taiwan (China)

2016-12-01

Highlights: • Tuning the relative reaction rate of component phases proved to be beneficial in controlling the reaction process. • Low-concentration samples display closely packed Cu{sub 2}SnS{sub 3} grains with a flat morphology. • Optical band-gap energy measured at 1.346 eV suitable for thin-film solar cell applications. - Abstract: In this study, Cu-Sn-S nanoinks were synthesized by combining chelating polyetheramine to Cu, Sn, S powders of various concentrations. X-ray diffraction patterns indicate that nanoinks synthesized at low concentrations are composed almost entirely of binary phases SnS and Cu{sub 2}S. Synthesizing nanoinks at higher concentrations decreased the quantity of binary phase and led to the appearance of ternary phase Cu{sub 4}SnS{sub 4}. Following sulfurization, single phase Cu{sub 2}SnS{sub 3} (CTS) thin film was obtained from nanoinks of low concentration; however, impurities, such as Cu{sub 2}S were detected in the thin film obtained from nanoinks of high concentration. This can be attributed to the fact that lower concentrations reduce the reactivity of all the elements. As a result, the SnS phase reacted more readily and more rapidly, resulting in the early formation of a stoichiometric CTS thin film during sulfurization. Under these reaction conditions, Cu{sub 2}S and SnS transform into CTS and thereby prevent the formation of unwanted phases of Cu{sub 2}S and Cu{sub 4}SnS{sub 4}. Raman spectra revealed that second phase Cu{sub 2}S phase remained in the high-concentration samples, due to an increase in reactivity due to the participation of a greater proportion of the copper in the reaction. The surface microstructure of low-concentration samples display closely packed Cu{sub 2}SnS{sub 3} grains with a flat morphology and an atomic composition ratio of Cu:Sn:S = 34.69:15.90:49.41, which is close to stoichiometric. Hall measurement revealed that low-concentration sample has superior electrical properties; i.e., a hole

2D magnetization of grain-oriented 3%-Si steel under uniaxial stress

International Nuclear Information System (INIS)

Permiakov, V.; Dupre, L.; Pulnikov, A.; Melkebeek, J.

2005-01-01

Magnetization in electrical steels is strongly affected by mechanical stress. The stress dependence of magnetic properties of non-oriented steels has been studied at one- and two-dimensional magnetization. This paper deals with the stress effect on one- and two-dimensional magnetization in grain-oriented 3%-Si steel. The special magnetic measurements system is applied to combine uniaxial stress and 2D magnetic measurements. The uniaxial stress ranges from 10 MPa compressive stress to 100 MPa tensile stress. A domain theory is a suitable tool for prediction and a physical explanation of stress dependency in grain-oriented steel

Oxygen diffusion in cuprate superconductors

Energy Technology Data Exchange (ETDEWEB)

Routbort, J.L.; Rothman, S.J.

1995-01-01

Superconducting properties of the cuprate superconductors depend on the oxygen content of the material; the diffusion of oxygen is thus an important process in the fabrication and application of these materials. This article reviews studies of the diffusion of oxygen in La{sub 2}{sub {minus}}{sub {times}}Sr{sub {times}}CuO{sub 4}, YBa{sub 2}Cu{sub 3}O{sub 7}{sub {minus}}{delta}, YBa{sub 2}Cu{sub 4}O{sub 8}, and the Bi{sub 2}Sr{sub 2}Ca{sub n}{sub {minus}}{sub 1}Cu{sub n}O{sub 2}{sub +}{sub 4} (n = 1, and 2) superconductors, and attempt to elucidate the atomic mechanisms responsible.

The crystallisation of Cu{sub 2}ZnSnS{sub 4} thin film solar cell absorbers from co-electroplated Cu-Zn-Sn precursors

Energy Technology Data Exchange (ETDEWEB)

Schurr, R. [Chair for Crystallography and Structural Physics, University of Erlangen-Nuernberg, Staudtstrasse 3, D-91058 Erlangen (Germany)], E-mail: schurr@krist.uni-erlangen.de; Hoelzing, A.; Jost, S.; Hock, R. [Chair for Crystallography and Structural Physics, University of Erlangen-Nuernberg, Staudtstrasse 3, D-91058 Erlangen (Germany); Voss, T.; Schulze, J.; Kirbs, A. [Atotech Deutschland GmbH, Erasmusstrasse 20, D-10553 Berlin (Germany); Ennaoui, A.; Lux-Steiner, M. [Heterogeneous Material Systems SE II, Hahn-Meitner-Institut, Glienickerstr.100, D-14109 Berlin (Germany); Weber, A.; Koetschau, I.; Schock, H.-W. [Technology SE III, Hahn-Meitner-Institut, Glienickerstr.100, D-14109 Berlin (Germany)

2009-02-02

The best CZTS solar cell so far was produced by co-sputtering continued with vapour phase sulfurization method. Efficiencies of up to 5.74% were reached by Katagiri et al. The one step electrochemical deposition of copper, zinc, tin and subsequent sulfurization is an alternative fabrication technique for the production of Cu{sub 2}ZnSnS{sub 4} based thin film solar cells. A kesterite based solar cell (size 0.5 cm{sup 2}) with a conversion efficiency of 3.4% (AM1.5) was produced by vapour phase sulfurization of co-electroplated Cu-Zn-Sn films. We report on results of in-situ X-ray diffraction (XRD) experiments during crystallisation of kesterite thin films from electrochemically co-deposited metal films. The kesterite crystallisation is completed by the solid state reaction of Cu{sub 2}SnS{sub 3} and ZnS. The measurements show two different reaction paths depending on the metal ratios in the as deposited films. In copper-rich metal films Cu{sub 3}Sn and CuZn were found after electrodeposition. In copper-poor or near stoichiometric precursors additional Cu{sub 6}Sn{sub 5} and Sn phases were detected. The formation mechanism of Cu{sub 2}SnS{sub 3} involves the binary sulphides Cu{sub 2-x}S and SnS{sub 2} in the absence of the binary precursor phase Cu{sub 6}Sn{sub 5}. The presence of Cu{sub 6}Sn{sub 5} leads to a preferred formation of Cu{sub 2}SnS{sub 3} via the reaction educts Cu{sub 2-x}S and SnS{sub 2} in the presence of a SnS{sub 2}(Cu{sub 4}SnS{sub 6}) melt. The melt phase may be advantageous in crystallising the kesterite, leading to enhanced grain growth in the presence of a liquid phase.

Magnetization studies in ceramic YBa sub 2 Cu sub 3 O sub 7-x. Issledovanie namagnichennosti v keramicheskom YBa sub 2 Cu sub 3 O sub 7-x

Energy Technology Data Exchange (ETDEWEB)

Gamtsemlidze, G A; Bibiluri, D I; Gamkrelidze, K P; Mirzoeva, M I; Sharikadze, L A; Shoniya, G K [Tbilisskij Gosudarstvennyj Univ., Tbilisi (Georgia)

1991-05-01

The behaviour of ceramic YBa{sub 2}Cu{sub 3}O{sub 7-x} sample magnetization is studied as a function of the external field, prehistory and temperature using the ballistic method. The results obtained are interpreted is terms of the vortex model.

Measurements of ultrafast dynamics in a superconductor, YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}, and a semiconductor, GaSb

Energy Technology Data Exchange (ETDEWEB)

Smith, D.C

1998-07-01

Measurements of ultrafast dynamics in GaSb and YBa{sub 2}Cu{sub 3}O{sub 7-}{delta} (YBCO) have been made with 1 ps or better resolution using time-resolved optical spectroscopy; pump-probe transmission and reflection, and time-resolved Raman spectroscopy. The study of carrier dynamics in GaSb focuses on the scattering of electrons between the F and L conduction band valleys by zone-boundary phonons {gamma}-L scattering in bulk GaSb and a GaSb/AlSb multiple quantum well sample has been investigated in a series of room temperature degenerate pump-probe transmission experiments with near bandgap excitation. There is a clear difference in the dynamics between experiments where electrons excited in {gamma} can/cannot directly scatter to the L valleys. Ensemble Monte Carlo simulations are presented which are in good agreement with the experiments. The strength of {gamma}-L scattering is quantified using an intervalley deformation potential for a single 'effective' zone-boundary phonon (25meV). A deformation potential of 3.6{+-}0.4 eVA{sup -1} is consistent with both the bulk and quantum well results. The temperature dependence of the dynamics in bulk GaSb is also explored. Time-resolved Raman spectroscopy (E{sub laser}{approx}E{sub 0}+{delta}{sub 0}) has been used to study {gamma}-F scattering by measuring the dynamics of phonons emitted during intravalley scattering. All the measured non-equilibrium phonon populations have a component whose lifetime is greater the phonons anharmonic lifetime. This component is interpreted as following the return of electrons from L to {gamma}. Comparison of the results with the pump-probe experiments indicates that this return is slowed by blocking of {gamma} states. The study of YBCO consists of pump-probe transmission and reflection measurements of thin films and single crystals in both the normal and superconducting states. Measurements of dynamics have been made with a wide range of probe energies lower than in any

Measurement and correlation of optical and TEM twins in Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7-δ/

International Nuclear Information System (INIS)

Chumbley, L.S.; Verhoeven, J.D.; Kim, M.R.; Cornelius, A.L.; Kramer, M.J.

1989-01-01

The spacing of the twins present in Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7-δ/ has been investigated using optical and Transmission Electron Microscopy (TEM). Studies have reported that the value of the average twin spacing obtained by optical measurements is much larger than that measured in thin foils prepared for TEM observation, and controversy exists as to the exact nature of the optical twins. Experiments have been conducted which show that the twins observed optically correspond to those seen using TEM and are not produced by an optical interference effect. Using electron channeling, equations have been formulated which allow optical determination of the true spacing of twins present in a selected grain as well as the orientation of that grain. The average twin spacing measured in TEM has been found to vary with sample preparation method, being smaller for crushed chip samples than for bulk samples prepared by ion milling or jet-polishing. A variation of the twin spacing with grain size has also been noted

Cu{sub 2}ZnSnS{sub 4} thin films obtained by sulfurization of evaporated Cu{sub 2}SnS{sub 3} and ZnS layers: Influence of the ternary precursor features

Energy Technology Data Exchange (ETDEWEB)

Robles, V.; Guillén, C., E-mail: c.guillen@ciemat.es; Trigo, J.F.; Herrero, J.

2017-04-01

Highlights: • Kesterite Cu{sub 2}ZnSnS{sub 4} is got by sulfurization of evaporated Cu{sub 2}SnS{sub 3} and ZnS layers. • Smooth films are obtained by decreasing the growth temperature of Cu{sub 2}SnS{sub 3}. • The lattice strain and the electrical conductivity increase with the Cu-content. • The energy gap diminishes as the Cu-content and/or the surface roughness increase. - Abstract: Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films have been grown by sulfurization of Cu{sub 2}SnS{sub 3} (CTS) and ZnS layers evaporated on glass substrates. Four CTS precursor films have been tested, with two different atomic compositions (Cu/Sn = 1.7 and Cu/Sn = 2.1) and substrate temperatures (350 and 450 °C), together with analogous ZnS layers deposited by maintaining the substrate at 200 °C. The sulfurization of the CTS and ZnS stacked layers was performed at 500 °C during 1 h. The evolution of the crystalline structure, morphology, optical and electrical properties from each CTS precursor to the CZTS compound has been studied, especially the influence of the ternary precursor features on the quaternary film characteristics. The kesterite structure has been identified after sulfurization of the various samples, with main (112) orientation and mean crystallite sizes S{sub 112} = 40–56 nm, being higher for the Cu-poor compositions. The CZTS average roughness has varied in a wide interval R{sub a} = 8–66 nm, being directly related to the CTS precursor layer, which becomes rougher for a higher deposition temperature or Cu content. Besides, the band gap energy and the electrical resistivity of the CZTS films have changed in the ranges E{sub g} = 1.54–1.64 eV and ρ = 0.2–40 Ωcm, both decreasing when the Cu content and/or the surface roughness increase.

Magnetic properties of high temperature superconductors. AC susceptibility and magnetostriction studies

Energy Technology Data Exchange (ETDEWEB)

Heill, L K

1995-05-01

The author of this thesis has measured the ac magnetic response function {mu} = {mu}`+i{mu}`` in melt-powder-melt-growth YBa{sub 2}Cu{sub 3}O{sub 7} (Y123) with insulating Y{sub 2}BaCuO{sub 5} (Y211) and in single crystal YBa{sub 2}Cu{sub 3}O{sub 7} (SC) in applied dc fields up to 8 T, oriented both parallel and perpendicular to the crystalline c-axis. Both samples are cubes with sides of about 1 mm. The response of the two samples was mapped out as a function of temperature, excitation field amplitude and frequency, dc field and field orientation. It is found that for both samples the loss peak line (LPL) and hence the irreversibility line (IL) exists at higher temperatures and fields for perpendicular field orientation than for parallel. Strong frequency but weak amplitude dependence is observed for parallel orientation, vice versa for perpendicular orientation. The measured response is strongly non-linear for perpendicular orientation, and intermediate between linear (ohmic) and extremely non-linear (Bean critical state) for parallel orientation. The situation at parallel orientation is close to but above the transition into a vortex solid state, and a power law temperature dependence with exponent 1.5 is obtained for the vortex glass transition line. For perpendicular orientation the response is consistent with that expected in a vortex solid. Pinning barriers are found by means of thermal activation analysis. Anomalous loss peaks {mu}``(T) are observed for the SC sample for intermediate fields in perpendicular orientation. Large magnetostriction is found in a flat single crystal Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} sample at low temperature and fields up to 6 T applied along the c-axis. 332 refs., 59 figs., 7 tabs.

Controllable growth and photocatalytic activity of Cu{sub 2}O solid microspheres

Energy Technology Data Exchange (ETDEWEB)

Gao, Hong; Zhang, Junying, E-mail: zjy@buaa.edu.cn; Wang, Mei

2013-09-01

Graphical abstract: - Highlights: • 3 μm uniform Cu{sub 2}O solid microspheres with abundant nanopores are achieved. • NH{sub 2}OH·HCl and SDS are main factors that manipulate morphologies of Cu{sub 2}O particles. • Surface features of microspheres influenced the photocatalytic activity of Cu{sub 2}O. • Microspheres are transforming to polyhedrons with extended holding time. - Abstract: A series of Cu{sub 2}O solid microspheres with different surface features were prepared and their photocatalytic activities were studied. The experiment conditions were investigated and the formation mechanism was explored systematically. It was found that varying the amounts of NH{sub 2}OH·HCl reductant in alkaline solutions changed the reaction process and thus altered the surface features of Cu{sub 2}O microspheres. Sodium dodecyl sulfate (SDS) surfactant, introduced as a morphology directing agent, caused the nuclei aggregation and growth process of Cu{sub 2}O solid microspheres by precisely realizing the opposite charges’ directional attraction. This SDS-mediated method can be readily extended to synthesizing solid microspheres of other metal oxides. Meanwhile, it was found that Cu{sub 2}O solid microspheres with abundant nanopores on the surface showed much higher efficient catalytic activity for decoloring methyl orange (MO) aqueous solution than with other surface features under visible light irradiation. Furthermore, we found that prolonging the holding time made Cu{sub 2}O microspheres transform to polyhedrons.

Irradiation effects in superconductor oxides. Effets d'irradiation dans les oxydes supraconducteurs

Energy Technology Data Exchange (ETDEWEB)

Rullier-Albenque, F; Konczykowski, M [CEA-Ecole Polytechnique, 91 - Palaiseau (France). Lab. d' Etudes des Solides Irradies

1993-01-01

Several effects of irradiation on the 92 K - oxide superconductor YBa[sub 2]Cu[sub 3]O[sub 7] are reported. Whatever irradiation type, the critical temperature T[sub c] is found to decrease and the resistivity to increase. At sufficiently high damage levels, YBa[sub 2]Cu[sub 3]O[sub 7] is no longer superconducting and even displays a semiconducting-like behaviour. The alterations of superconducting properties are clearly related to oxygen defects - in the CuO[sub 2] planes or CuO chains... but we have shown experimentally that copper defects are also important. Magnetic properties of YBa[sub 2]Cu[sub 3]O[sub 7] in mixed state are also very sensitive to irradiation. By pinning the flux lines, irradiation defects can considerably increase the critical current density j[sub c]. At present, irradiations by highly energetic heavy ions (6 GeV Pb for instance), which produce cylindrical tubes of amorphous material (latent tracks) throughout the whole thickness of the samples, are probably the most efficient way to enhance j[sub c]. (Author). 18 refs., 7 figs.

Electronic, magnetic, elastic and thermodynamic properties of Cu{sub 2}MnGa

Energy Technology Data Exchange (ETDEWEB)

Ghosh, Sukriti [Department of Physics, Government Kamla Raja Girls Autonomous Post Graduate College, Gwalior 474001, Madhya Pradesh (India); Condensed Matter Theory Group, School of Studies in Physics, Jiwaji University, Gwalior 474 011, Madhya Pradesh (India); Gupta, Dinesh C., E-mail: sosfizix@gmail.com [Condensed Matter Theory Group, School of Studies in Physics, Jiwaji University, Gwalior 474 011, Madhya Pradesh (India)

2016-08-01

The full-potential linearized augmented plane wave method in the stable Fm-3m phase has been implemented to investigate the structural, elastic, magnetic and electronic properties of Cu{sub 2}MnGa. The optimized equilibrium lattice parameter in stable phase is found to be 5.9495 Å. By the spin resolved density of states calculations, we have shown that the exchange splitting due to Mn atom is the main reason of ferromagnetic behavior of Cu{sub 2}MnGa. The absence of energy gap in both the spin channels predicts that the material is metallic. The total and partial density of states, elastic constants, Shear, Bulk and Young’s moduli, Zener isotropy factor, Cauchy pressure, Pugh's ductility, Kleinman parameter and Poisson's ratio are reported for the first time for the alloy. Cauchy's pressure and Pugh's index of ductility label Cu{sub 2}MnGa as ductile. Cu{sub 2}MnGa is found to be ferromagnetic and anisotropic in nature. The quasi-harmonic approximations have been employed to study the pressure and temperature dependent thermodynamic properties of Cu{sub 2}MnGa. - Highlights: • It is the first attempt to predict a variety of crystal properties of Cu{sub 2}MnGa. • Cu{sub 2}MnGa shows magnetism and hence can prove to be important in modern technology. • Cu{sub 2}MnGa is ductile and hence can attract attention of scientists and technologists.

The influence of precursor Cu content and two-stage processing conditions on the microstructure of Cu{sub 2}ZnSnSe{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Márquez-Prieto, J., E-mail: jose.prieto@northumbria.ac.uk [Northumbria Photovoltaic Application Centre, Faculty of Engineering and Environment, Northumbria University, Ellison Building, Newcastle upon Tyne NE1 8ST (United Kingdom); Ren, Y. [Ångström Solar Center, Solid State Electronics, Uppsala University, Uppsala 751 21 (Sweden); Miles, R.W.; Pearsall, N.; Forbes, I. [Northumbria Photovoltaic Application Centre, Faculty of Engineering and Environment, Northumbria University, Ellison Building, Newcastle upon Tyne NE1 8ST (United Kingdom)

2015-05-01

This paper reports the influence of processing temperature on the microstructure of Cu{sub 2}ZnSnSe{sub 4} (CZTSe) absorber layers for temperatures between 380 and 550 °C produced using a 2-stage process. X-ray diffraction analysis showed the formation of Cu{sub 2}ZnSnSe{sub 4} over this temperatures range. The Williamson-Hall method was used for microstructural analysis of the CZTSe absorbers, and this showed a progressive decrease of the micro-strain of the CZTSe with increasing selenisation temperature. The influence of precursor Cu content on the microstructure of the CZTSe was also studied. An increase of Cu content in the precursor is correlated to an increase in grain size and a decrease in micro-strain. Raman measurements show an asymmetrical broadening towards lower energies of the main 197 cm{sup −1} mode for Cu-poor compositions. This study provides an insight into the dependency of the crystallinity of CZTSe on composition and synthesis temperature. - Highlights: • We fabricate Cu{sub 2}ZnSnSe{sub 4} thin films by sputtering and post-reactive annealing. • The micro-strain of Cu{sub 2}ZnSnSe{sub 4} increases when Cu content decreases. • The micro-strain of Cu{sub 2}ZnSnSe{sub 4} decreases with increasing processing temperature. • The defect concentration of Cu{sub 2}ZnSnSe{sub 4} increases when Cu content decreases.

Photoelectrochemical oxidation of ibuprofen via Cu{sub 2}O-doped TiO{sub 2} nanotube arrays

Energy Technology Data Exchange (ETDEWEB)

Sun, Qiannan [College of Environment and Energy, South China University of Technology, Guangzhou (China); Peng, Yen-Ping, E-mail: yppeng@thu.edu.tw [Department of Environmental Science and Engineering, Tunghai University, Taichung, Taiwan (China); Chen, Hanlin [College of Environment and Energy, South China University of Technology, Guangzhou (China); Chang, Ken-Lin [School of Environmental Science and Engineering and Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 51006 China (China); Qiu, Yang-Neng; Lai, Shiau-Wu [Department of Environmental Science and Engineering, Tunghai University, Taichung, Taiwan (China)

2016-12-05

Highlights: • A p–n junction material was synthesized to enhance photocatalytic ability. • Cu{sub 2}O-doped TiO{sub 2} nanotube arrays works as a photoanode in a PEC system. • Recombination of photo-generated holes and electrons were greatly reduced. • Synergetic effect was quantified in PEC degradation. • Recombination of photogenerated holes and electrons was greatly enhanced. - Abstract: A p–n junction based Cu{sub 2}O-doped TiO{sub 2} nanotube arrays (Cu{sub 2}O-TNAs) were synthesized and used as a working anode in a photoelectrochemical (PEC) system. The results revealed that the Cu{sub 2}O-TNAs were dominated by the anatase phase and responded significantly to visible light. XPS analyses indicated that with an amount of 24.79% Cu doping into the structure, the band gap of Cu{sub 2}O-TNAs was greatly reduced. SEM images revealed that the supported TiO{sub 2} nanotubes had diameters of approximately 80 nm and lengths of about 2.63 μm. Upon doping with Cu{sub 2}O, the TiO{sub 2} nanotubes maintained their structural integrity, exhibiting no significant morphological change, favoring PEC applications. Under illumination, the photocurrent from Cu{sub 2}O/TNAs was 2.4 times larger than that from TNAs, implying that doping with Cu{sub 2}O significantly improved electron mobility by reducing the rate of recombination of electron-hole pairs. The EIS and Bode plot revealed that the estimated electron lifetimes, τ{sub el}, of TNAs and Cu{sub 2}O/TNAs were 6.91 and 26.26 ms, respectively. The efficiencies of degradation of Ibuprofen by photoelectrochemical, photocatalytic (PC), electrochemical (EC) and photolytic (P) methods were measured.

Anisotropy and intergrain current density in oriented grained bulk YBa2Cu3Ox superconductor

International Nuclear Information System (INIS)

Selvamanickam, V.; Salama, K.

1990-01-01

The intergrain transport current density and its anisotropy have been studied in oriented grained bulk YBa 2 Cu 3 O x superconductors fabricated by the liquid phase processing method. Current density measurements were performed on oriented grained samples with the transport current aligned at different angles to the a-b plane. In these measurements, the transport current passed through several oriented grain boundaries. The results indicate that the critical current density drops rapidly when the transport current flows at small angles to the a-b plane and then decreases slowly at larger angles. At 77 K and zero magnetic field, an anisotropy ratio of about 25 is observed between J c along a-b plane and that perpendicular to the plane. Further, the critical current density in these samples is found to depend weakly on magnetic field even though the current crosses grain boundaries. These results support the notion that grain boundaries of these superconductors are different in nature from those of solid-state sintered samples.

LaNiO(3) Buffer Layers for High Critical Current Density YBa(2)Cu(3)O(7-delta) and Tl(2)Ba(2)CaCu(2)O(8-delta) Films

Energy Technology Data Exchange (ETDEWEB)

Carlson, C.M.; Parilla, P.A.; Siegal, M.P.; Ginley, D.S.; Wang, Y.-T.; Blaugher, R.D.; Price, J.C.; Overmyer, D.L.; Venturini, E.L.

1999-08-24

We demonstrate high critical current density superconducting films of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} (YBCO) and Tl{sub 2}Ba{sub 2}CaCu{sub 2}O{sub 8{minus}{delta}} (Tl-2212) using LaNiO{sub 3} (LNO) buffer layers. YBCO films grown on an LNO buffer layer have only a slightly lower J{sub c} (5K, H=0) than films grown directly on a bare LaAlO{sub 3} substrate. It is noteworthy that YBCO films grown on LNO buffer layers exhibit minor microstructural disorder and enhanced flux pinning. LNO-buffered Tl-2212 samples show large reductions in J{sub c} at all temperatures and fields compared to those grown on bare LaAlO{sub 3}, correlating to both a-axis grain and nonsuperconducting phase formation. With additional optimization, LNO could be a promising buffer layer for both YBCO and Tl-based superconducting films, perhaps ideally suited for coated conductor applications.

Effects of artificial holes in very large single-grain Y{sub 1.5}Ba{sub 2}Cu{sub 3}O{sub 7-y} bulk superconductors

Energy Technology Data Exchange (ETDEWEB)

Park, S. D.; Jun, B. H.; Kim, C. J. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, H. W. [Korea University of Technology and Education, Cheonan (Korea, Republic of)

2017-09-15

The effects of artificial holes on the trapped magnetic fields and magnetic levitation forces of very large single-grain Y{sub 1.5}Ba{sub 2}Cu{sub 3}O{sub 7-y} (Y1.5) bulk superconductors were studied. Artificial holes were made for Y1.5 powder compacts by die pressing using cylindrical dies with a diameter of 30 mm or 40 m, or rectangular dies with a side length of 50 mm. The single grain Y1.5 bulk superconductors (25 mm, 33 mm in diameter and 42 mm in side length) with artificial holes were fabricated using a top-seeded melt growth (TSMG) process for the die-pressed Y1.5 powder compacts. The magnetic levitation forces at 77 K of the 25 mm single grain Y1.5 samples with one (diameters of 4.2 mm) or six artificial holes (diameters of 2.5 mm) were 10-17% higher than that of the Y1.5 sample without artificial holes. The trapped magnetic fields at 77 K of the Y1.5 samples with artificial holes were also 9.6-18% higher than that of the Y1.5 sample without artificial holes. The 33 mm and 42 mm single grain Y1.5 samples with artificial holes (2.5 mm and 4.2 mm in diameter) also showed trapped magnetic fields 10-13% higher than that of the Y1.5 samples without artificial holes in spite of the reduced superconducting volume fraction due to the presence of artificial holes. The property enhancement in the large single grain Y1.5 bulk superconductors appears to be attributed to the formation of the pore-free regions near the artificial holes and the homogeneous oxygen distribution in the large Y123 grains.

Sodium induced grain growth, defect passivation and enhancement in the photovoltaic properties of Cu{sub 2}ZnSnS{sub 4} thin film solar cell

Energy Technology Data Exchange (ETDEWEB)

Singh, Om Pal; Gour, Kuldeep Singh [Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110012 (India); Academy of Scientific and Innovative Research, CSIR-National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110012 (India); Parmar, Rahul [Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110012 (India); Singh, Vidya Nand, E-mail: singhvn@nplindia.org [Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110012 (India); Academy of Scientific and Innovative Research, CSIR-National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110012 (India)

2016-07-01

Sodium diffusion from soda lime glass (SLG) during high temperature annealing is known to play a crucial role in affecting the grain growth and defect passivation in chalocogenide/kesterite solar cells. Additional sodium is required when low temperature or short term annealing is used. Although this fact is known, a systematic comparative study for kesterite films is seldom reported. In the present study, Cu{sub 2}ZnSnS{sub 4} thin films were deposited on SLG and Mo coated SLG using stacked layer reactive sputtering. Na was deposited over the CZTS thin film and the film was annealed in N{sub 2} atmosphere in order to enhance the grain growth. This resulted in the shift in the XRD peak towards lower diffraction angle. The optical bandgap shifted from 1.45 eV to 1.38 eV with Na addition. Significant grain growth from hundreds of nanometer to micrometer was observed in samples with Na. Device fabricated in SLG/Mo/CZTS/CdS/ZnO/ITO configuration with Al front contact shows increase in efficiencies values from 1.50% to 2.84%. - Highlights: • Reactive sputtering with reduced annealing time have been used for the growth of CZTS thin film. • NaF has been deposited over precursor film before annealing. • Na addition resulted in grain growth, improved compactness and reduction in band gap. • An enhancement in the photovoltaic characteristics have been observed with addition of Na.

Crystallographic structure and grain size of polycrystalline Cu{sub 2}ZnSnS{sub 4} nanoparticles and thin films studied with XRD and SEM

Energy Technology Data Exchange (ETDEWEB)

Zutz, Folker; Chory, Christine; Riedel, Ingo; Parisi, Juergen [Thin Film Photovoltaics, Energy and Semiconductor Research Laboratory, University of Oldenburg, D-26111 Oldenburg (Germany)

2011-07-01

Cu{sub 2}ZnSnS{sub 4} (CZTS) is a compound semiconductor with an absorption coefficient of >10{sup 4} cm{sup -1} and energy gap of about 1.5 eV. Because CZTS is comprised of abundant and non-toxic precursor elements the semiconductor represents an attractive material for low-cost thin film solar cells. CZTS nanoparticles (NP) were prepared in a low-temperature colloidal synthesis yielding high amounts per synthesis cycle. For thin film deposition the NPs were converted to an ink which can be processed to thin films via printing techniques. Finally, the thin films were annealed in argon atmosphere at different temperatures in order to control the growth of microcrystallites. The photoelectrical quality of the semiconductor sensitively depends on the relative concentrations of the precursor elements (band gap, crystallographic phases) and the average grain size (charge transport). We report on structural investigations (X-ray diffraction, electron microscopy) of CZTS dried powders and thin films processed from inks with varying chemical compositions. Further, the evolution of the grain size was studied as function of the annealing temperature.

Preparation of transparent Cu{sub 2}Y{sub 2}O{sub 5} thin films by RF magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Chiu, Te-Wei, E-mail: tewei@ntut.edu.tw; Chang, Chih-Hao; Yang, Li-Wei; Wang, Yung-Po

2015-11-01

Highlights: • Cu{sub 2}Y{sub 2}O{sub 5} thin films were prepared by RF magnetron sputtering. • Cu{sub 2}Y{sub 2}O{sub 5} thin films have high transmittance and antibacterial properties. • Mechanical properties of Cu{sub 2}Y{sub 2}O{sub 5} thin films were investigated. - Abstract: Cu{sub 2}Y{sub 2}O{sub 5} thin films were deposited on non-alkali glass substrates by RF magnetron sputtering. Its crystal structure, microstructure, optical property, mechanical property, and antibacterial activity were investigated by grazing-incidence X-ray diffraction, transmittance spectra, nanoindenter, and antibiotics test, respectively. A single-phase of Cu{sub 2}Y{sub 2}O{sub 5} was obtained while annealing at 700 °C in air and its optical transparency was >80% in the visible region. The hardness and elastic modulus of the film were 6.7 GPa and 82 GPa, respectively. Antibiotics testing result revealed that Cu{sub 2}Y{sub 2}O{sub 5} surface had a superior antibacterial performance even at a dark environment. Therefore, Cu{sub 2}Y{sub 2}O{sub 5} is a promising novel transparent antibacterial hard coating material.

Effects of the copper content on the structural and electrical properties of Cu{sub 2}ZnSnSe{sub 4} bulks

Energy Technology Data Exchange (ETDEWEB)

Tsega, Moges, E-mail: mogestsega@yahoo.com [Department of Physics, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa); Department of Physics, Bahir Dar University (Ethiopia); Dejene, F.B.; Koao, L.F. [Department of Physics, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa)

2016-01-01

We have investigated the concept of defect in Cu{sub x}ZnSnSe{sub 4} (x=1.6–2.0) and Cu{sub y}(Zn{sub 0.9}Sn{sub 1.1})Se{sub 4} (y= 1.6–2.0) bulks prepared by liquid-phase sintering at 600 °C for 2 h with soluble sintering aids of Sb{sub 2}S{sub 3} and Te. All samples were found to exhibit p-type semiconductor for Cu{sub x}ZnSnSe{sub 4}, while n-type of behavior obtained at y= 1.8–2.0 for Cu{sub y}(Zn{sub 0.9}Sn{sub 1.1})Se{sub 4} pellets. The Cu vacancy acts as an acceptor point defect to form the p-type semiconductor, and Sn{sup 4+} acts as a donor to form the n-type behavior for the Sn-rich CZTSe. SEM images of pellets show dense surface morphology, and increase in grain size upon Cu inclusion. The largely increased Hall mobility and the slightly changed carrier concentration for Cu{sub y}(Zn{sub 0.9}Sn{sub 1.1})Se{sub 4} with increasing the Cu content is related to the types of its defects. At y=2.0 with carrier concentration of 4.88×10{sup 17} cm{sup −3} showed the highest mobility of around 58 cm{sup 2}/V s. Based upon the proposed point defects, the CZTSe property can be consistently explained.

Fabrication, characterization and application of Cu{sub 2}ZnSn(S,Se){sub 4} absorber layer via a hybrid ink containing ball milled powders

Energy Technology Data Exchange (ETDEWEB)

Li, Chunran [State Key Laboratory of Superhard Materials and College of Physics, Jilin University, Changchun 130023 (China); Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012 (China); College of Mathematics and Physics, Bohai University, Jinzhou 121013 (China); Yao, Bin, E-mail: binyao@jlu.edu.cn [State Key Laboratory of Superhard Materials and College of Physics, Jilin University, Changchun 130023 (China); Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012 (China); Li, Yongfeng, E-mail: liyongfeng@jlu.edu.cn [Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012 (China); Xiao, Zhenyu [State Key Laboratory of Superhard Materials and College of Physics, Jilin University, Changchun 130023 (China); Ding, Zhanhui [Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012 (China); Zhao, Haifeng; Zhang, Ligong; Zhang, Zhenzhong [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, No. 3888 Dongnanhu Road, Changchun 130033 (China)

2015-09-15

Highlights: • CZTS powders are prepared from binary sulfides by a low cost ball milling process. • Elaborated on phase evolution and formation mechanism of CZTS. • Proposed a hybrid ink approach to resolve difficulty in deposition of CZTS film. • CZTSSe solar cells with highest efficiency of 4.2% are fabricated. • Small-grained CZTS layer hinders the collection of minority carriers. - Abstract: Cu{sub 2}ZnSnS{sub 4} (CZTS) powder with kesterite structure was prepared by ball milling of mixture of Cu{sub 2}S, ZnS and SnS{sub 2} powders for more than 15 h. By dispersing the milled CZTS powder in a Cu-, Zn- and Sn-chalcogenide precursor solution, a hybrid ink was fabricated. With the hybrid ink, a precursor CZTS film was deposited on Mo coated soda-lime glass by spin-coating. In order to obtain Cu{sub 2}ZnSn(S,Se){sub 4} (CZTSSe) absorber film with kesterite structure, the CZTS film was annealed at 560 °C for 15 min in Se ambient. It is demonstrated that the annealed film is dominated by a thick layer of kesterite CZTSSe with larger grain size and Cu{sub 8}Fe{sub 3}Sn{sub 2}(S,Se){sub 12} impurity phase with the exception of a very thin layer of kesterite CZTS with smaller grain size at interface between the CZTSSe and Mo layers. Solar cell device was fabricated by using the annealed CZTSSe film as absorber layer, and its conversion efficiency reached 4.2%. Mechanism of formation of the kesterite CZTS powder and CZTSSe film as well as effect of impurity phases on conversion efficiency are discussed in the present paper. The present results suggest that the hybrid ink approach combining with ball milling is a simple, low cost and promising method for preparation of kesterite CZTSSe absorber film and CZTSSe-based solar cell.

Morphology transformation of Cu{sub 2}O by adding TEOA and their antibacterial activity

Energy Technology Data Exchange (ETDEWEB)

Duan, Weijia; Zheng, Min, E-mail: zhengmin@suda.edu.cn; Li, Rong; Wang, Yuyuan [Soochow University, National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering (China)

2016-11-15

Cu{sub 2}O polyhedral particles and hollow spheres were successfully synthesized by adjusting the concentration of triethanolamine (TEOA). The as-prepared samples were structurally characterized by the scanning electron microscope (SEM), X-ray powder diffraction (XRD), and transmission electron microscopy (TEM). The results revealed that the solid polyhedral Cu{sub 2}O with sizes ranging from 70 to 150 nm was in good crystallization. The diameter of the hollow Cu{sub 2}O spheres increased to 350–450 nm. It was found that the sizes and morphologies of the products could be significantly affected by the concentration of TEOA. And the morphology of Cu{sub 2}O transformed from solid polyhedrons to hollow spheres with the further enrichment of TEOA concentration. A possible mechanism was proposed to explain the formation of the hollow Cu{sub 2}O spheres. In addition, we investigated the antibacterial activities of the samples. It was demonstrated that the hollow Cu{sub 2}O sphere exhibited better antibacterial activities for Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) compared with the solid polyhedral Cu{sub 2}O.

Nanostructured Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction photoelectrode for efficient hydrogen production

Energy Technology Data Exchange (ETDEWEB)

Sharma, Dipika; Upadhyay, Sumant; Verma, Anuradha [Department of Chemistry, Dayalbagh Educational Institute, Agra-282 110 India (India); Satsangi, Vibha R. [Department of Physics Computer Sciences, Dayalbagh Educational Institute, Agra-282 110 India (India); Shrivastav, Rohit [Department of Chemistry, Dayalbagh Educational Institute, Agra-282 110 India (India); Dass, Sahab, E-mail: drsahabdas@gmail.com [Department of Chemistry, Dayalbagh Educational Institute, Agra-282 110 India (India)

2015-01-01

Nanostructured thin films of pristine Fe{sub 2}O{sub 3}, Ti-doped Fe{sub 2}O{sub 3}, Cu{sub 2}O, and Fe{sub 2}O{sub 3}/Cu{sub 2}O, and Ti-doped Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction were deposited on tin-doped indium oxide (Sn:In{sub 2}O{sub 3}) glass substrate using spray pyrolysis method. Ti doping is done to improve photoelectric conversion efficiency and electrical conductivity of hematite thin films. Further enhanced photocurrent is achieved for Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction electrodes. All samples were characterized using X-ray diffractometry, scanning electron microscopy, atomic force microscopy, and UV-Vis spectrometry. Photoelectrochemical properties were also investigated in a three-electrode cell system. UV-Vis absorption spectrum for pristine Fe{sub 2}O{sub 3}, Ti-Fe{sub 2}O{sub 3}, Cu{sub 2}O, Fe{sub 2}O{sub 3}/Cu{sub 2}O, and Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction thin films exhibited absorption in visible region. Nanostructured thin films as prepared were used as photoelectrode in the photoelectrochemical cell for water splitting reaction. Maximum photocurrent density of 2.60 mA/cm{sup 2} at 0.95 V/SCE was exhibited by 454 nm thick Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction photoelectrode. Increased photocurrent density and enhanced incident photon-to-electron conversion efficiency, offered by the heterojunction thin films may be attributed to improved conductivity and efficient separation of the photogenerated charge carriers at the Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O interface. - Highlights: • Heterojunction thin films were deposited using spray pyrolysis techniques. • Titanium doping in Fe{sub 2}O{sub 3} played a significant role in PEC response. • Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction shows the absorption in visible range. • Improved charge separation and enhanced PEC response were achieved in Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O.

Effects of Cold Rolling Reduction and Initial Goss Grains Orientation on Texture Evolution and Magnetic Performance of Ultra-thin Grain-oriented Silicon Steel

Directory of Open Access Journals (Sweden)

LIANG Rui-yang

2017-06-01

Full Text Available The ultra-thin grain-oriented silicon steel strips with a thickness of 0.06-0.12mm were produced by one-step-rolling methods with different Goss-orientation of grain-oriented silicon steel sheets. The effect of cold rolling reduction and initial Goss-orientation of samples on texture evolution and magnetic performance of ultra-thin grain-oriented silicon steel strips was studied by EBSD. The result shows that with the increase of cold rolling reduction and decrease of strips thickness, the recrystallization texture is enhanced after annealing.When the cold rolling reduction is 70%,RD//〈001〉 recrystallization texture is the sharpest, and the magnetic performance is the best. The higher degree of Goss orientation in initial sample is, the better magnetic performance of ultra-thin grain-oriented silicon steel.Therefore, for producing an ultra-thin grain-oriented silicon steel with high performance, a material with a concentrated orientation of Goss grains can be used.

Formation of Self-Assembled Ba₂YNbO₆ Nanocolumns and their Contribution to Flux-Pinning and J_c in Nb-doped YBa>2Cu₃O_7- Films

Energy Technology Data Exchange (ETDEWEB)

Wee, Sung Hun [ORNL; Goyal, Amit [ORNL; Zuev, Yuri L [ORNL; Cantoni, Claudia [ORNL; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York; Specht, Eliot D [ORNL

2010-01-01

Ba{sub 2}RENbO{sub 6} (RE = rare earth elements including Y) compounds are considered new additives for superior flux-pinning in YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) films due to their excellent chemical inertness to and large lattice mismatches with YBCO. Simultaneous laser ablation of a YBCO target and a Nb metal foil attached to the surface of the target resulted in epitaxial growth of YBCO films having columnar defects comprised of self-aligned Ba{sub 2}YNbO{sub 6} (BYNO) nanorods parallel to the c-axis of the film. Compared to pure YBCO, YBCO+BYNO films exhibited no T{sub c} reduction as well as superior J{sub c} performance with higher self- and in-field J{sub c} by a factor of 1.5-7 and also exhibited a strong J{sub c} peak for H {parallel} c indicative of strong c-axis correlated flux-pinning.

The two-dimensional vibrating reed technique. A study of anisotropic pinning in high-temperature superconductors

Energy Technology Data Exchange (ETDEWEB)

Karelina, Anna

2004-02-18

In this work the anisotropy of the pinning forces of vortices in a-b plane of high temperature-supraconductors was examined. For this purpose vibrating reed with two degrees of freedom of the oscillation was constructed. The pinning forces were examined in single crystals of YBa{sub 2}Cu{sub 3}O{sub 7} and Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}. The experiments with YBa{sub 2}Cu{sub 3}O{sub 7} show that at temperatures lower than 78 K the vortices are in a nonequilibrium state. This leads to a flux creep and to a drift of the resonance frequency with time. This prevents the comparison of resonance curves in different directions of oscillations. In Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} single crystals the vortices are in more stable state, but the measurements of the resonance curves in different directions show no indication of the four-fold symmetry. At temperatures below 60 K a strong hysteresis of the resonance frequency and the resonance-oscillation amplitude was found in YBa{sub 2}Cu{sub 3}O{sub 7} crystals as a function of the magnetic field. (orig.)

Selenization of mixed metal oxides for dense and ZnSe-free Cu{sub 2}ZnSnSe{sub 4} absorber films

Energy Technology Data Exchange (ETDEWEB)

Deng, Yitao; Chen, Guilin; Pan, Bin; Li, JianMin; Jiang, Guoshun; Liu, Weifeng, E-mail: liuwf@ustc.edu.cn; Zhu, Changfei, E-mail: cfzhu@ustc.edu.cn

2014-04-05

Highlights: • ZnSe-free CZTSe films with large grains was prepared from mixed oxides nanopraticles. • Appearance of Zn{sub 2}SnO{sub 4} in mixed oxides precursors leads to the absence of ZnSe secondary phrase. • To obtain pure CZTSe phase, different treating temperature was used. -- Abstract: Cu{sub 2}ZnSnSe{sub 4} (CZTSe) films were prepared by direct selenization of Cu{sub 2}O, SnO{sub 2} and Zn{sub 2}SnO{sub 4} precursors. Oxides precursors were prepared by baking hydroxides precipitation. In order to obtain ZnSe-free CZTSe films, Zn{sub 2}SnO{sub 4} was used to replace separated ZnO and SnO{sub 2} as one of the precursors. Through X-ray diffraction (XRD), scanning electron microscopy (SEM), it was found that CZTSe films, with micron-sized dense grains, were obtained in our work. From Raman spectra, it was also found that the ZnSe secondary phase was absent after the selenization. An energy bandgap about 0.86 eV was obtained in our work, which confirmed the Stannite-CZTSe structure.

Epitaxial solution deposition of YBa2Cu3O7-6 coated conductors.

Energy Technology Data Exchange (ETDEWEB)

Overmyer, Donald L.; Clem, Paul Gilbert; Siegal, Michael P.; Holesinger, Terry A. (Los Alamos National Laboratory, Los Alamos, NM); Voigt, James A.; Richardson, Jacob J.; Dawley, Jeffrey Todd

2004-11-01

A variety of solution deposition routes have been reported for processing complex perovskite-based materials such as ferroelectric oxides and conductive electrode oxides, due to ease of incorporating multiple elements, control of chemical stoichiometry, and feasibility for large area deposition. Here, we report an extension of these methods toward long length, epitaxial film solution deposition routes to enable biaxially oriented YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO)-coated conductors for superconducting transmission wires. Recent results are presented detailing an all-solution deposition approach to YBCO-coated conductors with critical current densities J{sub c} (77 K) > 1 MA/cm{sup 2} on rolling-assisted, biaxially textured, (200)-oriented Ni-W alloy tapes. Solution-deposition methods such as this approach and those of other research groups appear to have promise to compete with vapor phase methods for superconductor electrical properties, with potential advantages for large area deposition and low cost/kA {center_dot} m of wire.

Evolution of orientations and deformation structures within individual grains in cold rolled columnar grained nickel

DEFF Research Database (Denmark)

Wu, G.L.; Godfrey, A.; Winther, Grethe

2011-01-01

Columnar grained Ni is used as a model material allowing simultaneous non-surface investigations of the evolution of crystallographic orientations and deformation microstructures within individual grains as a function of rolling strain up to ε=0.7. Electron channelling contrast and electron...... backscattered diffraction are used to visualise microstructures and crystallographic orientations. It is found that both the microstructural and the textural development depend strongly on the initial grain orientation. A grain size effect is observed on the deformation-induced orientation scatter within...

Study of the magnetic phase transitions and magnetocaloric effect in Dy{sub 2}Cu{sub 2}In compound

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yikun, E-mail: ykzhang10@hotmail.com [State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai, 200072 (China); Shanghai Key Laboratory of Advanced Ferrometallurgy, Shanghai University, Shanghai, 200072 (China); School of Materials Science and Engineering, Shanghai University, 200072 (China); Institute of Materials Physics, University of Münster, Wilhelm-Klemm-Straße 10, D-48149, Münster (Germany); Xu, Xiao; Yang, Yang; Hou, Long; Ren, Zhongming [State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai, 200072 (China); Shanghai Key Laboratory of Advanced Ferrometallurgy, Shanghai University, Shanghai, 200072 (China); School of Materials Science and Engineering, Shanghai University, 200072 (China); Li, Xi, E-mail: lx_net@sina.com [State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai, 200072 (China); Shanghai Key Laboratory of Advanced Ferrometallurgy, Shanghai University, Shanghai, 200072 (China); School of Materials Science and Engineering, Shanghai University, 200072 (China); Wilde, Gerhard [Institute of Materials Physics, University of Münster, Wilhelm-Klemm-Straße 10, D-48149, Münster (Germany)

2016-05-15

The magnetic properties and magnetocaloric effect (MCE) in Dy{sub 2}Cu{sub 2}In compound have been investigated. Dy{sub 2}Cu{sub 2}In undergoes two magnetic phase transitions, a paramagnetic to ferromagnetic (FM) at T{sub C} ∼ 49.5 K followed by a spin reorientation (SR) at T{sub SR} ∼ 19.5 K. For a magnetic field change of 0–7 T, the maximum values of the magnetic entropy change (−ΔS{sub M}{sup max}) are estimated to be 16.5 around T{sub C} and 6.7 J/kg K around T{sub SR} with a large relative cooling power (RCP) value of 617 J/kg. The modified Arrott plots and universal curves of the rescaled ΔS{sub M} confirmed that the magnetic phase transitions in Dy{sub 2}Cu{sub 2}In compound belongs the second order phase transitions. The present results may provide some clues to search for new magnetocaloric materials belonging to RE{sub 2}T{sub 2}X system. - Highlights: • Magnetic properties and magnetocaloric effect in Dy{sub 2}Cu{sub 2}In was studied. • The Dy{sub 2}Cu{sub 2}In undergoes 2 s order magnetic phase transitions. • A large reversible MCE was observed in Dy{sub 2}Cu{sub 2}In. • The origin of MCE and its potential application in Dy{sub 2}Cu{sub 2}In were discussed.

Effects of hydrazine on the solvothermal synthesis of Cu{sub 2}ZnSnSe{sub 4} and Cu{sub 2}CdSnSe{sub 4} nanocrystals for particle-based deposition of films

Energy Technology Data Exchange (ETDEWEB)

Chiang, Ming-Hung [Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan 701 (China); Fu, Yaw-Shyan, E-mail: ysfu@mail.nutn.edu.tw [Department of Greenergy, National University of Tainan, Tainan, Taiwan 700 (China); Shih, Cheng-Hung; Kuo, Chun-Cheng [Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan 701 (China); Guo, Tzung-Fang [Department of Photonics, Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan, Taiwan 701 (China); Lin, Wen-Tai, E-mail: wtlin@mail.ncku.edu.tw [Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan 701 (China)

2013-10-01

The effects of hydrazine on the synthesis of Cu{sub 2}ZnSnSe{sub 4} (CZTSe) and Cu{sub 2}CdSnSe{sub 4} (CCTSe) nanocrystals in an autoclave as a function of temperature and time were explored. On heating at 190 °C for 24-72 h, pure CZTSe and CCTSe nanocrystals could readily grow in the hydrazine-added solution, while in the hydrazine-free solution the intermediate phases such as ZnSe, Cu{sub 2}Se, and Cu{sub 2}SnSe{sub 3}, and Cu{sub 2}SnSe{sub 3} and CdSe associated with the CZTSe and CCTSe nanocrystals grew, respectively. This result reveals that hydrazine can speed up the synthesis of pure CZTSe and CCTSe nanocrystals via a solvothermal process. The mechanisms for the hydrazine-enhanced growth of CZTSe and CCTSe nanocrystals were discussed. The pure CZTSe and CCTSe nanocrystals were subsequently fabricated to the smooth films by spin coating without further annealing in selenium atmosphere. This processing may be beneficial to the fabrication of the absorber layer for solar cells and thermoelectric devices. - Highlights: • Hydrazine enhances the growth of pure Cu{sub 2}ZnSnSe{sub 4} and Cu{sub 2}CdSnSe{sub 4} nanocrystals. • The nanocrystals can be fabricated to films by spin coating without annealing. • This solvothermal processing is promising for the fabrication of thin film devices.

Interactive contribution of grain size and grain orientation to coercivity of melt spun ribbons

International Nuclear Information System (INIS)

Wang, N.; Li, G.; Yao, W.J.; Wen, X.X.

2010-01-01

During melt spinning process, the improvement of certain grain orientation and the refinement of grain size with surface velocity have interactive and contradictory effects on the magnetic properties. The contributions of these effects have seldom been taken into account and they were discussed in this paper via Fe-2, 4, 6.5 wt% Si alloys. Heat treatment at 1173 K for 1 h was performed to show the annealing impact. The X-ray diffraction patterns show that the high surface velocity and heat treatment increase the intensity ratio of line (2 0 0) to (1 1 0) of A2 phase. The (2 0 0) line corresponds to (2 0 0) plane in direction, easy magnetization direction of α-Fe phase in Fe-Si alloy. The improvement of this grain orientation with the surface velocity decreases the coercivity, which should increase due to the grain refinement. It is revealed that the texture promoted by the anisotropic heat release during melt spinning process is one factor to improve the magnetic properties and should be considered when preparing soft magnetic materials.

Processing, microstructure and properties of grain-oriented ferroelectric ceramics

International Nuclear Information System (INIS)

Okazaki, K.; Igarashi, H.; Nagata, K.; Yamamoto, T.; Tashiro, S.

1986-01-01

Grain oriented ferroelectric ceramics such as PbBi/sub 2/Nb/sub 2/O/sub 9/, bismuth compound with layer structure, (PbLa)Nb/sub 2/O/sub 6/, tungsten-bronze structure and SbSI were prepared by an uni-axial hot-pressing, a double-stage hot-pressing and tape casting methods. Microstructures of them were examined by SEM and the prefered textures of the ceramics composed of thin plate and/or needle crystallites were ascertained. Grain orientation effects on electrical, piezoelectric, optical and mechanical properties are discussed

Study by neutrons diffusion and X-rays of structural and magnetic properties of Bi{sub 2}Sr{sub 2}Ca{sub n-1}Cu{sub n}O{sub 2n+4+{delta}} type superconductive cuprates; Etude par diffusion des neutrons et des rayons X des proprietes structurales et magnetiques des cuprates supraconducteurs de type Bi{sub 2}Sr{sub 2}Ca{sub n-1}Cu{sub n}O{sub 2n+4+{delta}}

Energy Technology Data Exchange (ETDEWEB)

Vasiliu-Doloc, L

1995-09-22

In this work we have used inelastic and elastic neutron and X-ray scattering techniques for characterizing the incommensurate structural distortions in compounds belonging to the family Bi{sub 2}Sr{sub 2}Ca{sub n-1}Cu{sub n}O{sub 2n+4+{delta}} of high-Tc superconducting cuprates. We have searched the existence of structural instabilities specific of the CuO{sub 2} planes and of magnetic instabilities. The modulated structure of the 2212 phase has been refined from single-crystal neutron diffraction results and importance of distortion of CuO{sub 2} planes has thus been determined. It is shown that the additional oxygen is not ordered three-dimensionally within the modulated structure and that the information about it is contained in diffuse scattering results. A model of the short-range order associated with additional oxygen atoms is proposed and discussed. The temperature studies of the long-range order have shown a great stability of the amplitude and period of the incommensurate distortion wave in the one-layer, as well as in the double-layer compounds, either superconducting or insulating. We find such a behaviour to be highly incompatible with a distortion resulting from a charge-density-wave instability. The results we have obtained indicate that the bismuth-based high-Tc superconducting cuprates have essentially the same physics of the CuO{sub 2} planes as the previous two families, La{sub 2-x}Sr{sub x}CuO{sub 4} and YBa{sub 2}Cu{sub 3}O{sub 6+{delta}}, being at the proximity of three instabilities: a metal-insulator transition, an antiferromagnetic instability and a structural instability specific of the CuO{sub 2} planes. (author).

Reduction of secondary phases in Cu{sub 2}SnSe{sub 3} absorbers for solar cell application

Energy Technology Data Exchange (ETDEWEB)

Tang, Zeguo, E-mail: tangzg@fc.ritsumei.ac.jp [Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, Shiga (Japan); Nukui, Yuki; Kosaka, Kiichi; Ashida, Naoki; Uegaki, Hikaru; Minemoto, Takashi [College of Science and Engineering, Ritsumeikan University, Shiga (Japan)

2014-09-01

Highlights: • Cu{sub 2}SnSe{sub 3} thin films for absorber of solar cell are fabricated by selenization of Cu–Sn precursors. • Secondary phase of Cu{sub 2–x}Se can be suppressed via using Se and SnSe mixture powders as Se source. • Selective etching of secondary phase of Cu{sub 2–x}Se is realized by potassium cyanide solution. • Cu{sub 2–x}Se rather than SnSe makes major contribution to the high carrier concentration of CTSe films. - Abstract: The creation of secondary phases, such as Cu{sub 2−x}Se and SnSe, and their influence on electrical properties of Cu{sub 2}SnSe{sub 3} (CTSe) thin films fabricated by selenization of Cu–Sn metal precursors are investigated. The Cu{sub 2−x}Se content in CTSe films is estimated via deconvolution of grazing incidence X-ray diffraction (GIXRD) patterns, and the results suggest that the Cu{sub 2−x}Se content increases with the increasing Cu/Sn ratio in metal precursors. We also found that using Se and SnSe mixture powders as Se source is an effective approach to suppress the creation of Cu{sub 2−x}Se secondary phase. Meanwhile, selective etching of Cu{sub 2−x}Se is realized by potassium cyanide (KCN) solution. Hall measurement results reveal that the secondary phase of Cu{sub 2−x}Se rather than SnSe makes major contribution to the high carrier concentration (larger than 10{sup 18} cm{sup −3}) of CTSe films. The approach to further decrease the carrier concentration in CTSe films is discussed.

Phase-Separated, Epitaxial, Nanostructured LaMnO₃+MgO Composite Cap Layer Films for Propagation of Pinning Defects in YBa>2Cu₃O_7-x Coated Conductors

Energy Technology Data Exchange (ETDEWEB)

Wee, Sung Hun [ORNL; Shin, Junsoo [ORNL; Cantoni, Claudia [ORNL; Meyer III, Harry M [ORNL; Cook, Sylvester W [ORNL; Zuev, Yuri L [ORNL; Specht, Eliot D [ORNL; Xiong, Xuming [ORNL; Paranthaman, Mariappan Parans [ORNL; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York; Goyal, Amit [ORNL

2009-01-01

Nanostructural modulation in the cap layer used in coated conductors can be a potential source for nucleating microstructural defects into the superconducting layer for improving the flux-pinning. We report on the successful fabrication of phase separated, epitaxial, nanostructured films comprised of LaMnO{sub 3} (LMO) and MgO via pulsed laser deposition (PLD) on biaxially-textured MgO metallic templates with a LMO buffer layer. Scanning Auger compositional mapping and transmission electron microscopy cross sectional images confirm the nanoscale, spatial modulation corresponding to the nanostructured phase separation in the film. YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} films (0.8 {micro}m thick) grown using PLD on such phase separated, nanostructured cap layers show reduced field dependence of the critical current density with an ? value of -0.38 (in J{sub c}-H{sup -{alpha}}).

Coercivity enhancement of NdFeB sintered magnets by low melting point Dy{sub 32.5}Fe{sub 62}Cu{sub 5.5} alloy modification

Energy Technology Data Exchange (ETDEWEB)

Liang, Liping; Ma, Tianyu, E-mail: maty@zju.edu.cn; Zhang, Pei; Jin, Jiaying; Yan, Mi, E-mail: mse_yanmi@zju.edu.cn

2014-04-15

To improve coercivity without sacrificing other magnetic performance of NdFeB sintered magnets, a low melting point Dy{sub 32.5}Fe{sub 62}Cu{sub 5.5} alloy was introduced as an intergranular additive. Magnetic properties and microstructure of the magnets with different Dy{sub 32.5}Fe{sub 62}Cu{sub 5.5} contents were studied. At the optimum addition of 3 wt%, coercivity H{sub cj} was enhanced from 12.7 to 15.2 kOe, the maximum magnetic energy product (BH){sub max} was simultaneously increased from 46.6 to 47.8 MG Oe, accompanied by a slight reduction in remanence B{sub r}. Further investigation on microstructure and grain boundary composition indicated that the enhanced H{sub cj} and (BH){sub max} could be attributed to the refined and uniform 2:14:1 phase grains, continuous grain boundaries and a (Nd,Dy){sub 2}Fe{sub 14}B hardening shell surrounding the 2:14:1 phase grains. - Highlights: • Low melting-point Dy{sub 32.5}Fe{sub 62}Cu{sub 5.5} alloy was introduced to NdFeB magnets. • The doped magnet exhibits enhanced coercivity and maximum energy product. • (Nd,Dy){sub 2}Fe{sub 14}B shell was expected to form in the surface of Nd{sub 2}Fe{sub 14}B grains. • The continuous grain boundary layer formed between neighboring Nd{sub 2}Fe{sub 14}B grains.

Incorporation of Cu{sub 2}O nanocrystals into TiO{sub 2} photonic crystal for enhanced UV–visible light driven photocatalysis

Energy Technology Data Exchange (ETDEWEB)

Geng, Zhi; Zhang, Yu; Yuan, Xing; Huo, Mingxin; Zhao, Yahui; Lu, Ying, E-mail: luy332@nenu.edu.cn; Qiu, Yue

2015-09-25

Highlights: • The Cu{sub 2}O NCs/TiO{sub 2} PC composite was synthesized and exhibited high photocatalysis. • The improved light harvesting and increased quantum yield was achieved. • The hydroxyl radical was the primary oxidant in Cu{sub 2}O NCs/TiO{sub 2} PC photocatalysis. - Abstract: A 3D UV–visible light responsive photocatalyst was fabricated by infiltrating Cu{sub 2}O nanocrystals (NCs) into TiO{sub 2} photonic crystal (PC). Morphology characterization presented that Cu{sub 2}O NCs with average diameter around 10 nm were dispersed uniformly into TiO{sub 2} PC. The transmittance spectra showed that Cu{sub 2}O NCs/TiO{sub 2} 260, prepared by integrating Cu{sub 2}O NCs with TiO{sub 2} 260 which was fabricated from 260 nm polystyrene spheres, exhibited the highest light harvesting. The photoluminescence spectra confirmed the electron/hole pairs recombination of Cu{sub 2}O NCs/TiO{sub 2} 260 was efficiently inhibited due to the unique heterojunction structure between TiO{sub 2} and Cu{sub 2}O. In the photocatalytic degradation of Rhodamine B and Bisphenol A under UV–visible light (320 nm < λ < 780 nm) irradiation, the kinetic constant using Cu{sub 2}O NCs/TiO{sub 2} 260 was 3.99 and 8.37-fold larger than that using TiO{sub 2} nanoparticle (NP), respectively. The enhanced photocatalysis benefited from the increased light harvesting owing to the excitation of both TiO{sub 2} and Cu{sub 2}O NCs whose optical absorption was intensified by the photonic effect of TiO{sub 2} 260 and the high quantum efficiency due to the Cu{sub 2}O/TiO{sub 2} heterojunction. The hydroxyl radical, generated from the protonation of superoxide radical which was derived from the reduction of oxygen by photogenerated electrons, was the main oxidant responsible for pollutant degradation.

Nanocrystalline Cu{sub 2}ZnSnSe{sub 4} thin films for solar cells application: Microdiffraction and structural characterization

Energy Technology Data Exchange (ETDEWEB)

Quiroz, Heiddy P., E-mail: hpquirozg@unal.edu.co; Dussan, A., E-mail: adussanc@unal.edu.co [Departmento de Física, Grupo de Materiales Nanoestructurados y sus Aplicaciones, Universidad Nacional de Colombia, Bogotá 11001 (Colombia)

2016-08-07

This work presents a study of the structural characterization of Cu{sub 2}ZnSnSe{sub 4} (CZTSe) thin films by X-ray diffraction (XRD) and microdiffraction measurements. Samples were deposited varying both mass (M{sub X}) and substrate temperature (T{sub S}) at which the Cu and ZnSe composites were evaporated. CZTSe samples were deposited by co-evaporation method in three stages. From XRD measurements, it was possible to establish, with increased Ts, the presence of binary phases associated with the quaternary composite during the material's growth process. A stannite-type structure in Cu{sub 2}ZnSnSe{sub 4} thin films and sizes of the crystallites varying between 30 and 40 nm were obtained. X-ray microdiffraction was used to investigate interface orientations and strain distributions when deposition parameters were varied. It was found that around the main peak, 2ϴ = 27.1°, the Cu{sub 1.8}Se and ZnSe binary phases predominate, which are formed during the subsequent material selenization stage. A Raman spectroscopy study revealed Raman shifts associated with the binary composites observed via XRD.

Behavior of Goss, {411}<148>, and {111}<112> Oriented Grains During Recrystallization and Decarburization After Cold-rolling of Fe-3.1% GrainOriented Electrical Steel

Energy Technology Data Exchange (ETDEWEB)

Choi, Sung-Ji; Park, No-Jin [Kumoh National Institute of Technology, Gumi (Korea, Republic of); Joo, Hyung-Don; Park, Jong-Tae [POSCO, Pohang (Korea, Republic of)

2016-07-15

Grain-oriented electrical steel is used as a core material in transformers and motors. To obtain improved magnetic properties from the grain-oriented electrical steel, the steel should have a strong {110}<001> Goss texture. Recently, controlled manufacturing processes have been employed for developing electrical steels with a strong Goss texture. It is important to carry out research on the {411}<148> and {111}<112> oriented grains in relation to coincidence site lattice (CSL) boundaries, as they have an effect on the easy growth of the Goss grains upon secondary recrystallization. In this study, the behavior of the{411}<148> and {111}<112> oriented grains, which are neighbored with Goss grains after recrystallization with rapid and typical heating rates, and after decarburization, was examined by using x-ray diffraction (XRD) and electron back-scattered diffraction (EBSD) measurements. In the decarburized specimen, the Goss grains encroached the {411}<148> and {111}<112> oriented grains to a greater extent with a rapid heating rate than with a typical heating rate, and larger Goss grains were observed with the rapid heating rate. The {111}<112> oriented grains especially affect the easy growth of the Goss grains, as they are located near the Goss grains. Therefore, larger Goss grains can be produced at rapid heating rates, and the product is estimated to exhibit improved magnetic properties after secondary recrystallization.

Preparation and properties of KCl-doped Cu{sub 2}O thin film by electrodeposition

Energy Technology Data Exchange (ETDEWEB)

Yu, Xiaojiao, E-mail: yxjw@xaut.edu.cn [Xi’an University of Technology, Xi’an 710048 (China); Li, Xinming [Xi’an University of Technology, Xi’an 710048 (China); Zheng, Gang [Xi’an University of Technology, Xi’an 710048 (China); Northwestern Polytechnical University, Xi’an 710072 (China); Wei, Yuchen [The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China); Zhang, Ama; Yao, Binghua [Xi’an University of Technology, Xi’an 710048 (China)

2013-04-01

With the indium tin oxide-coated glass as working electrode, cuprous oxide thin film is fabricated by means of electrodeposition. The effects of KCl doped and annealing treatment upon Cu{sub 2}O thin film morphology, surface resistivity, open-circuit voltage, electric conduction types and visible light response are studied. The research results indicate that KCl doped has a great effect upon Cu{sub 2}O crystal morphology, thus, making Cu{sub 2}O thin film surface resistivity drop, and the open-circuit voltage increase and that electric conduction types are transformed from p type into n type, and the visible light (400–500 nm) absorption rate is slightly reduced. Annealing treatment can obviously decrease Cu{sub 2}O thin film surface resistivity and improve its open-circuit voltage. When KCl concentration in electrolytic solution reaches 7 mmol/L, Cu{sub 2}O thin film morphology can be changed from the dendritic crystal into the cubic crystal and Cu{sub 2}O thin film surface resistivity decreases from the initial 2.5 × 10{sup 6} Ω cm to 8.5 × 10{sup 4} Ω cm. After annealing treatment at 320 °C for 30 min, the surface resistivity decreases to 8.5 × 10{sup 2} Ω cm, and the open-circuit voltage increases from the initial 3.1 mV to 79.2 mV.

Critical parameters in the sputter-deposition of NdBa{sub 2}Cu{sub 3}O{sub 7-{delta}} thin films

Energy Technology Data Exchange (ETDEWEB)

Hakuraku, Y.; Yokoyama, N.; Doi, T.; Inoue, T. [Faculty of Engineering, Kagoshima University, Koorimoto, Kagoshima 890, (Japan); Mori, Z.; Koba, S. [Yatsushiro National College of Technology, Yatsushiro 866 (Japan)

1999-08-01

A superconducting thin film of NdBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (NBCO) was prepared on an MgO(100) substrate by dc magnetron sputtering. Superconducting properties as well as features such as resistivity at room temperature and surface morphology were improved by optimizing the composition of sputtering target and critical parameters such as substrate temperature and oxidation gas pressure. A highly c-axis oriented thin film with T{sub c} (zero resistance temperature) = 95.2 K was obtained reproducibly with NdBa{sub 2}Cu{sub 3.2}O{sub 7-{delta}} off-stoichiometric target sputtering. T{sub c} = 95.2 K was 8 K higher than that deposited by stoichiometric target sputtering. Critical current density was 1x10{sup 6} A cm{sup -2} at 77 K, and surface roughness was 35 nm. (author)

Novel chemical route for deposition of Cu{sub 2}ZnSnS{sub 4} photovoltaic absorbers

Energy Technology Data Exchange (ETDEWEB)

Gordillo, Gerardo; Becerra, Raul A.; Calderón, Clara L., E-mail: ggordillog@unal.edu.co [Universidad Nacional de Colombia, Bogota (Colombia)

2018-05-01

This work reports results of a study carried out to optimize the preparation conditions of Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films grown by sequential deposition of Cu{sub 2}SnS{sub 3} (CTS) and ZnS layers, where the Cu{sub 2}SnS{sub 3} compound was grown using a novel procedure consisting of simultaneous precipitation of Cu{sub 2}S and SnS{sub 2} performed by diffusion membrane assisted chemical bath deposition (CBD) technique. The precipitation across the diffusion membranes allows achieving moderate control of release of metal ions into the work solution favoring the heterogeneous growth mainly through an ion-ion mechanism. Through a parameters study, conditions were found to grow Cu{sub 2}SnS{sub 3} thin films which were used as precursors for the formation of Cu{sub 2}ZnSnS{sub 4} films. The formation of CZTS thin films grown in the Cu{sub 2}ZnSnS{sub 4} phase was verified through measurements of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Solar cells with efficiencies of 4.9% were obtained using CZTS films prepared by membrane assisted CBD technique as absorber layer. (author)

Mechanism of secondary recrystallization of Goss grains in grain-oriented electrical steel

Science.gov (United States)

Hayakawa, Yasuyuki

2017-12-01

Since its invention by Goss in 1934, grain-oriented (GO) electrical steel has been widely used as a core material in transformers. GO exhibits a grain size of over several millimeters attained by secondary recrystallization during high-temperature final batch annealing. In addition to the unusually large grain size, the crystal direction in the rolling direction is aligned with , which is the easy magnetization axis of α-iron. Secondary recrystallization is the phenomenon in which a certain very small number of {110} (Goss) grains grow selectively (about one in 106 primary grains) at the expense of many other primary recrystallized grains. The question of why the Goss orientation is exclusively selected during secondary recrystallization has long been a main research subject in this field. The general criterion for secondary recrystallization is a small and uniform primary grain size, which is achieved through the inhibition of normal grain growth by fine precipitates called inhibitors. This paper describes several conceivable mechanisms of secondary recrystallization of Goss grains mainly based on the selective growth model.

Synthesis and characterization of Cu{sub 2}O/TiO{sub 2} photocatalysts for H{sub 2} evolution from aqueous solution with different scavengers

Energy Technology Data Exchange (ETDEWEB)

Li, Yanping; Wang, Baowei, E-mail: wangbw@tju.edu.cn; Liu, Sihan; Duan, Xiaofei; Hu, Zongyuan

2015-01-01

Graphical abstract: - Highlights: • Cu{sub 2}O/TiO{sub 2} photocatalyst are prepared by a facile ethanol reduction method. • The heterojunction between p-type Cu{sub 2}O and n-type TiO{sub 2} improves activity of TiO{sub 2}. • An optimal molar fraction of Cu{sub 2}O is reported in Cu{sub 2}O/TiO{sub 2} photocatalysts. • The effect of different alcohols scavengers on activity of Cu{sub 2}O/TiO{sub 2} is discussed. - Abstract: A series of Cu{sub 2}O/TiO{sub 2} photocatalysts with different molar fraction of Cu{sub 2}O were prepared by a facile modified ethanol-induced approach followed by a calcination process. The chemical state of copper compound was proved to be cuprous oxide by the characterization of X-ray photoelectron spectra (XPS). Furthermore, these composite oxides were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N{sub 2} adsorption desorption and UV–vis techniques to study the morphologies, structures, and optical properties of the as-prepared samples. The results indicated that the photocatalytic activity of n-type TiO{sub 2} was significantly enhanced by combined with p-type Cu{sub 2}O, due to the efficient p–n heterojunction. The p–n heterojunction between Cu{sub 2}O and TiO{sub 2} can enhance visible-light adsorption, efficiently suppress charge recombination, improve interfacial charge transfer, and especially provide plentiful reaction active sites on the surface of photocatalyst. As a consequence, the prepared 2.5-Cu{sub 2}O/TiO{sub 2} photocatalyst exhibited the highest photocatalytic activity for H{sub 2} evolution rate and reached 2048.25 μmol/(g h), which is 14.48 times larger than that of pure P25. The apparent quantum yield (AQY) of the 2.5-Cu{sub 2}O/TiO{sub 2} sample at 365 nm was estimated to be 4.32%. In addition, the influence of different scavengers, namely methanol, anhydrous ethanol, ethylene glycol and glycerol, on the photocatalytic activity for H{sub 2} evolution rate was

Unexpected large room-temperature ferromagnetism in porous Cu{sub 2}O thin films

Energy Technology Data Exchange (ETDEWEB)

Hou, Xue [College of Physics Science & Information Engineering, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Advanced Films of Hebei Province, Shijiazhuang 050024 (China); Sun, Huiyuan, E-mail: huiyuansun@126.com [College of Physics Science & Information Engineering, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Advanced Films of Hebei Province, Shijiazhuang 050024 (China); Liu, Lihu; Jia, Xiaoxuan; Liu, Huiyuan [College of Physics Science & Information Engineering, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Advanced Films of Hebei Province, Shijiazhuang 050024 (China)

2015-05-15

Porous Cu{sub 2}O films have been fabricated on porous anodic alumina substrates using DC-reactive magnetron sputtering with pure Cu targets, and unexpectedly large room temperature ferromagnetism has been observed in the films. The maximum saturation magnetic moment along the out-of-plane direction was as high as 94 emu/cm{sup 3}. Photoluminescence spectra show that the ferromagnetism originates with oxygen vacancies. The ferromagnetism could be adjusted by changing the concentration of oxygen vacancies through annealing in an oxygen atmosphere. These observations suggest that the origin of the ferromagnetism is due to coupling between oxygen vacancies with local magnetic moments in the porous Cu{sub 2}O films, which can occur either directly through exchange interactions between oxygen vacancies, or through the mediation of conduction electrons. Such a ferromagnet without the presence of any ferromagnetic dopant may find applications in spintronic devices. - Highlights: • Porous Cu{sub 2}O films were deposited on porous anodic alumina (PAA) substrates. • Significant room-temperature ferromagnetism has been observed in porous Cu{sub 2}O films. • Ferromagnetism of Cu{sub 2}O films exhibited different magnetic signals with the field. • The saturation magnetization is 94 emu/cm{sup 3} with an out-of-plane.

Comparative study of nano-sized particles CoFe{sub 2}O{sub 4} effects on superconducting properties of Y-123 and Y-358

Energy Technology Data Exchange (ETDEWEB)

Slimani, Y.; Hannachi, E.; Ben Salem, M.K.; Hamrita, A. [Laboratory of Physics of Materials-Structures and Properties, Department of Physics, Faculty of Sciences of Bizerte, University of Carthage, 7021 Zarzouna (Tunisia); Varilci, A. [Faculty of Arts and Sciences, Department of Physics, Abant Izzet Baysal University, 14280 Bolu (Turkey); Dachraoui, W. [CINaM-CNRS, Luminy Campus, 13288 Marseille (France); Ben Salem, M., E-mail: salemwiem2005@yahoo.fr [Laboratory of Physics of Materials-Structures and Properties, Department of Physics, Faculty of Sciences of Bizerte, University of Carthage, 7021 Zarzouna (Tunisia); Ben Azzouz, F. [Laboratory of Physics of Materials-Structures and Properties, Department of Physics, Faculty of Sciences of Bizerte, University of Carthage, 7021 Zarzouna (Tunisia); College of Sciences-Girls, Department of Physics, University of Dammam (Saudi Arabia)

2014-10-01

The effects of nano-sized CoFe{sub 2}O{sub 4} particles (10 nm) addition on the structural and the normal state resistivity of YBa{sub 2}Cu{sub 3}O{sub 7} (noted Y-123) and Y{sub 3}Ba{sub 5}Cu{sub 8}O{sub 18} (noted Y-358) polycrystalline were systematically studied. Samples were synthesized in oxygen atmosphere using a standard solid state reaction technique by adding CoFe{sub 2}O{sub 4} up to 2 wt%. Phases, microstructure and superconductivity have been systematically investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrical measurements ρ(T). XRD results reveal that the lattice parameters change for both Y-123 and Y-358 phases. SEM observations reveal that the grain size is reduced with increasing the content of CoFe{sub 2}O{sub 4}. The measurements for the resistivity dependence of temperature show that the depression in superconducting temperature is more pronounced for CoFe{sub 2}O{sub 4} addition in Y-358 compound than in Y-123 one. These results may be attributed to the existence of much more disorder due to a greater number of Cu sites to be substituted by Fe and Co in Y-358 compared to Y-123.

Influences of oxygen incorporation on the structural and optoelectronic properties of Cu{sub 2}ZnSnS{sub 4} thin films

Energy Technology Data Exchange (ETDEWEB)

Yu, Ruei-Sung, E-mail: rsyu@asia.edu.tw [Department of Photonics and Communication Engineering, Asia University, 500, Lioufeng Rd., Wufeng, Taichung 41354, Taiwan (China); Department of Medical Research, China Medical University Hospital, China Medical University, Taichung 40402, Taiwan (China); Hung, Ta-Chun [Department of Photonics and Communication Engineering, Asia University, 500, Lioufeng Rd., Wufeng, Taichung 41354, Taiwan (China)

2016-02-28

Highlights: • Oxygen incorporation in Cu{sub 2}ZnSnS{sub 4} changes the energy band structure. • The material has a comparatively high-absorptive capacity for short wavelength. • Absorption coefficients of the film increase from 10{sup 4} to 10{sup 5} cm{sup −1}. • The oxygen-containing CZTS film has a mixture of crystallite and crystalline states. • The material could be a candidate as an absorber layer in multi-junction solar cells. - Abstract: This study used the sol–gel method to prepare Cu{sub 2}ZnSnS{sub 4} thin films containing oxygen and explored the composition, structural, and optoelectronic properties of the films. The non-vacuum process enabled the oxygen content of the Cu{sub 2}ZnSnS{sub 4} films to be 8.89 at% and 10.30 at% for two different annealing conditions. In the crystal structure, oxygen was substituted at the positions of sulfur and appeared in the interstitial sites of the lattice. The compositions of the thin films deviated from the stoichiometric ratio. Both films had kesterite structures with no secondary phase structure. The kesterite CZTS film possessed a composite microstructure of crystallite and crystalline states. The microstructure of the Cu{sub 2}ZnSnS{sub 4} film with higher oxygen content was denser and the average grain size was smaller. Incorporating oxygen atoms into crystalline Cu{sub 2}ZnSnS{sub 4} changed the energy band structure: the direct energy band gaps were, respectively, 2.75 eV and 2.84 eV; the thin films mainly adsorbed photons with wavelengths less than 500 nm; and the absorption coefficients increased from 10{sup 4} cm{sup −1} to 10{sup 5} cm{sup −1}. The films had a comparatively high absorptive capacity for photons less than 350 nm. Increasing the oxygen content of the film lowered the resistivity. Thus, the oxygen-containing Cu{sub 2}ZnSnS{sub 4} thin film could be a candidate for the p-type absorber layer material required in multi-junction solar cells.

Preparation of Uniform Hexapod Cu{sub 2}O and Hollow Hexapod CuO

Energy Technology Data Exchange (ETDEWEB)

Cho, Youngsik; Huh, Youngduk [Dankook Univ., Yongin (Korea, Republic of)

2013-10-15

The filled hexapod Cu{sub 2}O precursors were also prepared under microwave irradiation for only 120 s using a commercial microwave oven. The optimal experimental conditions for the perfect and uniform hexapod-like Cu{sub 2}O precursors were examined. The control of the cooling rate by adding cold water was also examined for the elimination of further crystal growth at the end of the arm of the hexapod Cu{sub 2}O precursors due to the thermal diffusion in reaction medium. The uniform hollow structure and hexapod CuO products were also prepared from the direct thermal oxidation of the filled hexapod Cu{sub 2}O precursors. The morphology-dependent properties of inorganic materials, such as magnetic, photocatalytic, and antibacterial activities, is one of the most important experimental issues in inorganic technology. Many researchers have prepared uniform and specific shaped inorganic oxides to understand the morphology-dependent properties of inorganic oxides.

Highly conductive grain boundaries in copper oxide thin films

Energy Technology Data Exchange (ETDEWEB)

Deuermeier, Jonas, E-mail: j.deuermeier@campus.fct.unl.pt [Department of Materials Science, Faculty of Science and Technology, i3N/CENIMAT, Universidade NOVA de Lisboa and CEMOP/UNINOVA, Campus de Caparica, 2829-516 Caparica (Portugal); Department of Materials and Earth Sciences, Technische Universität Darmstadt, Jovanka-Bontschits-Straße 2, D-64287 Darmstadt (Germany); Wardenga, Hans F.; Morasch, Jan; Siol, Sebastian; Klein, Andreas, E-mail: aklein@surface.tu-darmstadt.de [Department of Materials and Earth Sciences, Technische Universität Darmstadt, Jovanka-Bontschits-Straße 2, D-64287 Darmstadt (Germany); Nandy, Suman; Calmeiro, Tomás; Martins, Rodrigo; Fortunato, Elvira [Department of Materials Science, Faculty of Science and Technology, i3N/CENIMAT, Universidade NOVA de Lisboa and CEMOP/UNINOVA, Campus de Caparica, 2829-516 Caparica (Portugal)

2016-06-21

High conductivity in the off-state and low field-effect mobility compared to bulk properties is widely observed in the p-type thin-film transistors of Cu{sub 2}O, especially when processed at moderate temperature. This work presents results from in situ conductance measurements at thicknesses from sub-nm to around 250 nm with parallel X-ray photoelectron spectroscopy. An enhanced conductivity at low thickness is explained by the occurrence of Cu(II), which is segregated in the grain boundary and locally causes a conductivity similar to CuO, although the surface of the thick film has Cu{sub 2}O stoichiometry. Since grains grow with an increasing film thickness, the effect of an apparent oxygen excess is most pronounced in vicinity to the substrate interface. Electrical properties of Cu{sub 2}O grains are at least partially short-circuited by this effect. The study focuses on properties inherent to copper oxide, although interface effects cannot be ruled out. This non-destructive, bottom-up analysis reveals phenomena which are commonly not observable after device fabrication, but clearly dominate electrical properties of polycrystalline thin films.

An Ab-initio study of structural, elastic, electronic and thermodynamic properties of triclinic Cu{sub 7}In{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Yu, Ching-Feng [Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Cheng, Hsien-Chie, E-mail: hccheng@fcu.edu.tw [Department of Aerospace and Systems Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Chen, Wen-Hwa, E-mail: whchen@pme.nthu.edu.tw [Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

2016-05-01

First principles density functional theory calculations within the generalized gradient approximation are performed to comprehensively study the structural, elastic, electronic and thermodynamic properties of triclinic single and polycrystalline Cu{sub 7}In{sub 3}. The polycrystalline elastic properties are predicted using the Voigt–Reuss–Hill approximation and the thermodynamic properties are evaluated based on the quasi-harmonic Debye model. Their temperature, hydrostatic pressure or crystal orientation dependences are also addressed, and the predicted physical properties are compared with the literature experimental and theoretical data and also with those of three other Cu–In compounds, i.e., CuIn, Cu{sub 2}In and Cu{sub 11}In{sub 9}. The present calculations show that in addition to being a much better conductor compared to Cu{sub 2}In and Cu{sub 11}In{sub 9}, Cu{sub 7}In{sub 3} crystal reveals weak elastic anisotropy, high ductility and low stiffness, and tends to become more elastically isotropic at very high hydrostatic pressure. Moreover, the Cu{sub 7}In{sub 3} holds the largest high-temperature heat capacity among the four Cu–In compounds. - Highlights: • The physical property of Cu{sub 7}In{sub 3} is reported by first-principles calculations. • Pressure effect on the physical property of Cu{sub 7}In{sub 3} is presented. • The calculated lattice constants of Cu{sub 7}In{sub 3} agree well with the experimental data. • Cu{sub 7}In{sub 3} tends to become more elastically isotropic at very high pressure. • The heat capacity of Cu{sub 7}In{sub 3} is much larger than that of CuIn, Cu{sub 2}In and Cu{sub 11}In{sub 9}.

Measurements of the London penetration depths in YBa sub 2 Cu sub 3 O sub x by means of muon spin rotation (. mu. SR) experiments

Energy Technology Data Exchange (ETDEWEB)

Puempin, B.; Keller, H.; Kuendig, W.; Odermatt, W.; Savic, I.M.; Schneider, J.W.; Simmler, H.; Zimmermann, P. (Physik-Inst., Univ. Zuerich (Switzerland)); Bednorz, J.G.; Maeno, Y.; Mueller, K.A.; Rossel, C. (IBM Research Div., Zuerich Research Lab., Rueschlikon (Switzerland)); Kaldis, E.; Rusiecki, S. (Lab. fuer Festkoerperphysik, ETH Zuerich (Switzerland)); Assmus, W.; Kowalewski, J. (Physikalisches Inst., Univ. Frankfurt (Germany, F.R.))

1989-12-01

To get accurate values of the London penetration depths in YBa{sub 2}Cu{sub 3}O{sub x}, {mu}SR measurements were performed on a high quality, sintered sample and a c-axis-oriented polycrystal. For the sintered sample the temperature dependence of the effective penetration depth {lambda}{sub eff} is well described by the two-fluid model, with {lambda}{sub eff}(0) = 155(10) nm. This behavior of {lambda}{sub eff}(T) is consistent with conventional s-wave pairing. The anisotropy ratio {lambda}{sub c}/{lambda}{sub ab} {approx equal} 5(1) was determined from measurements on the polycrystal. These results were used to calculate {lambda}{sub ab}(0) = 130(10) nm and {lambda}{sub c}(0) {approx equal} 500-800 nm. (orig.).

Grain orientation, deformation microstructure and flow stress

International Nuclear Information System (INIS)

Hansen, N.; Huang, X.; Winther, G.

2008-01-01

Dislocation structures in deformed metals have been analyzed quantitatively by transmission electron microscopy, high-resolution electron microscopy and Kikuchi line analysis. A general pattern for the microstructural evolution with increasing strain has been established and structural parameters have been defined and quantified. It has been found that two dislocation patterns co-exist in all grains, however, with very different characteristics dependent on grain orientation. This correlation with the grain orientation has been applied in modeling of the tensile flow stress and the flow stress anisotropy of fcc polycrystals. In conclusion some future research areas are briefly outlined

Synthesis, surface properties and photocatalytic abilities of semiconductor In{sub 2}Cu{sub 2}O{sub 5} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Xu, Jian; Wan, Yingpeng; Huang, Yanlin [State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Wang, Yaorong, E-mail: yrwang@suda.edu.cn [State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Qin, Lin [Department of Physics and Interdisciplinary Program of Biomedical, Mechanical & Electrical Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of); Seo, Hyo Jin, E-mail: hjseo@pknu.ac.kr [Department of Physics and Interdisciplinary Program of Biomedical, Mechanical & Electrical Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of)

2016-12-15

Highlights: • In{sub 2}Cu{sub 2}O{sub 5} has high absorption in the UV-green and red wavelength region. • The nanoparticles present efficient photocatalytsis under visible light. • The photochemical properties were elucidated on its structure properties. - Abstract: In{sub 2}Cu{sub 2}O{sub 5} photocatalyst was prepared by the sol-gel method which produced worm-like nanoparticles. The X-ray powder diffraction (XRD) measurement and Rietveld structural refinement were applied to elucidate the phase formation and structural properties. The morphological properties of the surfaces were measured by scanning electron microscope (SEM), energy dispersive spectrum (EDS), and transmission electron microscopy (TEM). The nanoparticles present optical absorption from both the host lattices and the d–d transitions of distorted Cu{sup 2+} octahedra in UV–vis light wavelength region. The band-gap of In{sub 2}Cu{sub 2}O{sub 5} photocatalyst is about 2.31 eV. The photocatalytic abilities of In{sub 2}Cu{sub 2}O{sub 5} nanoparticles were verified by photo-degradation of methylene blue (MB) solutions irradiated by visible light. The energy potential and bad structure were discussed. In{sub 2}Cu{sub 2}O{sub 5} nanoparticles have the potential application for the efficient photocatalysis on MB dye solutions.

Impact of sodium on the secondary phases and current pathway in Cu{sub 2}(Zn,Sn)Se{sub 4} thin film solar cell

Energy Technology Data Exchange (ETDEWEB)

Lin, Yi-Cheng, E-mail: ielinyc@cc.ncue.edu.tw [Department of Mechatronics Engineering, National Changhua University of Education, Changhua, Taiwan (China); Lai, Chien-Mu [Department of Mechatronics Engineering, National Changhua University of Education, Changhua, Taiwan (China); Hsu, Hung-Ru [Green Energy & Environment Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan (China)

2017-05-01

In this study, we investigated the influence of Na content on secondary phases and current pathway in Cu{sub 2}(Zn,Sn)Se{sub 4} (CZTSe) thin film solar cells with the following structure: Ti/Mo:Na/Mo/CZTSe/CdS/i-ZnO/ZnO:Al/Al. The application of Na-doped Mo target as a source of sodium. Experimental results demonstrate that increasing the Na content leads to an increase in the quantity of secondary phase SnSe{sub 2} on the surface of the absorber layer; however, it did not appear to affect the secondary phases of Cu{sub 2}SnSe{sub 3} (CTSe) or ZnSe. Excessive quantities of Na were shown to have an adverse effect on device efficiency. Our results using conductive atomic force microscopy (C-AFM) revealed that an increase in the quantity of secondary phase SnSe{sub 2} can shift the current pathway on the surface of CZTSe from CZTSe grain boundaries (GBs) to the SnSe{sub 2} grains. The role of secondary phase SnSe{sub 2} of the CZTSe acted as a channel for the current flow, which results in high leakage current and low device efficiency. - Highlights: • Increasing the Na content leads to an increase in the quantity of secondary phase SnSe{sub 2}. • An increase of secondary phase SnSe{sub 2} can shift the current pathway from CZTSe grain boundaries to the SnSe{sub 2} grains. • The secondary phase SnSe{sub 2} acted as a channel for the current flow, which results in high leakage current.

Inductive current measurements in an oriented grained YBa2Cu3Ox superconductor

International Nuclear Information System (INIS)

Kupfer, H.; Keller, C.; Salama, K.; Selvamanickam, V.

1989-01-01

The critical current of grain aligned YBa 2 Cu 3 O x bulk material was investigated by inductive flux profile and ac susceptibility measurements. The induced current was directed perpendicular to the a-b plane oriented grains where high values of the transport current, have been previously reported. In spite of the unfavorable geometry of the investigated shielding current, no features of granularity were observed. The results yield a uniform bulk critical current density j c of 3x10 4 A/cm 2 at zero field and 77 K. Field and temperature dependences of this j c are discussed and compared with those in a granular Y-Ba-Cu-O material

One-pot synthesis of Cu{sub 2}O octahedron particles and their catalytic application

Energy Technology Data Exchange (ETDEWEB)

Li, Biao; Li, Dan; Mu, Lei; Yang, Sung Ik [Dept. of Applied Chemistry, Kyung Hee University, Yongin (Korea, Republic of)

2017-04-15

We report a facile one-step synthesis method of cuprous oxide (Cu{sub 2}O) hollow octahedrons with controllable size Cu{sub 2}O exhibited a great catalytic activity for the reduction of methylene blue by N{sub 2}H{sub 4} as well as NABH{sub 4}.

Preparation and characterization of co-evaporated Cu{sub 2}ZnGeSe{sub 4} thin films

Energy Technology Data Exchange (ETDEWEB)

Uday Bhaskar, P.; Suresh Babu, G.; Kishore Kumar, Y.B.; Sundara Raja, V., E-mail: sundararajav@rediffmail.com

2013-05-01

Cu{sub 2}ZnGeSe{sub 4} (CZGSe), a member of Cu{sub 2}–II–IV–VI{sub 4} family, is a promising material for solar cell absorber layer in thin film heterojunction solar cells like Cu{sub 2}ZnSnS{sub 4} and Cu{sub 2}ZnSnSe{sub 4} which have been explored in recent years as alternate to CuInGaSe{sub 2} solar cells. The effect of substrate temperature (523 K–723 K) on the growth of CZGSe films is investigated by studying their structural, morphological and optical properties. Raman spectroscopy studies have been done to identify the phases in addition to X-ray diffraction studies. CZGSe films deposited at different substrate temperatures and annealed at 723 K in selenium atmosphere are Cu-rich and Ge-poor and contained secondary phases Cu{sub (2−x)}Se and ZnSe. CZGSe films obtained by reducing the starting Cu mass by 10% were found to be single phase with stannite structure, the lattice parameters being a = 0.563 nm, c = 1.101 nm. The direct optical band gap of CZGSe films is found to be 1.63 eV which is close to ideal band gap of 1.50 eV for the highest photovoltaic conversion efficiency. The films are found to be p-type. - Highlights: • Synthesis of Cu{sub 2}ZnGeSe{sub 4} films for solar cell absorber layer • Effect of substrate temperature on the growth of co-evaporated Cu{sub 2}ZnGeSe{sub 4} films • X-ray diffraction, Raman and morphological studies of Cu{sub 2}ZnGeSe{sub 4} thin films.

Fabrication of Cu{sub 2}S nanoneedles by self-assembly of nanoparticles via simple wet chemical route

Energy Technology Data Exchange (ETDEWEB)

Kumarakuru, Haridas, E-mail: haridas.kumarakuru@nmmu.ac.za; Coombes, Matthew J.; Neethling, Johannes H.; Westraadt, Johan E.

2014-03-15

Highlights: • An inexpensive wet chemical method was used at room temperature to grow Cu{sub 2}S. • Growth of Cu{sub 2}S nanostructures influences by the Cl{sup −} ion concentration. • Thioglycerol and Cl{sup −} ions are used as a blend capping agents. • Cu{sub 2}S nanoneedles were formed via self-assembly of nanoparticles. • We can propose a growth model for Cu{sub 2}S nanoneedles based on our observations. -- Abstract: Cu{sub 2}S nanoneedles, fabricated by self-assembly of Cu{sub 2}S nanoparticles via wet chemical method are investigated. Crystallinity and surface morphologies of the as-grown needles are examined using X-ray diffraction and scanning and transmission electron microscopy. It is observed that the nanoparticle formation is controlled by the blend concentration of capping agents, thioglycerol, added during the synthesis and the Cl{sup −} ions delivered by the CuCl source. The likely reasons for the elongated structure of the nanoparticle self-assembly are also discussed.

Infrared detection with high-[Tc] bolometers and response of Nb tunnel junctions to picosecond voltage pulses

Energy Technology Data Exchange (ETDEWEB)

Verghese, S.

1993-05-01

Oxide superconductors with high critical temperature [Tc] make sensitive thermometers for several types of infrared bolometers. The authors built composite bolometers with YBa[sub 2]Cu[sub 3]O[sub 7[minus][delta

Influence of various parameters on the elaboration of superconducting oxides. Influence de divers parametres sur la synthese d'oxydes supraconducteurs

Energy Technology Data Exchange (ETDEWEB)

Remy, F; Monnereau, O; Vacquier, G; Sorbier, J P; Fournel, A [Aix-Marseille-1 Univ., 13 - Marseille (FR); Mokrani, R [Aix-Marseille-3 Univ., 13 - Marseille (FR)

1989-01-01

Several oxides able to give rise to a high T{sub c} superconductivity have been studied. Samples were prepared in both series: La(Ba{sub 2-x}La{sub x}) Cu{sub 3}O{sub 7+y} and YBa{sub 2} (Cu{sub 3-x}Ag{sub x})O{sub 7-y}. The evolution of the resistance versus the composition has been studied on sintered samples. The results assess the importance of the experimental conditions of the synthesis. In the system La(Ba{sub 2-x}La{sub x})Cu{sub 3}O{sub 7+y} our results complete the work of Segre et al. and precise composition at which the superconductivity transition disappear for the profit of the semiconductive behaviour. The samples YBa{sub 2}(Cu{sub 3-x}Ag{sub x})O{sub 7-y} has for x = 0 electrical properties very dependent of the thermal treatment. Some characteristic data are shown. The partial substitution of Cu by Ag for x {ge} 1 enables to keep the superconducting behaviour.

La{sub 3}Cu{sub 4}P{sub 4}O{sub 2} and La{sub 5}Cu{sub 4}P{sub 4}O{sub 4}Cl{sub 2}. Synthesis, structure and {sup 31}P solid state NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Bartsch, Timo; Eul, Matthias; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Benndorf, Christopher; Eckert, Hellmut [Muenster Univ. (Germany). Inst. fuer Physikalische Chemie; Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. of Physics

2016-04-01

The phosphide oxides La{sub 3}Cu{sub 4}P{sub 4}O{sub 2} and La{sub 5}Cu{sub 4}P{sub 4}O{sub 4}Cl{sub 2} were synthesized from lanthanum, copper(I) oxide, red phosphorus, and lanthanum(III) chloride through a ceramic technique. Single crystals can be grown in a NaCl/KCl flux. Both structures were refined from single crystal X-ray diffractometer data: I4/mmm, a = 403.89(4), c = 2681.7(3) pm, wR2 = 0.0660, 269 F{sup 2} values, 19 variables for La{sub 3}Cu{sub 4}P{sub 4}O{sub 2} and a = 407.52(5), c = 4056.8(7) pm, wR2 = 0.0905, 426 F{sup 2} values, 27 variables for La{sub 5}Cu{sub 4}P{sub 4}O{sub 4}Cl{sub 2}. Refinement of the occupancy parameters revealed full occupancy for the oxygen sites in both compounds. The structures are composed of cationic (La{sub 2}O{sub 2}){sup 2+} layers and covalently bonded (Cu{sub 4}P{sub 4}){sup 5-} polyanionic layers with metallic characteristics, and an additional La{sup 3+} between two adjacent (Cu{sub 4}P{sub 4}){sup 5-} layers. The structure of La{sub 5}Cu{sub 4}P{sub 4}O{sub 4}Cl{sub 2} comprises two additional LaOCl slabs per unit cell. Temperature-dependent magnetic susceptibility studies revealed Pauli paramagnetism. The phosphide substructure of La{sub 3}Cu{sub 4}P{sub 4}O{sub 2} was studied by {sup 31}P solid state NMR spectroscopy. By using a suitable dipolar re-coupling approach the two distinct resonances belonging to the P{sub 2}{sup 4-} and the P{sup 3-} units could be identified.

Magnetic uni- and tri-axial grain-orientation in superconductors with layered structures

International Nuclear Information System (INIS)

Horii, S.; Yamaki, M.; Ogino, H.; Maeda, T.; Shimoyama, J.

2010-01-01

We report the grain-orientation effects under a modulated rotation magnetic field for Y-based cuprate superconductors and LaFeAsO (La1111). Tri-axial orientation has been successfully achieved only for orthorhombic Y 2 Ba 4 Cu 7 O y and YBa 2 Cu 4 O 8 powders without a twin microstructure, while separation of three crystallographic axes could not be observed in twinned YBa 2 Cu 3 O y (Y123) and tetragonal La1111 powders. The morphology of grains, in addition to the symmetry of crystal structures, seriously affects the degrees of tri-axial orientation, which means that the control of twin microstructures is required for the tri-axial magnetic orientation in Y123.

Ultrafast one-step combustion synthesis and thermoelectric properties of In-doped Cu{sub 2}SnSe{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Li, Yuyang [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190 (China); University of Chinese Academy of Sciences, Beijing, 100049 (China); Liu, Guanghua, E-mail: liugh02@163.com [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190 (China); Li, Jiangtao, E-mail: lijiangtao@mail.ipc.ac.cn [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190 (China); Chen, Kexin [State Key Laboratory of New Ceramics & Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084 (China); He, Gang; Yang, Zengchao; Han, Yemao; Zhou, Min; Li, Laifeng [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190 (China)

2016-07-01

Bulk In-doped Cu{sub 2}SnSe{sub 3} samples were prepared by a fast and one-step method of high-gravity combustion synthesis. All the synthesized samples were dense with relative densities of >98%. The influence of Indium-doping on the phase composition of the samples was investigated. SEM and EDS measurements confirm the existence of SnSe and Cu{sub 2}Se as secondary phase in the Cu{sub 2}Sn{sub 1−x}In{sub x}Se{sub 3} samples. In addition, the experimental results show that there is a solubility limit of indium in the Cu{sub 2}SnSe{sub 3} matrix. The thermoelectric properties of the samples were measured in a temperature range from 323 K to 773 K, and the Cu{sub 2}Sn{sub 0.8}In{sub 0.2}Se{sub 3} sample achieved a maximum ZT of 0.65 at 773 K, which was comparable with the best-reported result for Cu{sub 2}SnSe{sub 3} materials prepared by conventional sintering approaches. With much reduced time and energy consumption, high-gravity combustion synthesis may offer a more efficient and economical way for producing thermoelectric materials. - Highlights: • Dense bulk Cu{sub 2}SnSe{sub 3} materials are prepared by one-step combustion synthesis. • The solubility limit of Indium into the Cu{sub 2}SnSe{sub 3} matrix has been discussed. • A maximum ZT of 0.65 is obtained for the Cu{sub 2}Sn{sub 1−x}In{sub x}Se{sub 3} (x = 0.2) at 773 K.

Synthesis of Bi{sub 1.8}Pb{sub 0.4}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} superconductor

Science.gov (United States)

Smith, M.G.

1996-10-29

Two-powder processes for the synthesis of superconducting (Bi, Pb)-2223/Ag-clad wires by the oxide-powder-in-the-robe are provided. The first precursor powder, of nominal stoichiometry CaCuO{sub x}, is a solution-synthesized mixture of Ca{sub 0.45}Cu{sub 0.55}O{sub 2} and CaO. Using these oxide precursor mixtures, superconducting tapes with well-aligned grains and reproducible critical current densities J{sub c} in the range of 20,000 to 26,000 A/cm{sup 2} at 75 K in self-field after annealing less than 200 hours were obtained. 2 figs.

Conductivity fluctuation in the high temperature superconductor with planar weight disparity Y{sub 0.5}Sm{sub 0.5}Ba{sub 2}Cu{sub 3}O{sub 7-{delta}}

Energy Technology Data Exchange (ETDEWEB)

Barrera, E.W.; Rojas Sarmiento, M.P.; Rincon, L.F.; Landinez Tellez, D.A.; Roa-Rojas, J. [Grupo de Fisica de Nuevos Materiales, Departamento de Fisica, Universidad Nacional de Colombia, A.A. 14490, Bogota DC (Colombia)

2007-07-01

The synthesis of the Y{sub 0.5}Sm{sub 0.5}Ba{sub 2}Cu{sub 3}O{sub 7-{delta}} superconducting material by the standard solid state reaction is reported. DC resistivity measurements reveal the improvement of the critical temperature (T{sub c}) when substitution of exact 50-50 mix of Yttrium and Samarium is performed. A bulk T{sub c} = 101 K was determined by the criterion of the maximum in the temperature derivative of electrical resistivity. Structure characterization by means the x-ray diffraction technique shows the crystalline appropriated distribution of Yttrium and Samarium to create substantial planar weight disparity (PWD) in alternating layers. This PWD increases T{sub c} in copper-oxide superconductors. In order to examine the effect of PWD on the pairing mechanism close to T{sub c}, conductivity fluctuation analysis was performed by the method of logarithmic temperature derivative of the conductivity excess. We found the occurrence of Gaussian and genuinely critical fluctuations. Our results are in agreement with reports on YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}, but an enhancement of the Gaussian fluctuation regimes was experimentally detected as a result of the PWD. The correlations of the critical exponents with the dimensionality of the fluctuation system for each Gaussian regime were performed by using the Aslamazov-Larkin theory. The genuinely critical exponent is interpreted by the 3D-XY model as corresponding with the dynamical universality class of the E-model. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Cu{sub 2}O/TiO{sub 2} heterostructures on a DVD as easy&cheap photoelectrochemical sensors

Energy Technology Data Exchange (ETDEWEB)

Zanatta, Michele; Calvillo, Laura; Zheng, Jian; Rizzi, Gian Andrea, E-mail: gianandrea.rizzi@unipd.it; Durante, Christian; Giallongo, Giuseppe; Chirkov, Dymitrov; Colazzo, Luciano; Marega, Carla; Gennaro, Armando; Granozzi, Gaetano

2016-03-31

Cu{sub 2}O nanoparticles have been grown by pulse-electrochemical deposition on a Digital Versatile Disk (DVD) which acts as a nanostructured electrode. Prior to Cu{sub 2}O deposition, the silver-coated rectangular-shaped grooves of the disassembled DVD were coated with a TiO{sub 2} thin film by a modified sol–gel method, where oxalic acid is used in place of the usual mineral acids to peptize the precipitated hydrous titania formed from the hydrolysis of titanium iso-propoxide. This procedure leaves no inorganic residues after UV-curing, resulting in a high quality film, mainly composed of TiO{sub 2}-anatase. As demonstrated by Atomic Force Microscopy (AFM) measurements, the DVD grooves are filled by a 120–130 nm thick TiO{sub 2} film, while the thickness of the TiO{sub 2} deposit on the crests is only ca. 50 nm. This inhomogeneous thickness leads to an inhomogeneous electric field when the DVD is used as an electrode for depositing Cu{sub 2}O nanoparticles, which eventually leads to the growth of Cu{sub 2}O nanoparticles only on the DVD crests. A highly regular and reproducible Cu{sub 2}O/TiO{sub 2} stripe-like heterostructure is obtained where both semiconducting oxides are aside. This system has been characterized by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), X-ray photoemission spectroscopy (XPS), Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy, Raman spectroscopy and photocurrent measurements. A possible use of this easy&cheap electrode as a visible light responsive sensor to water soluble organics in basic solution is suggested. - Highlights: • A commercial DVD is recycled to prepare cheap photo-electrochemical sensors. • The sensing elements are Cu{sub 2}O nanostripes grown on a nanostructured TiO{sub 2} thin film obtained at room temperature. • Water soluble organics can be detected by dissolved O{sub 2} activation with visible light.

Current flow mechanism in Cu{sub 2}O/p-Si heterojunction prepared by chemical method

Energy Technology Data Exchange (ETDEWEB)

Serin, T; Guerakar, S; Serin, N; Yildirim, N; Oezyurt Kus, F, E-mail: serin@eng.ankara.edu.t [Department of Engineering Physics, Faculty of Engineering, Ankara University, 06100 Ankara (Turkey)

2009-11-21

Cu{sub 2}O thin films were chemically deposited on single-crystal p-Si substrates to form Cu{sub 2}O/p-Si heterojunctions. The structure of the Cu{sub 2}O films was analysed by x-ray diffraction spectroscopy and UV-Vis-NIR transmittance spectra. In order to investigate the dark current transport mechanism in Cu{sub 2}O/p-Si heterojunctions the current-voltage characteristics were measured in the temperature range 120-320 K and capacitance-voltage characteristics at a high frequency of {approx}1 MHz at room temperature. The I-V-T characteristics revealed that the forward current was determined by trap-assisted multi-step tunnelling. The activation energy determined from the saturation current and the junction built-in potential determined from the capacitance-voltage characteristics were about 0.18 eV and 1.10 V at room temperature, respectively.

Electromigration in 3D-IC scale Cu/Sn/Cu solder joints

Energy Technology Data Exchange (ETDEWEB)

Ho, Cheng-En, E-mail: ceho1975@hotmail.com; Lee, Pei-Tzu; Chen, Chih-Nan; Yang, Cheng-Hsien

2016-08-15

The electromigration effect on the three-dimensional integrated circuits (3D-IC) scale solder joints with a Cu/Sn(25–50 μm)/Cu configuration was investigated using a field-emission scanning electron microscope (FE–SEM) combined with electron backscatter diffraction (EBSD) analysis system. Electron current stressing for a few days caused the pronounced accumulation of Cu{sub 6}Sn{sub 5} in specific Sn grain boundaries (GBs). The EBSD analysis indicated that both the β-Sn crystallographic orientation and GB orientation play dominant roles in this accumulation. The dependencies of the Cu{sub 6}Sn{sub 5} accumulation on the two above factors (i.e., Sn grain orientation and GB orientation) can be well rationalized via a proposed mathematic model based on the Huntington and Grone's electromigration theory with the Cu anisotropic diffusion data in a β-Sn lattice. - Highlights: • Anisotropic Cu electromigration in the 3D-IC scale microelectronic solder joints. • Pronounced accumulation of Cu{sub 6}Sn{sub 5} intermetallic in specific Sn grain boundaries. • A linear dependence of Cu{sub 6}Sn{sub 5} accumulation over the current stressing time. • β-Sn and grain boundary orientations are the dominant factors in Cu{sub 6}Sn{sub 5} accumulation.

Electrodeposition of flake-like Cu{sub 2}O on vertically aligned two-dimensional TiO{sub 2} nanosheet array films for enhanced photoelectrochemical properties

Energy Technology Data Exchange (ETDEWEB)

Yang, Lei [School of Physics & Material Science, Anhui University, Hefei 230601 (China); Co-operative Innovation Research Center for Weak Signal-Detecting Materials and Devices Integration, Anhui University, Hefei 230601 (China); Institute of Applied Physics AOA, Hefei 230031 (China); Zhang, Miao; Zhu, Kerong [School of Physics & Material Science, Anhui University, Hefei 230601 (China); Lv, Jianguo [School of Electronic & Information Engineering, Hefei Normal University, Hefei 230601 (China); He, Gang [School of Physics & Material Science, Anhui University, Hefei 230601 (China); Sun, Zhaoqi, E-mail: szq@ahu.edu.cn [School of Physics & Material Science, Anhui University, Hefei 230601 (China)

2017-01-01

Highlights: • Flake-like Cu{sub 2}O/TNS with exposed {001} facets constructed p-n heterostructure. • The TNS arrays were used as starting substrates for Cu{sub 2}O growth. • The Cu{sub 2}O/TNS prepared at −0.4 V exhibits the best photoelectrochemical property. - Abstract: A novel Cu{sub 2}O/TNS composite structure of single crystal TiO{sub 2} nanosheet (TNS) arrays decorated with flake-like Cu{sub 2}O were synthesized by a facile hydrothermal reaction followed by the electrodeposition process. The effects of deposition potential on the microstructure, morphology, and optical property of the thin films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–vis spectrophotometer. When the deposition potential is higher than −0.4 V, peaks corresponding to Cu appear, meanwhile, flake-like Cu{sub 2}O become agglomerating, and transform into dense Cu{sub 2}O particles. Additionally, photoelectrochemical experiments indicate that the films deposited at −0.4 V show the lowest resistivity and highest exciton separation efficiency. This enhanced photoelectrochemical properties can be explained by synergistic effect of p-type flake-like Cu{sub 2}O and n-type TiO{sub 2} heterojunctions combined with two-dimensional TiO{sub 2} nanosheet with exposed highly reactive {001} facets.

Microstructure-grain orientation relationship in coarse grain nickel cold-rolled to large strain

International Nuclear Information System (INIS)

Chen, H.S.; Godfrey, A.; Hansen, N.; Xie, J.X.; Liu, Q.

2008-01-01

The relationship between crystallographic orientation and the deformation microstructure formed during cold-rolling to high strains (up to ε vM = 4.5) has been investigated. The starting material was Ni (99.96% purity) with a coarse initial average grain size (approximately 500 μm). Microstructural characterization was carried out using a combination of electron channeling contrast imaging and electron back-scatter diffraction orientation mapping. An orientation dependence of the deformation microstructure was observed even at the highest strain examined. A large increase in the average boundary misorientation is found at strains above ε vM = 1.8 for regions with the {1 1 2} and {1 2 3} orientations. This increase accompanies the structural transition from a medium strain microstructure to a high strain lamellar microstructure. In contrast, the average misorientation in regions of {1 1 0} orientation increases only slowly even up to the highest strain examined

Dominant effect of high anisotropy in β-Sn grain on electromigration-induced failure mechanism in Sn-3.0Ag-0.5Cu interconnect

Energy Technology Data Exchange (ETDEWEB)

Huang, M.L., E-mail: huang@dlut.edu.cn; Zhao, J.F.; Zhang, Z.J.; Zhao, N.

2016-09-05

The effect of high diffusivity anisotropy in β-Sn grain on electromigration behavior of micro-bumps was clearly demonstrated using Sn-3.0Ag-0.5Cu solder interconnects with only two β-Sn grains. The orientation of β-Sn grain (θ is defined as the angle between the c-axis of β-Sn grain and the electron flow direction) is becoming the most crucial factor to dominate the different electromigration-induced failure modes: 1) the excessive dissolution of the cathode Cu, blocking at the grain boundary and massive precipitation of columnar Cu{sub 6}Sn{sub 5} intermetallic compounds (IMCs) in the small angle θ β-Sn grain occur when electrons flow from a small angle θ β-Sn grain to a large one; 2) void formation and propagation occur at the cathode IMC/solder interface and no Cu{sub 6}Sn{sub 5} IMCs precipitate within the large angle θ β-Sn grain when electrons flow in the opposite direction. The EM-induced failure mechanism of the two β-Sn grain solder interconnects is well explained in viewpoint of atomic diffusion flux in β-Sn. - Highlights: • High anisotropy in β-Sn dominates different electromigration-induced failure mode. • Excessive dissolution of cathode Cu occurs if electrons flow in forward direction. • Voids initiate and propagate at cathode if electrons flow in reverse direction. • Failure modes are well explained in viewpoint of atomic diffusion flux in β-Sn.

Synthesis of Cu{sub 2}O/graphene/rutile TiO{sub 2} nanorod ternary composites with enhanced photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Sun, Mingxuan, E-mail: mingxuansun@sues.edu.cn; Fang, Yalin; Wang, Ying; Sun, Shanfu; He, Jia; Yan, Zhi

2015-11-25

A ternary composite of Cu{sub 2}O, graphene and rutile TiO{sub 2} nanorods was prepared using Cu(CH{sub 3}COO){sub 2}·H{sub 2}O, graphene oxide and TiCl{sub 4} as the starting materials and its enhanced photocatalytic performance was demonstrated. Graphene/TiO{sub 2} nanorod composites (GT) were obtained by a simple hydrothermal method and then, Cu{sub 2}O was coupled onto the surface of graphene/rutile TiO{sub 2} to form Cu{sub 2}O/graphene/rutile TiO{sub 2} nanorod (CGT) composites via a chemical bath deposition process. The as-prepared sample was characterized by X-ray diffraction (XRD), emission field scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), specific surface area analyzer (BET), Raman spectroscopy and ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS). It is found that the introduction of graphene and Cu{sub 2}O has little effect on the morphology of TiO{sub 2} nanorods with average dimensions of 140 nm (length) × 30 nm (diameter) (L/D ratio ≈5). A red shift of light absorption edge and more absorption in the visible light region were observed for the resulted ternary samples compared with TiO{sub 2} and graphene/TiO{sub 2} composites. The photocatalytic activity was evaluated by the photodegradation of methylene blue under visible light irradiation, which showed 2.8 times corresponding enhancement of the degradation efficiency for the ternary composites compared with TiO{sub 2}. This work provides a new strategy to improve the visible light response of TiO{sub 2} and facilitate its application in environmental remediation. - Highlights: • A ternary composite of Cu{sub 2}O/graphene/rutile TiO{sub 2} nanorods were successfully fabricated. • Red shift and more absorption in the visible light region were observed for the ternary composites. • Improved photocatalytic degradation was detected with the introduction of Cu{sub 2}O and graphene. • Both Cu{sub 2}O and graphene played an important role

Effect of annealing on structural and optical properties of Cu{sub 2}ZnSnS{sub 4} thin films grown by pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Surgina, G.D., E-mail: silvereye@bk.ru [National Research Nuclear University “Moscow Engineering Physics Institute”, Moscow 115409 (Russian Federation); Moscow Institute of Physics and Technology, Dolgoprudny, Moscow region 141700 (Russian Federation); Nevolin, V.N. [National Research Nuclear University “Moscow Engineering Physics Institute”, Moscow 115409 (Russian Federation); P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); Sipaylo, I.P.; Teterin, P.E. [National Research Nuclear University “Moscow Engineering Physics Institute”, Moscow 115409 (Russian Federation); Medvedeva, S.S. [Immanuel Kant Baltic Federal University, Kaliningrad 236041 (Russian Federation); Lebedinsky, Yu.Yu.; Zenkevich, A.V. [National Research Nuclear University “Moscow Engineering Physics Institute”, Moscow 115409 (Russian Federation); Moscow Institute of Physics and Technology, Dolgoprudny, Moscow region 141700 (Russian Federation)

2015-11-02

In this work, we compare the effect of different types of thermal annealing on the morphological, structural and optical properties of Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films grown by reactive Pulsed Laser Deposition in H{sub 2}S flow. Rutherford backscattering spectrometry, atomic force microscopy, X-ray diffraction, Raman spectroscopy and optical spectrophotometry data reveal dramatic increase of the band gap and the crystallite size without the formation of secondary phases upon annealing in N{sub 2} at the optimized conditions. - Highlights: • Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films were grown at room temperature. • Reactive Pulsed Laser Deposition in H{sub 2}S flow was used as a growth method. • Effect of annealing conditions on CZTS structural and optical properties is revealed. • Both the grain size and the band gap of CZTS film increase following the annealing. • Annealing in N{sub 2} effectively inhibits the formation of Sn{sub x}S secondary phases.

Lattice parameter values and phase transitions for the Cu{sub 2}Cd{sub 1-z}Mn{sub z}SnSe{sub 4} and Cu{sub 2}Cd{sub 1-z}Fe{sub z}SnSe{sub 4} alloys

Energy Technology Data Exchange (ETDEWEB)

Moreno, E. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela, Bolivarian Republic of); Quintero, M., E-mail: mquinter@ula.v [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela, Bolivarian Republic of); Morocoima, M.; Quintero, E.; Grima, P.; Tovar, R.; Bocaranda, P. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela, Bolivarian Republic of); Delgado, G.E.; Contreras, J.E. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela, Bolivarian Republic of); Mora, A.E.; Briceno, J.M.; Avila Godoy, R.; Fernandez, J.L. [Laboratorio de Analisis Quimico y Estructural de Materiales, Departamento de Fisica, Universidad de Los Andes, Merida 5101 (Venezuela, Bolivarian Republic of); Henao, J.A.; Macias, M.A. [Grupo de Investigacion en Quimica Estructural (GIQUE), Facultad de Ciencias, Escuela de Quimica, Universidad Industrial de Santander, Apartado aereo 678, Bucaramanga (Colombia)

2009-11-03

X-ray powder diffraction measurements and differential thermal analysis (DTA) were made on polycrystalline samples of the Cu{sub 2}Cd{sub 1-z}Mn{sub z}SnSe{sub 4} and Cu{sub 2}Cd{sub 1-z}Fe{sub z}SnSe{sub 4} alloy systems. The diffraction patterns were used to show the equilibrium conditions and to derive lattice parameter values. For Cu{sub 2}Cd{sub 0.8}Fe{sub 0.2}SnSe{sub 4} as well as for Cu{sub 2}Cd{sub 0.2}Fe{sub 0.8}SnSe{sub 4} the crystal structures were refined using the Rietveld method. It was found that the internal distortion parameter sigma decreases as Cd is replaced by either Mn and/or Fe. For the Cu{sub 2}Cd{sub 1-z}Mn{sub z}SnSe{sub 4} and Cu{sub 2}Cd{sub 1-z}Fe{sub z}SnSe{sub 4} alloy systems, only two single solid phase fields, the tetragonal stannite alpha(I4-bar2m) and the wurtz-stannite delta (Pmn2{sub 1}) structures were found to occur in the diagram. In addition to the tetragonal stannite alpha phase extra X-ray diffraction lines due to MnSe and/or FeSe{sub 2} were observed for as grown samples in the range 0.7 < z < 1.0. However, it was found that the amount of the extra phase decreased for the compressed samples.

Effects of copper excess and copper deficiency on the structural and electrical properties of bulk Cu{sub x}SnSe{sub 3} with x=1.6–2.2

Energy Technology Data Exchange (ETDEWEB)

Wubet, Walelign; Kuo, Dong-Hau, E-mail: dhkuo@mail.ntust.edu.tw

2015-03-15

Effects of the Cu variation on the morphological, structural, and electrical properties of bulk Cu{sub x}SnSe{sub 3} (CTSe) with x=1.6–2.2 have been investigated. Dense CTSe pellets with grains of 3–4 µm were obtained after sintering at 550 °C. All CTSe pellets showed a dominant p-type behavior. CTSe at x=2.0 with a hole concentration (n{sub p}) of 1.02×10{sup 18} cm{sup −3} and Hall mobility (μ) of 225 cm{sup 2}/V/s had a highest conductivity (σ) of 39 S/cm. CTSe at x=1.6 with n{sub p} of 5.0×10{sup 17} cm{sup −3} and of 11 cm{sup 2}/V/s had a lowest of 0.90 S/cm. The explanation, based upon vacancies and antisite defects, for the changes in electrical property with the Cu content is supported by the data from lattice parameter. The study in bulk properties of CTSe and its defects is helpful for selecting the suitable absorber composition to fabricate thin film solar cells. - Graphical abstract: Cu{sub 2}SnSe{sub 3} is an absorber candidate for solar cells. The Cu stoichiometry on electrical properties, which is important for CIGS and CZTS, is investigated and the Cu-deficiency composition is recommended. - Highlights: • Cu{sub x}SnSe{sub 3} (CTSe) bulks with 1.6≤x≤2.2 were prepared by reactive sintering. • Cu{sub 2}SnSe{sub 3} with n{sub p} of 1.02×10{sup 18} cm{sup −3} and μ of 225 cm{sup 2}/V/s had highest σ of 39 S/cm. • Cu{sub 1.6}SnSe{sub 3} with n{sub p}=5.0×10{sup 17} cm{sup −3} and μ=11 cm{sup 2}/V/s had lowest σ=0.90 S/cm. • Lower n{sub p} at CTSe at x=1.6 is related to the formation of the Sn-to-Cu defect. • The drop in n{sub p} for CTSe at x=2.2 indicates V{sub Sn}{sup 4−} dominates over Cu{sub Sn}{sup 3−} defect.

Relative effect(s) of texture and grain size on magnetic properties in a low silicon non-grain oriented electrical steel

International Nuclear Information System (INIS)

PremKumar, R.; Samajdar, I.; Viswanathan, N.N.; Singal, V.; Seshadri, V.

2003-01-01

Hot rolled low Si (silicon) non-grain oriented electrical steel was cold rolled to different reductions. Cold rolled material was subsequently recrystallized, 650 deg. C and 2 h, and then temper rolled (to 7% reduction) for the final grain growth annealing and decarburization treatment at 850 deg. C for 2-24 h. The development of texture, grain size and magnetic properties were characterized at different stages of processing. Effect of texture on magnetic properties (watt loss and permeability) was observed to be best represented by the ratio of volume fractions of (1 1 1) /(0 0 1) fibers, as estimated by convoluting X-ray ODFs (orientation distribution functions) with respective model functions. Such a ratio was termed as generalized texture factor (tf) for the non-grain oriented electrical steel. An effort was made to delink effects of grain size and texture, as represented by respective tf, on watt loss and permeability by careful analysis of experimental data. In general, low tf and/or high grain size were responsible for low watt loss and high permeability. However, individual effect of grain size or tf on magnetic properties was less significant at low tf or large grain size, respectively. An attempt was made to fit regression equations, namely--linear, exponential and power, relating magnetic properties with tf and grain size, limiting the fitting parameters to 3. Least standard deviations, between experimental and predicted values, were obtained by power regression equations for both magnetic properties

Cu{sub 2}ZnSn(S,Se){sub 4} from Cu{sub x}SnS{sub y} nanoparticle precursors on ZnO nanorod arrays

Energy Technology Data Exchange (ETDEWEB)

Kavalakkatt, Jaison, E-mail: jai.k@web.de [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Freie Universitaet Berlin, Berlin (Germany); Lin, Xianzhong; Kornhuber, Kai [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Kusch, Patryk [Freie Universitaet Berlin, Berlin (Germany); Ennaoui, Ahmed [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Reich, Stephanie [Freie Universitaet Berlin, Berlin (Germany); Lux-Steiner, Martha Ch. [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Freie Universitaet Berlin, Berlin (Germany)

2013-05-01

Solar cells with Cu{sub 2}ZnSnS{sub 4} absorber thin films have a potential for high energy conversion efficiencies with earth-abundant and non-toxic elements. In this work the formation of CZTSSe from Cu{sub x}SnS{sub y} nanoparticles (NPs) deposited on ZnO nanorod (NR) arrays as precursors for zinc is investigated. The NPs are prepared using a chemical route and are dispersed in toluene. The ZnO NRs are grown on fluorine doped SnO{sub 2} coated glass substrates by electro deposition method. A series of samples are annealed at different temperatures between 300 °C and 550 °C in selenium containing argon atmosphere. To investigate the products of the reaction between the precursors the series is analyzed by means of X-ray diffraction (XRD) and Raman spectroscopy. The morphology is recorded by scanning electron microscopy (SEM) images of broken cross sections. The XRD measurements and the SEM images show the disappearing of ZnO NRs with increasing annealing temperature. Simultaneously the XRD and Raman measurements show the formation of CZTSSe. The formation of secondary phases and the optimum conditions for the preparation of CZTSSe is discussed. - Highlights: ► Cu{sub x}SnS{sub y} nanoparticles are deposited on ZnO nanorod arrays. ► Samples are annealed at different temperatures (300–550 °C) in Se/Ar-atmosphere. ► Raman spectroscopy, X-ray diffraction and electron microscopy are performed. ► ZnO disappears with increasing annealing temperature. ► With increasing temperature Cu{sub x}SnS{sub y} and ZnO form Cu{sub 2}ZnSn(S,Se){sub 4}.

Fabrication of a Cu{sub 2}O/Au/TiO{sub 2} composite film for efficient photocatalytic hydrogen production from aqueous solution of methanol and glucose

Energy Technology Data Exchange (ETDEWEB)

Wang, Xi; Dong, Haitai; Hu, Zhe; Qi, Zhong; Li, Laisheng, E-mail: llsh@scnu.edu.cn

2017-05-15

Highlights: • A Cu{sub 2}O/Au/TiO{sub 2} film was synthesized successfully. • Hydrogen production of Cu{sub 2}O/Au/TiO{sub 2} film improved significantly. • The highest hydrogen production rate of the film was 125.3 mmol/h/m{sup 2}. • A Z-scheme charge transfer pathway was proposed. - Abstract: A novel Cu{sub 2}O/Au/TiO{sub 2} photocatalyst composite film was fabricated on a copper substrate for photocatalytic hydrogen production. The composite films, Cu{sub 2}O/Au/TiO{sub 2}, were stepwise synthesized by using electrochemical deposition, photodeposition, and coating methods. First, a Cu{sub 2}O film was synthesized using the electrochemical deposition method, after which Au was deposited onto the Cu{sub 2}O film through in-site photodeposition. Finally, TiO{sub 2} was coated on the surface of the Cu{sub 2}O/Au film. Its morphology and surface chemical composition was characterized by SEM, TEM, XRD and XPS. The optical characteristics (UV–Vis DRS, PL spectrum) of the films were also examined. The photocatalytic hydrogen production rate of the Cu{sub 2}O/Au/TiO{sub 2} composite film from a 20% vol. methanol solution increased to125.3 mmol/h/m{sup 2} under 300 W xenon lamp light irradiation. Compared to the TiO{sub 2} (13.5 mmol/h/m{sup 2}) film and Cu{sub 2}O/TiO{sub 2} film (83.2 mmol/h/m{sup 2}), the Cu{sub 2}O/Au/TiO{sub 2} film showed excellent photocatalytic performance for hydrogen generation. The Cu{sub 2}O/Au/TiO{sub 2} film has highly effective photocatalytic properties, which are attributed to the Z-scheme system and can not only enhance the absorption of solar light but also suppress the recombination of photogenerated electron-hole pairs. It is worth noting that by introducing Au into the interface of Cu{sub 2}O/TiO{sub 2}, the surface plasmon resonance (SPR)-induced local electric field formed at the Au site induces a Z-scheme charge transfer pathway inside the composite film (Cu{sub 2}O/Au/TiO{sub 2}), which promotes both the charge of the

The Role of Grain Orientation and Grain Boundary Characteristics in the Mechanical Twinning Formation in a High Manganese Twinning-Induced Plasticity Steel

Science.gov (United States)

Shterner, Vadim; Timokhina, Ilana B.; Rollett, Anthony D.; Beladi, Hossein

2018-04-01

In the current study, the dependence of mechanical twinning on grain orientation and grain boundary characteristics was investigated using quasi in-situ tensile testing. The grains of three main orientations (i.e., , , and parallel to the tensile axis (TA)) and certain characteristics of grain boundaries (i.e., the misorientation angle and the inclination angle between the grain boundary plane normal and the TA) were examined. Among the different orientations, and were the most and the least favored orientations for the formation of mechanical twins, respectively. The orientation was intermediate for twinning. The annealing twin boundaries appeared to be the most favorable grain boundaries for the nucleation of mechanical twinning. No dependence was found for the inclination angle of annealing twin boundaries, but the orientation of grains on either side of the annealing twin boundary exhibited a pronounced effect on the propensity for mechanical twinning. Annealing twin boundaries adjacent to high Taylor factor grains exhibited a pronounced tendency for twinning regardless of their inclination angle. In general, grain orientation has a significant influence on twinning on a specific grain boundary.

Compensated electron and hole pickets in an underdoped high Tc superconductor

Energy Technology Data Exchange (ETDEWEB)

Harrison, Neil [Los Alamos National Laboratory; Altarawneh, Moaz M [Los Alamos National Laboratory; Mielke, Charles H [Los Alamos National Laboratory; Sebastian, Suchitra E [CAMBRIDGE U; Goddard, P A [U OF OXFORD; Liang, Ruixing [U BRITISH COLUMBIA; Bonn, D A [U BRITISH COLUMBIA; Hardy, W N [U BRITISH COLUMBIA; Andersen, O K [MAX PLANCK INST.; Lonzarich, G G [CAMBRIDGE U

2010-01-01

Important to the question of high temperature superconductivity is whether bound fermionic pairs with zero or finite momentum - exhibiting bosonic physics - are involved. Here we use angle-dependent magnetic quantum oscillation measurements in underdoped YBa{sub 2}Cu{sub 3}O{sub 6+x} to reveal two significantly differently corrugated small sections of Fermi surface, identifying them as comprising opposite carriers located at different locations of the Brillouin zone. The surprising finding that these disproportionately heavy small pockets are equal in size indicates they are prone to a finite momentum excitonic insulator instability. We discuss the possibility that reducing the doping drives YBa{sub 2}Cu{sub 3}O{sub 6+x} closer to an instability of this nature, its ultimate realization occuring at the metal-insulator quantum critical point, accompanied by a potential enhancement of superconducting transition temperatures.

Grain Orientation and Interface Character Distribution During Austenite Precipitation Phase in Duplex Stainless Steel

Directory of Open Access Journals (Sweden)

XU Ting

2018-02-01

Full Text Available The grain orientation and the interface character distribution were investigated for γ precipitation from the supersaturated α during aging at 1323K in duplex stainless steel by using EBSD technique and misorientation analysis based on Rodrigues-Frank (R-F space. The results show that sharp texture and the grain boundary character distribution featured by a high population of low angle grain boundary (LAB and a small number of twin boundaries (TBs are produced in the γ precipitated from cold-rolled supersaturated coarse α with pre-strain of ε=2. The precipitated γ grains approximately possess K-S, N-W and Bain orientation relationship with the α matrix equally. For the unstrained α matrix of the same orientation, nearly random texture and the grain boundary character predominated by TBs are introduced in the γ precipitation after aging. Most of γ have K-S relation with the α matrix. However, twining in γ leads to the deviation from typical K-S orientation relationship. And also, one-fourth of phase boundaries along γ grains containing twins are found to obey a new orientation relationship of 35°/〈110〉 with α matrix.

Epitaxial growth of YBa sub 2 Cu sub 3 O sub 7 minus. delta. thin films on LiNbO sub 3 substrates

Energy Technology Data Exchange (ETDEWEB)

Lee, S.G.; Koren, G.; Gupta, A.; Segmuller, A.; Chi, C.C. (IBM Thomas J. Watson Research Center, P.O. Box 218, Yorktown Heights, New York 10598 (US))

1989-09-18

{ital In} {ital situ} epitaxial growth of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} thin films on {ital Y}-cut LiNbO{sub 3} substrates using a standard laser ablation technique is reported. Resistance of the films shows a normal metallic behavior and a very sharp ({lt}1 K) superconducting transition with {ital T}{sub {ital c}}({ital R}=0) of 92 K. High critical current density of {ital J}{sub {ital c}}(77 K)=2{times}10{sup 5} A/cm{sup 2} is observed, which is in accordance with epitaxial growth. Film orientation observed from x-ray diffraction spectra indicates that the {ital c} axis is normal to the substrate plane and the {ital a} axis is at 45{degree} to the (11.0) direction of the hexagonal lattice of the substrate with two domains in mirror image to the (110) plane.

Magnetically separable Cu{sub 2}O/chitosan–Fe{sub 3}O{sub 4} nanocomposites: Preparation, characterization and visible-light photocatalytic performance

Energy Technology Data Exchange (ETDEWEB)

Cao, Chunhua [School of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China); Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Chemical and Environmental Engineering, Jianghan University, Wuhan 430056 (China); Xiao, Ling, E-mail: xiaoling9119@whu.edu.cn [School of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China); Chen, Chunhua [Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Chemical and Environmental Engineering, Jianghan University, Wuhan 430056 (China); Cao, Qihua [School of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China)

2015-04-01

Highlights: • A novel magnetically-separable Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} photocatalyst was in situ prepared. • Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs had rough and porous chitosan surface layer embedded with Fe{sub 3}O{sub 4} NPs. • Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs showed large surface areas and special dimodal pore structure. • Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs showed superparamagnetism and could be easily magnetic separated. • Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs exhibited good visible-light photocatalytic activity and stability. - Abstract: A novel magnetically-separable visible-light-induced photocatalyst, Cu{sub 2}O/chitosan–Fe{sub 3}O{sub 4} nanocomposite (Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NC), was prepared via a facile one-step precipitation–reduction process by using magnetic chitosan chelating copper ions as precursor. The structure and properties of Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs were characterized by XRD, FT-IR, SEM, HRTEM, SAED, EDS, BET, VSM, XPS and UV–vis/DRS. The photocatalytic activity of Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs was evaluated by decolorization of reactive brilliant red X-3B (X-3B) under visible light irradiation. The characterization results indicated that Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs exhibited relatively large specific surface areas and special dimodal pore structure because Cu{sub 2}O was wrapped in chitosan matrix embedded with Fe{sub 3}O{sub 4} nanoparticles. The tight combination of magnetic Fe{sub 3}O{sub 4} and semiconductor Cu{sub 2}O through chitosan made the nanocomposites show good superparamagnetism and photocatalytic activity. It was found that X-3B could be decolorized more efficiently in acidic media than in neutral or alkaline media. The decolorization of X-3B was ascribed to the synergistic effect of photocatalysis and adsorption. Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs could be easily separated from the solution by an external magnet, and the decolorization rates of X-3B

Simulation of growing grains under orientation relation - dependent quadruple point dragging

International Nuclear Information System (INIS)

Ito, K

2015-01-01

The growth behaviour of a specified grain embedded in matrix grains, for which the migration mobility of the quadruple points depended on the relation between the orientations of the growing and shrinking grains, was studied using a modified Potts MC-type threedimensional simulation. Large embedded grains continued to grow without being overcome by coarsening matrix grains, whereas small embedded grains disappeared, under the influence of the relative mobilities of the quadruple points, the composition of the matrix grain texture and the width of the grain size distribution of the matrix grains. These results indicate that orientation relation-dependent quadruple point dragging can affect the recrystallization texture during the grain coarsening stage. (paper)

Cooling rate dependence of simulated Cu{sub 64.5}Zr{sub 35.5} metallic glass structure

Energy Technology Data Exchange (ETDEWEB)

Ryltsev, R. E. [Institute of Metallurgy, Ural Branch of Russian Academy of Sciences, 101 Amundsen Str., 620016 Ekaterinburg (Russian Federation); Ural Federal University, 19 Mira Str., 620002 Ekaterinburg (Russian Federation); L.D. Landau Institute for Theoretical Physics, Russian Academy of Sciences, 2 Kosygina Str., 119334 Moscow (Russian Federation); Klumov, B. A. [L.D. Landau Institute for Theoretical Physics, Russian Academy of Sciences, 2 Kosygina Str., 119334 Moscow (Russian Federation); Aix-Marseille-Université, CNRS, Laboratoire PIIM, UMR 7345, 13397 Marseille Cedex 20 (France); High Temperature Institute, Russian Academy of Sciences, 13/2 Izhorskaya Str., 125412 Moscow (Russian Federation); Chtchelkatchev, N. M. [Institute of Metallurgy, Ural Branch of Russian Academy of Sciences, 101 Amundsen Str., 620016 Ekaterinburg (Russian Federation); L.D. Landau Institute for Theoretical Physics, Russian Academy of Sciences, 2 Kosygina Str., 119334 Moscow (Russian Federation); Moscow Institute of Physics and Technology, 9 Institutskiy Per., Dolgoprudny, 141700 Moscow Region (Russian Federation); All-Russia Research Institute of Automatics, 22 Sushchevskaya, 127055 Moscow (Russian Federation); Shunyaev, K. Yu. [Institute of Metallurgy, Ural Branch of Russian Academy of Sciences, 101 Amundsen Str., 620016 Ekaterinburg (Russian Federation); Ural Federal University, 19 Mira Str., 620002 Ekaterinburg (Russian Federation)

2016-07-21

Using molecular dynamics simulations with embedded atom model potential, we study structural evolution of Cu{sub 64.5}Zr{sub 35.5} alloy during the cooling in a wide range of cooling rates γ ∈ (1.5 ⋅ 10{sup 9}, 10{sup 13}) K/s. Investigating short- and medium-range orders, we show that the structure of Cu{sub 64.5}Zr{sub 35.5} metallic glass essentially depends on cooling rate. In particular, a decrease of the cooling rate leads to an increase of abundances of both the icosahedral-like clusters and Frank-Kasper Z16 polyhedra. The amounts of these clusters in the glassy state drastically increase at the γ{sub min} = 1.5 ⋅ 10{sup 9} K/s. Analysing the structure of the glass at γ{sub min}, we observe the formation of nano-sized crystalline grain of Cu{sub 2}Zr intermetallic compound with the structure of Cu{sub 2}Mg Laves phase. The structure of this compound is isomorphous with that for Cu{sub 5}Zr intermetallic compound. Both crystal lattices consist of two types of clusters: Cu-centered 13-atom icosahedral-like cluster and Zr-centered 17-atom Frank-Kasper polyhedron Z16. That suggests the same structural motifs for the metallic glass and intermetallic compounds of Cu–Zr system and explains the drastic increase of the abundances of these clusters observed at γ{sub min}.

Cu{sub 2}ZnSnS{sub 4} thin film solar cells from electroplated precursors: Novel low-cost perspective

Energy Technology Data Exchange (ETDEWEB)

Ennaoui, A. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Solar Energy Division, Glienickerstrasse 100, D-14109 Berlin (Germany)], E-mail: ennaoui@helmholtz-berlin.de; Lux-Steiner, M.; Weber, A.; Abou-Ras, D.; Koetschau, I.; Schock, H.-W. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Solar Energy Division, Glienickerstrasse 100, D-14109 Berlin (Germany); Schurr, R.; Hoelzing, A.; Jost, S.; Hock, R. [Crystallography and Structural Physics, University of Erlangen-Nuernberg, Staudtstrasse 3, D-91058 Erlangen (Germany); Voss, T.; Schulze, J.; Kirbs, A. [Atotech Deutschland GmbH, Erasmusstr. 20, D-10553 Berlin (Germany)

2009-02-02

Thin-film solar cells based on Cu{sub 2}ZnSnS{sub 4} (CZTS) absorbers were fabricated successfully by solid-state reaction in H{sub 2}S atmosphere of electrodeposited Cu-Zn-Sn precursors. These ternary alloys were deposited in one step from a cyanide-free alkaline electrolyte containing Cu(II), Zn (II) and Sn (IV) metal salts on Mo-coated glass substrates. The solar cell was completed by a chemical bath-deposited CdS buffer layer and a sputtered i-ZnO/ZnO:Al bilayer. The best solar cell performance was obtained with Cu-poor samples. A total area (0.5 cm{sup 2}) efficiency of 3.4% is achieved (V{sub oc} = 563 mV, j{sub sc} = 14.8 mA/cm{sup 2}, FF = 41%) with a maximum external quantum efficiency (EQE) of 80%. The estimated band-gap energy from the external quantum efficiency (EQE) measurements is about 1.54 eV. Electron backscatter-diffraction maps of cross-section samples revealed CZTS grain sizes of up to 10 {mu}m. Elemental distribution maps of the CZTS absorber show Zn-rich precipitates, probably ZnS, and a Zn-poor region, presumably Cu{sub 2}SnS{sub 3}, close to the interface Mo/CZTS.

Superconducting composites materials. Materiaux composites supraconducteurs

Energy Technology Data Exchange (ETDEWEB)

Kerjouan, P; Boterel, F; Lostec, J; Bertot, J P; Haussonne, J M [Centre National d' Etudes des Telecommunications (CNET), 22 - Lannion (FR)

1991-11-01

The new superconductor materials with a high critical current own a large importance as well in the electronic components or in the electrotechnical devices fields. The deposit of such materials with the thick films technology is to be more and more developed in the years to come. Therefore, we tried to realize such thick films screen printed on alumina, and composed mainly of the YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} material. We first realized a composite material glass/YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}, by analogy with the classical screen-printed inks where the glass ensures the bonding with the substrate. We thus realized different materials by using some different classes of glass. These materials owned a superconducting transition close to the one of the pure YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} material. We made a slurry with the most significant composite materials and binders, and screen-printed them on an alumina substrate preliminary or not coated with a diffusion barrier layer. After firing, we studied the thick films adhesion, the alumina/glass/composite material interfaces, and their superconducting properties. 8 refs.; 14 figs.; 9 tabs.

Anisotropy model for modern grain oriented electrical steel based on orientation distribution function

Directory of Open Access Journals (Sweden)

Fan Jiang

2018-05-01

Full Text Available Accurately modeling the anisotropic behavior of electrical steel is mandatory in order to perform good end simulations. Several approaches can be found in the literature for that purpose but the more often those methods are not able to deal with grain oriented electrical steel. In this paper, a method based on orientation distribution function is applied to modern grain oriented laminations. In particular, two solutions are proposed in order to increase the results accuracy. The first one consists in increasing the decomposition number of the cosine series on which the method is based. The second one consists in modifying the determination method of the terms belonging to this cosine series.

The production of grain oriented lanthanum titanate (La2Ti2O7) ceramics by uniaxial hot-forging process for improved fracture toughness

International Nuclear Information System (INIS)

Ceylan, Ali

2008-01-01

The layered-structural ceramics, such as lanthanum titanate (La 2 Ti 2 O 7 ), have been known for their good electrical and optical properties at high frequencies and temperatures. However, few studies have been conducted on the mechanical properties of these ceramics. The interest in ceramic hot-forging (HF) has been greatly increased recently due to the enhancement in fracture toughness via bridging effect of oriented grains. In this study, grain oriented lanthanum titanate was produced by the hot-forging process. The characterizations of the samples were achieved by density measurement, scanning electron microscopy (SEM), optical microscopy, X-ray diffraction (XRD), Vickers indentation and three-point bending test. According to X-ray diffraction patterns, the orientation factor (f) was found to be 0.73 for certain hot-forging conditions resulting an improved fracture toughness. The improved fracture toughness of La 2 Ti 2 O 7 (3.2 MPa m 1/2 ) reached to the value of monolithic alumina (Al 2 O 3 ) between 3 and 4 MPa m 1/2

Accurate determination of the composition of Y-Ba-Cu-O superconductor by spectrophotometry, gravimetry and flame AAS

Energy Technology Data Exchange (ETDEWEB)

Bruneel, E [Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281(S3), 9000 Ghent (Belgium); Verbauwhede, D [Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281(S3), 9000 Ghent (Belgium); Vyver, D Van de [Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281(S3), 9000 Ghent (Belgium); Schaubroeck, J [Departement Industriele Wetenschappen, Hogeschool Gent, Schoonmeerstraat 52 9000 Ghent (Belgium); Hoste, S [Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281(S3), 9000 Ghent (Belgium); Driessche, I Van [Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281(S3), 9000 Ghent (Belgium)

2005-06-01

A procedure for the accurate analytical determination of yttrium, barium and copper in an YBa{sub 2}Cu{sub 3}O{sub x} superconductor is described. After dissolution of the material the concentration of Y and Cu was spectrophotometrically determined as an Y-Arsenazo III and a Cu-Nitroso-R-salt complex, respectively. Ba was determined either gravimetrically as BaCrO{sub 4}, after precipitation using a K{sub 2}CrO{sub 4} solution or using flame atomic absorption spectroscopy (AAS). An accuracy better than 0.7% and a coefficient of variation better then 1.2% are obtained. It is illustrated that this analytical procedure can be used to determine the composition of a bulk superconducting YBa{sub 2}Cu{sub 3}O{sub x} sample. For determination of Ba in thin films we suggest the use of flame AAS, with an accuracy of 0.03% and a coefficient of variation of 1.7%.

Electrical and thermal transport properties of layered Bi{sub 2}YO{sub 4}Cu{sub 2}Se{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Xiao, Yu; Pei, Yanling; Chang, Cheng; Zhang, Xiao [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Tan, Xing [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Ye, Xinxin [Department of Physics, South University of Science and Technology of China, Shenzhen 518055 (China); Gong, Shengkai [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Lin, Yuanhua [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); He, Jiaqing [Department of Physics, South University of Science and Technology of China, Shenzhen 518055 (China); Zhao, Li-Dong, E-mail: zhaolidong@buaa.edu.cn [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China)

2016-07-15

Bi{sub 2}YO{sub 4}Cu{sub 2}Se{sub 2} possesses a low thermal conductivity and high electrical conductivity at room temperature, which was considered as a potential thermoelectric material. In this work, we have investigated the electrical and thermal transport properties of Bi{sub 2}YO{sub 4}Cu{sub 2}Se{sub 2} system in the temperature range from 300 K to 873 K. We found that the total thermal conductivity decreases from ~1.8 W m{sup −1} K{sup −1} to ~0.9 W m{sup −1} K{sup −1}, and the electrical conductivity decreases from ~850 S/cm to ~163 S/cm in the measured temperature range. To investigate how potential of Bi{sub 2}YO{sub 4}Cu{sub 2}Se{sub 2} system, we prepared the heavily Iodine doped samples to counter-dope intrinsically high carrier concentration and improve the electrical transport properties. Interestingly, the Seebeck coefficient could be enhanced to ~+80 μV/K at 873 K, meanwhile, we found that a low thermal conductivity of ~0.7 W m{sup −1} K{sup −1} could be achieved. The intrinsically low thermal conductivity in this system is related to the low elastic properties, such as Young's modulus of 70–72 GPa, and Grüneisen parameters of 1.55–1.71. The low thermal conductivity makes Bi{sub 2}YO{sub 4}Cu{sub 2}Se{sub 2} system to be a potential thermoelectric material, the ZT value ~0.06 at 873 K was obtained, a higher performance is expected by optimizing electrical transport properties through selecting suitable dopants, modifying band structures or by further reducing thermal conductivity through nanostructuring etc. - Highlights: • The total thermal conductivity decreases from 1.8 to 0.9 Wm{sup –1}K{sup –1} at 300–873K. • The electrical conductivity decreased from 850 to 163 S/cm at 300–873K. • The Seebeck coefficients were enhanced through heavily Iodine doping. • The ZT ~0.06 at 873K suggests that Bi{sub 2}YO{sub 4}Cu{sub 2}Se{sub 2} systems are potential thermoelectrical materials.

Mechanical, electronic and thermal properties of Cu{sub 5}Zr and Cu{sub 5}Hf by first-principles calculations

Energy Technology Data Exchange (ETDEWEB)

Yi, Guohui [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Zhang, Xinyu, E-mail: xyzhang@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Qin, Jiaqian, E-mail: jiaqianqin@gmail.com [Metallurgy and Materials Science Research Institute, Chulalongkorn University, Bangkok 10330 (Thailand); Ning, Jinliang; Zhang, Suhong; Ma, Mingzhen; Liu, Riping [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China)

2015-08-15

Highlights: • The mechanical and fundamental thermal data of Cu{sub 5}Zr and Cu{sub 5}Hf are determined. • The technologically important elastic anisotropy is obtained and discussed according to its industrial applications. • The brittle/ductile and bonding nature of Cu{sub 5}Zr and Cu{sub 5}Hf are analyzed in details. - Abstract: The structural, elastic, electronic and thermodynamic properties of Cu{sub 5}Zr and Cu{sub 5}Hf compounds are investigated by first-principles calculations combined with the quasi-harmonic Debye model. The calculated lattice parameters of cubic AuBe{sub 5}-type Cu{sub 5}Zr and Cu{sub 5}Hf agree well with available experimental and other theoretical results and the formation enthalpy calculations show that AuBe{sub 5}-type Cu{sub 5}Hf is more energetically stable than the competing hexagonal CaCu{sub 5}-type phase. The mechanical properties such as mechanical stabilities, anisotropy character, ductility (estimated from the value of B/G, Poisson’s ratio υ and Cauchy pressures C{sub 12}–C{sub 44}) and thermodynamic properties such as volume change under temperature and pressure (V/V{sub 0}), heat capacity (C{sub v}), Debye temperature (Θ), thermal expansion coefficient (α) of AuBe{sub 5}-type Cu{sub 5}Zr and Cu{sub 5}Hf are calculated together. Cu{sub 5}Hf has better performances than Cu{sub 5}Zr with higher hardness and better resistance to fracture which are rationalized from the calculated electronic structure (including density of states, charge density distributions, Mulliken’s population analysis) and we find that all ionic, covalent and metallic components exist in bonding of Cu{sub 5}Zr and Cu{sub 5}Hf but the covalent bonding in Cu{sub 5}Hf is stronger.

Magnetism and structure of Cu{sub 2}O{sub 1+x} and 3d-doped TiO{sub 2-x} nanopowders

Energy Technology Data Exchange (ETDEWEB)

Yermakov, A.Ye. [Institute of Metal Physics, Ural Division of RAS, Ekaterinburg 620041 (Russian Federation)]. E-mail: yermakov@imp.uran.ru; Uimin, M.A. [Institute of Metal Physics, Ural Division of RAS, Ekaterinburg 620041 (Russian Federation); Mysik, A.A. [Institute of Metal Physics, Ural Division of RAS, Ekaterinburg 620041 (Russian Federation); Vykhodets, V.B. [Institute of Metal Physics, Ural Division of RAS, Ekaterinburg 620041 (Russian Federation); Kurennykh, T.E. [Institute of Metal Physics, Ural Division of RAS, Ekaterinburg 620041 (Russian Federation); Sokolov, V.I. [Institute of Metal Physics, Ural Division of RAS, Ekaterinburg 620041 (Russian Federation); Gaviko, V.S. [Institute of Metal Physics, Ural Division of RAS, Ekaterinburg 620041 (Russian Federation); Schegoleva, N.N. [Institute of Metal Physics, Ural Division of RAS, Ekaterinburg 620041 (Russian Federation); Gruzdev, N.B. [Institute of Metal Physics, Ural Division of RAS, Ekaterinburg 620041 (Russian Federation)

2007-03-15

The structural features and magnetic properties of non-stoichiometric nanocrystalline semiconductors Cu{sub 2}O{sub 1+x} and TiO{sub 2-x} doped with 3d-metals were investigated. The nanopowders were obtained by gas-phase synthesis in the oxygen contained argon atmosphere. For nanocrystalline samples Cu{sub 2}O{sub 1+x} with oxygen concentration more than stoichiometry (x>0) magnetic hysteresis properties up to temperatures above room temperature (RT) were discovered. In the case of oxygen deficit in TiO{sub 2-x} on the condition that rutile or anatase structure remains, the magnetic moment value grows and the magnetization curves at RT become nonlinear. On doping TiO{sub 2-x} with cobalt, the magnetic moment value increases without indications of magnetic ordering at RT. In the optical absorption spectra of Cu{sub 2}O{sub 1+x} nanopowders at 77K, the peaks in the range of wavelengths 480 and 460nm were revealed, which are close to peaks at n=1 of the blue and indigo exciton series for Cu{sub 2}O single crystal.

Development of microstructure and texture in strip casting grain oriented silicon steel

Energy Technology Data Exchange (ETDEWEB)

Wang, Yang; Xu, Yun-Bo, E-mail: yunbo_xu@126.com; Zhang, Yuan-Xiang; Fang, Feng; Lu, Xiang; Liu, Hai-Tao; Wang, Guo-Dong

2015-04-01

Grain oriented silicon steel was produced by strip casting and two-stage cold rolling processes. The development of microstructure and texture was investigated by using optical microscopy, X-ray diffraction and electron backscattered diffraction. It is shown that the microstructure and texture evolutions of strip casting grain oriented silicon steel are significantly distinct from those in the conventional processing route. The as-cast strip is composed of coarse solidification grains and characterized by pronounced 〈001〉//ND texture together with very weak Goss texture. The initial coarse microstructure enhances {111} shear bands formation during the first cold rolling and then leads to the homogeneously distributed Goss grains through the thickness of intermediate annealed sheet. After the secondary cold rolling and primary annealing, strong γ fiber texture with a peak at {111}〈112〉 dominates the primary recrystallization texture, which is beneficial to the abnormal growth of Goss grain during the subsequent high temperature annealing. Therefore, the secondary recrystallization of Goss orientation evolves completely after the high temperature annealing and the grain oriented silicon steel with a good magnetic properties (B{sub 8}=1.94 T, P{sub 1.7/50}=1.3 W/kg) can be prepared. - Highlights: • Grain oriented silicon steel was developed by a novel ultra-short process. • Many evenly distributed Goss “seeds” were originated from cold rolled shear bands. • More MnS inhibitors were obtained due to the rapid cooling of strip casing. • The magnetic induction of grain oriented silicon steel was significantly improved.

High temperature neutron powder diffraction study of the Cu{sub 12}Sb{sub 4}S{sub 13} and Cu{sub 4}Sn{sub 7}S{sub 16} phases

Energy Technology Data Exchange (ETDEWEB)

Lemoine, Pierric, E-mail: pierric.lemoine@univ-rennes1.fr [Institut des Sciences Chimiques de Rennes, UMR-CNRS 6226, 263 Avenue du Général Leclerc, CS 74205, 35042 Rennes Cedex (France); Bourgès, Cédric; Barbier, Tristan [Laboratoire CRISMAT, UMR-CNRS 6508, ENSICAEN, 6 Boulevard du Maréchal Juin, 14050 Caen Cedex 04 (France); Nassif, Vivian [CNRS Institut NEEL, F-38000 Grenoble (France); Université de Grenoble Alpes, Institut NEEL, F-38000 Grenoble (France); Cordier, Stéphane [Institut des Sciences Chimiques de Rennes, UMR-CNRS 6226, 263 Avenue du Général Leclerc, CS 74205, 35042 Rennes Cedex (France); Guilmeau, Emmanuel [Laboratoire CRISMAT, UMR-CNRS 6508, ENSICAEN, 6 Boulevard du Maréchal Juin, 14050 Caen Cedex 04 (France)

2017-03-15

Ternary copper-containing sulfides Cu{sub 12}Sb{sub 4}S{sub 13} and Cu{sub 4}Sn{sub 7}S{sub 16} have attracted considerable interest since few years due to their high-efficiency conversion as absorbers for solar energy and promising thermoelectric materials. We report therein on the decomposition study of Cu{sub 12}Sb{sub 4}S{sub 13} and Cu{sub 4}Sn{sub 7}S{sub 16} phases using high temperature in situ neutron powder diffraction. Our results obtained at a heating rate of 2.5 K/min indicate that: (i) Cu{sub 12}Sb{sub 4}S{sub 13} decomposes above ≈792 K into Cu{sub 3}SbS{sub 3}, and (ii) Cu{sub 4}Sn{sub 7}S{sub 16} decomposes above ≈891 K into Sn{sub 2}S{sub 3} and a copper-rich sulfide phase of sphalerite ZnS-type structure with an assumed Cu{sub 3}SnS{sub 4} stoichiometry. Both phase decompositions are associated to a sulfur volatilization. While the results on Cu{sub 12}Sb{sub 4}S{sub 13} are in fair agreement with recent published data, the decomposition behavior of Cu{sub 4}Sn{sub 7}S{sub 16} differs from other studies in terms of decomposition temperature, thermal stability and products of reaction. Finally, the crystal structure refinements from neutron powder diffraction data are reported and discussed for the Cu{sub 4}Sn{sub 7}S{sub 16} and tetrahedrite Cu{sub 12}Sb{sub 4}S{sub 13} phases at 300 K, and for the high temperature form of skinnerite Cu{sub 3}SbS{sub 3} at 843 K. - Graphical abstract: In situ neutron powder diffraction data (heating rate of 2.5 K/min) indicates that (i) the ternary Cu{sub 12}Sb{sub 4}S{sub 13} phase is stable up to 792 K and decomposes at higher temperature into Cu{sub 3}SbS{sub 3} and Cu{sub 1.5}Sb{sub 0.5}S{sub 2}, and (ii) the Cu{sub 4}Sn{sub 7}S{sub 16} phase is stable up to 891 K and decomposes at higher temperature into Sn{sub 2}S{sub 3} and a cubic phase of sphalerite ZnS-type structure. Sulfur volatilization likely occurs in order to balance the overall stoichiometry.

Controlled synthesis, formation mechanism, and carbon oxidation properties of Ho{sub 2}Cu{sub 2}O{sub 5} nanoplates prepared with a coordination-complex method

Energy Technology Data Exchange (ETDEWEB)

Guo, Rui [School of Resources and Materials, Northeastern University at Qinhuangdao 066004 (China); School of Metallurgy, Northeastern University, Shenyang 110004 (China); You, Junhua [School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870 (China); Han, Fei; Li, Chaoyang; Zheng, Guiyuan; Xiao, Weicheng [School of Resources and Materials, Northeastern University at Qinhuangdao 066004 (China); Liu, Xuanwen, E-mail: lxw@mail.neuq.edu.cn [School of Resources and Materials, Northeastern University at Qinhuangdao 066004 (China); School of Metallurgy, Northeastern University, Shenyang 110004 (China)

2017-02-28

Highlights: • The crystallization mechanism relies on Ho{sup 3+} and Cu{sup 2+} diffusion. • The Ho{sub 2}Cu{sub 2}O{sub 5} particles are refined by the coordination complex method under N{sub 2} environment. • The catalytic oxidation activity of Ho{sub 2}Cu{sub 2}O{sub 5} samples for carbon is enhanced. - Abstract: Ho{sub 2}Cu{sub 2}O{sub 5} nanoplates with perovskite structures were synthesized via a simple solution method (SSM) and a coordination-complex method (CCM) using [HoCu(3,4-pdc){sub 2}(OAc)(H{sub 2}O){sub 3}]·8H{sub 2}O (L = 3,4-pyridinedicarboxylic acid) as a precursor. The CCM was also performed in an N{sub 2} environment (CCMN) under various calcination conditions. The crystallization processes were characterized using X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. Ho{sub 2}Cu{sub 2}O{sub 5} formed through the diffusion of CuO into Ho{sub 2}O{sub 3} particles. Cu{sup 2+} diffused faster than Ho{sup 3+} during this process. The initial products of CCMN (along with the thermal decomposition products) were initially laminarized in the N{sub 2} atmosphere, which prevented the growth of CuO particles and decreased the size of the Ho{sub 2}Cu{sub 2}O{sub 5} particles. The final Ho{sub 2}Cu{sub 2}O{sub 5} particles from CCMN had a nanoplate morphology with an average thickness of 75 nm. The decomposition of organic molecules and protection from N{sub 2} played important roles in determining the morphology of the resulting Ho{sub 2}Cu{sub 2}O{sub 5}. The catalytic oxidation activity of Ho{sub 2}Cu{sub 2}O{sub 5} samples for carbon was characterized using a specific surface area measurement and thermogravimetric analysis, which revealed that the samples produced by CCMN had the highest catalytic activity.

Grain interaction mechanisms leading to intragranular orientation spread in tensile deformed bulk grains of interstitial-free steel

DEFF Research Database (Denmark)

Winther, Grethe; Wright, Jonathan P.; Schmidt, Søren

2017-01-01

environments representing the bulk texture, yet their deformation-induced rotations are very different. The ALAMEL model is employed to analyse the grain interaction mechanisms. Predictions of this model qualitatively agree with the directionality and magnitude of the experimental orientation spread. However......, quantitative agreement requires fine-tuning of the boundary conditions. The majority of the modelled slip is accounted for by four slip systems also predicted to be active by the classical Taylor model in uniaxial tension, and most of the orientation spread along the grain boundaries is caused by relative...... variations in the activities of these. Although limited to two grains, the findings prove that shear at the grain boundaries as accounted for by the ALAMEL model is a dominant grain interaction mechanism....

Ba{sub 2}Cu{sub 2}Te{sub 2}P{sub 2}O{sub 13}: A new telluro-phosphate with S=1/2 Heisenberg chain

Energy Technology Data Exchange (ETDEWEB)

Xia, Mingjun [Beijing Center for Crystal Research and Development, Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Shen, Shipeng; Lu, Jun; Sun, Young [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Li, R.K., E-mail: rkli@mail.ipc.ac.cn [Beijing Center for Crystal Research and Development, Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

2015-10-15

A new telluro-phosphate compound Ba{sub 2}Cu{sub 2}Te{sub 2}P{sub 2}O{sub 13} with S=1/2 Heisenberg chain has been successfully synthesized by solid state reaction and grown by flux method. Single crystal X-ray diffraction reveals that Ba{sub 2}Cu{sub 2}Te{sub 2}P{sub 2}O{sub 13} crystallizes into a monoclinic space group C2/c and cell parameters of a=17.647(3) Å, b=7.255(2) Å, c=9.191(2) Å and β=100.16 (3)°. In the structure of Ba{sub 2}Cu{sub 2}Te{sub 2}P{sub 2}O{sub 13}, one dimensional [CuTePO{sub 7}]{sup 3−} chains are formed by tetrahedral PO{sub 4} and trigonal bi-pyramidal TeO{sub 4} joining square planar CuO{sub 4} groups. Those [CuTePO{sub 7}]{sup 3−} chains are inter-connected by sharing one oxygen atom from the TeO{sub 4} group to form two dimensional layers. Magnetic susceptibility and specific heat measurements confirm that the title compound is a model one dimensional Heisenberg antiferromagnetic chain system. - Graphical abstract: Ba{sub 2}Cu{sub 2}Te{sub 2}P{sub 2}O{sub 13}, containing (CuTePO{sub 7}){sup 3−} chains formed by PO{sub 4} and TeO{sub 4} joining CuO{sub 4} groups, shows typical 1D Heisenberg antiferromagnetic chain model behavior as confirmed by magnetic measurements. - Highlights: • New telluro-phosphate Ba{sub 2}Cu{sub 2}Te{sub 2}P{sub 2}O{sub 13} has been grown. • It features layered structure composed of [CuTePO{sub 7}]{sup 3−} chains and TeO{sub 4} groups. • It shows the Heisenberg antiferromagnetic chain behavior. • It is transparent in the range of 1000–2500 nm with a UV absorption edge of 393 nm.

Thermoluminescence characteristics of Cu{sub 2}O doped Calcium Lithium borate glass irradiated with the cobalt-60 gamma rays

Energy Technology Data Exchange (ETDEWEB)

Rammadhan, Ismail, E-mail: ismail.rammadhan@koyauniversity.org [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Department of Physics, Faculty of Sciences and Health, Koya University, Danielle Mitterrand Boulevard, Koya 45, Kurdistan Region (Iraq); Taha, Saddon [Department of Physics, Faculty of Sciences and Health, Koya University, Danielle Mitterrand Boulevard, Koya 45, Kurdistan Region (Iraq); Wagiran, H. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia)

2017-06-15

The aim of this study is to prepare and investigate the thermoluminescence characteristics for the un-doped and Cu{sub 2}O doped calcium lithium borate glass upon adding various Cu{sub 2}O concentrations of 0.005% to 0.1 mol%. The glasses were prepared by melt quenching method and irradiated with {sup 60}CO gamma-ray having different doses in the range of (0.5–4) Gy, (5–10) Gy, and (20–100) Gy. The amorphous phases were identified for optimization glass samples, effect of heating rate, glowing curves, linearity, sensitivity, fading, reproducibility of response and minimum detectable dose are also studied. The TL sample with 0.02 mol% Cu{sub 2}O concentration has higher response compared to the other samples concentration for a delivered dose of 50 Gy, The recorded glow curves consist a dominant peak at 187 °C for a heating rate of 5 °C s{sup −1}. However, the value of effective atomic number Z{sub eff} is 8.84 for 0.02Cu{sub 2}O doped which are near to the atomic number of soft tissue. - Highlights: •We have prepared and investigate the crystalline structure for the un-doped and Cu{sub 2}O doped calcium lithium borate glass are carried out. •Investigate the amorphous structure of calcium lithium borate glass. •Determine the best setting of annealing temperature, annealing time and heating rate for Cu{sub 2}O doped calcium lithium borate glass. •The doping effects of Cu{sub 2}O on the thermoluminescence properties of calcium lithium borate glass subjected gamma radiations. •The new dosimeter showed simple glow curve with single prominent peak centred at 187 °C and linear dose–response range 0.5–100 Gy, good reproducibility, the fading of the signal is relatively slow. •Effective atomic number for Cu{sub 2}O doped Calcium lithium borate close to the effective atomic number of soft tissue.

Lattice parameter values and phase transitions for the Cu{sub 2}Cd{sub 1-z}Mn {sub z}GeSe{sub 4} and Cu{sub 2}Cd{sub 1-z}Fe {sub z}GeSe{sub 4} alloys

Energy Technology Data Exchange (ETDEWEB)

Quintero, E. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Tovar, R. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Quintero, M. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela)]. E-mail: mquinter@ula.ve; Delgado, G.E. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Morocoima, M. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Caldera, D. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Ruiz, J. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Mora, A.E. [Laboratorio de Analisis Quimico y Estructural de Materiales, Departamento de Fisica, Universidad de Los Andes, Merida 5101 (Venezuela); Briceno, M. [Laboratorio de Analisis Quimico y Estructural de Materiales, Departamento de Fisica, Universidad de Los Andes, Merida 5101 (Venezuela); Fernandez, J.L. [Laboratorio de Analisis Quimico y Estructural de Materiales, Departamento de Fisica, Universidad de Los Andes, Merida 5101 (Venezuela)

2007-04-25

X-ray powder diffraction measurements and differential thermal analysis (DTA) were made on polycrystalline samples of the Cu{sub 2}Cd{sub 1-z}Mn {sub z}GeSe{sub 4} and Cu{sub 2}Cd{sub 1-z}Fe {sub z}GeSe{sub 4} alloy systems. The diffraction patterns were used to show the equilibrium conditions and to derive lattice parameter values. The effect of the annealing temperature and cooling rate to room temperature are discussed. For the Cu{sub 2}Cd{sub 1-z}Fe {sub z}GeSe{sub 4} system, only two single solid phase fields, the tetragonal stannite {alpha} and the wurtz-stannite {delta} structures were found to occur in the diagram. For the Cu{sub 2}Cd{sub 1-z}Mn {sub z}GeSe{sub 4} system, in addition to the tetragonal stannite {alpha} and the wurtz-stannite {delta} phases, MnSe was found to exist in the diagram. The DTA experiments showed that the cooling curves for both systems exhibited effects of undercooling.

The influence of slow cooling on Y211 size and content in single-grain YBCO bulk superconductor through the infiltration-growth process

Energy Technology Data Exchange (ETDEWEB)

Ouerghi, A [Systems and Applied Mechanics Laboratory LASMAP, Polytechnic School of Tunisia, Rue El Kawarezmi La Marsa 743, Université de Carthage Tunis (Tunisia); Moutalbi, N., E-mail: nahed.moutalbi@yahoo.fr [Systems and Applied Mechanics Laboratory LASMAP, Polytechnic School of Tunisia, Rue El Kawarezmi La Marsa 743, Université de Carthage Tunis (Tunisia); Noudem, J.G. [CRISMAT-ENSICAEN (UMR-CNRS 6508), Université de Caen-Basse-Normandie, F-14050 Caen (France); LUSAC, Université de Caen-Basse-Normandie F-50130 Cherbourg-Octeville (France); M' chirgui, A. [Systems and Applied Mechanics Laboratory LASMAP, Polytechnic School of Tunisia, Rue El Kawarezmi La Marsa 743, Université de Carthage Tunis (Tunisia)

2017-03-15

Highlights: • YBCO bulk superconductors are produced by optimized Seeded Infiltration and Growth process. • The slow cooling time, in a fixed slow cooling temperature window, affects considerably the surface morphology and the bulk’s microstructure. • The Y211 particle’s size and content depend on the slow cooling time and its distribution behavior changes from one position to another. • There is an optimum slow cooling time, estimated to 88h, over which the shrinkage for both the liquid phase and the Y211 pellet is maximal, without any improvement of the crystal grain growth. • The magnetic trapped flux distribution for a given sample brings out the single grain characteristic. - Abstract: Highly textured YBa{sub 2}Cu{sub 3}O{sub 7-δ} (Y123) superconductors were produced using modified Textured Top Seeded Infiltration Growth (TSIG) process. The liquid source is made of only Y123 powder whereas the solid source is composed of Y{sub 2}BaCuO{sub 5} (Y211) powder. We aim to control the amount of liquid that infiltrates the solid pellet, which in turn controls the final amount of Y{sub 2}BaCuO{sub 5} particles in Y123 matrix. The effect of the slow cooling kinetics on sample morphology, on grain growth and on final microstructure was too investigated. It is shown that appropriate slow cooling time may also contribute to the control of the amount of Y211 inclusions in the final structure of Y123 bulk. We report herein the Y211 particle size and density distribution in the whole Y123 matrix. The present work proves that finest Y211 particles locate under the seed and that their size and density increase with distance from the seed.

Transport current anisotropy in oriented grained bulk YBa2Cu3Ox superconductor

International Nuclear Information System (INIS)

Selvamanickam, V.; Salama, K.

1990-01-01

The anisotropy in transport current density has been studied on bulk YBa 2 Cu 3 O x superconductor. The transport current density measurements were performed on oriented grained YBa 2 Cu 3 O x superconductor with the current aligned at different angles to the a endash b plane. The angular dependence of J c shows a rapid drop when the transport current is misaligned from the a endash b plane at small angles and then a slow decrease at higher angles. An anisotropy ratio of about 25 is observed at 77 K and zero field between the J c along a endash b plane and that perpendicular to the plane

Dynamics of d-wave YBa{sub 2}Cu{sub 3}O{sub 7-x} dc SQUIDs

Energy Technology Data Exchange (ETDEWEB)

Bauch, T [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Goeteborg (Sweden); Cedergren, K [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Goeteborg (Sweden); Johansson, J [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Goeteborg (Sweden); Rotoli, G [Dipartimento di Ingeneria Meccanica, Energetica e Gestionale, Universita of L' Aquila, Localita Moneluco, L' Aquila (Italy); Tafuri, F [Dipartimento Ingeneria dell' Informatione, INFM, Seconda Universita di Napoli, Aversa (Italy); Lombardi, F [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Goeteborg (Sweden)

2007-02-15

The predominant d-wave pairing symmetry in high temperature superconductors leads to an unconventional current-phase relation in Josephson junctions. This circumstance may induce new effects in the dynamics of dc SQUIDs. In this contribution we report on the measurements of the dependence of the SQUID Josephson current on the external magnetic field taken at very low temperatures, down to 20 mK. Different grain boundaries have been fabricated by using the biepitaxial and the bicrystal technique. Some of the effects which are induced by a nonsinusoidal current-phase relation can be clearly identified in the dynamics of the SQUIDs. The experimental data are also compared with theoretical simulations taking into account the inductance of the loop. The data show that, in specific conditions, a non-negligible inductance of the loop can induce effects similar to an unconventional current-phase relation, with a pronounced second harmonic sin(2{psi}) term. This fact has to be taken into account when designing d-wave SQUIDs for quantum circuitry.

Preparation and characterization of Y-Ba-Cu-O-F superconductors

Energy Technology Data Exchange (ETDEWEB)

Yokoyama, Yuko; Okumura, Tomoyuki; Sugise, Ryoji; Matsubara, Toshiya; Koshizuka, Naoki; Hirabayashi, Masayuki; Terada, Norio; Ihara, Hideo

1988-04-01

Samples were prepared by powder composition method which uses fluoride for annealing and by the method which anneals YBa/sub 2/Cu/sub 3/O/sub x/ in fluorine to elucidate fluorine substitution effects on the superconducting properties of YBa/sub 2/Cu/sub 3/O/sub/x/F/sub/y/. Their structures, magnetic properties and electrical conductivities were investigated. The samples were prepared with the appropriate mixture of BaCO/sub 3/, Y/sub 2/O/sub 3/, CuO, and fluoride such as CuF/sub 2/. Since the samples had strong peaks of BaF/sub 2/ phase together with the perovskite phase in the X-ray diffraction patterns, it was difficult to obtain information on the fluorine substitution effects on the physical properties. Next, the samples were prepared by annealing YBa/sub 2/CuO/sub/x/ sintred pellets and CoF/sub 3/ powder in a sealed quartz tube. In this case, the diffraction patterns showed that the crystalline state of the samples was a single phase of the orthorohombic perovskite structure. The behaviors against the changes in magnetic field and temperature can be considered to be substantially identical. It is hard to consider that the fluorine substitution will play a direct role in attaining higher Tc. (6 figs, 2 refs)

Synthesis of highly non-stoichiometric Cu{sub 2}ZnSnS{sub 4} nanoparticles with tunable bandgaps

Energy Technology Data Exchange (ETDEWEB)

Hamanaka, Yasushi, E-mail: hamanaka@nitech.ac.jp; Oyaizu, Wataru; Kawase, Masanari [Nagoya Institute of Technology, Department of Materials Science and Engineering (Japan); Kuzuya, Toshihiro [Muroran Institute of Technology, College of Design and Manufacturing Technology (Japan)

2017-01-15

Non-stoichiometric Cu{sub 2}ZnSnS{sub 4} nanoparticles with average diameters of 4–15 nm and quasi-polyhedral shape were successfully synthesized by a colloidal method. We found that a non-stoichiometric composition of Zn to Cu in Cu{sub 2}ZnSnS{sub 4} nanoparticles yielded a correlation where Zn content increased with a decrease in Cu content, suggesting formation of lattice defects relating to Cu and Zn, such as a Cu vacancy (V{sub Cu}), antisite with Zn replacing Cu (Zn{sub Cu}), and/or defect cluster of V{sub Cu} and Zn{sub Cu}. The bandgap energy of Cu{sub 2}ZnSnS{sub 4} nanoparticles systematically varies between 1.56 and 1.83 eV depending on the composition ratios of Cu and Zn, resulting in a wider bandgap for Cu-deficient Cu{sub 2}ZnSnS{sub 4} nanoparticles. These characteristics can be ascribed to the modification in electronic band structures due to formation of V{sub Cu} and Zn{sub Cu} on the analogy of ternary copper chalcogenide, chalcopyrite CuInSe{sub 2}, in which the top of the valence band shifts downward with decreasing Cu contents, because much like the structure of CuInSe{sub 2}, the top of the valence band is composed of a Cu 3d orbital in Cu{sub 2}ZnSnS{sub 4}.

Investigation of the properties of carbon-base nanostructures doped YBa{sub 2}Cu{sub 3}O{sub 7−δ} high temperature superconductor

Energy Technology Data Exchange (ETDEWEB)

Dadras, Sedigheh, E-mail: dadras@alzahra.ac.ir; Ghavamipour, Mahshid

2016-03-01

In this research, we have investigated the effects of three samples of carbon-base nanostructures (carbon nanoparticles, carbon nanotubes and silicon carbide nanoparticles) doping on the properties of Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7−δ} (YBCO) high temperature superconductor. The pure and doped YBCO samples were synthesized by sol–gel method and characterized by resistivity versus temperature (ρ–T), current versus voltage (I–V), through X-ray diffraction (XRD) and scanning electron microscope (SEM) analysis. The results confirmed that for all the samples, the orthorhombic phase of YBCO compound is formed. We found that the pinning energy and critical current density of samples increase by adding carbon nanostructures to YBCO compound. Also critical temperature is improved by adding carbon nanotubes to YBCO compound, while it does not change much for carbon and silicon carbide nanoparticles doped compounds. Furthermore, the samples were characterized by UV–vis spectroscopy in 300 K and the band gap of the samples was determined. We found that the carbon nanotubes doping decreases YBCO band gap in normal state from 1.90 eV to 1.68 eV, while carbon and SiC nanoparticles doping increases it to 2.20 and 3.37 eV respectively.

A facile room temperature route to ternary Cu{sub 7.2}S{sub 2}Se{sub 2} compounds and their photovoltaic properties based on elemental copper

Energy Technology Data Exchange (ETDEWEB)

Cheng, Jiamei [Department of Chemistry, Zhengzhou University, Henan 450001 (China); Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, Xuchang University, Henan 461000 (China); Jia, Huimin, E-mail: zhengzhi99999@gmail.com [Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, Xuchang University, Henan 461000 (China); Lei, Yan [Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, Xuchang University, Henan 461000 (China); Liu, Songzi [Department of Chemistry, Zhengzhou University, Henan 450001 (China); Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, Xuchang University, Henan 461000 (China); Gao, Yuanhao [Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, Xuchang University, Henan 461000 (China); Hou, Hongwei [Department of Chemistry, Zhengzhou University, Henan 450001 (China); Zheng, Zhi, E-mail: zzheng@xcu.edu.cn [Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, Xuchang University, Henan 461000 (China)

2017-06-01

A one-pot synthesis of novel hierarchical flower-like Cu{sub 7.2}S{sub 2}Se{sub 2} nanocrystals was developed based on the direct metal surface elemental reaction (DMSER) method. This new room temperature synthesis is an economic and environmentally friendly soft chemical approach. The prepared Cu{sub 7.2}S{sub 2}Se{sub 2} nanocrystals uniformly cover the surface of the Cu substrates. The mechanism of formation was investigated by observing the materials produced from changing the reaction time, the molar ratio of Na{sub 2}S to elemental selenium, and the volume of solvent. The crystal structure, surface morphologies and light absorption properties were collected by X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV–visible spectroscopy. The results show that the as-prepared ternary nanocrystals are face-centered cubic and have an optical bandgap of 1.58 eV, which is ideal for potential solar cell applications. Transient photovoltage spectroscopy (TPV) was used to evaluate the photovoltaic performance of pure Cu{sub 7.2}S{sub 2}Se{sub 2} nanocrystalline powder as well as in-situ generated Cu{sub 7.2}S{sub 2}Se{sub 2}/ZnO heterojunctions. The current work offers a novel and simple approach for preparing ternary chalcogenide semiconductors for photoelectric and photocatalytic applications. - Highlights: • A one-pot synthesis of novel hierarchical flower-like Cu{sub 7.2}S{sub 2}Se{sub 2} was developed. • This work offers a facile way for prepare ternary chalcogenide at room temperature. • TPV was firstly used to evaluate the photovoltaic performance of Cu{sub 7.2}S{sub 2}Se{sub 2}.

Preparation of Cu{sub 2}O nanowire-blended polysulfone ultrafiltration membrane with improved stability and antimicrobial activity

Energy Technology Data Exchange (ETDEWEB)

Xu, Zehai; Ye, Shuaiju; Fan, Zheng; Ren, Fanghua; Gao, Congjie [Zhejiang University of Technology, Institute of Oceanic and Environmental Chemical Engineering, College of Chemical Engineering and Material Science and College of Ocean, and State Key Lab Breeding Base of Green Chemical Synthesis Technology and Zhejiang Collaborative Innovation Center of Membrane Separation and Water Treatment (China); Li, Qingbiao; Li, Guoqing [Quanzhou Normal University, College of Chemistry and Life Science (China); Zhang, Guoliang, E-mail: membrane86571@163.com, E-mail: guoliangz@zjut.edu.cn [Zhejiang University of Technology, Institute of Oceanic and Environmental Chemical Engineering, College of Chemical Engineering and Material Science and College of Ocean, and State Key Lab Breeding Base of Green Chemical Synthesis Technology and Zhejiang Collaborative Innovation Center of Membrane Separation and Water Treatment (China)

2015-10-15

Polysulfone (PSF) membranes have been widely applied in water and wastewater treatment, food-processing and biomedical fields. In this study, we report the preparation of modified PSF membranes by blending PSF with Cu{sub 2}O nanowires (NWs) to improve their stability and antifouling activity. Synthesis of novel Cu{sub 2}O NWs/PSF-blended ultrafiltration membrane was achieved via phase inversion method by dispersing one-dimensional Cu{sub 2}O nanowires in PSF casting solutions. Various techniques such as XRD, SEM, TEM, and EDS were applied to characterize and investigate the properties of nanowires and membranes. The introduced Cu{sub 2}O nanowires can firmly be restricted into micropores of PSF membranes, and therefore, they can effectively prevent the serious leaking problem of inorganic substances in separation process. The blended PSF membranes also provided enhanced antimicrobial activity and superior permeation property compared to pure PSF membrane. The overall work can not only provide a new way for preparation of novel blended membranes with multidimensional nanomaterials, but can also be beneficial to solve the annoying problem of biofouling.

Microstructure Control of Barium Titanate Grain-oriented Ceramics and Their Piezoelectric Properties

International Nuclear Information System (INIS)

Mori, Rintaro; Nakashima, Koichi; Fujii, Ichiro; Wada, Satoshi; Hayashi, Hiroshi; Nagamori, Yoshitaka; Yamamoto, Yuichi

2011-01-01

The Barium titanate (BaTiO 3 , BT) [110] grain-oriented ceramics along [110] direction were prepared by a templated grain growth (TGG) method. The [110] oriented BT platelike particles (t-BT) were used as template particles. The relationship between poling treatment program and piezoelectric constant was investigated. The change in the poling conditions did not greatly influence domain size and the piezoelectric constant. The relationship between piezoelectric properties and domain size in BT grain-oriented ceramics was investigated. The smaller domain size was required to increase the piezoelectric constant.

Effect of twins in Ni substrates on the microstructure of La{sub 2}Zr{sub 2}O{sub 7} films for coated conductors

Energy Technology Data Exchange (ETDEWEB)

Petit, Sarah [CRETA-CNRS, 25 av. des Martyrs, BP166, 38042 Grenoble Cedex (France); Institut Néel-CNRS, 25 av. des Martyrs, BP166, 38042 Grenoble Cedex (France); Pairis, Sébastien [Institut Néel-CNRS, 25 av. des Martyrs, BP166, 38042 Grenoble Cedex (France); Mikolajczyk, Mélissa [CRETA-CNRS, 25 av. des Martyrs, BP166, 38042 Grenoble Cedex (France); Institut Néel-CNRS, 25 av. des Martyrs, BP166, 38042 Grenoble Cedex (France); Ortega, Luc [Institut Néel-CNRS, 25 av. des Martyrs, BP166, 38042 Grenoble Cedex (France); Soubeyroux, Jean-Louis [CRETA-CNRS, 25 av. des Martyrs, BP166, 38042 Grenoble Cedex (France); Institut Néel-CNRS, 25 av. des Martyrs, BP166, 38042 Grenoble Cedex (France); Odier, Philippe [CRETA-CNRS, 25 av. des Martyrs, BP166, 38042 Grenoble Cedex (France); Institut Néel-CNRS, 25 av. des Martyrs, BP166, 38042 Grenoble Cedex (France)

2013-03-01

La{sub 2}Zr{sub 2}O{sub 7} (LZO) films were deposited by chemical solution deposition on Ni{sub 95}Wi{sub 5}rolling assisted bi-axially textured substrates to be used in YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) coated conductors. These LZO films were proved of good qualities for YBCO deposition by metal organic chemical vapor deposition that is an economic process. The mosaic of LZO films is only slightly degraded by the process of grain-to-grain epitaxial transfer (16% with respect to that of the substrate). The film is composed of small crystallites (20–40 nm) and larger anomalous crystallites (100–400 nm) found in great number in transferred twins from the substrate. The anomalous crystallites are poorly crystallized or amorphous and contain more C than areas with normal crystallites. High temperature in-situ X-ray diffraction shows a sudden crystallization at 860 °C that does not seem to involve a solid state reaction. The anomalous crystallites are analyzed to result from a locally enhanced barrier to nucleation and might reveal poor characteristics of the crystallization. - Highlights: ► La{sub 2}Zr{sub 2}O{sub 7} film on Ni{sub 95}W{sub 5} RABiT. ► Anomalous crystallites (100-400 nm) are amorphous on transferred twins. ► La{sub 2}Zr{sub 2}O{sub 7} crystallization appears above 860 °C.

Characterizing Grain-Oriented Silicon Steel Sheet Using Automated High-Resolution Laue X-ray Diffraction

Science.gov (United States)

Lynch, Peter; Barnett, Matthew; Stevenson, Andrew; Hutchinson, Bevis

2017-11-01

Controlling texture in grain-oriented (GO) silicon steel sheet is critical for optimization of its magnetization performance. A new automated laboratory system, based on X-ray Laue diffraction, is introduced as a rapid method for large scale grain orientation mapping and texture measurement in these materials. Wide area grain orientation maps are demonstrated for both macroetched and coated GO steel sheets. The large secondary grains contain uniform lattice rotations, the origins of which are discussed.

Specific features of band structure and optical anisotropy of Cu{sub 2}CdGeSe{sub 4} quaternary compounds

Energy Technology Data Exchange (ETDEWEB)

Brik, M.G., E-mail: brik@fi.tartu.ee [College of Mathematics and Physics, Chongqing University of Posts and Telecommunications, Chongqing 400065 (China); Institute of Physics, University of Tartu, Riia 142, Tartu 51014 (Estonia); Institute of Physics, Jan Dlugosz University, Armii Krajowej 13/15, PL-42200 Czestochowa (Poland); Parasyuk, O.V. [Department of Chemistry, Eastern European National University, Voli 13, Lutsk 43025 (Ukraine); Myronchuk, G.L. [Department of Physics, Eastern European National University, Voli 13, Lutsk 43025 (Ukraine); Kityk, I.V. [Institute of Materials Science and Engineering, Technical University of Czestochowa, Al. Armii Krajowej 19, 42-200 Czestochowa (Poland)

2014-09-15

Complex theoretical and experimental studies of the band structure and optical functions of a new Cu{sub 2}CdGeSe{sub 4} quaternary crystal are reported. The benchmark band structure calculations were performed using the first-principles methods. As a result, the structural, electronic, optical and elastic properties of Cu{sub 2}CdGeSe{sub 4} were calculated in the general gradient approximation (GGA) and local density approximation (LDA). The calculated dielectric function and optical absorption spectra exhibit some anisotropic behavior. Detailed analysis of the band energy dispersion and effective space charge density helped in establishing the origin of the band structure anisotropy. All calculated properties are compared with the experimental data. An additional comparison with a similar crystal of Cu{sub 2}CdGeSe{sub 4} allowed to reveal the role played by the anions (S or Se) in formation of the optical properties of these two materials. - Highlights: • The structural, electronic, optical properties of Cu{sub 2}CdGeSe{sub 4} were calculated. • Pressure effects on these properties were modeled. • Comparison with a similar compound of Cu{sub 2}CdGeS{sub 4} was performed.

Vibrational properties of stannite and kesterite type compounds: Raman scattering analysis of Cu{sub 2}(Fe,Zn)SnS{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Fontane, X.; Izquierdo-Roca, V.; Saucedo, E. [IREC: Catalonia Institute for Energy Research, C. Jardins de les Dones de Negre 1, Sant Adria del Besos, Barcelona 08930 (Spain); Schorr, S. [Free University Berlin, Institute of Geological Sciences, Malteserstr. 74-100, Berlin (Germany); Yukhymchuk, V.O.; Valakh, M.Ya. [V.E. Lahskaryov Institute of Semiconductor Physics, National Academy of Sciences, Prospekt Nauki 41, Kiev 03028 (Ukraine); Perez-Rodriguez, A., E-mail: aperezr@irec.cat [IREC: Catalonia Institute for Energy Research, C. Jardins de les Dones de Negre 1, Sant Adria del Besos, Barcelona 08930 (Spain); IN2UB, Departament d' Electronica, Universitat de Barcelona, C. Marti i Franques 1, 08028 Barcelona (Spain); Morante, J.R. [IREC: Catalonia Institute for Energy Research, C. Jardins de les Dones de Negre 1, Sant Adria del Besos, Barcelona 08930 (Spain); IN2UB, Departament d' Electronica, Universitat de Barcelona, C. Marti i Franques 1, 08028 Barcelona (Spain)

2012-10-25

Highlights: Black-Right-Pointing-Pointer Analysis of main and weaker Raman peaks from Cu{sub 2}FeZnS{sub 4} and Cu{sub 2}ZnSnS{sub 4} compounds. Black-Right-Pointing-Pointer Identification of a cation disorder induced Raman peak in Cu{sub 2}ZnSnS{sub 4}. Black-Right-Pointing-Pointer Analysis of spectral features of main Raman peaks from Cu{sub 2}(Fe,Zn)SnS{sub 4}. - Abstract: This work reports the analysis of the vibrational properties of stannite-kesterite Cu{sub 2}(Fe,Zn)SnS{sub 4} compounds that has been performed by Raman scattering measurements. The detailed analysis of the experimental spectra has allowed determining the frequency and symmetry assignment of the main and weaker peaks from both stannite Cu{sub 2}FeSnS{sub 4} (CFTS) and kesterite Cu{sub 2}ZnSnS{sub 4} (CZTS) phases. The measurements performed in the kesterite CZTS samples have also revealed the presence of local inhomogeneities that are characterised by an additional peak in the spectra at about 331 cm{sup -1}. This peak has been related to the presence in these local regions of a high degree of disorder in the cation sublattice, in agreement with previous neutron diffraction analysis in similar samples. Finally, the spectra from the solid solution alloys show a one-mode behaviour of the main A/A{sub 1} peak with the chemical composition.

Synthesis and characterization of Cu{sub 2}Se prepared by hydrothermal co-reduction

Energy Technology Data Exchange (ETDEWEB)

Liu Kegao, E-mail: liukg163@163.co [School of Materials Science and Engineering, Shandong Jianzhu University, Fengming Road, Jinan 250101 (China); Liu Hong, E-mail: hongliu@sdu.edu.c [State Key Laboratory of Crystal Materials, Shandong University, 27 Shandanan Road, Jinan 250100 (China); Wang Jiyang [State Key Laboratory of Crystal Materials, Shandong University, 27 Shandanan Road, Jinan 250100 (China); Shi Lei [School of Materials Science and Engineering, Shandong Jianzhu University, Fengming Road, Jinan 250101 (China)

2009-09-18

Cu{sub 2}Se compounds were synthesized by hydrothermal co-reduction at 150-200 deg. C from CuSO{sub 4}.5H{sub 2}O and SeO{sub 2} in deionized water. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and field emission scanning electron microscope (FESEM). Experimental results show that, the product powders with Cu{sub 2}Se phase obtained at 180 and 200 deg. C almost consist of regular hexagonal flakes which grow along (1 1 1) crystal plane. The side lengths between 100 and 200 nm of hexagonal flakes synthesized at 180 deg. C are much smaller than those of the product with 1.3-2 mum side length at 200 deg. C.

Phase controlled solvothermal synthesis of Cu{sub 2}ZnSnS{sub 4}, Cu{sub 2}ZnSn(S,Se){sub 4} and Cu{sub 2}ZnSnSe{sub 4} Nanocrystals: The effect of Se and S sources on phase purity

Energy Technology Data Exchange (ETDEWEB)

Pal, Mou [Instituto de Energías Renovables, Universidad Nacional Autónoma de México, 62580 Temixco, Morelos (Mexico); Instituto de Física, BUAP, Av. San Claudio y Blvd. 18 Sur Col. San Manuel, Ciudad Universitaria, C.P. 72570, Puebla (Mexico); Mathews, N.R. [Instituto de Energías Renovables, Universidad Nacional Autónoma de México, 62580 Temixco, Morelos (Mexico); Paraguay-Delgado, F. [Departamento de Materiales Nanoestructurados, Centro de Investigación en Materiales Avanzados (CIMAV), Chihuahua (Mexico); Mathew, X., E-mail: xm@ier.unam.mx [Instituto de Energías Renovables, Universidad Nacional Autónoma de México, 62580 Temixco, Morelos (Mexico)

2015-09-15

In this study, we have reported the synthesis of Cu{sub 2}ZnSnSe{sub 4} (CZTSe), Cu{sub 2}ZnSnS{sub 4} (CZTS) and Cu{sub 2}ZnSn(S,Se){sub 4} (CZTSSe) nanocrystals with tunable band gap and composition obtained by solvothermal method. The crystalline structure, composition, morphology and optical properties of the nanoparticles were characterized by X-ray diffraction (XRD), Raman scattering, energy dispersive X-ray spectroscopy, transmission electron microscopy and diffuse reflectance (DR) spectroscopy. While the XRD patterns of CZTS and CZTSe nanoparticles prepared with elemental S/Se powder revealed the presence of phase pure nanoparticles, the CZTSSe nanoparticles obtained using a mixture of S and Se, were found to contain many secondary phases under the same synthesis protocol. Formation of impurity phases in CZTSSe sample, can be avoided by using a mixture of 1-dodecanethiol (DT; CH{sub 3}(CH{sub 2}){sub 11}SH)/oleylamine (OLA) instead of S powder and following the same experimental procedure. The incorporation of S in CZTSe nanocrystals prepared in presence of DDT/OLA mixture was confirmed through structural and optical characterizations. The optical properties of the quaternary chalcogenide nanocrystals were found to vary with the chemical composition of the material. - Highlights: • Solvothermal synthesis of CZTS, CZTSSe and CZTSe nanocrystals and discussion on possible formation mechanism. • Use of dodecanethiol/oleylamine mixture to synthesize phase-pure CZTSSe nanocrystals. • Formation of impurity phases can be controlled with proper S and Se sources.

Thermoelectric and mechanical properties of spark plasma sintered Cu{sub 3}SbSe{sub 3} and Cu{sub 3}SbSe{sub 4}: Promising thermoelectric materials

Energy Technology Data Exchange (ETDEWEB)

Tyagi, Kriti; Gahtori, Bhasker; Bathula, Sivaiah; Toutam, Vijaykumar; Sharma, Sakshi; Singh, Niraj Kumar; Dhar, Ajay, E-mail: adhar@nplindia.org [CSIR-Network of Institutes for Solar Energy, Materials Physics and Engineering, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India)

2014-12-29

We report the synthesis of thermoelectric compounds, Cu{sub 3}SbSe{sub 3} and Cu{sub 3}SbSe{sub 4}, employing the conventional fusion method followed by spark plasma sintering. Their thermoelectric properties indicated that despite its higher thermal conductivity, Cu{sub 3}SbSe{sub 4} exhibited a much larger value of thermoelectric figure-of-merit as compared to Cu{sub 3}SbSe{sub 3}, which is primarily due to its higher electrical conductivity. The thermoelectric compatibility factor of Cu{sub 3}SbSe{sub 4} was found to be ∼1.2 as compared to 0.2 V{sup −1} for Cu{sub 3}SbSe{sub 3} at 550 K. The results of the mechanical properties of these two compounds indicated that their microhardness and fracture toughness values were far superior to the other competing state-of-the-art thermoelectric materials.

Electronic structures of PrBa{sub 2}Cu{sub 3}O{sub 7}, Pr{sub 2}Ba{sub 4}Cu{sub 7}O{sub 15-y}(y=0,1), and PrBa{sub 2}Cu{sub 4}O{sub 8} based on LSDA+U method

Energy Technology Data Exchange (ETDEWEB)

Tavana, A. [Magnet Research Laboratory (MRL), Department of Physics, Sharif University of Technology, Tehran (Iran); Department of Physics, University of Mohaghegh Ardabili, Ardabil (Iran); Shirazi, M.; Akhavan, M. [Magnet Research Laboratory (MRL), Department of Physics, Sharif University of Technology, Tehran (Iran)

2009-10-15

The electronic structures of PrBa{sub 2}Cu{sub 3}O{sub 7} (Pr123), Pr{sub 2}Ba{sub 4}Cu{sub 7}O{sub 15-y} (Pr247), and PrBa{sub 2}Cu{sub 4}O{sub 8} (Pr124) cuprates have been obtained using density-functional theory in the local spin density approximation plus onsite Coulomb interaction (LSDA+U). Onsite Hubbard correlation, U, has been considered for Pr-f and Cu-d orbitals and the effects of considering these correlation corrections on the Pr-O hybridizations have been inspected. Results imply that the Pr ionization state in Pr123 system is constituted from two different configurations, and the energy of the f states in these two configurations has an important role in superconductivity properties of the system. Our calculations also show that in both Pr124 and Pr247 systems, suppression of superconductivity is weaker than that in the Pr123 system. This occurs due to the weaker Pr-O bond in both Pr124 and Pr247 systems. The role of the double chain and single chain on the conduction properties of these compounds has been investigated. We have also studied the effect of oxygen deficiency in Pr247 system, which seems to revive superconductivity in this system. Investigating the hole carriers in the CuO{sub 2} plane shows a correlation between superconductivity suppression and hole decrement in the planes. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

Effects of seed orientation on the growth behavior of single grain REBCO bulk superconductors

Energy Technology Data Exchange (ETDEWEB)

Lee, Hee Gyoun [Korea Polytechnic University, Siheung (Korea, Republic of)

2017-06-15

This study presents a simple method to control the seed orientation which leads to the various growth characteristics of a single grain REBCO (RE: rare-earth elements) bulk superconductors. Seed orientation was varied systematically from c-axis to a-axis with every 30 degree rotation around b-axis. Orientations of a REBCO single grain was successfully controlled by placing the seed with various angles on the prismatic indent prepared on the surface of REBCO powder compacts. Growth pattern was changed from cubic to rectangular when the seed orientation normal to compact surface was varied from c-axis to a-axis. Macroscopic shape change has been explained by the variation of the wetting angle of un-reacted melt depending on the interface energy between YBa2Cu3O7-y (Y123) grain and melt. Higher magnetic levitation force was obtained for the specimen prepared using tilted seed with an angle of 30 degree rotation around b-axis.

Nanoscale Cu{sub 2}O films: Radio-frequency magnetron sputtering and structural and optical studies

Energy Technology Data Exchange (ETDEWEB)

Kudryashov, D. A., E-mail: kudryashovda@apbau.ru; Gudovskikh, A. S. [Russian Academy of Sciences, St. Petersburg National Research Academic University — Nanotechnology Research and Education Center (Russian Federation); Babichev, A. V.; Filimonov, A. V. [Connector Optics LLC (Russian Federation); Mozharov, A. M. [Russian Academy of Sciences, St. Petersburg National Research Academic University — Nanotechnology Research and Education Center (Russian Federation); Agekyan, V. F.; Borisov, E. V.; Serov, A. Yu.; Filosofov, N. G. [St. Petersburg State University (Russian Federation)

2017-01-15

Nanoscale copper (I) oxide layers are formed by magnetron-assisted sputtering onto glassy and silicon substrates in an oxygen-free environment at room temperature, and the structural and optical properties of the layers are studied. It is shown that copper oxide formed on a silicon substrate exhibits a lower degree of disorder than that formed on a glassy substrate, which is supported by the observation of a higher intensity and a smaller half-width of reflections in the diffraction pattern. The highest intensity of reflections in the diffraction pattern is observed for Cu{sub 2}O films grown on silicon at a magnetron power of 150 W. The absorption and transmittance spectra of these Cu{sub 2}O films are in agreement with the well-known spectra of bulk crystals. In the Raman spectra of the films, phonons inherent in the crystal lattice of cubic Cu{sub 2}O crystals are identified.

Raman spectra, microstructure and superconducting properties of Sb(III)-YBCO composite superconductor

Energy Technology Data Exchange (ETDEWEB)

Elsabawy, Khaled M. [Chemistry Department, Faculty of Science, Tanta University, Tanta (Egypt)]. E-mail: ksabawy@yahoo.com

2005-11-15

The pure YBCO (YBa{sub 2}Cu{sub 3}O{sub 7}) and its variant antimony containing composites with general formula; Y{sub 1+x}Sb {sub x}Ba{sub 2}Cu{sub 3}O {sub z}, where x = 0.1, 0.2, 0.4 and 0.6 mol%, respectively, were prepared by the solid-state reaction route. X-ray measurements indicated that Sb{sup 3+} ions have a negligible effect on the main crystalline structure and substitutes Y-sites successfully in lattice structure of 123-YBCO at low concentrations of doping (x = 0.1 {sup {yields}} 0.2). From SE-microscopy mapping and EDX elemental analysis, Sb{sup 3+} was detected qualitatively with good approximation to the actual molar ratio but not observed at 123-YBCO grain boundaries which confirm that antimony (III) has diffused regularly into material bulk of superconducting 123-YBCO-phase at low concentrations. Additions of Sb(III) affected sharply on the main vibrating modes of YBCO regime particularly, on the apical oxygen (O{sub 4}) vibrational mode A {sub 1g}. Magnetic susceptibility measurements proved that antimony oxide additions have slight effect on the transport properties of YBCO-composites regime.

Effect of magnetic ion Ni doping for Cu in the CuO{sub 2} plane on electronic structure and superconductivity on Y123 cuprate

Energy Technology Data Exchange (ETDEWEB)

Cao Shixun; Li Pinglin; Cao Guixin; Zhang Jincang

2003-05-15

The YBa{sub 2}Cu{sub 3-x}Ni{sub x}O{sub 7-{delta}} with x=0-0.4 have been studied using positron annihilation technique. The changes of positron annihilation parameters with the Ni substitution concentration x are given. From the change of electronic density n{sub e} and T{sub c}, it would prove that the localized carriers (electron and hole) in Cu-O chain and CuO{sub 2} planes have enormous influence on superconductivity by affecting charge transfer between the reservoir layer and CuO{sub 2} planes.

Efficiency of Cu{sub 2}O/BiVO{sub 4} particles prepared with a new soft procedure on the degradation of dyes under visible-light irradiation

Energy Technology Data Exchange (ETDEWEB)

Aguilera-Ruiz, Eduardo [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, Centro de Investigación e Innovación en Ingeniería Aeronáutica, Carretera a Salinas Victoria, Km 2.3, 66600 Apodaca, NL (Mexico); García-Pérez, Ulises M., E-mail: ulisesma.garcia@gmail.com [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, Centro de Investigación e Innovación en Ingeniería Aeronáutica, Carretera a Salinas Victoria, Km 2.3, 66600 Apodaca, NL (Mexico); Garza-Galván, María de la; Zambrano-Robledo, Patricia; Bermúdez-Reyes, Bárbara [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, Centro de Investigación e Innovación en Ingeniería Aeronáutica, Carretera a Salinas Victoria, Km 2.3, 66600 Apodaca, NL (Mexico); and others

2015-02-15

Graphical abstract: - Highlights: • Cu{sub 2}O/BiVO{sub 4} p–n heterojunctions were synthesized by a simple impregnation method. • The photocatalytic performance was evaluated using a LED lamp as visible source. • The composite with 1 wt.% of Cu{sub 2}O exhibits the best visible-light-activity. • A mechanism for the carriers transfer is proposed. • Factors as pH and O{sub 2} were found to influence the degradation rate. - Abstract: Cu{sub 2}O/BiVO{sub 4} composites with different concentrations of Cu{sub 2}O were synthesized by a simple impregnation method at 200 °C under N{sub 2} atmosphere for 4 h. The as-synthesized samples were characterized by X-ray powder diffraction, scanning electron microscopy, UV–vis diffuse reflection absorption and vis photoluminescence. The morphology of the as-synthesized composites with different weight ratios of Cu{sub 2}O is composed by quasi-spherical and dendrite-like particles. The photocatalytic performance of the Cu{sub 2}O/BiVO{sub 4} composites was evaluated by degradation of methyl orange solutions under visible-LED irradiation. The results obtained show that the photocatalytic behavior of the p–n heterojunction Cu{sub 2}O/BiVO{sub 4} composites was better than pure Cu{sub 2}O and BiVO{sub 4}. The variation of the reaction parameters, such as solution pH and presence of O{sub 2}, improved the photocatalytic performance of Cu{sub 2}O/BiVO{sub 4} composite. Meanwhile, a possible mechanism for methyl orange photocatalytic degradation over Cu{sub 2}O/BiVO{sub 4} photocatalysts was proposed. The chemical stability and reusability of Cu{sub 2}O/BiVO{sub 4} powders were also investigated.

Magnetic field and temperature dependence of flux creep in oriented grained and single-crystalline YBa2Cu3Ox

International Nuclear Information System (INIS)

Keller, C.; Kuepfer, H.; Gurevich, A.; Meier-Hirmer, R.; Wolf, T.; Fluekiger, R.; Selvamanickam, V.; Salama, K.

1990-01-01

Thermally activated flux creep of oriented grained and single-crystalline YBa 2 Cu 3 O x was studied in fields up to 12 T and at temperatures ranging between 4 and 90 K. In fixed fields the activation energy U 0 of both samples was found to increase with temperature, pass through some maximum and drop to the order of k B T around the irreversibility line. While at constant temperature U 0 of the oriented grained sample showed a monotonous decrease with field; in the case of the single crystal it was found to follow a characteristic minimum-maximum structure paralleled by the previously observed field dependence of the shielding current. This clearly demonstrates the influence of the coupling properties, i.e., bulk behavior of the oriented grained sample and granularity of the single crystal, on relaxation. Therefore, models exclusively based either on a pinning or on a junction approach alone could not describe our experimental findings. A more appropriate explanation is based on the properties of the defect structure. Depending on field and temperature, defective regions are driven into the normal state whereby additional pinning centers are created which in turn give rise to increasing activation energies. The connectivity of the sample then depends on size and density of these defects

Cu{sub 2}ZnSnS{sub 4} solar cells prepared by sulfurization of sputtered ZnS/Sn/CuS precursors

Energy Technology Data Exchange (ETDEWEB)

Li, Zhi-Shan; Wang, Shu-Rong, E-mail: shrw88@aliyun.com; Jiang, Zhi; Yang, Min; Lu, Yi-Lei; Liu, Si-Jia; Zhao, Qi-Chen; Hao, Rui-Ting

2016-12-01

Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films were grown on Mo-coated Soda-lime-glass (SLG) substrates by sulfurization of sputtered ZnS/Sn/CuS precursors at different temperatures i.e. 560 °C, 580 °C and 600 °C. The effects of sulfurization temperature on the quality of CZTS thin films and solar cells were investigated. The crystal structure, surface morphology, chemical composition, phase purity and surface roughness of CZTS thin films fabricated at different sulfurization temperatures were characterized by X Ray Diffraction (XRD), scanning electron microscopy (SEM) equipped with an energy dispersive spectrometer (EDS), Raman spectroscopy and atomic force microscope (AFM), respectively. The results show that all CZTS thin films exhibit a polycrystalline kesterite structure and preferred (112) orientation. For the sulfurization temperature of 580 °C, the obtained CZTS thin films are dense and flat with larger grain size. Meanwhile composition studying indicates that the fabricated CZTS with single phase is copper poor and zinc rich. Furthermore, the surface roughness of CZTS film is the lowest. Finally, the CZTS solar cells with the structure of SLG/Mo/CZTS/CdS/i-ZnO/ITO/Al were fabricated and demonstrated the best power conversion efficiency of 3.59% when used sulfurization temperature was 580 °C.

Solid solutions on the base of CuCr2Se4 and CUsUb(1/2)Insub(1/2)Crsub(2)Sesub(4)

International Nuclear Information System (INIS)

Smirnov, S.G.; Rozantsev, A.V.; Kesler, Ya.A.; Gordeev, I.V.; Tret'yakov, Yu.D.

1983-01-01

The CuCr 2 Se 4 interaction with Cusub(1/2)Insub(1/2)Crsub(2)Sesub(4) for determining the fields of solid solutions existence and studying their crystallochemical properties is investigated. Solid solutions of the (1-x)Cusub(1/2)Insub(1/2)Crsub(2)Sesub(4)xxCuCrsub(2)Sesub(4) are prepared, two limited regions of solid solutions of spinel type at 0 <= x <= 0.2 and 0.8 <= x <= 1 are determined. X-ray radiography investigation of synthesized solid solutions is carried out. It has been found that at 0 <= x <= 0.2 solid solutions are crystallized in the ordered spinel structure F anti 43m

Transport current anisotropy in oriented grained bulk YBa2Cu3O(x) superconductor

International Nuclear Information System (INIS)

Selvamanickam, V.; Salama, K.

1990-01-01

The anisotropy in transport current density has been studied on bulk YBa2Cu3O(x) superconductor. The transport current density measurements were performed on oriented grained YBa2Cu3O(x) superconductor with the current aligned at different angles to the a-b plane. The angular dependence of Jc shows a rapid drop when the transport current is misaligned from the a-b plane at small angles and then a slow decrease at higher angles. An anisotropy ratio of about 25 is observed at 77 K and zero field between the Jc along a-b plane and that perpendicular to the plane. 15 refs

Nanostructure investigation of magnetic nanomaterial Ni{sub 0.5}Zn{sub 0.3}Cu{sub 0.2}Fe{sub 2}O{sub 4} synthesized by sol-gel method

Energy Technology Data Exchange (ETDEWEB)

Pransisco, Prengki, E-mail: prengkipransisco@gmail.com [Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Badan Lingkungan Hidup Derah Kabupaten Empat Lawang South of Sumatera (Indonesia); Shafie, Afza, E-mail: afza@petronas.com.my; Guan, Beh Hoe, E-mail: beh.hoeguan@petronas.com.my [Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia)

2015-07-22

Magnetic nanomaterial Ni{sub 0.5}Zn{sub 0.3}Cu{sub 0.2}Fe{sub 2}O{sub 4} was successfully prepared by using sol-gel method. Heat treatment on material is always giving defect on properties of material. This paper investigates the effect of heat treatment on nanostructure of magnetic nanomaterial Ni{sub 0.5}Zn{sub 0.3}Cu{sub 0.2}Fe{sub 2}O{sub 4}. According to thermo gravimetric analysis (TGA) that after 600°C there is no more weight loss detected and it was decided as minimum calcination temperature. Intensity, crystallite size, structure, lattice parameter and d-spacing of the material were investigated by using X-ray diffraction (XRD). High resolution transmission electron microscope (HRTEM) was used to examine nanostructure, nanosize, shape and distribution particle of magnetic material Ni{sub 0.5}Zn{sub 0.3}Cu{sub 0.2}Fe{sub 2}O{sub 4} and variable pressure field emission scanning electron microscope (VP-FESEM) was used to investigate the surface morphology and topography of the material. The XRD result shows single-phase cubic spinel structure with average crystallite size in the range of 25.6-95.9 nm, the value of the intensity of the material was increased with increasing temperature, and followed by lattice parameter was increased with increasing calcination temperature, value of d-spacing was relatively decreased with accompanied increasing temperature. From HRTEM result the distribution of particles was tend to be agglomerates with particle size of 7.8-17.68 nm. VP-FESEM result shows that grain size of the material increases with increasing calcination temperature and the surface morphology shows that the material is in hexagonal shape and it was also proved by mapping result which showing the presence each of constituents inside the compound.

Combustion synthesis as a novel approach in preparation of polycrystalline Y{sub 2}Cu{sub 2}O{sub 5}

Energy Technology Data Exchange (ETDEWEB)

Gebrel, Z., E-mail: z_gebrel@yahoo.com; Blanusa, J.; Spasojevic, V.; Kusigerski, V.; Mrakovic, A.; Alqat, A.; Perovic, M.

2013-08-15

Highlights: •Y{sub 2}Cu{sub 2}O{sub 5} was successfully synthesized by both the glycine–nitrate and SHS method. •The reduction of synthesis duration down to 12 h has been achieved. •The detailed crystal structure and magnetic analyses of obtained material are provided. -- Abstract: Polycrystalline samples of Y{sub 2}Cu{sub 2}O{sub 5} were for the first time sintered from precursors obtained by two combustion routes – the glycine–nitrate method (sample S1) and a modified self-propagating high-temperature synthesis (sample S2). The detailed X-ray diffraction analysis has confirmed that both samples are well crystallized and single phase, with the high crystallization degree and cation ordering within a Cu sublattice. Magnetic characterization has shown magnetic behavior typical of pure Y{sub 2}Cu{sub 2}O{sub 5}. The distinctive advantages of these new synthesis routes in comparison to the ceramic sintering are in simplification of the overall procedure as well as in a significant reduction of synthesis duration from several days down to 31 h (S1) or 12 h (S2)

Visible-light photocatalytic decolorization of reactive brilliant red X-3B on Cu{sub 2}O/crosslinked-chitosan nanocomposites prepared via one step process

Energy Technology Data Exchange (ETDEWEB)

Cao, Chunhua [College of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China); Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Chemical and Environmental Engineering, Jianghan University, Wuhan 430056 (China); Xiao, Ling, E-mail: xiaoling9119@yahoo.cn [College of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China); Liu, Li; Zhu, Huayue [College of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China); Chen, Chunhua; Gao, Lin [Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Chemical and Environmental Engineering, Jianghan University, Wuhan 430056 (China)

2013-04-15

Cu{sub 2}O/crosslinked-chitosan nanocomposites (Cu{sub 2}O/CS NCs) were in situ prepared via a simple one-step liquid phase precipitation–reduction process and characterized by XRD, FT-IR, SEM, TEM, BET, XPS and UV–vis/DRS. The characterization results showed that Cu{sub 2}O/CS NCs were almost similar spherical or ellipsoidal and the surface was rough and porous because Cu{sub 2}O particle was wrapped in chitosan. The chitosan layer was especially favorable for improving the adsorption ability of dye and molecular oxygen and restraining the recombination of electrons–holes pair. The visible-light photocatalytic decolorization behavior on Cu{sub 2}O/CS NCs was evaluated using reactive brilliant red X-3B (X-3B) as a model pollutant. The influences of various experimental factors on X-3B decolorization were investigated. It was found that the photocatalytic decolorization process on Cu{sub 2}O/CS NCs followed apparent pseudo-first-order kinetics model. The dye X-3B could be decolorized more efficiently in acidic media than in alkaline media. Cu{sub 2}O/CS NCs exhibited enhanced visible-light photocatalytic activity compared with other photocatalysts reported before under similar experimental conditions.

Secondary recrystallization behavior in a twin-roll cast grain-oriented electrical steel

Energy Technology Data Exchange (ETDEWEB)

Song, Hong-Yu; Liu, Hai-Tao, E-mail: liuht@ral.neu.edu.cn; Wang, Yin-Ping; Wang, Guo-Dong

2017-04-15

The microstructure and texture evolution along the processing was investigated with a particular focus on the secondary recrystallization behavior in a 0.23 mm-thick twin-roll cast grain-oriented electrical steel. A striking feature is that Goss orientation originated during twin-roll casting as a result of shear deformation and it was further enhanced during hot rolling and normalizing. After primary recrystallization annealing, a homogeneous microstructure associated with a sharp γ-fiber texture was produced. During secondary recrystallization annealing, the γ-fiber texture was first strengthened and weakened with increasing temperature prior to the onset of secondary recrystallization. Goss grains always exhibited more 20–45° misoriented boundaries than the matrix. The matrix was quite stable during secondary recrystallization with the aid of dense inhibitors. Finally, a complete secondary recrystallization microstructure consisting of large Goss grains was produced. The grain boundary characteristics distribution indicated that the high energy model was responsible for the abnormal growth of Goss grains under the present conditions. - Highlights: • A 0.23 mm twin-roll cast grain-oriented silicon steel sheet was produced. • Goss orientation originated during twin-roll casting. • Secondary recrystallization behavior was briefly investigated. • γ-fiber texture was enhanced prior to the onset of secondary recrystallization. • A complete secondary recrystallization microstructure was produced.

Facile synthesis of SiO{sub 2}@Cu{sub x}O@TiO{sub 2} heterostructures for catalytic reductions of 4-nitrophenol and 2-nitroaniline organic pollutants

Energy Technology Data Exchange (ETDEWEB)

Zelekew, Osman Ahmed; Kuo, Dong-Hau, E-mail: dhkuo@mail.ntust.edu.tw

2017-01-30

Highlights: • The synthesis of SiO{sub 2}@Cu{sub x}O@TiO{sub 2}catalystwasillustrated (*). • The p-n junction between p-type Cu{sub x}O and n-type TiO{sub 2} built electric field. • The electric field results in avoiding the recombination of electron and hole. • The n-type TiO{sub 2} rich in electron outward facilitates the reduction. - Abstract: Herein, we designed the p-type Cu{sub x}O (x = 1 or 2) nanoparticles deposited on SiO{sub 2} spherical particle inside and coated with thin layered n-type TiO{sub 2} semiconductors outside for reduction purpose. The composite material, abbreviated as SiO{sub 2}@Cu{sub x}O@TiO{sub 2}, was characterized. The catalytic performance of the composite was tested for the reductions of 4-nitrophenol (4-NP) and 2-nitroaniline (2-NA). Complete reductions of 4-NP and 2-NA took, 210 and 150 s, respectively. The catalytic efficiency of the composite material may be associated with electron and hole separation resulted from the p-n junction formation between p-type Cu{sub x}O and n-type TiO{sub 2} and the built-in electric field. Moreover, the hydride ion and electrons released from NaBH{sub 4} together with outward electrons from n-type TiO{sub 2}, synergistically, are also responsible for the reduction of nitro aromatic compounds. Our design of composite material from low-priced metal oxides was successful towards reduction of nitro-aromatic compounds.

Crystallization and electrical resistivity of Cu{sub 2}O and CuO obtained by thermal oxidation of Cu thin films on SiO{sub 2}/Si substrates

Energy Technology Data Exchange (ETDEWEB)

De Los Santos Valladares, L., E-mail: ld301@cam.ac.uk [Cavendish Laboratory, University of Cambridge, J.J Thomson Av., Cambridge CB3 0HE (United Kingdom); Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503 (Japan); Departamento de Fisica, Universidade Federal de Pernambuco, 50670-901, Recife-Pe (Brazil); Salinas, D. Hurtado [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503 (Japan); Laboratorio de Ceramicos y Nanomateriales, Facultad de Ciencias Fisicas, Universidad Nacional Mayor de San Marcos, Ap. Postal 14-0149, Lima (Peru); Dominguez, A. Bustamante [Laboratorio de Ceramicos y Nanomateriales, Facultad de Ciencias Fisicas, Universidad Nacional Mayor de San Marcos, Ap. Postal 14-0149, Lima (Peru); Najarro, D. Acosta [Instituto de Fisica, Departamento de Materia Condensada, Universidad Nacional Autonoma de Mexico, Ap. Postal 20-364, CP 01000 (Mexico); Khondaker, S.I. [NanoScience Technology Centre and Department of Physics, University of Central Florida, Orlando, FL 32826 (United States); Mitrelias, T.; Barnes, C.H.W. [Cavendish Laboratory, University of Cambridge, J.J Thomson Av., Cambridge CB3 0HE (United Kingdom); Aguiar, J. Albino [Departamento de Fisica, Universidade Federal de Pernambuco, 50670-901, Recife-Pe (Brazil); Majima, Y. [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503 (Japan); CREST, Japan Science and Technology Agency (JST), 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503 (Japan)

2012-08-01

In this work, we study the crystallization and electrical resistivity of the formed oxides in a Cu/SiO{sub 2}/Si thin film after thermal oxidation by ex-situ annealing at different temperatures up to 1000 Degree-Sign C. Upon increasing the annealing temperature, from the X ray diffractogram the phase evolution Cu {yields} Cu + Cu{sub 2}O {yields} Cu{sub 2}O {yields} Cu{sub 2}O + CuO {yields} CuO was detected. Pure Cu{sub 2}O films are obtained at 200 Degree-Sign C, whereas uniform CuO films without structural surface defects such as terraces, kinks, porosity or cracks are obtained in the temperature range 300-550 Degree-Sign C. In both oxides, crystallization improves with annealing temperature. A resistivity phase diagram, which is obtained from the current-voltage response, is presented here. The resistivity was expected to increase linearly as a function of the annealing temperature due to evolution of oxides. However, anomalous decreases are observed at different temperatures ranges, this may be related to the improvement of the crystallization and crystallite size when the temperature increases. - Highlights: Black-Right-Pointing-Pointer The crystallization and electrical resistivity of oxides in a Cu films are studied. Black-Right-Pointing-Pointer In annealing Cu films, the phase evolution Cu + Cu{sub 2}O {yields} Cu{sub 2}O {yields} Cu{sub 2}O + CuO {yields} CuO occurs. Black-Right-Pointing-Pointer A resistivity phase diagram, obtained from the current-voltage response, is presented. Black-Right-Pointing-Pointer Some decreases in the resistivity may be related to the crystallization.

Exciton spectra and energy band structure of Cu{sub 2}ZnSiSe{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Guc, M., E-mail: gmax@phys.asm.md [Institute of Applied Physics, Academy of Sciences of Moldova, Academiei Str. 5, Chisinau MD 2028, Republic of Moldova (Moldova, Republic of); Levcenko, S. [Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Dermenji, L. [Institute of Applied Physics, Academy of Sciences of Moldova, Academiei Str. 5, Chisinau MD 2028, Republic of Moldova (Moldova, Republic of); Gurieva, G. [Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Schorr, S. [Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Free University Berlin, Institute of Geological Sciences, Malteserstr. 74-100, Berlin (Germany); Syrbu, N.N. [Technical University of Moldova, Chisinau MD-2004, Republic of Moldova (Moldova, Republic of); Arushanov, E. [Institute of Applied Physics, Academy of Sciences of Moldova, Academiei Str. 5, Chisinau MD 2028, Republic of Moldova (Moldova, Republic of)

2014-02-25

Highlights: • Reflection spectra of Cu{sub 2}ZnSiSe{sub 4} were studied for E ⊥ c and E || c light polarizations. • Four excitonic series are revealed in the reflection spectra at 10 K. • Model of exciton dispersion and the presence of a dead-layer. • Exciton Rydberg energies and free carriers effective masses were calculated. • Reflectivity for E ⊥ c and E || c were analyzed in the region 3–6 eV at 300 K. -- Abstract: Exciton spectra are studied in Cu{sub 2}ZnSiSe{sub 4} single crystals at 10 and 300 K by means of reflection spectroscopy. The exciton parameters, dielectric constant and free carriers effective masses are deduced from experimental spectra by calculations in the framework of a model taking into account the spatial dispersion and the presence of a dead-layer. The structure found in the reflectivity was analyzed and related to the theoretical electronic band structure of close related Cu{sub 2}ZnSiS{sub 4} semiconductor.

Rapid synthesis of flower shaped Cu{sub 2}ZnSnS{sub 4} nanoparticles by microwave irradiation for solar cell application

Energy Technology Data Exchange (ETDEWEB)

Ansari, Mohd Zubair, E-mail: mhd.zubair1@gmail.com; Khare, Neeraj [Department of Physics, Indian Institute of Technology Delhi, New Delhi (India)

2016-05-06

Single phase Cu{sub 2}ZnSnS{sub 4} (CZTS) nanoparticles have been synthesized by the microwave-assisted solution method in a one step process. Structural, morphological and optical characterizations of the CZTS nanoparticles have been carried out. X-ray diffraction confirms the single phase formation of CZTS nanoparticles with kesterite structure. SEM confirms the homogenous distribution of CZTS nanoparticles flower like assemblies. High resolution TEM image confirms the good crystallinity of the CZTS nanoparticles with the average grain size ~20 nm. The CZTS nanoparticles have strong optical absorption in the visible region with direct band gap as ~1.6 eV which is optimal for photovoltaic application.

Large-scale synthesis of hierarchical-structured weissite (Cu{sub 2−x}Te) flake arrays and their catalytic properties

Energy Technology Data Exchange (ETDEWEB)

Cao, Xinjiang [State Key Laboratory of Bioelectronics (Chien-Shiung Wu Lab), School of Biological Science and Medical Engineering, Southeast University, Si Pai Lou 2#, Nanjing 210096 (China); Yan, Shancheng [School of Geography and Biological Information, Nanjing University of Posts and Telecommunications, Nanjing 210046 (China); Ortiz, Lazarus Santiago; Liang, Gaofeng; Sun, Bo; Huang, Ningping [State Key Laboratory of Bioelectronics (Chien-Shiung Wu Lab), School of Biological Science and Medical Engineering, Southeast University, Si Pai Lou 2#, Nanjing 210096 (China); Xiao, Zhongdang, E-mail: zdxiao@seu.edu.cn [State Key Laboratory of Bioelectronics (Chien-Shiung Wu Lab), School of Biological Science and Medical Engineering, Southeast University, Si Pai Lou 2#, Nanjing 210096 (China)

2014-03-01

Graphical abstract: - Highlights: • Large-scale Cu{sub 2−x}Te flake arrays grown on copper foam were synthesized. • They possess superior catalytic efficiency on methylene blue with the assistance of H{sub 2}O{sub 2}. • The effects of preparing conditions on the growth of Cu{sub 2−x}Te flake arrays were investigated. - Abstract: Large-scale weissite (Cu{sub 2−x}Te) flake arrays with three-dimensional (3D) hierarchical structure have been successfully fabricated via a facile one-step solution-phase strategy through the reaction of tellurium powder and copper foam. At the end of the reaction Cu{sub 2−x}Te flakes were distributed evenly on the surface of a porous solid copper substrate. Field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analysis showed the abundance of flakes grown on the 3D porous copper architecture, while X-ray diffraction (XRD) and energy-dispersive X-ray spectra (EDS) were used to determine the crystal structure and phase composition of these products. A series of experiments discovered that the size and morphology of the products could be affected by some reactive parameters including the reaction time, synthesis temperature and volume ratio of absolute ethanol/deionized water. Catalysis experiments using the in situ synthesized of Cu{sub 2−x}Te flakes to catalyze the degradation of methylene blue (MB) demonstrated the strong catalytic ability of these flakes.

Origin of grain orientation during solidification of an aluminum alloy

International Nuclear Information System (INIS)

Wei, H.L.; Elmer, J.W.; DebRoy, T.

2016-01-01

The evolution of grain morphology during solidification of a moving aluminum alloy pool is simulated by considering heat transfer, flow of liquid metal in the molten pool and solidification parameters. The computationally efficient model consists of a 3D coupled heat transfer and fluid flow simulation to predict the molten pool shape and temperature field, and a 2D model of grain formation in the molten pool. The results demonstrate that columnar grains grow in a curved pattern rather than along straight lines from the fusion boundary towards the center of the molten pool. The calculated results are validated with independent experimental data. The computed ratio of local temperature gradient to solidification rate, G/R, is used to model the columnar to equiaxed transition during solidification. The simulated results show that only curved columnar grains are formed when the scanning speed is low (2.0 mm/s). In contrast, a transition from curved columnar to equiaxed morphologies occurs at the higher scanning speeds of 8.0 mm/s and 11.5 mm/s, with higher equiaxed grain fraction at higher speed. The similarities between the physical processes governing fusion welding and additive manufacturing (AM) make the model capable of predicting grain orientation in both processes.

Cu{sub 2−x}S films as counter-electrodes for dye solar cells with ferrocene-based liquid electrolytes

Energy Technology Data Exchange (ETDEWEB)

Congiu, M., E-mail: mirko.congiu@fc.unesp.br [UNESP, Univ. Estadual Paulista, POSMAT — Programa de Pós-Graduação em Ciência e Tecnologia de Materiais, Av. Eng. Luiz Edmundo Carrijo Coube14-01, 17033-360 Bauru, SP (Brazil); Nunes-Neto, O. [UNESP, Univ. Estadual Paulista, POSMAT — Programa de Pós-Graduação em Ciência e Tecnologia de Materiais, Av. Eng. Luiz Edmundo Carrijo Coube14-01, 17033-360 Bauru, SP (Brazil); De Marco, M.L.; Dini, D. [University of Rome “La Sapienza”, Department of Chemistry, Piazzale Aldo Moro 5, Rome, RM (Italy); Graeff, C.F.O. [UNESP, Univ. Estadual Paulista, POSMAT — Programa de Pós-Graduação em Ciência e Tecnologia de Materiais, Av. Eng. Luiz Edmundo Carrijo Coube14-01, 17033-360 Bauru, SP (Brazil); DC-FC, UNESP, Univ. Estadual Paulista, Av. Eng. Luiz Edmundo Carrijo Coube14-01, 17033-360 Bauru, SP (Brazil)

2016-08-01

In this work, the application of hexagonal CuS nanoparticle layers as counter electrodes for dye sensitized solar cells has been studied. A fast, cheap and reliable deposition method was proposed for the one-step preparation of Cu{sub 2−x}S layers on F-doped SnO{sub 2} within 30 min through an ink-based technique. The electrodes prepared with our method were tested with iodine/iodide electrolyte, Co(II)/(III) bipyridine redox shuttle and Fe(II)/(III) ferrocene-based liquid electrolyte. The Cu{sub 2−x}S layers showed high efficiency and stability with the ferrocene/ferrocenium redox couple, showing a fast charge recombination kinetic, low charge transfer resistance (R{sub ct} = 0.73 Ω cm{sup 2}), reasonably high limiting current (11.8 mA cm{sup −2}) and high stability in propylene carbonate. - Highlights: • We proposed a low-cost Cu{sub 2−x}S electrode for dye solar cells. • Easy deposition and processing • Suitable for large-area applications • Advantages and limitations of Cu{sub 2−x}S with three different redox electrolytes • High electro-catalytic efficiency and stability with the ferrocene/ferrocenium redox couple.

Electrochemically deposited Cu{sub 2}O cubic particles on boron doped diamond substrate as efficient photocathode for solar hydrogen generation

Energy Technology Data Exchange (ETDEWEB)

Mavrokefalos, Christos K. [Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, England (United Kingdom); Hasan, Maksudul, E-mail: maksudul.hasan@chem.ox.ac.uk [Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, England (United Kingdom); Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland); Rohan, James F. [Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland); Compton, Richard G. [Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, England (United Kingdom); Foord, John S., E-mail: john.foord@chem.ox.ac.uk [Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, England (United Kingdom)

2017-06-30

Highlights: • Fabrication of low-cost photocathode by electrochemical method is described. • Boron-doped diamond is presented as catalyst support. • NiO nanoparticles on Cu{sub 2}O surface enhances photocurrent and electrode stability. • Synergy of metallic interaction between Cu and Ni leads to high efficiency. - Abstract: Herein, we report a novel photocathode for the water splitting reaction. The electrochemical deposition of Cu{sub 2}O particles on boron doped diamond (BDD) electrodes and the subsequent decoration with NiO nanoparticles by a dip coating method to act as co-catalyst for hydrogen evolution reaction is described. The morphology analysis by scanning electron microscope (SEM) revealed that Cu{sub 2}O particles are cubic and decorated sporadically with NiO nanoparticles. X-ray photoelectron spectroscopy (XPS) confirmed the electronic interaction at the interface between Cu{sub 2}O and NiO through a binding energy shift of the main Cu 2p peak. The photoelectrochemical (PEC) performance of NiO-Cu{sub 2}O/BDD showed a much higher current density (−0.33 mA/cm{sup 2}) and photoconversion efficiency (0.28%) compared to the unmodified Cu{sub 2}O/BDD electrode, which are only −0.12 mA/cm{sup 2} and 0.06%, respectively. The enhancement in PEC performance is attributable to the synergy of NiO as an electron conduction mediator leading to the enhanced charge separation and transfer to the reaction interface for hydrogen evolution as evidenced by electrochemical impedance spectroscopy (EIS) and charge carrier density calculation. Stability tests showed that the NiO nanoparticles loading content on Cu{sub 2}O surface is a crucial parameter in this regard.

Method of manufacture of single phase ceramic superconductors

Science.gov (United States)

Singh, Jitrenda P.; Poeppel, Roger B.; Goretta, Kenneth C.; Chen, Nan

1995-01-01

A ceramic superconductor is produced by close control of oxygen partial pressure during sintering of the material. The resulting microstructure of YBa.sub.2 Cu.sub.3 O.sub.x indicates that sintering kinetics are enhanced at reduced p(O.sub.2) and that because of second phase precipitates, grain growth is prevented. The density of specimens sintered at 910.degree. C. increased from 79 to 94% theoretical when p(O.sub.2) was decreased from 0.1 to 0.0001 MPa. The increase in density with decrease in p(O.sub.2) derives from enhanced sintering kinetics, due to increased defect concentration and decreased activation energy of the rate-controlling species undergoing diffusion. Sintering at 910.degree. C resulted in a fine-grain microstructure, with an average grain size of about 4 .mu.m. Post sintering annealing in a region of stability for the desired phase converts the second phases and limits grain growth. The method of pinning grain boundaries by small scale decompositive products and then annealing to convert its product to the desired phase can be used for other complex asides. Such a microstructure results in reduced microcracking, strengths as high as 230 MPa and high critical current density capacity.

Grain orientation mapping of passivated aluminum interconnect wires with X-ray micro-diffraction

International Nuclear Information System (INIS)

MacDowell, A.A.; Padmore, H.A.; Thompson, A.C.; Chang, C.H.; Patel, J.R.

1998-06-01

A micro x-ray diffraction facility is under development at the Advanced Light source. Spot sizes are typically about 1-microm size generated by means of grazing incidence Kirkpatrick-Baez focusing mirrors. Photon energy is either white of energy range 6--14 keV or monochromatic generated from a pair of channel cut crystals. A Laue diffraction pattern from a single grain in passivated 2-microm wide bamboo structured Aluminum interconnect line has been recorded. Acquisition times are of the order of a few seconds. The Laue pattern has allowed the determination of the crystallographic orientation of individual grains along the line length. The experimental and analysis procedures used are described, as is a grain orientation result. The future direction of this program is discussed in the context of strain measurements in the area of electromigration

Enhancement of mechanical properties of 123 superconductors

Science.gov (United States)

Balachandran, Uthamalingam

1995-01-01

A composition and method of preparing YBa.sub.2 Cu.sub.3 O.sub.7-x superconductor. Addition of tin oxide containing compounds to YBCO superconductors results in substantial improvement of fracture toughness and other mechanical properties without affect on T.sub.c. About 5-20% additions give rise to substantially improved mechanical properties.

Levitation force and magnetization in bulk and thin film high T{sub c} superconductors

Energy Technology Data Exchange (ETDEWEB)

Riise, A.B

1998-04-01

The authors present high-resolution measurements of the repulsive vertical force and its associated stiffness between a Nd-B-Fe magnet and a YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} superconductor in cylindrical geometry. The results are compared with theoretical predictions. The calculations are based on a model in which the superconductor is assumed to be either a sintered granular material or consisting of grains embedded in a nonactive matrix so that only intragranular currents are important. The critical state model is applied to each grain individually and closed form expressions for both vertical force F{sub z} and stiffness are obtained in a configuration with cylindrical symmetry. The model explains all features of the experimental results in a consistent way. A good quantitative agreement has been obtained using only three adjustable parameters. Several central aspects of the phenomenon of magnetic levitation with high-T{sub c} superconductors are presented. High-resolution measurements are made of the repulsive vertical force and its associated stiffness as well as the horizontal stabilizing force and the stiffness governing lateral vibrations. The results obtained at 77 K using a granular YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} sample and Nd-Fe-B magnet in a rectangular levitation configuration are compared with theoretical predictions. The calculations, which are based on the critical state model with the assumption that it applies to the grins individually, give closed-form expressions for all the measured quantities. It is concluded that the present model explains all features of the observations in a consistent way. Using only three adjustable parameters a good agreement exists also at a quantitative level. Experimental studies and theoretical modelling of the levitation force on a permanent magnet placed above a superconducting thin film are offered. It is shown that measurements of the levitation force is a simple and precise method to determine the

Metal insulator semiconductor solar cell devices based on a Cu{sub 2}O substrate utilizing h-BN as an insulating and passivating layer

Energy Technology Data Exchange (ETDEWEB)

Ergen, Onur; Gibb, Ashley; Vazquez-Mena, Oscar; Zettl, Alex, E-mail: azettl@berkeley.edu [Department of Physics, University of California at Berkeley, Berkeley, California 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Kavli Energy Nanosciences Institute at the University of California, Berkeley, and the Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Regan, William Raymond [Department of Physics, University of California at Berkeley, Berkeley, California 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2015-03-09

We demonstrate cuprous oxide (Cu{sub 2}O) based metal insulator semiconductor Schottky (MIS-Schottky) solar cells with efficiency exceeding 3%. A unique direct growth technique is employed in the fabrication, and hexagonal boron nitride (h-BN) serves simultaneously as a passivation and insulation layer on the active Cu{sub 2}O layer. The devices are the most efficient of any Cu{sub 2}O based MIS-Schottky solar cells reported to date.

Atomic and electronic structures of lattice mismatched Cu{sub 2}O/TiO{sub 2} interfaces

Energy Technology Data Exchange (ETDEWEB)

Wang, Shuzhi [Materials Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Mail Stop 66, Berkeley, California 94720 (United States); Kavaipatti, Balasubramaniam; Ramesh, Ramamoorthy [Department of Materials Science and Engineering, University of California at Berkeley, Berkeley, California 94720 (United States); Kim, Sung-Joo; Pan, Xiaoqing [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Ager, Joel W.; Wang, Lin-Wang, E-mail: lwwang@lbl.gov [Materials Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Mail Stop 66, Berkeley, California 94720 (United States); Joint Center of Artificial Photosynthesis, Berkeley, California 94720 (United States)

2014-05-26

Heterojunction interfaces between metal oxides are often highly lattice mismatched. The atomic and electronic structures of such interfaces, however, are not well understood. We have synthesized Cu{sub 2}O/TiO{sub 2} heterojunction thin films with 13% lattice mismatch and studied the interface via experimental methods and large-scale density function theory calculations of supercells containing ∼1300 atoms. We find that an interface of epitaxial quality is formed via a coincidence site lattice of 8 Cu{sub 2}O unit cells matching 9 TiO{sub 2} unit cells. Calculations reveal the existence of a dislocation core of the O sublattices at the interface and a random arrangement of one layer of interfacial Cu atoms. The interfacial electronic structure is found to be mostly determined by the interfacial Cu distribution, rather than by the O dislocation core. The conduction band minimum and valence band maximum states are spatially separated, and there is no strongly localized state near the core.

Correlation between grain orientation and the shade of color etching

International Nuclear Information System (INIS)

Szabo, Peter J.; Kardos, I.

2010-01-01

Color etching is an extremely effective metallographic technique not only for making grains well visible, but also for making them distinguishable for automated image analyzers. During color etching, a thin film is formed on the surface of the specimen. The thickness of this layer is in the order of magnitude of the visible light and since both the metal-film boundary and the film surface reflect light, an interference occurs. A wavelength-component of the white line is eliminated and its complementary color will be seen on the surface. As the thickness changes, the colors also change grain by grain. The thickness of the film is dependent on several factors, mostly on the type of the phase. However, different color shades can be observed on the surfaces of single phase materials, which phenomenon is caused by the different crystallographic orientations of the grains. This paper shows a combined color etching electron backscatter diffraction (EBSD) investigation of cast iron. An area of the surface of a gray cast iron specimen was etched. Colors were characterized by their luminescence and their red, green and blue intensity. An EBSD orientation map was taken from the same area and the orientations of the individual grains were determined. Results showed that a strong correlation was found between the luminescence and the R, G, B intensity of the color and the angle between the specimen normal and the direction, while such correlation was not observed between the color parameters and the and directions, respectively. This indicates that film thickness is sensitive to the direction of the crystal.

A density functional theory study of the adsorption behaviour of CO{sub 2} on Cu{sub 2}O surfaces

Energy Technology Data Exchange (ETDEWEB)

Mishra, Abhishek Kumar, E-mail: akmishra@ddn.upes.ac.in, E-mail: abhishek.mishra@ucl.ac.uk, E-mail: deleeuwn@cardiff.ac.uk [Research & Development, University of Petroleum and Energy Studies (UPES), Bidholi, Dehradun 248007 (India); Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom); Roldan, Alberto [School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT (United Kingdom); Leeuw, Nora H. de, E-mail: akmishra@ddn.upes.ac.in, E-mail: abhishek.mishra@ucl.ac.uk, E-mail: deleeuwn@cardiff.ac.uk [Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom); School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT (United Kingdom)

2016-07-28

Copper has many applications, particularly in electro-catalysis, where the oxidation state of the copper electrode plays a significant role in the selectivity towards products. Although copper-based materials have clear potential as catalysts in the reduction of CO{sub 2} and conversion to products, fundamental understanding of CO{sub 2} adsorption and activation on different copper oxide surfaces is still limited. We have used DFT+U methodology to study the surface reconstruction of the three most exposed (111), (110), and (001) surfaces of Cu{sub 2}O with different possible terminations. Considering several adsorbate geometries, we have investigated CO{sub 2} adsorption on five different possible terminations and proposed eight different configurations in which CO{sub 2} binds with the surface. Similar to earlier findings, CO{sub 2} binds weakly with the most stable Cu{sub 2}O(111):O surface showing no molecular activation, whereas a number of other surfaces, which can appear in the Cu{sub 2}O particles morphology, show stronger binding as well as activation of the CO{sub 2} molecule. Different CO{sub 2} coverages were studied and a detailed structural and electronic charge analysis is presented. The activation of the CO{sub 2} molecule is characterized by structural transformations and charge transfer between the surface and the CO{sub 2} molecule, which is further confirmed by considerable red shifts in the vibrational frequencies.

Nanocompositional Electron Microscopic Analysis and Role of Grain Boundary Phase of Isotropically Oriented Nd-Fe-B Magnets

Directory of Open Access Journals (Sweden)

Gregor A. Zickler

2017-01-01

Full Text Available Nanoanalytical TEM characterization in combination with finite element micromagnetic modelling clarifies the impact of the grain misalignment and grain boundary nanocomposition on the coercive field and gives guidelines how to improve coercivity in Nd-Fe-B based magnets. The nanoprobe electron energy loss spectroscopy measurements obtained an asymmetric composition profile of the Fe-content across the grain boundary phase in isotropically oriented melt-spun magnets and showed an enrichment of iron up to 60 at% in the Nd-containing grain boundaries close to Nd2Fe14B grain surfaces parallel to the c-axis and a reduced iron content up to 35% close to grain surfaces perpendicular to the c-axis. The numerical micromagnetic simulations on isotropically oriented magnets using realistic model structures from the TEM results reveal a complex magnetization reversal starting at the grain boundary phase and show that the coercive field increases compared to directly coupled grains with no grain boundary phase independently of the grain boundary thickness. This behaviour is contrary to the one in aligned anisotropic magnets, where the coercive field decreases compared to directly coupled grains with an increasing grain boundary thickness, if Js value is > 0.2 T, and the magnetization reversal and expansion of reversed magnetic domains primarily start as Bloch domain wall at grain boundaries at the prismatic planes parallel to the c-axis and secondly as Néel domain wall at the basal planes perpendicular to the c-axis. In summary our study shows an increase of coercive field in isotropically oriented Nd-Fe-B magnets for GB layer thickness > 5 nm and an average Js value of the GB layer < 0.8 T compared to the magnet with perfectly aligned grains.

Enhancement of mechanical properties of 123 superconductors

Science.gov (United States)

Balachandran, U.

1995-04-25

A composition and method are disclosed of preparing YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} superconductor. Addition of tin oxide containing compounds to YBCO superconductors results in substantial improvement of fracture toughness and other mechanical properties without affect on T{sub c}. About 5-20% additions give rise to substantially improved mechanical properties.

Observation of magnetostatic wave electron absorption in ferrite-high temperature superconductor structure. Nablyudenie ehlektronnogo pogloshcheniya magnitostaticheskikh voln v strukture ferrit-vysokotemperaturnyj sverkhprovodnik

Energy Technology Data Exchange (ETDEWEB)

Anfinogenov, V B; Gulyaev, Yu V; Zil' berman, P E; Kotelyanskij, I M; Polzikova, N I; Sukhanov, A A [AN SSSR, Moscow (USSR). Inst. Radiotekhniki i Ehlektroniki

1989-07-26

Conditions for magneto-static wave (MSW) propagation in laminar structures ferrite-high-temperature superconductor (YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}) and effect of transition into superconducting state under the temperature drop on these conditions are investigated. MSW electron absorption effrect in such structures (strongly dependent on the temperature) is detected and its interpretation is given.

Grain orientation mapping of passivated aluminum interconnect lines with X-ray micro-diffraction

International Nuclear Information System (INIS)

Chang, C.H.; Patel, J.R.; MacDowell, A.A.; Padmore, H.A.; Thompson, A.C.

1998-01-01

A micro x-ray diffraction facility is under development at the Advanced Light Source. Spot sizes are typically about 1-microm size generated by means of grazing incidence Kirkpatrick-Baez focusing mirrors. Photon energy is either white of energy range 6--14 keV or monochromatic generated from a pair of channel cut crystals. Laue diffraction pattern from a single grain in a passivated 2-microm wide bamboo structured Aluminum interconnect line has been recorded. Acquisition times are of the order of seconds. The Laue pattern has allowed the determination of the crystallographic orientation of individual grains along the line length. The experimental and analysis procedure used is described, as is the latest grain orientation result. The impact of x-ray micro-diffraction and its possible future direction are discussed in the context of other developments in the area of electromigration, and other technological problems

Grain orientation mapping of passivated aluminum interconnect lines by x-ray micro-diffraction

International Nuclear Information System (INIS)

Chang, C. H.; Patel, J. R.; MacDowell, A. A.; Padmore, H. A.; Thompson, A. C.

1998-01-01

A micro x-ray diffraction facility is under development at the Advanced Light Source. Spot sizes are typically about 1-μm size generated by means of grazing incidence Kirkpatrick-Baez focusing mirrors. Photon energy is either white of energy range 6-14 keV or monochromatic generated from a pair of channel cut crystals. Laue diffraction pattern from a single grain in a passivated 2-μm wide bamboo structured Aluminum interconnect line has been recorded. Acquisition times are of the order of seconds. The Laue pattern has allowed the determination of the crystallographic orientation of individual grains along the line length. The experimental and analysis procedure used is described, as is the latest grain orientation result. The impact of x-ray micro-diffraction and its possible future direction are discussed in the context of other developments in the area of electromigration, and other technological problems

(Pt{sub 1–x}Cu{sub x}){sub 3}Cu{sub 2}B and Pt{sub 9}Cu{sub 3}B{sub 5}, the first examples of copper platinum borides. Observation of superconductivity in a novel boron filled β-Mn-type compound

Energy Technology Data Exchange (ETDEWEB)

Salamakha, Leonid P. [Institute of Solid State Physics, TU Wien, A-1040 Wien (Austria); Sologub, Oksana, E-mail: oksana.sologub@univie.ac.at [Institute of Solid State Physics, TU Wien, A-1040 Wien (Austria); Stöger, Berthold [Institute of Chemical Technologies and Analytics, TU Wien, A-1040 Wien (Austria); Michor, Herwig; Bauer, Ernst [Institute of Solid State Physics, TU Wien, A-1040 Wien (Austria); Rogl, Peter F. [Institute of Physical Chemistry, University of Vienna, A-1090 Wien (Austria)

2015-09-15

New ternary copper platinum borides have been synthesized by arc melting of pure elements followed by annealing at 600 °C. The structures have been studied by X-ray single crystal and powder diffraction. (Pt{sub 1−x}Cu{sub x}){sub 3}Cu{sub 2}B (x=0.33) forms a B-filled β-Mn-type structure (space group P4{sub 1}32; a=0.6671(1) nm). Cu atoms are distributed preferentially on the 8c atom sites, whereas the 12d site is randomly occupied by Pt and Cu atoms (0.670(4) Pt±0.330(4) Cu). Boron is located in octahedral voids of the parent β-Mn-type structure. Pt{sub 9}Cu{sub 3}B{sub 5} (space group P-62m; a=0.9048(3) nm, c=0.2908(1) nm) adopts the Pt{sub 9}Zn{sub 3}B{sub 5–δ}-type structure. It has a columnar architecture along the short translation vector exhibiting three kinds of [Pt{sub 6}] trigonal prism columns (boron filled, boron semi-filled and empty) and Pt channels with a pentagonal cross section filled with Cu atoms. The striking structural feature is a [Pt{sub 6}] cluster in form of an empty trigonal prism at the origin of the unit cell, which is surrounded by coupled [BPt{sub 6}] and [Pt{sub 6}] trigonal prisms, rotated perpendicularly to the central one. There is no B–B contact as well as Cu–B contact in the structure. The relationships of Pt{sub 9}Cu{sub 3}B{sub 5} structure with the structure of Ti{sub 1+x}Os{sub 2−x}RuB{sub 2} as well as with the structure families of metal sulfides and aluminides have been elucidated. (Pt{sub 1–x}Cu{sub x}){sub 3}Cu{sub 2}B (x=0.3) (B-filled β-Mn-type structure) is a bulk superconductor with a transition temperature of about 2.06 K and an upper critical field μ{sub 0}H{sub C2}(0){sup WHH} of 1.2 T, whereas no superconducting transition has been observed up to 0.3 K in Pt{sub 9}Cu{sub 3}B{sub 5} (Pt{sub 9}Zn{sub 3}B{sub 5–δ}-type structure) from electrical resistivity measurements. - Highlights: • First two copper platinum borides, (Pt{sub 0.67}Cu{sub 0.33}){sub 3}Cu{sub 2}B and Pt{sub 9}Cu{sub 3}B

Electrodeposited copper oxide films: Effect of bath pH on grain orientation and orientation-dependent interfacial behavior

International Nuclear Information System (INIS)

Wang, L.C.; Tacconi, N.R. de; Chenthamarakshan, C.R.; Rajeshwar, K.; Tao, M.

2007-01-01

Copper (I) oxide (Cu 2 O) films were cathodically electrodeposited on Sn-doped indium oxide substrates. The influence of electrodeposition bath pH on grain orientation and crystallite shape was carefully re-examined using X-ray diffraction and scanning electron microscopy. In addition to the (100) and (111) preferred orientations identified in two previous sets of studies, as the bath pH was varied in the present study from ∼ 7.5 to ∼ 12, a third preferred orientation, (110), was identified in a narrow pH range, ∼ 9.4 to ∼ 9.9. A remarkable shift in the flat-band potential (spanning ∼ 500 mV) was measured in a non-aqueous electrolyte medium for the various Cu 2 O samples obtained from baths of varying pH

Coercivity enhancement of hot-deformed Nd-Fe-B magnets by the eutectic grain boundary diffusion process

Energy Technology Data Exchange (ETDEWEB)

Liu, Lihua [Elements Strategy Initiative Center for Magnetic Materials, National Institute of Materials Science, Tsukuba 305-0047 (Japan); Graduate School of Pure and Applied Science, University of Tsukuba, Tsukuba 305-8577 (Japan); Sepehri-Amin, H.; Ohkubo, T. [Elements Strategy Initiative Center for Magnetic Materials, National Institute of Materials Science, Tsukuba 305-0047 (Japan); Yano, M.; Kato, A.; Shoji, T. [Toyota Motor Corporation, Advanced Material Engineering Div., Susono 410-1193 (Japan); Hono, K., E-mail: kazuhiro.hono@nims.go.jp [Elements Strategy Initiative Center for Magnetic Materials, National Institute of Materials Science, Tsukuba 305-0047 (Japan); Graduate School of Pure and Applied Science, University of Tsukuba, Tsukuba 305-8577 (Japan)

2016-05-05

Nd-M (M = Al, Cu, Ga, Zn, Mn) alloys with compositions close to eutectic points were investigated as diffusion sources for the grain boundary diffusion process to hot-deformed Nd-Fe-B magnets. Coercivity enhancement was observed for most of the alloys. Among them, the sample processed with Nd{sub 90}Al{sub 10} exhibited the highest coercivity of 2.5 T at room temperature. However, the sample processed with Nd{sub 70}Cu{sub 30} exhibited the highest coercivity of 0.7 T at 200 {sup °}C. Microstructural observations using scanning transmission electron microscope (STEM) showed that nonferromagnetic Nd-rich intergranular phase envelops the Nd{sub 2}Fe{sub 14}B grains after the diffusion process. Abnormal grain growth and the dissolution of Al into the Nd{sub 2}Fe{sub 14}B grains were observed in the sample processed with Nd{sub 90}Al{sub 10}, which explains its inferior thermal stability of coercivity compared to the sample processed with Nd{sub 70}Cu{sub 30}. The coercivity enhancement and poor thermal stability of the coercivity of the Nd{sub 90}Al{sub 10} diffusion-processed sample are discussed based on microstructure studies by transmission electron microscopy. - Highlights: • Coercivity of hot-deformed Nd-Fe-B magnets is enhanced by the infiltration of various R-TM eutectic alloys. • The sample infiltrated with Nd{sub 90}Al{sub 10} shows the highest coercivity of 2.5 T at room temperature. • At 200 °C, Nd{sub 70}Cu{sub 30} diffusion-processed sample possesses the highest coercivity of 0.7 T.

Application of Cu{sub 2}O-doped phosphate glasses for bandpass filter

Energy Technology Data Exchange (ETDEWEB)

Elhaes, H. [Physics Department, Faculty of Women for Arts, Science and Education, Ain Shams University, 11757 Cairo (Egypt); Attallah, M., E-mail: m_atallah94@yahoo.com [Basic Science Department, Higher Technological Institute, 10th of Ramadan City (Egypt); Elbashar, Y.; El-Okr, M. [Physics Department, Faculty of Science, Al Azhar University, Cairo (Egypt); Ibrahim, M. [Spectroscopy Department, National Research Centre, 12311 Dokki, Cairo (Egypt)

2014-09-15

Phosphate glasses doped with copper ions having general composition 42P{sub 2}O{sub 5}–39ZnO–(18−x) Na{sub 2}O–1CaO–xCu{sub 2}O [x=2, 4, 6, 8, 10 mol%] were prepared using a conventional melt-quench technique. Physical and chemical properties of the glasses were investigated using X-ray diffraction technique and UV–visible optical absorption. The density was measured by Archimedes' method, and molar volume (V{sub M}) was calculated. It is found that density and molar volume show opposite trend by increasing Cu{sub 2}O content. Absorbance and transmittance at the normal incidence are measured by a spectrophotometer in the spectral range of 190–1100 nm. Analyses of the obtained results were considered in the frame of current theories. Absorption data were used for absorption coefficient, the optical band gap (E{sub opt}), the cutoff in UV and IR bands to the bandpass filter, which confirmed the optical properties of this type of filter. E{sub opt} values for different glass samples are found to decrease with increasing Cu{sub 2}O content.

Metallicity of Ca{sub 2}Cu{sub 6}P{sub 5} with single and double copper-pnictide layers

Energy Technology Data Exchange (ETDEWEB)

Li, Li, E-mail: lil2@ornl.gov [Materials Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Parker, David [Materials Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Chi, Miaofang [Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Tsoi, Georgiy M.; Vohra, Yogesh K. [Department of Physics, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Sefat, Athena S., E-mail: sefata@ornl.gov [Materials Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

2016-06-25

We report thermodynamic and transport properties, and also theoretical calculations, for Cu-based compound Ca{sub 2}Cu{sub 6}P{sub 5} and compare with CaCu{sub 2-δ}P{sub 2}. Both materials have layers of edge-sharing copper pnictide tetrahedral CuP{sub 4}, similar to Fe–As and Fe–Se layers (with FeAs{sub 4}, FeSe{sub 4}) in the iron-based superconductors. Despite the presence of this similar transition-metal pnictide layer, we find that both Ca{sub 2}Cu{sub 6}P{sub 5} and CaCu{sub 2-δ}P{sub 2} have temperature-independent magnetic susceptibility and show metallic behavior with no evidence of either magnetic ordering or superconductivity down to 1.8 K CaCu{sub 2-δ}P{sub 2} is slightly off-stoichiometric, with δ = 0.14. Theoretical calculations suggest that unlike Fe 3d-based magnetic materials with a large density of states (DOS) at the Fermi surface, Cu have comparatively low DOS, with the majority of the 3d spectral weight located well below Fermi level. The room-temperature resistivity value of Ca{sub 2}Cu{sub 6}P{sub 5} is only 9 μΩ-cm, due to a substantial plasma frequency and an inferred electron-phonon coupling λ of 0.073 (significantly smaller than that of metallic Cu). Also, microscopy result shows that Cu–Cu distance along the c-axis within the double layers can be very short (2.5 Å), even shorter than metallic elemental copper bond (2.56 Å). The value of dρ/dT for CaCu{sub 2-δ}P{sub 2} at 300 K is approximately three times larger than in Ca{sub 2}Cu{sub 6}P{sub 5}, which suggests the likelihood of stronger electron-phonon coupling. This study shows that the details of Cu–P layers and bonding are important for their transport characteristics. In addition, it emphasizes the remarkable character of the DOS of ‘122’ iron-based materials, despite much structural similarities. - Highlights: • A comprehensive study on Cu-based compound Ca{sub 2}Cu{sub 6}P{sub 5} and compare with CaCu{sub 2-δ}P{sub 2}. • Both materials have layers of

Investigations on the role of alkali to obtain modulated defect concentrations for Cu{sub 2}O thin films

Energy Technology Data Exchange (ETDEWEB)

Chowdhury, Anirban, E-mail: anirban.chowdhury@gmail.com [Research and Development, Tata Steel Limited, Jamshedpur, 831001 (India); Bijalwan, Pavan Kumar [Research and Development, Tata Steel Limited, Jamshedpur, 831001 (India); Sahu, Ranjan Kumar [MST Division, CSIR-National Metallurgical Laboratory, Jamshedpur, 831007 (India)

2014-01-15

An economic successive ionic layer adsorption and reaction (SILAR) method has been investigated for depositing thin Cu{sub 2}O layers on steel. The mole ratios of the Cu{sup +} ions to OH{sup −} ions in the alkali bath were varied and the changes in the properties were characterised by X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy, scanning electron microscopy (SEM) and Ultraviolet–visible spectroscopy techniques. The increase in the binding energy values of the Cu 2p peaks in XPS established that an optimum copper vacancy concentration can be obtained for a Cu{sup +}/OH{sup −} mole ratio between 1:10 and 1:15; SEM studies confirmed a dense, uniform microstructure for Cu{sub 2}O thin films coated with these compositions. The strongest absolute peak intensity counts in PL for the peak at 580 nm along with low energy peaks (1.2–1.4 eV) due to Cu vacancy was found to be most prominent for thin film made with Cu{sup +}/OH{sup −} mole ratio 1:15. The role of alkali concentration has been explained in relation to create a stable Cu{sub 2−δ}O structure with optimum copper vacancy. This is an easy way to modulate surface reactivity of the Cu{sub 2}O thin layers and the concept can be utilised for large area device integrations for various electrical and mechanical applications.

Structure family and polymorphous phase transition in the compounds with soft sublattice: Cu{sub 2}Se as an example

Energy Technology Data Exchange (ETDEWEB)

Qiu, Wujie [Department of Physics, East China Normal University, Shanghai 200241 (China); State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Lu, Ping; Yuan, Xun; Liu, Huili; Shi, Xun; Chen, Lidong [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); CAS Key Laboratory of Energy conversion Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Xu, Fangfang; Wu, Lihua [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Ke, Xuezhi, E-mail: wqzhang@mail.sic.ac.cn, E-mail: xzke@phy.ecnu.edu.cn, E-mail: jihuiy@uw.edu [Department of Physics, East China Normal University, Shanghai 200241 (China); Yang, Jiong [Materials Genome Institute, Shanghai University, Shanghai 200444 (China); Yang, Jihui, E-mail: wqzhang@mail.sic.ac.cn, E-mail: xzke@phy.ecnu.edu.cn, E-mail: jihuiy@uw.edu [Materials Science and Engineering Department, University of Washington, Seattle, Washington 98195 (United States); Zhang, Wenqing, E-mail: wqzhang@mail.sic.ac.cn, E-mail: xzke@phy.ecnu.edu.cn, E-mail: jihuiy@uw.edu [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Materials Genome Institute, Shanghai University, Shanghai 200444 (China)

2016-05-21

Quite a few interesting but controversial phenomena, such as simple chemical composition but complex structures, well-defined high-temperature cubic structure but intriguing phase transition, coexist in Cu{sub 2}Se, originating from the relatively rigid Se framework and “soft” Cu sublattice. However, the electrical transport properties are almost uninfluenced by such complex substructures, which make Cu{sub 2}Se a promising high-performance thermoelectric compound with extremely low thermal conductivity and good power factor. Our work reveals that the crystal structure of Cu{sub 2}Se at the temperature below the phase-transition point (∼400 K) should have a group of candidate structures that all contain a Se-dominated face-centered-cubic-like layered framework but nearly random site occupancy of atoms from the “soft” Cu sublattice. The energy differences among those structures are very low, implying the coexistence of various structures and thus an intrinsic structure complexity with a Se-based framework. Detailed analyses indicate that observed structures should be a random stacking of those representative structure units. The transition energy barriers between each two of those structures are estimated to be zero, leading to a polymorphous phase transition of Cu{sub 2}Se at increasing temperature. Those are all consistent with experimental observations.

Effect of crystal orientation on grain boundary migration and radiation-induced segregation

International Nuclear Information System (INIS)

Hashimoto, N.; Eda, Y.; Takahashi, H.

1996-01-01

Fe-Cr-Ni, Ni-Al and Ni-Si alloys were electron-irradiated using a high voltage electron microscope (1 MeV), and in situ observations of the structural evolution and micro-chemical analysis were carried out. During the irradiation, the grain boundaries in the irradiated region migrated, while no grain boundary migration occurred in the unirradiated area. The occurrence of boundary migration depended on the orientation relationship of the boundary interfaces. Grain boundary migration took place in Fe-Cr-Ni and Ni-Si alloys with large crystal orientation difference between the two grains across a grain boundary. In Ni-Al, however, the grain boundary migration did not occur. The solute segregation was caused at grain boundary under irradiation and this segregation behavior was closely related to solute size, namely the concentrations of undersized Ni and oversized Cr elements in Fe-Cr-Ni alloy increased and reduced at grain boundary, respectively. The same dependence of segregation on the solute size was derived in Ni-Si and Ni-Al alloys, in which Si and Al solutes are undersized and oversized elements, respectively. Therefore, Si solute enriched and Al solute depleted at grain boundary. From the present segregation behavior, it is suggested that the flow of point defects into the boundary is the cause of grain boundary migration. (orig.)

Shape preferred orientation of iron grains compatible with Earth's uppermost inner core hemisphericity

Science.gov (United States)

Calvet, Marie; Margerin, Ludovic

2018-01-01

Constraining the possible patterns of iron fabrics in the Earth's Uppermost Inner Core (UIC) is key to unravel the mechanisms controlling its growth and dynamics. In the framework of crystalline micro-structures composed of ellipsoidal, aligned grains, we discuss possible textural models of UIC compatible with observations of P-wave attenuation and velocity dispersion. Using recent results from multiple scattering theory in textured heterogeneous materials, we compute the P-wave phase velocity and scattering attenuation as a function of grain volume, shape, and orientation wrt to the propagation direction of seismic P-waves. Assuming no variations of the grain volume between the Eastern and Western hemisphere, we show that two families of texture are compatible with the degree-one structure of the inner core as revealed by the positive correlation between seismic velocity and attenuation. (1) Strong flattening of grains parallel to the Inner Core Boundary in the Western hemisphere and weak anisometry in the Eastern hemisphere. (2) Strong radial elongation of grains in the Western hemisphere and again weak anisometry in the Eastern hemisphere. Both textures can quantitatively explain the seismic data in a limited range of grain volumes. Furthermore, the velocity and attenuation anisotropy locally observed under Africa demands that the grains be locally elongated in the direction of Earth's meridians. Our study demonstrates that the hemispherical seismic structure of UIC can be entirely explained by changes in the shape and orientation of grains, thereby offering an alternative to changes in grain volumes. In the future, our theoretical toolbox could be used to systematically test the compatibility of textures predicted by geodynamical models with seismic observations.

Excellent photocatalytic hydrogen production over CdS nanorods via using noble metal-free copper molybdenum sulfide (Cu{sub 2}MoS{sub 4}) nanosheets as co-catalysts

Energy Technology Data Exchange (ETDEWEB)

Hong, Sangyeob; Kumar, D. Praveen; Reddy, D. Amaranatha; Choi, Jiha; Kim, Tae Kyu, E-mail: tkkim@pusan.ac.kr

2017-02-28

Highlights: • Developed Cu{sub 2}MoS{sub 4} nanosheets as co-catalysts. • Cu{sub 2}MoS{sub 4} as active replacements for precious noble metal. • Controlled charge recombination for use in photocatalytic H{sub 2} evolution. • Obtained superior rate of H{sub 2} production by using Cu{sub 2}MoS{sub 4} loaded CdS nanorods. - Abstract: Charge carrier recombination and durability issues are major problems in photocatalytic hydrogen (H{sub 2}) evolution processes. Thus, there is a very important necessitate to extend an efficient photocatalyst to control charge-carrier dynamics in the photocatalytic system. We have developed copper molybdenum sulfide (Cu{sub 2}MoS{sub 4}) nanosheets as co-catalysts with CdS nanorods for controlling charge carriers without recombination for use in photocatalytic H{sub 2} evolution under simulated solar light irradiation. Effective control and utilization of charge carriers are possible by loading Cu{sub 2}MoS{sub 4} nanosheets onto the CdS nanorods. The loading compensates for the restrictions of CdS, and stimulated synergistic effects, such as efficient photoexcited charge separation, lead to an improvement in photostability because of the layered structure of the Cu{sub 2}MoS{sub 4}nanosheets. These layered Cu{sub 2}MoS{sub 4} nanosheets have emerged as novel and active replacements for precious noble metal co-catalysts in photocatalytic H{sub 2} production by water splitting. We have obtained superior H{sub 2} production rates by using Cu{sub 2}MoS{sub 4} loaded CdS nanorods. The physicochemical properties of the composites are analyzed by diverse characterization techniques.

Study of magnetic fluctuations in superconducting cuprates with high critical temperature; Etude des fluctuations magnetiques dans les cuprates supraconducteurs a haute temperature critique

Energy Technology Data Exchange (ETDEWEB)

Sidis, Y

1995-11-27

Elastic and inelastic neutron scattering has been used to study the magnetic properties of YBa{sub 2} Cu{sub 3} O{sub 6+x} (YBCO) and of La{sub 2} CuO{sub 4} (LSCO), non-doped and doped with Zn or various amounts of oxygen. The influence of the variation of the composition on magnetic and superconducting properties has been measured. (C.B.) 182 refs.

Synthesis and characterisation of Cu{sub 2}ZnSnSe{sub 4} thin films prepared via a vacuum evaporation-based route

Energy Technology Data Exchange (ETDEWEB)

Volobujeva, O., E-mail: v.olga@staff.ttu.ee; Bereznev, S.; Raudoja, J.; Otto, K.; Pilvet, M.; Mellikov, E.

2013-05-01

Different sequentially stacked binary chalcogenide layers (CuSe, ZnSe, and SnSe) deposited by vacuum evaporation onto molybdenum covered soda-lime glass substrates were used as precursors to form Cu{sub 2}ZnSnSe{sub 4} films. The influence of the stacked binary layer sequence, substrate temperature, both the duration and speed of deposition and the post deposition treatment atmosphere on the structural and the morphological parameters of the Cu{sub 2}ZnSnSe{sub 4} thin films was studied. Our results indicate the possibility of replacing the Se{sub 2} selenisation with a thermal treatment in an SnSe{sub 2} atmosphere to avoid the selenisation of the Mo substrate and MoSe{sub 2} formation. This SnSe{sub 2} treatment forms p-type Cu{sub 2}ZnSnSe{sub 4} films with an optical band-gap of 1.14 eV and a solar cell structure with an efficiency of up to 3%. - Highlights: ► Cu{sub 2}ZnSnSe{sub 4} thin films were grown using binary precursors and selenisation. ► Composition and morphology were studied in dependence of selenisation atmosphere. ► The use of SnSe{sub 2} selenisation allows to avoid Mo substrate selenisation. ► The high quality of films is indicated by the value of their E{sub g} = 1.14 eV. ► Cu{sub 2}ZnSnSe{sub 4} thin films were in p-type conductivity and were realized as solar cells.

Ultra-large current transport in thick SmBa{sub 2}Cu{sub 3}O{sub 7−x} films grown by reactive co-evaporation

Energy Technology Data Exchange (ETDEWEB)

Kim, G.; Jin, H.J. [Department of Physics, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Jo, W., E-mail: wmjo@ewha.ac.kr [Department of Physics, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Nam, D.H.; Cheong, H. [Department of Physics, Sogang University, Seoul 121-742 (Korea, Republic of); Kim, H.S.; Oh, S.S.; Ko, R.K.; Jo, Y.S.; Ha, D.W. [The Korea Electrotechnology Research Institute (KERI), Changwon 641-120 (Korea, Republic of)

2015-06-15

Highlights: • Transport properties of 5 μm thick SmBa{sub 2}Cu{sub 3}O{sub 7−x} thin films were investigated. • Laser scanning microscopy was used to demonstrate local transport properties. • Temperature variable laser scanning microscopy shows correlation between structural and transport properties. • Optical measurements described nature of current transport properties in the coated conductors. - Abstract: Structural and transport properties of high performance SmBa{sub 2}Cu{sub 3}O{sub 7−x} coated conductors produced by a dual-chamber co-evaporation are presented. The 5 μm-thick SmBCO coated conductors grown on IBAD-MgO based Hastelloy metal templates show critical currents larger than 1020–1560 A/cm at 77 K and self-field. The current transport characteristics of the conductors are investigated by room-temperature thermoelectric microscopy and low-temperature bolometric microscopy. The local thermoelectric images show the tilted grains, grain boundaries, and microstructural defects on the surface of the coated conductors. The bias current-dependent bolometric response at low temperature displays the current of the local flux flow dissipation as an increasing bias. Furthermore, we measured micro-Raman scattering microscopic imaging on oxygen-related peaks of the conductors. Comparing the Raman signal images with the low temperature optical scanning maps, it is remarkable that the structural disorders represented by oxygen-related Raman peaks are closely related to the low temperature bolometric abnormalities. From this result, a nature of the dissipative current distribution in coated conductors is revealed. The scanning optical microscopic study will provide a promising method for quality assurance of coated conductors.

78 FR 70574 - Grain-Oriented Electrical Steel From China, Czech Republic, Germany, Japan, Korea, Poland, and...

Science.gov (United States)

2013-11-26

...)] Grain-Oriented Electrical Steel From China, Czech Republic, Germany, Japan, Korea, Poland, and Russia..., Germany, Japan, Korea, Poland, and Russia of grain-oriented electrical steel, provided for in subheadings... alleged to be sold in the United States at less than fair value (LTFV), and by reason of imports of grain...

The n-type conduction of indium-doped Cu{sub 2}O thin films fabricated by direct current magnetron co-sputtering

Energy Technology Data Exchange (ETDEWEB)

Cai, Xing-Min; Su, Xiao-Qiang; Ye, Fan, E-mail: yefan@szu.edu.cn; Wang, Huan; Tian, Xiao-Qing; Zhang, Dong-Ping; Fan, Ping; Luo, Jing-Ting; Zheng, Zhuang-Hao; Liang, Guang-Xing [Institute of Thin Film Physics and Applications, School of Physical Science and Technology and Shenzhen Key Laboratory of Sensor Technology, Shenzhen University, Shenzhen 518060 (China); Roy, V. A. L. [Center of Super-Diamond and Advanced Films (COSDAF) and Department of Physics and Materials Science, City University of Hong Kong, Kowloon Tong, Hong Kong (China)

2015-08-24

Indium-doped Cu{sub 2}O thin films were fabricated on K9 glass substrates by direct current magnetron co-sputtering in an atmosphere of Ar and O{sub 2}. Metallic copper and indium disks were used as the targets. X-ray diffraction showed that the diffraction peaks could only be indexed to simple cubic Cu{sub 2}O, with no other phases detected. Indium atoms exist as In{sup 3+} in Cu{sub 2}O. Ultraviolet-visible spectroscopy showed that the transmittance of the samples was relatively high and that indium doping increased the optical band gaps. The Hall effect measurement showed that the samples were n-type semiconductors at room temperature. The Seebeck effect test showed that the films were n-type semiconductors near or over room temperature (<400 K), changing to p-type at relatively high temperatures. The conduction by the samples in the temperature range of the n-type was due to thermal band conduction and the donor energy level was estimated to be 620.2–713.8 meV below the conduction band. The theoretical calculation showed that indium doping can raise the Fermi energy level of Cu{sub 2}O and, therefore, lead to n-type conduction.

A model for the ethylene and acetylene adsorption on the surface of Cu{sub n}(n = 10–15) nanoclusters: A theoretical study

Energy Technology Data Exchange (ETDEWEB)

Farmanzadeh, Davood, E-mail: d.farmanzad@umz.ac.ir; Abdollahi, Tahereh

2016-11-01

Highlights: • The most stable structures of Cu{sub n} (n = 10–15) were structures with C{sub S} symmetry. • It is expected that even clusters are better electron donors than the odd clusters. • Acetylene and ethylene adsorb molecularly on the Cu nanoclusters surface. • Acetylene never orient toward di-σ mode for Cu−Cu bond in odd copper nanoclusters. • For di- σ-Cu{sub n}C{sub 2}H{sub 4}, no stable structure is identified. - Abstract: In this work, we report the results of density functional theory calculations of ethylene and acetylene adsorption on the most stable Cu{sub n} (n = 10–15) nanoclusters, in two π and di- σ adsorption modes. Both the hydrocarbons molecularly adsorbed on the surface. Our results show that the quality of interaction of ethylene and acetylene with odd copper nanoclusters (n = 11, 13, 15) is different from what is found on even copper nanoclusters (n = 10, 12, 14). One of the interesting features of this adsorption is that acetylene never orient toward di-σ mode for Cu−Cu bond in odd copper nanoclusters. Also, for di- σ-Cu{sub n}C{sub 2}H{sub 4}, no stable structure is identified. The highest interaction and deformation energies are seen for the adsorption of acetylene and ethylene on Cu{sub 11} in π-mode.

Magneto-optical measurements on high-temperature superconductors influenced by AC-fields; Magnetooptische Untersuchungen an Hochtemperatursupraleitern unter Einfluss von Frequenzfeldern

Energy Technology Data Exchange (ETDEWEB)

Che' Rose, Simon

2007-01-15

In this work magneto-optical measurements on YBa{sub 2}Cu{sub 3}O{sub 7-x} and MgB{sub 2} thin films were done. For YBCO the influence of AC-pulses on the flux and current density of a thin film with transport current was investigated. For MgB{sub 2} the influence of AC-fields on the homogenous and dendritic flux penetration was researched. (orig.)

The high temperature superconductor YBa>2Cu₃O_7-δ: symmetry of the order parameter, and gradiometers for biomagnetic applications

Energy Technology Data Exchange (ETDEWEB)

Kouznetsov, Konstantin Alexander [Univ. of California, Berkeley, CA (US). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

1999-12-01

The cuprate YBa>2Cu₃O_7-δ is the material that drives the majority of the technological applications of high transition temperature (T_c) superconductors, particularly in the area of superconducting electronics. Despite the widespread use of high-T_c superconducting materials in a variety of applications, the nature of the superconducting state in these materials remains unknown since their discovery more than a decade ago. Many properties of the high-T_c superconductors are determined by their order parameter, which is a wavefunction describing the superconducting condensate. The symmetry of the order parameter in cuprates has been the subject of intensive investigation, leading to conflicting sets of results. Some experiments supported conventional, s-wave symmetry of the order parameter, while others indicated an unconventional, d-wave symmetry. The first part of this thesis is an experimental study of the symmetry of the order parameter in YBa>2Cu₃O_7-δ. A new class of phase sensitive experiments is described that involve Josephson tunneling along the c-axis of twinned crystals of YBa>2Cu₃O_7-δ. These experiments showed that an s-wave component must reverse sign across the twin boundary, providing direct evidence for a mixed, s+d symmetry of the order parameter in YBa>2Cu₃O_7-δ, and thereby reconciling two conflicting sets of previous findings and establishing the dominant d-wave pairing symmetry. The second part of the thesis focuses on practical applications of YBa>2Cu₃O_7-δ in superconducting electronics. The authors introduce a novel Superconducting Quantum Interference Device (SQUID) gradiometer. The principle of operation of these long baseline high-T{sub c} SQUID gradiometers is based on the inductive coupling of the input coil of a planar flux transformer to the

Interfacial effects of the Cu{sub 2}O nano-dots decorated Co{sub 3}O{sub 4} nanorods array and its photocatalytic activity for cleaving organic molecules

Energy Technology Data Exchange (ETDEWEB)

Qiu, X.P. [Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Yu, J.S. [Department of Chemistry and Chemical Engineering, University of New Haven, 300 Boston Post Road, West Haven, CT 06516 (United States); Xu, H.M.; Chen, W.X.; Hu, W. [Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Chen, G.L., E-mail: glchen@zstu.edu.cn [Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018 (China)

2016-09-30

Highlights: • Co{sub 3}O{sub 4} rods were grown on plasma treated Ti foil. • Cu{sub 2}O QDs were uniformly distributed on the surface of nanorods. • Ti/Co{sub 3}O{sub 4}/Cu{sub 2}O exhibited visible light photocatalytic activity with KHSO{sub 5}. • Degradation mechanism was supported by ESR technique and radical scavenger tests. • The heterojunction was highly stable even after recycling many times. - Abstract: A heterogeneous nanocomposite catalyst constructed by the Co{sub 3}O{sub 4} nanorods decorated with the Cu{sub 2}O quantum dots (QDs) were successfully synthesized via a simple hydrothermal method followed by an oxidation-reduction processing. The fabricated Cu{sub 2}O/Co{sub 3}O{sub 4} nanocomposite was characterized by the SEM, TEM, XPS, XRD, UV–vis and PL, and the (2 2 0) and (3 1 1) facets of the Co{sub 3}O{sub 4} were exposed. Compared with the original Co{sub 3}O{sub 4} nanorods with an average diameter of 350 nm, a substantial decrease in the band gap was observed after doping the nanorods with the Cu{sub 2}O QDs (average diameter of 5 nm). Such a dramatic decrease in the band gap indicated a significant enhancement of the photocatalytic activities under visible light. The methylene blue (MB) dye and the phenol were used as model organic pollutants, and the Cu{sub 2}O/Co{sub 3}O{sub 4} nanocomposite catalyst exhibited both high catalytic activity and good recycling stability. The catalytic activities of the Cu{sub 2}O/Co{sub 3}O{sub 4}/potassium monopersulfate triple salt (PMS) system for cleaving the MB and the phenol were dependent on the dosages of the Cu{sub 2}O QDs, and the calculated degradation rates achieved by 7.0 wt% Cu{sub 2}O/Co{sub 3}O{sub 4} nanocomposite catalyst were about 11.3 and 1.8 times than that of the pristine Co{sub 3}O{sub 4} nanorod catalyst for the MB and the phenol, respectively. The reactive species of ·O{sub 2}{sup −} and the holes were determined to be the main active species for the phenol photocatalytic

Superhydrophobic Cu{sub 2}S@Cu{sub 2}O film on copper surface fabricated by a facile chemical bath deposition method and its application in oil-water separation

Energy Technology Data Exchange (ETDEWEB)

Pi, Pihui, E-mail: phpi@scut.edu.cn; Hou, Kun; Zhou, Cailong; Li, Guidong; Wen, Xiufang; Xu, Shouping; Cheng, Jiang; Wang, Shuangfeng

2017-02-28

Highlights: • A superhydrophobic film with macro/nano structure was fabricated on copper surface. • The as-prepared film shows outstanding water repellency and long-term storage stability. • The same method was used to fabricate superhydrophobic/superoleophilic copper mesh. • The obtained mesh could realize separation of various oily sewages with separation efficiency above 94%. - Abstract: Cu{sub 2}S and Cu{sub 2}O composite (Cu{sub 2}S@Cu{sub 2}O) film with micro/nano binary structure was created on copper surface using the mixing solution of sodium thiosulphate and copper sulfate by a facile chemical bath deposition method. After modification with low-cost polydimethylsioxane (PDMS), the superhydrophobic Cu{sub 2}S@Cu{sub 2}O film was obtained. The as-prepared film shows outstanding water repellency with a water contact angle larger than 150° and long-term storage stability. The geometric morphology and chemical composition of the film were characterized by scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), respectively. Moreover, the same method was used to fabricate superhydrophobic/superoleophilic copper mesh, and it could realize separation of various oily sewages with separation efficiency above 94%. This strategy has potential to fabricate the practical superhydrophobic Cu{sub 2}S@Cu{sub 2}O film on copper surface on a large scale due to its simplicity and low cost.

STM and x-ray diffraction temperature-dependent growth study of SrRuO{sub 3} PLD thin films

Energy Technology Data Exchange (ETDEWEB)

Hawley, M.E.; Jia, Q.X.; Brown, G.W.

1996-12-31

SrRuO{sub 3} (SRO) has recently found a number of applications in different fields, e.g. as a buffer layer for the growth of high temperature superconductor (HTS) YBa{sub 2}Cu{sub 3}O{sub 7-x} films and as a bottom electrode for ferroelectric or high dielectric constant thin film capacitors and nonvolatile data storage. The growth of high crystallinity SRO films with good structural and electrical properties is the prerequisite for each of these applications. In this paper we describe the affect of one growth parameters temperature (T), on the crystalline quality, epitaxial substrate relationship and resulting electrical properties. SRO films were deposited on LaAlO{sub 3} single crystal substrates by pulsed laser deposition at substrate temperatures (T{sub s}) ranging from room temperature (RT) up to 800{degrees}C with a nominal film thickness of 150 nm range. The resulting films were characterized by x-ray diffraction, 4-point transport, and STM. The films` microstructures, as revealed by STM, evolved from polygranular at RT to a layered plate-like structure at higher deposition temperatures, T{sub s}, Increasing T{sub s} was marked first by increasing grain size, then a stronger orientational relationship between film and substrate, finally followed by the development of increased connectivity between grains to an extended island or condensed layered state. The transition from polygranular to layered structure occurred at T{sub s} > 650{degrees}C. Increased conductivity paralleled the changes in microstructure. The surfaces of all of the films were relatively smooth; the oriented films are suitable for use as conductive templates in multilayer structures.

Effect of grain orientation and heat treatment on mechanical properties of pure W

Energy Technology Data Exchange (ETDEWEB)

Noto, Hiroyuki, E-mail: noto_hiroyuki@iae.kyoto-u.ac.jp [Graduate School of Energy Science, Kyoto University, Kyoto 611-0011 (Japan); Research Fellow of Japan Society for the Promotion of Science (Japan); Taniguchi, Shuichi [Graduate School of Energy Science, Kyoto University, Kyoto 611-0011 (Japan); Kurishita, Hiroaki; Matsuo, Satoru [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Ukita, Takashi; Tokunaga, Kazutoshi [Institute for Applied Mechanics, Kyushu University, Kasuga, Fukuoka 816-8580 (Japan); Kimura, Akihiko [Institute of Advanced Energy, Kyoto University, Kyoto 611-0011 (Japan)

2014-12-15

The effect of grain orientation, heat-treatment temperature and test temperature on the mechanical properties of tungsten (W), which vary depending on plastic working and fabrication process, was investigated by mechanical testing of tensile or bending. Heavily worked W samples (1.5–2.0 mm in the final thickness) exhibit degradation of fracture strength due to recrystallization embrittlement after heat-treatment at 1240 °C (temperature of diffusion bonding between W and a candidate material of the Fe base support structure). On the other hand, W samples with lower thickness reduction rates do not suffer degradation of fracture strength after heating up to around 1300 °C, and show somewhat higher fracture strength by heat-treatment below 1300 °C than the samples in the as-received state. The observed behavior is a reflection of recovery of dislocations introduced by plastic working. High temperature tensile testing of ITER grade W with an anisotropic grain structure and S-TUN with an equiaxed grain structure revealed that both W grades exhibit plastic elongation at temperatures higher than 200 °C with essentially the same temperature dependence of yield strength, which is relatively insensitive to grain orientation in the structure at 200–1300 °C.

Effect of grain orientation and heat treatment on mechanical properties of pure W

International Nuclear Information System (INIS)

Noto, Hiroyuki; Taniguchi, Shuichi; Kurishita, Hiroaki; Matsuo, Satoru; Ukita, Takashi; Tokunaga, Kazutoshi; Kimura, Akihiko

2014-01-01

The effect of grain orientation, heat-treatment temperature and test temperature on the mechanical properties of tungsten (W), which vary depending on plastic working and fabrication process, was investigated by mechanical testing of tensile or bending. Heavily worked W samples (1.5–2.0 mm in the final thickness) exhibit degradation of fracture strength due to recrystallization embrittlement after heat-treatment at 1240 °C (temperature of diffusion bonding between W and a candidate material of the Fe base support structure). On the other hand, W samples with lower thickness reduction rates do not suffer degradation of fracture strength after heating up to around 1300 °C, and show somewhat higher fracture strength by heat-treatment below 1300 °C than the samples in the as-received state. The observed behavior is a reflection of recovery of dislocations introduced by plastic working. High temperature tensile testing of ITER grade W with an anisotropic grain structure and S-TUN with an equiaxed grain structure revealed that both W grades exhibit plastic elongation at temperatures higher than 200 °C with essentially the same temperature dependence of yield strength, which is relatively insensitive to grain orientation in the structure at 200–1300 °C

Structural and optical properties of Cu{sub 2}ZnSnS{sub 4} thin film absorbers from ZnS and Cu{sub 3}SnS{sub 4} nanoparticle precursors

Energy Technology Data Exchange (ETDEWEB)

Lin, Xianzhong, E-mail: lin.xianzhong@helmholtz-berlin.de [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Kavalakkatt, Jaison [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Freie Universität Berlin, Berlin (Germany); Kornhuber, Kai; Levcenko, Sergiu [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Lux-Steiner, Martha Ch. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Freie Universität Berlin, Berlin (Germany); Ennaoui, Ahmed, E-mail: ennaoui@helmholtz-berlin.de [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany)

2013-05-01

Cu{sub 2}ZnSnS{sub 4} (CZTS) has been considered as an alternative absorber layer to Cu(In,Ga)Se{sub 2} due to its earth abundant and environmentally friendly constituents, optimal direct band gap of 1.4–1.6 eV and high absorption coefficient in the visible range. In this work, we propose a solution-based chemical route for the preparation of CZTS thin film absorbers by spin coating of the precursor inks composed of Cu{sub 3}SnS{sub 4} and ZnS NPs and annealing in Ar/H{sub 2}S atmosphere. X-ray diffraction and Raman spectroscopy were used to characterize the structural properties. The chemical composition was determined by energy dispersive X-ray spectroscopy. Optical properties of the CZTS thin film absorbers were studied by transmission, reflection and photoluminescence spectroscopy.

Ceramic superconductors II

International Nuclear Information System (INIS)

Yan, M.F.

1988-01-01

This volume compiles papers on ceramic superconductors. Topics include: structural patterns in High-Tc superconductors, phase equilibria of barium oxide superconductors, localized electrons in tetragonal YBa/sub 2/Cu/sub 3/O/sub 7-δ/, lattice and defect structure and properties of rare earth/alkaline earth-copper-oxide superconductors, alternate candidates for High-Tc superconductors, perovskite-structure superconductors; superconductive thin film fabrication, and superconductor/polymer composites

Quality of YBCO thin films grown on LAO substrates exposed to the film deposition - film removal processes

Energy Technology Data Exchange (ETDEWEB)

Blagoev, B; Nurgaliev, T [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia (Bulgaria); Mozhaev, P B [Institute of Physics and Technology, Russian Academy of Sciences, 117218 Moscow (Russian Federation); Sardela, M; Donchev, T [Materials Research Laboratory, University of Illinois, 104 South Goodwin Ave., Urbana, IL 61801 (United States)], E-mail: blago_sb@yahoo.com

2008-05-01

The characteristics are investigated of high temperature superconducting YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) films grown on LaAlO{sub 3} (LAO) substrates being exposed a different number of times to YBCO film deposition and acid-solution-based cleaning procedures. Possible mechanisms of degradation of the substrate surface quality reflecting on the growing YBCO film parameters are discussed and analyzed.

Cu{sub 2}ZnSnS{sub 4} thin films grown by flash evaporation and subsequent annealing in Ar atmosphere

Energy Technology Data Exchange (ETDEWEB)

Caballero, R., E-mail: raquel.caballero@uam.es [Universidad Autónoma de Madrid, Departamento de Física Aplicada, M12, C/Francisco Tomás y Valiente 7, E-28049 Madrid (Spain); Izquierdo-Roca, V. [IREC, Catalonia Institute for Energy Research, C. Jardins de les Dones de Negre 1, Sant Adriá del Besòs, E-08930 Barcelona (Spain); Merino, J.M.; Friedrich, E.J. [Universidad Autónoma de Madrid, Departamento de Física Aplicada, M12, C/Francisco Tomás y Valiente 7, E-28049 Madrid (Spain); Climent-Font, A. [Universidad Autónoma de Madrid, Departamento de Física Aplicada, M12, C/Francisco Tomás y Valiente 7, E-28049 Madrid (Spain); CMAM, Universidad Autónoma de Madrid, C/Faraday 3, E-28049, Madrid (Spain); Saucedo, E. [IREC, Catalonia Institute for Energy Research, C. Jardins de les Dones de Negre 1, Sant Adriá del Besòs, E-08930 Barcelona (Spain); Pérez-Rodríguez, A. [IREC, Catalonia Institute for Energy Research, C. Jardins de les Dones de Negre 1, Sant Adriá del Besòs, E-08930 Barcelona (Spain); IN" 2UB, Departament d' Electrònica, Universitat de Barcelona, C. Martí i Franquès 1, E-08028 Barcelona (Spain); León, M. [Universidad Autónoma de Madrid, Departamento de Física Aplicada, M12, C/Francisco Tomás y Valiente 7, E-28049 Madrid (Spain)

2013-05-01

A study of Cu{sub 2}ZnSnS{sub 4} thin films grown by flash evaporation and subsequently annealed in Ar atmosphere has been carried out. Prior to thin film deposition, Cu{sub 2}ZnSnS{sub 4} bulk compounds with stoichiometric and Zn-rich compositions were synthesized as evaporation sources. The characteristics of the bulk compounds and thin films were investigated by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and elastic back scattering. Cu{sub 2}ZnSnS{sub 4} deposited films contain lower concentrations of Zn than the bulk compounds used as evaporation sources, which is related to a preferential Zn re-evaporation during the deposition process. The desired kesterite composition for solar cell applications was achieved by using a Zn-rich compound as the evaporation source plus a thermal treatment at 620 °C in Ar atmosphere. - Highlights: ► Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films by flash evaporation + annealing in Ar atmosphere ► Difficulty of growing a single phase kesterite material ► X-ray diffraction and Raman spectroscopy to identify the different phases ► Importance of the starting film composition to get the desired CZTS material ► Annealing treatment to obtain the optimum material to be used for CZTS solar cells.

Optical analysis of lens-like Cu{sub 2}CdSnS{sub 4} quaternary alloy nanostructures

Energy Technology Data Exchange (ETDEWEB)

Odeh, Ali Abu; Ayub, R.M. [University Malaysia Perlis, Institute of Nano Electronic Engineering, Kangar, Perlis (Malaysia); Al-Douri, Y. [University Malaysia Perlis, Institute of Nano Electronic Engineering, Kangar, Perlis (Malaysia); University of Sidi-Bel-Abbes, Physics Department, Faculty of Science, Sidi-Bel-Abbes (Algeria); Ameri, M. [Universite Djilali Liabes de Sidi Bel- Abbes, Laboratoire Physico-Chimie des Materiaux Avances (LPCMA), Sidi-Bel-Abbes (Algeria); Bouhemadou, A. [University of Setif 1, Laboratory for Developing New Materials and Their Characterization, Setif (Algeria); Prakash, Deo [SMVD University, Faculty of Engineering, School of Computer Science and Engineering, Kakryal, Katra, J and K (India); Verma, K.D. [S.V. College, Material Science Research Laboratory, Department of Physics, Aligarh, U.P. (India)

2016-10-15

Cu{sub 2}CdSnS{sub 4} quaternary alloy nanostructures with different copper concentrations (0.2, 0.4, 0.6, 0.8 and 1.0 M) were successfully synthesized on n-type silicon substrates using spin coating technique with annealing temperature at 300 C. Optical properties were analyzed through UV-Vis and Photoluminescence spectroscopies, and thus, there is a change in energy band gap with increasing Cu concentration from 0.2 to 1.0 M. The structural properties of Cu{sub 2}CdSnS{sub 4} quaternary alloy nanostructures were investigated by X-ray diffraction. The particles size and shape have a direct relationship with copper concentration. Morphological and topographical studies were carried out by using scanning electron microscopy and atomic force microscopy. The obtained results are investigated to be available in the literature for future studies. (orig.)

Evolution of surface topography in dependence on the grain orientation during surface thermal fatigue of polycrystalline copper

CERN Document Server

Aicheler, M; Taborelli, M; Calatroni, S; Neupert, H; Wuensch, W; Sgobba, S

2011-01-01

Surface degradation due to cyclic thermal loading plays a major role in the Accelerating Structures (AS) of the future Compact Linear Collider (CLIC) In this article results on surface degradation of thermally cycled polycrystalline copper as a function of the orientation of surface grains are presented Samples with different grain sizes were subjected to thermal fatigue using two different methods and were then characterized using roughness measurements and Orientation Imaging Scanning-Electron-Microscopy (OIM-SEM) Samples fatigued by a pulsed laser show the same trend in the orientation-fatigue damage accumulation as the sample fatigued by pulsed Radio-Frequency-heating (RF) it is clearly shown that 11 1 1] surface grains develop significantly more damage than the surface grains oriented in {[}100] and three reasons for this behaviour are pointed out Based on observations performed near grain boundaries their role in the crack initiation process is discussed The results are in good agreement with previous f...

Crystal structure and magnetic properties of Y{sub 2}(Cu{sub 1−x}Mg{sub x}){sub 2}O{sub 5} obtained by SHS method

Energy Technology Data Exchange (ETDEWEB)

Gebrel, Z., E-mail: z_gebrel@yahoo.com; Blanusa, J.; Kusigerski, V.; Spasojevic, V.; Mrakovic, A.; Perovic, M.; Alqat, A.

2014-01-05

Highlights: • Y{sub 2}(Cu{sub 1−x}Mg{sub x}){sub 2}O{sub 5} solid solutions were synthesized for the first time by SHS method. • Ferromagnetic interactions are weakened by the induced structure changes. • Metamagnetism of the Y{sub 2}Cu{sub 2}O{sub 5} is preserved up to 15% of Mg concentration. • Significant influence of finite-size Cu–O chains is observed at low temperatures. -- Abstract: The single-phase polycrystalline samples of Y{sub 2}(Cu{sub 1−x}Mg{sub x}){sub 2}O{sub 5}, x = 0.0, 0.05, 0.15 were successfully synthesized by a modified self-propagating high temperature synthesis. Effects of Mg{sup +2} substitution for Cu{sup +2} in metamagnetic Y{sub 2}Cu{sub 2}O{sub 5} on its crystal structure and magnetic properties have been analyzed by X-ray diffraction and magnetic measurements performed within 2–300 K range. Mg doping was found to introduce small distortions in the main intradimmer superexchange paths so that ferromagnetic correlations decrease with Mg concentration. More significant impact of Cu substitution was found on the low temperature magnetism due to the breaking of infinite Cu–O chains. The formation of finite size chains introduces low temperature paramagnetic contribution and reduction in Néel temperature. Overall results give a strong indication that the antiferromagnetic ordering as well as metamagnetism persists up to the 15% of the Mg concentration.

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.

Growth and analysis of highly oriented (11n) BCSCO films for device research

Energy Technology Data Exchange (ETDEWEB)

Raina, K.K.; Pandey, R.K. [Texas A& M Univ., College Station, TX (United States)

1994-12-31

Films of BCSCO superconductor of the type Bi{sub 2}CaSr{sub 2}Cu{sub 2}O{sub x} have been grown by liquid phase epitaxy method (LPE), using a partially closed growth chamber. The films were grown on (001) and (110) NdGaO{sub 3} substrates by slow cooling process in an optimized temperature range below the peritectic melting point (880{degrees}C) of Bi{sub 2}CaSr{sub 2}Cu{sub 2}O{sub 8}. Optimization of parameters, such as seed rotation, soak of initial growth temperature and growth period results in the formation of 2122 phase BCSCO films. The films grown at rotation rates of less than 30 and more than 70 rpm are observed to be associated with the second phase of Sr-Ca-Cu-O system. Higher growth temperatures (>860{degrees}C) also encourage to the formation of this phase. XRD measurements show that the films grown on (110) NdGaO{sub 3} have a preferred (11n)-orientation. It is pertinent to mention here that in our earlier results published elsewhere we obtained c-axis oriented Bi{sub 2}CaSr{sub 2}Cu{sub 2}O{sub 8} phase films on (001) NdGaO{sub 3} substrate. Critical current density is found to be higher for the films grown on (110) than (001) NdGaO{sub 3} substrate orientation. The best values of zero resistance (T{sub co}) and critical current density obtained are 87 K and 10{sup 5} A/cm{sup 2}, respectively.

Place oriented ecological footprint analysis. The case of Israel's grain supply

International Nuclear Information System (INIS)

Kissinger, Meidad; Gottlieb, Dan

2010-01-01

In today's world, any nation's ecological footprint is spread all over the globe. Still, most footprint studies are not yet sensitive to the specific locations on which the footprint falls and to the unique production characteristics of each supporting region. In recent years some studies have acknowledged the need to quantify the 'real land' footprints and particularly the share of the footprint embodied in trade. Our goal is to analyse the ecological footprint of grain-based consumption in the state of Israel during the last two decades. We present a detailed, place oriented calculation procedure of Israel's grain footprint on specific locations around the world. We document modes of production, major energy inputs in specific sources of supply, the energy required for shipping from each source, and the CO 2 emissions from those operations. Our research reveals that most of Israel's grain footprint falls on North America followed by the Black Sea region. It also shows that while the overall consumption of grain products has increased throughout the research period, the size of the footprint has been dropping in recent years as a consequence of changing sources of supply and grain composition. Finally, we discuss some of the implications of the method presented here for future footprint calculations and environmental resource management. (author)

Thermodynamic properties of CuCr2S4 solid solutions in Cusub(1/2)Msub(1/2)Crsub(2)Ssub(4) (M - Ga, In)

International Nuclear Information System (INIS)

Titov, V.V.; Kesler, Ya.A.; Shelkotunov, V.A.; Gordeev, I.V.; Tret'yakov, Yu.D.

1985-01-01

By means of an adiabatic calorimeter and quartz dilatometer for CuCr 2 S 4 in Cusub(1/2)Msub(1/2)Crsub(2)Ssub(4) (M-Ga, In) temperature dependences of heat capacity are determined. The contribution of various components into heat capacity is estimated, thermodynamic parameters of magnetic transformation are calculated

Study of secondary recrystallization in grain-oriented steel treated under dynamical heat treatment conditions

Directory of Open Access Journals (Sweden)

V. Stoyka

2009-04-01

Full Text Available The present study was made to investigate secondary recrystallization in grain-oriented steels annealed at short time temperature exposures with application of dynamical heating. The investigated GO steels for experiments were taken from one industrial line after final cold rolling reduction and subsequent box annealing. It was shown that application of short time heat treatment conditions could lead to complete abnormal grain growth in the investigated GO steel. The texture and microstructure obtained in the laboratory treated material is similar to that observed in the same GO steel taken after industrial final box-annealing. However, some “parasitic” grains were observed in the secondary recrystallized matrix of the laboratory treated GO steel. These “parasitic” grains possess the unwanted from magnetic properties point of view {111} orientation components.

Cu{sub x}Y compounds as thin films: crystallographic and compositional analyses of yttrium rich phases

Energy Technology Data Exchange (ETDEWEB)

Engels, J.M.; Blaise, G. [Paris-11 Univ., 91 - Orsay (France). Lab. de Physique des Solides; Gasgnier, M. [Laboratoire des Ractions Slectives sur Support, Bt. 410, Universit Paris-Sud, 91405, Orsay CEDEX (France)

1998-03-06

The interdiffusion of Y films deposited onto Cu substrate by flash evaporation and sputtering was studied (concentration profiles, X-ray and electron diffraction patterns) in the temperature range 373-553 K. In samples deposited by flash evaporation the first phase to be detected is CuY at 393 K. At higher temperatures an intermediate phase, close to the Cu{sub 3}Y{sub 2} compound, is formed before the Cu{sub 2}Y stoichiometric phase is produced at 513 K. Crystallographic data confirm the formation of this intermediate Cu{sub 3}Y{sub 2} phase (orthorhombic unit-cell) as resulting from the reaction CuY+Cu{sub 2}Y{yields}Cu{sub 3}Y{sub 2}. The results are identical for sputtered Y films deposited under a cryogenic vacuum (2-5 x 10{sup -7} Pa). When Y is deposited under a standard vacuum (2-5 x 10{sup -6} Pa), the influence of a diffusion barrier at the Cu-Y interface is noticed. This influence is characterized in the concentration profiles by an Y concentration hump at the Cu-Y interface and a depletion of Y at the front of the profile. Three main phases are observed. They correspond to the Cu{sub 5}Y{sub 2}, Cu{sub 2}Y and Cu{sub 3}Y{sub 2} compounds. (orig.) 24 refs.

Effect of particle size and particle size distribution on physical characteristics, morphology and crystal strucutre of explosively compacted high-Tc superconductors

Energy Technology Data Exchange (ETDEWEB)

Kotsis, I.; Enisz, M.; Oravetz, D. [Univ. of Veszprem (Hungary)] [and others

1994-12-31

A superconductor, of composition Y(Ba,K,Na){sub 2}Cu{sub 3}O{sub x}/F{sub y} and a composite, of composition Y(Ba,K,Na){sub 2}Cu{sub 3}O{sub x}/F{sub y}+Ag, with changing K, Na and F content, but a constant silver content (Ag=10 mass per cent) was prepared using a single heat treatment. The resulting material was ground in a corundum lined mill, separated to particle size fractions of 0-40 {mu}m, 0-63 {mu}m and 63-900 {mu}m and explosively compacted, using an explosive pressure of 10{sup 4} MPa and a subsequent heat treatment. Best results were obtained with the 63-900 {mu}m fraction of composition Y(Ba{sub 1,95}K{sub 0,01})Cu{sub 3}O{sub x}F{sub 0,05}/Ag: porosity <0.01 cm{sup 3}/g and current density 2800 A/cm{sup 2} at 77 K.

Creep in electronic ceramics

Energy Technology Data Exchange (ETDEWEB)

Routbort, J. L.; Goretta, K. C.; Arellano-Lopez, A. R.

2000-04-27

High-temperature creep measurements combined with microstructural investigations can be used to elucidate deformation mechanisms that can be related to the diffusion kinetics and defect chemistry of the minority species. This paper will review the theoretical basis for this correlation and illustrate it with examples from some important electronic ceramics having a perovskite structure. Recent results on BaTiO{sub 3}, (La{sub 1{minus}x}Sr){sub 1{minus}y}MnO{sub 3+{delta}}, YBa{sub 2}Cu{sub 3}O{sub x}, Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub x}, (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} and Sr(Fe,Co){sub 1.5}O{sub x} will be presented.

Reactive nanophase oxide additions to melt-processed high-{Tc} superconductors

Energy Technology Data Exchange (ETDEWEB)

Goretta, K.C.; Brandel, B.P.; Lanagan, M.T.; Hu, J.; Miller, D.J.; Sengupta, S. [Argonne National Lab., IL (United States); Parker, J.C.; Ali, M.N. [Nanophase Technologies Corp., Darien, IL (United States); Chen, Nan [Illinois Superconductor Corp., Evanston, IL (United States)

1994-10-01

Nanophase TiO{sub 2} and Al{sub 2}O{sub 3} powders were synthesized by a vapor-phase process and mechanically mixed with stoichiometric YBa{sub 2}Cu{sub 3}O{sub x} and TlBa{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} powders in 20 mole % concentrations. Pellets produced from powders with and without nanophase oxides were heated in air or O{sub 2} above the peritectic melt temperature and slow-cooled. At 4.2 K, the intragranular critical current density (J{sub c}) increased dramatically with the oxide additions. At 35--50 K, effects of the oxide additions were positive, but less pronounced. At 77 K, the additions decreased J{sub c}, probably because of inducing a depresion of the transition temperature.

Fabrication of Cu{sub 2}ZnSn(S{sub x}Se{sub 1−x}){sub 4} solar cells by ethanol-ammonium solution process

Energy Technology Data Exchange (ETDEWEB)

Xue, Cong; Li, Jianmin; Wang, Yaguang; Jiang, Guoshun; Weifeng, Liu, E-mail: liuwf@ustc.edu.cn; Zhu, Changfei, E-mail: cfzhu@ustc.edu.cn

2016-10-15

Highlights: • The CBD precipitates were utilized to fabricate the CZTS/CZTSSe solar cells. • A solvent mixture of ethanol and ammonium hydroxide was used to form SnS-Cu2O-ZnS slurry. • Formation of CZTS/CZTSSe with good crystalline quality confirmed by XRD and Raman spectra. • CZTS and CZTSSe thin film solar cells obtained the best PCE of 1.99% and 2.95%, respectively. - Abstract: In this paper, Cu{sub 2}ZnSn(S{sub x}Se{sub 1−x}){sub 4} precursor films were produced by doctor blade process from SnS-Cu{sub 2}O-ZnS slurry. To prepare the slurry, SnS, ZnS and Cu{sub 2}O precipitates, which are outgrowths of stacked layer ZnS/Cu/SnS by CBD (chemical bath deposition)-annealing route, were dissolved in the mixture solvent of ethanol and NH{sub 3}·H{sub 2}O. Synthesized precursor films were then annealed at different conditions. The post-annealed films were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman measurements and UV–vis–NIR spectroscopy. SEM studies reveal that the rough and relatively compact absorber thin films are obtained via the sulfidation and sulfidation-selenization processes. X-ray diffraction and Raman spectrum results verify that the obtained films are composed of Cu{sub 2}ZnSnS{sub 4} and Cu{sub 2}ZnSnSe{sub 4} phases, which have high absorbance in visible range and direct band gap energy of 1.01–1.47 eV. The best devices yield total area power conversion efficiency of 1.99% and 2.95% corresponding to Cu{sub 2}ZnSnS{sub 4} and Cu{sub 2}ZnSn(S{sub x}Se{sub 1−x}){sub 4} thin film solar cells under AM1.5 illumination without any anti-reflection layer.

Magnetic properties of nanoscaled paramelaconite Cu{sub 4}O{sub 3−x} (x=0.0 and 0.5)

Energy Technology Data Exchange (ETDEWEB)

Djurek, D., E-mail: danijel.djurek@zg.t-com.hr [A. Volta Applied Ceramics (AVAC), 49247 Zlatar Bistrica, A. Šenoe 14 (Croatia); Prester, M.; Drobac, Dj. [Institute of Physics, 10000 Zagreb, Bijenička c. 46 (Croatia); Ivanda, M.; Vojta, D. [Ruđer Bošković Institute, 10000 Zagreb, Bijenička c. 54 (Croatia)

2015-01-01

Pure paramelaconite Cu{sub 4}O{sub 3−x} has been prepared in the form of nanoparticles with 56 nm in diameter. This mixed valency oxide crystallizes in a tetragonal lattice with 4 unit formulae and forms a pyrochlore structure which manifests in two stoichiometric forms; Cu{sub 4}O{sub 3} and Cu{sub 4}O{sub 2.5}, the latter form having two oxygen vacancies per unit cell. Magnetic lattice consists of Cu spin 1/2, and both stoichiometric forms obey transition to the antiferromagnetic state at T{sub N}=45–55 K. Defect free Cu{sub 4}O{sub 3} is indicated by an inversion symmetry and exhibits both antiferromagnetic and ferromagnetic state, where the latter is supposedly due to the superexchange interaction in Cu–O(1n)–Cu bonds. An additional magnetic transition was observed in Cu{sub 4}O{sub 3} at T=120 K, probably as a result of an incommensurate ordering. Absence of an inversion symmetry in the oxygen defect Cu{sub 4}O{sub 2.5} results in a long range Dzyaloshinsky–Moriya interaction accompanied by the strong superparamagnetism. - Highlights: • The first successful preparation of pure paramelaconite Cu{sub 4}O{sub 3−x}. • High resolution AC susceptibility measurements. • Evidence is presented for two stoichiometric forms of paramelaconite; defect free Cu{sub 4}O{sub 3} and Cu{sub 4}O{sub 2.5}. • Additional magnetic transition is observed at T=120 K in the defect free Cu{sub 4}O{sub 3}.

Band offsets of n-type electron-selective contacts on cuprous oxide (Cu{sub 2}O) for photovoltaics

Energy Technology Data Exchange (ETDEWEB)

Brandt, Riley E., E-mail: rbrandt@alum.mit.edu, E-mail: buonassisi@mit.edu; Lee, Yun Seog; Buonassisi, Tonio, E-mail: rbrandt@alum.mit.edu, E-mail: buonassisi@mit.edu [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Young, Matthew; Dameron, Arrelaine; Teeter, Glenn [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); Park, Helen Hejin; Chua, Danny; Gordon, Roy G. [Harvard University, Cambridge, Massachusetts 02139 (United States)

2014-12-29

The development of cuprous oxide (Cu{sub 2}O) photovoltaics (PVs) is limited by low device open-circuit voltages. A strong contributing factor to this underperformance is the conduction-band offset between Cu{sub 2}O and its n-type heterojunction partner or electron-selective contact. In the present work, a broad range of possible n-type materials is surveyed, including ZnO, ZnS, Zn(O,S), (Mg,Zn)O, TiO{sub 2}, CdS, and Ga{sub 2}O{sub 3}. Band offsets are determined through X-ray photoelectron spectroscopy and optical bandgap measurements. A majority of these materials is identified as having a negative conduction-band offset with respect to Cu{sub 2}O; the detrimental impact of this on open-circuit voltage (V{sub OC}) is evaluated through 1-D device simulation. These results suggest that doping density of the n-type material is important as well, and that a poorly optimized heterojunction can easily mask changes in bulk minority carrier lifetime. Promising heterojunction candidates identified here include Zn(O,S) with [S]/[Zn] ratios >70%, and Ga{sub 2}O{sub 3}, which both demonstrate slightly positive conduction-band offsets and high V{sub OC} potential. This experimental protocol and modeling may be generalized to evaluate the efficiency potential of candidate heterojunction partners for other PV absorbers, and the materials identified herein may be promising for other absorbers with low electron affinities.

Express and low-cost microwave synthesis of the ternary Chevrel phase Cu{sub 2}Mo{sub 6}S{sub 8} for application in rechargeable magnesium batteries

Energy Technology Data Exchange (ETDEWEB)

Murgia, Fabrizio; Antitomaso, Philippe; Stievano, Lorenzo; Monconduit, Laure [Institut Charles Gerhardt de Montpellier (ICGM, UMR 5253CNRS Université de Montpellier), 2, Place Eugène Bataillon, CC1502, 34095 Montpellier cedex 5 (France); Réseau sur le Stockage Electrochimique de l' Energie (RS2E,FR 3459CNRS), 33, Rue Saint-Leu, 80039 Amiens cedex (France); Berthelot, Romain, E-mail: romain.berthelot@umontpellier.fr [Institut Charles Gerhardt de Montpellier (ICGM, UMR 5253CNRS Université de Montpellier), 2, Place Eugène Bataillon, CC1502, 34095 Montpellier cedex 5 (France); Réseau sur le Stockage Electrochimique de l' Energie (RS2E,FR 3459CNRS), 33, Rue Saint-Leu, 80039 Amiens cedex (France)

2016-10-15

The ternary Chevrel phase Cu{sub 2}Mo{sub 6}S{sub 8} was successfully synthetized using a simple and cost-effective solid-state microwave-assisted reaction. While solid-state routes require days of high-temperature treatment under inert atmosphere, highly pure and crystalline Cu{sub 2}Mo{sub 6}S{sub 8} could be obtained in only 400 s from this precursor, the Chevrel binary phase Mo{sub 6}S{sub 8} was then obtained by copper removal through acidic leaching, and was evaluated as a positive electrode material for Mg-battery. The electrochemical performance in half-cell configuration shows reversible capacity exceeding 80 mAh/g, which is comparable to previous works carried out with materials synthesized by conventional high-temperature solid-state routes. - Graphical abstract: Ultrafast micro-wave synthesis of Chevrel phase Cu{sub 2}Mo{sub 6}S{sub 8} towards Mo{sub 6}S{sub 8} as positive electrode of Mg-battery. - Highlights: • Chevrel phase Cu{sub 2}Mo{sub 6}S{sub 8} is synthesized by fast microwave-assisted solid-state reaction. • Highly-pure and well-crystalline Cu{sub 2}Mo{sub 6}S{sub 8} is obtained. • Mo{sub 6}S{sub 8} obtained from leaching is tested as a positive electrode for Mg batteries.

Synthesis and chemistry of the new Y-Based and Bi-Based high temperature superconducting perovskites

Energy Technology Data Exchange (ETDEWEB)

Tarascon, J.M.; Barboux, P.; Miceli, P.F.; Bagley, B.G.; Greene, L.H.; Hull, G.W.; Giroud, M.

1988-12-01

Chemical synstesis of the new high T{sub c} oxides using solid state reactions or solution techniques is shown. A solution process which allows the preparation of both homogeneous and dense ceramics and of superconducting thick films has been developed for the YBa{sub 2}Cu{sub 3}O{sub 7} system. Physical measurements performed on homogeneous YBa{sub 2}Cu{sub 3-x}Co{sub x}O{sub y} samples have shown that the Co substitution, associated with an uptake of oxygen, takes place on the Cu-O chains and that T{sub c} is depressed, leading ultimately to antiferromagnetic insulators whose magnetic structures are shown. Three phases of general formula Bi{sub 2}Sr{sub 2}Ca{sub n-1}Cu{sub n}O{sub y} with n = 1,2 and 3 have been isolated in the Bi system and characterized for their structural and physical properties. These phases crystallize in the same pseudotetragonal unit cell differing one from the next by the stacking sequence along the c-axis, with the main feature being the presence of a sheared Bi-O double layer. The T{sub c}s of the n = 1,2 and 3 phases are 10 K, 85 K and 110 K respectively, but because of phase intergrowth, these values depend upon sample processing, making chemical substitutions within the Bi system quite complex as is discussed. Finally, we succeeded in making superconducting thick films (having zero resistance around 100 K) of the Bi-based and T1-based matrials via the decomposition of aqueous-glycerol solutions containing the salts of the elements.

Surface plasmon resonance enhanced visible-light-driven photocatalytic activity in Cu nanoparticles covered Cu{sub 2}O microspheres for degrading organic pollutants

Energy Technology Data Exchange (ETDEWEB)

Cheng, Yahui, E-mail: chengyahui@nankai.edu.cn [Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Lin, Yuanjing [Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Xu, Jianping [Institute of Material Physics, Key Laboratory of Display Materials and Photoelectric Devices, Ministry of Education, Tianjin University of Technology, Tianjin 300384 (China); He, Jie; Wang, Tianzhao; Yu, Guojun; Shao, Dawei; Wang, Wei-Hua; Lu, Feng [Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Li, Lan [Institute of Material Physics, Key Laboratory of Display Materials and Photoelectric Devices, Ministry of Education, Tianjin University of Technology, Tianjin 300384 (China); Du, Xiwen [School of Material Science and Engineering, Tianjin University, Tianjin 300072 (China); Wang, Weichao [Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Liu, Hui, E-mail: liuhui@nankai.edu.cn [Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Zheng, Rongkun [School of Physics, The University of Sydney, Sydney, NSW 2006 (Australia)

2016-03-15

Graphical abstract: - Highlights: • Cu NPs introduce the SPR and result in an increase of visible light absorption. • The photocatalytic activity of Cu{sub 2}O/Cu improves greatly due to the SPR effect. • A dark catalytic activity is observed stemming from the Fenton-like reaction. • The • O{sub 2}{sup −} and • OH radicals contribute to the photocatalytic process. • The • OH radicals contribute to the dark catalytic process. - Abstract: Micron-sized Cu{sub 2}O with different coverage of Cu nanoparticles (NPs) on the sphere has been synthesized by a redox procedure. The absorption spectra show that Cu NPs induce the surface plasmon resonance (SPR) at the wavelength of ∼565 nm. Methylene blue (MB) photodegrading experiments under visible-light display that the Cu{sub 2}O–Cu–H{sub 2}O{sub 2} system exhibits a superior photocatalytic activity to Cu{sub 2}O–H{sub 2}O{sub 2} or pure H{sub 2}O{sub 2} with an evident dependency on Cu coverage. The maximum photodegradation rate is 88% after visible-light irradiating for 60 min. The role of the Cu NPs is clarified through photodegradation experiments under 420 nm light irradiation, which is different from the SPR wavelength of Cu NPs (∼565 nm). By excluding the SPR effect, it proves that Cu SPR plays a key role in the photodegradation. Besides, a dark catalytic activity is observed stemming from the Fenton-like reaction with the aid of H{sub 2}O{sub 2}. The radical quenching experiments indicate that both • O{sub 2}{sup −} and • OH radicals contribute to the photocatalysis, while the dark catalysis is only governed by the • OH radicals, leading to a lower activity comparing with the photocatalysis. Therefore, with introducing Cu NPs and H{sub 2}O{sub 2}, the Cu{sub 2}O-based photocatalytic activity could be significantly improved due to the SPR effect and dark catalysis.

Superconducting properties of GdBa{sub 2}Cu{sub 3}O{sub y} films by metal-organic deposition using new fluorine-free complex solutions

Energy Technology Data Exchange (ETDEWEB)

Nakamura, T. [Department of Electrical and Electronic Engineering, Faculty of Engineering, Shizuoka University, Johoku 3-5-1, Hamamatsu, Shizuoka 432-8561 (Japan); Kita, R. [Department of Electrical and Electronic Engineering, Faculty of Engineering, Shizuoka University, Johoku 3-5-1, Hamamatsu, Shizuoka 432-8561 (Japan); CREST-JST, Honcho 4-1-8, Kawaguchi, Saitama 332-0012 (Japan)], E-mail: terkita@ipc.shizuoka.ac.jp; Miura, O. [Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji, Tokyo 192-0364 (Japan); CREST-JST, Honcho 4-1-8, Kawaguchi, Saitama 332-0012 (Japan); Ichinose, A. [CRIEPI, Nagasaka 2-6-1, Yokosuka, Kanagawa 240-0916 (Japan); CREST-JST, Honcho 4-1-8, Kawaguchi, Saitama 332-0012 (Japan); Matsumoto, K. [Kyushu Institute of Techonology, Sensui-cho, Tobata-ku, Kitakyushu, Hukuoka 804-8550 (Japan); CREST-JST, Honcho 4-1-8, Kawaguchi, Saitama 332-0012 (Japan); Yoshida, Y. [Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); CREST-JST, Honcho 4-1-8, Kawaguchi, Saitama 332-0012 (Japan); Mukaida, M. [Kyushu University, Hakozaki 6-10-1, Higashi-ku 4-3-16, Fukuoka 992-8510 (Japan); CREST-JST, Honcho 4-1-8, Kawaguchi, Saitama 332-0012 (Japan); Horii, S. [University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8586 (Japan); CREST-JST, Honcho 4-1-8, Kawaguchi, Saitama 332-0012 (Japan)

2008-09-15

GdBa{sub 2}Cu{sub 3}O{sub y} (GdBCO) films have been prepared on LaAlO{sub 3} single-crystal substrates by metal-organic deposition (MOD) using new fluorine-free complex solutions consisting of metal 2-ethylhexanates (2-EH) and metal naphthenates. The dispersion of T{sub c} values for GdBCO films improved by using a complex solution, rather than only a solution of metal naphthenates. c-axis oriented GdBCO films with flat surfaces were grown under lower calcining temperatures and higher firing temperatures than in the process using only metal naphthenates. The T{sub c} and J{sub c} of the GdBCO films were 91.2 K and 0.61 MA/cm{sup 2}, respectively, at 77 K at self-field.

UV light-assisted fabrication of Cu{sub 0.91}In{sub 0.09}S microspheres sensitized TiO{sub 2} nanotube arrays and their photoelectrochemical properties

Energy Technology Data Exchange (ETDEWEB)

Cui, Xinyu; Gu, Hongmei [School of Public Health, Mudanjiang Medical University, Mudanjiang, Heilongjiang Province (China); Yin, Yuanyuan; Guan, Yue [Hongqi Hospital, Mudanjiang Medical University, Mudanjiang, Heilongjiang Province (China); Rong, Shengzhong; Yin, Yongkui; Chen, Yingying [School of Public Health, Mudanjiang Medical University, Mudanjiang, Heilongjiang Province (China); Wu, Qunhong; Hao, Yanhua [Department of Social Medicine, School of Health Management, Harbin Medical University, Harbin, Heilongjiang Province (China); Li, Miaojing, E-mail: limiaojing@aliyun.com [School of Public Health, Mudanjiang Medical University, Mudanjiang, Heilongjiang Province (China)

2015-04-15

Highlights: • Cu{sub 0.91}In{sub 0.09}S microspheres were deposited on TiO{sub 2} NTs by a photodeposition method. • The average diameter of Cu{sub 0.91}In{sub 0.09}S microspheres is 600 nm. • The TiO{sub 2} NTs/CIS shows high photocurrents and visible photocatalytic activity. - Abstract: TiO{sub 2} nanotube arrays sensitized with Cu{sub 0.91}In{sub 0.09}S microspheres (TiO{sub 2} NTs/CIS) were successfully fabricated by a two-step process of anodization and followed by an in situ photodeposition method. The structural investigation by scanning electron microscopy and transmission electron microscopy indicated that the Cu{sub 0.91}In{sub 0.09}S microspheres with average diameter of 600 nm grew on the surface of the TiO{sub 2} nanotubes. The TiO{sub 2} NTs/CIS exhibited more excellent photoelectrochemical properties and photocatalytic activities than those of TiO{sub 2} NTs under visible light irradiation, and the corresponding electron transformation was proposed in detail.

Properties of HTS YBCO thin films deposited on tilted NdGaO{sub 3} substrates

Energy Technology Data Exchange (ETDEWEB)

Nurgaliev, T. [Laboratory of Superconductivity and Cryoelectronics, Institute of Electronics BAS, 72 Tsarigradsko Chausse, 1784 Sofia (Bulgaria)]. E-mail: timur@ie.bas.bg; Donchev, T. [Laboratory of Superconductivity and Cryoelectronics, Institute of Electronics BAS, 72 Tsarigradsko Chausse, 1784 Sofia (Bulgaria); Mateev, E. [Laboratory of Superconductivity and Cryoelectronics, Institute of Electronics BAS, 72 Tsarigradsko Chausse, 1784 Sofia (Bulgaria); Miteva, S. [Laboratory of Superconductivity and Cryoelectronics, Institute of Electronics BAS, 72 Tsarigradsko Chausse, 1784 Sofia (Bulgaria); Mozhaev, P.B. [Institute of Physics and Technology RAS, Nakhimovsky Ave. 36, 117218 Moscow (Russian Federation); Mozhaeva, J.E. [Institute of Physics and Technology RAS, Nakhimovsky Ave. 36, 117218 Moscow (Russian Federation)

2005-03-15

Thin YBa{sub 2}Cu{sub 3}O{sub 7} films were fabricated by 2-opposed DC magnetron sputtering onto NdGaO{sub 3} substrates, tilted from standard (1 1 0) orientation by 0-26 deg , and their surface morphology and electrical characteristics were investigated. Normal state resistivity (at 295 K) and microwave surface resistance (at 77 K and {approx}8 GHz) of the films demonstrated anisotropy, introduced by the tilted substrate, and some improvement of the superconducting parameters of the films was observed at small tilt angles ({theta} {approx} 1.5-3 deg ). The increase of the microwave surface resistance at high tilt angles for the current tracks, perpendicular to the steps of the substrate, was described in the framework of a simple model, which takes into account the complex conductivity of the film and the weak links between the film terraces.

Lattice parameters values and phase diagram for the Cu{sub 2}Zn{sub 1-z}Fe{sub z}GeSe{sub 4} alloy system

Energy Technology Data Exchange (ETDEWEB)

Caldera, D. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Quintero, M. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela)], E-mail: mquinter@ula.ve; Morocoima, M.; Quintero, E.; Grima, P.; Marchan, N.; Moreno, E.; Bocaranda, P. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Delgado, G.E. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Mora, A.E.; Briceno, J.M.; Fernandez, J.L. [Laboratorio de Analisis Quimico y Estructura de Materiales, Departamento de Fisica, Universidad de Los Andes, Merida 5101 (Venezuela)

2008-06-12

X-ray powder diffraction and differential thermal analysis (DTA) measurements were made on polycrystalline samples of the Cu{sub 2}Zn{sub 1-z}Fe{sub z}GeSe{sub 4} alloy system. The diffraction patterns were used to show the equilibrium conditions and to estimate crystalline parameter values. It was found that, at room temperature, a single phase solid solution with the tetragonal stannite {alpha} structure (I4-bar2m) occurs across the whole composition range. The DTA thermograms were used to construct the phase diagram of the Cu{sub 2}Zn{sub 1-z}Fe{sub z}GeSe{sub 4} alloy system. It was confirmed that the Cu{sub 2}ZnGeSe{sub 4} compound melts incongruently. It was observed that undercooling effects occur for samples with z > 0.9.

Thermally-induced electronic relaxation in structurally-modified Cu{sub 0.1}Ni{sub 0.8}Co{sub 0.2}Mn{sub 1.9}O{sub 4} spinel ceramics

Energy Technology Data Exchange (ETDEWEB)

Shpotyuk, O., E-mail: shpotyuk@novas.lviv.ua [Institute of Materials, Scientific Research Company “Carat”, 202, Stryjska Street, Lviv 79031 (Ukraine); Institute of Physics, Jan Dlugosz University, 13/15, al. Armii Krajowej, Czestochowa 42200 Poland (Poland); Balitska, V. [Institute of Materials, Scientific Research Company “Carat”, 202, Stryjska Street, Lviv 79031 (Ukraine); Lviv State University of Vital Activity Safety, 35, Kleparivska Street, Lviv 79007 (Ukraine); Brunner, M. [Fachhochschule Köln/University of Applied Sciences, 2, Betzdorfer Strasse, Köln 50679 (Germany); Hadzaman, I. [Institute of Materials, Scientific Research Company “Carat”, 202, Stryjska Street, Lviv 79031 (Ukraine); Drohobych Ivan Franko State Pedagogical University, 24, I. Franko Street, Drohobych 82100 (Ukraine); Klym, H. [Institute of Materials, Scientific Research Company “Carat”, 202, Stryjska Street, Lviv 79031 (Ukraine); Lviv Polytechnic National University, 12, Bandera Street, Lviv 79013 (Ukraine)

2015-02-15

Thermally-induced electronic relaxation in structurally-modified Cu{sub 0.1}Ni{sub 0.8}Co{sub 0.2}Mn{sub 1.9}O{sub 4} spinel ceramics is shown to be adequately described by stretched exponential function on time. This kinetics is defined by microsctructure perfectness of the relaxing media, showing obvious onset to stretched exponential behaviour with non-exponentionality index attaining close to 0.43 values for high-monolith ceramics and smaller ones in fine-grained ceramics. Percolation threshold in relaxation-degradation kinetics is detected for ceramics with 10% of NiO extractions, showing the smallest but most prolonged single-path degradation effect. This finding is treated in terms of Phillips’ axiomatic diffusion-to-trap model, where only one of two relaxation channels (caused by operative short-range forces) occurs to be effective, while additional non-operative channels contribute to electronic relaxation in fine-grained ceramics.

Chemically deposed layer sytems for the realization of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} band conductors; Chemisch deponierte Schichtsysteme zur Realisierung von YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}-Bandleitern

Energy Technology Data Exchange (ETDEWEB)

Engel, Sebastian

2009-04-30

The aim of this thesis was to produce new buffer-layer systems for biaxially texturated Ni5at%W substrates by means of chemical processes. As very promising materials for the buffer layers CaTiO{sub 3} and SrTiO{sub 3} were chosen. The production of the single layers pursued from the organometallic prestage by means of dip coating and subsequent head treatment. During the work first the single precursor solutions were to be developed. A main component of the theses forms the understanding of the texture development during the heat treatment of precursor layers on biaxially texturated metallic substrates. Based on this the growth of thick buffer layers is studied and by means of YBCO layers, which were deposed by beans of a pulsed laser, the functionality of the synthesized buffer layers proved. A further component of this thesis formes the influence of nanoscaling precipitations in thew YBCO on its superconducting properties. The YBCO deposition pursued via a variation of the TFA process, as substrate (001)-oriented SrTiO{sub 3} monocrystals were applied.

Development of p-type amorphous Cu{sub 1−x}B{sub x}O{sub 2−δ} thin films and fabrication of pn hetero junction

Energy Technology Data Exchange (ETDEWEB)

Sanal, K.C., E-mail: sanalcusat@gmail.com [Nanophotonic and Optoelectronic Devices Laboratory, Department of Physics, Cochin University of Science and Technology, Kerala 682022 (India); Inter University Center for Nanomaterials and Devices (IUCND), Cochin University of Science and Technology, Kerala 682022 (India); Center for Advanced Materials, Cochin University of Science and Technology, Kerala 682022 (India); Jayaraj, M.K., E-mail: mkj@cusat.ac.in [Nanophotonic and Optoelectronic Devices Laboratory, Department of Physics, Cochin University of Science and Technology, Kerala 682022 (India); Center for Advanced Materials, Cochin University of Science and Technology, Kerala 682022 (India)

2014-07-01

Highlights: • Growth of p-type semiconducting amorphous Cu{sub 1−x}B{sub x}O{sub 2−δ} thin films by co-sputtering. • Atomic percentage of Cu{sub 1−x}B{sub x}O{sub 2−δ} thin films from the XPS analysis. • Variation of bandgap with boron concentration in Cu{sub 1−x}B{sub x}O{sub 2−δ} thin films. • Demonstration of p–n hetero junctions fabricated in the structure n-Si/p-Cu{sub 1−x}B{sub x}O{sub 2−δ}/Au. - Abstract: Transparent conducting amorphous p type Cu{sub 1−x}B{sub x}O{sub 2−δ} thin films were grown by RF magnetron co-sputtering at room temperature, using copper and boron targets in oxygen atmosphere. The structural, electrical as well as optical properties were studied. Composition of the films was analyzed by XPS. Amorphous structure of as deposited films was confirmed by GXRD. Surface morphology of the films was analyzed by AFM studies. p-Type nature and concentration of carriers were investigated by Hall effect measurement. Band gap of the films was found to increase with the atomic content of boron in the film. A p–n hetero junction using p-type Cu{sub 1−x}B{sub x}O{sub 2−δ} and n-type silicon was fabricated in the structure n-Si/p-Cu{sub 1−x}B{sub x}O{sub 2−δ}/Au which showed rectifying behavior. As deposited amorphous Cu{sub 1−x}B{sub x}O{sub 2−δ} thin films with lower carrier concentration can be used as a channel layer for thin film transistors.

Comparison of grain to grain orientation and stiffness mapping by spatially resolved acoustic spectroscopy and EBSD.

Science.gov (United States)

Mark, A F; Li, W; Sharples, S; Withers, P J

2017-07-01

Our aim was to establish the capability of spatially resolved acoustic spectroscopy (SRAS) to map grain orientations and the anisotropy in stiffness at the sub-mm to micron scale by comparing the method with electron backscatter diffraction (EBSD) undertaken within a scanning electron microscope. In the former the grain orientations are deduced by measuring the spatial variation in elastic modulus; conversely, in EBSD the elastic anisotropy is deduced from direct measurements of the crystal orientations. The two test-cases comprise mapping the fusion zones for large TIG and MMA welds in thick power plant austenitic and ferritic steels, respectively; these are technologically important because, among other things, elastic anisotropy can cause ultrasonic weld inspection methods to become inaccurate because it causes bending in the paths of sound waves. The spatial resolution of SRAS is not as good as that for EBSD (∼100 μm vs. ∼a few nm), nor is the angular resolution (∼1.5° vs. ∼0.5°). However the method can be applied to much larger areas (currently on the order of 300 mm square), is much faster (∼5 times), is cheaper and easier to perform, and it could be undertaken on the manufacturing floor. Given these advantages, particularly to industrial users, and the on-going improvements to the method, SRAS has the potential to become a standard method for orientation mapping, particularly in cases where the elastic anisotropy is important over macroscopic/component length scales. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

Refinement of the Al-rich part of the Al–Cu–Re phase diagram and atomic model of the ternary Al{sub 6.2}Cu{sub 2}Re phase

Energy Technology Data Exchange (ETDEWEB)

Samuha, S. [Department of Materials Engineering, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel); NRCN, P.O. Box 9001, Beer Sheva 84190 (Israel); Grushko, B. [MaTecK, Jülich D 52428 (Germany); PGI-5, Forschungszentrum Jülich, Jülich D 52425 (Germany); Meshi, L., E-mail: Louisa@bgu.ac.il [Department of Materials Engineering, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel); Ilse Katz Institute for Nanoscale Science & Technology, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel)

2016-06-15

Partial isothermal sections at 800, 650 and 590 °C were constructed for an Al-rich compositional range of Al–Cu–Re. The maximal solubility of Cu in the Al{sub 11}Re{sub 4}, h-Al{sub 4}Re and l-Al{sub 4}Re phases was found to be ∼6, 4.5, and 2.3 at% respectively, while the solubility of Re in the Al–Cu θ, η{sub 1} and ε{sub 2} phases was below 0.5 at%. Below 740 °C, a ternary hexagonal phase (P6{sub 3}, a = 1.1029 and c = 1.2746 nm) is formed in a small compositional range close to Al{sub 65}Cu{sub 25}Re{sub 10}. Its structural model was deduced by direct methods applied on the precession electron diffraction tomography data. - Highlights: • Al–Cu–Re was studied at 540–1030 °C up to 25 at% Re and 60 at% Cu. • Al{sub 11}Re{sub 4}, h-Al{sub 4}Re and l-Al{sub 4}Re dissolve 6, 4.5 and 2.3 at% Cu, respectively. • Earlier reported ternary compound Al{sub 8}CuRe was not confirmed. • Earlier reported ternary compound Al{sub 7}Cu{sub 2}Re is probably Al{sub 6.2}Cu{sub 2}Re. • Crystal structure of hexagonal Al{sub 6.2}Cu{sub 2}Re was solved.

Preparation and characterization of Cu{sub x}O{sub 1-y}@ZnO{sub 1-α} nanocomposites for enhanced room-temperature NO{sub 2} sensing applications

Energy Technology Data Exchange (ETDEWEB)

Geng, Xin [College of Mechanical Engineering, Yangzhou University, Yangzhou 225127 (China); College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China); Service de Science des Matériaux, Faculté Polytechnique, Université de Mons, Mons 7000 (Belgium); Zhang, Chao, E-mail: zhangc@yzu.edu.cn [College of Mechanical Engineering, Yangzhou University, Yangzhou 225127 (China); Luo, Yifan [College of Mechanical Engineering, Yangzhou University, Yangzhou 225127 (China); Debliquy, Marc [Service de Science des Matériaux, Faculté Polytechnique, Université de Mons, Mons 7000 (Belgium)

2017-04-15

Highlights: • Cu{sub x}O{sub 1-y}@ZnO{sub 1-(*)α} coatings with rich donor defects were successfully prepared. • Many p-n heterojunctions were formed in the as-sprayed Cu{sub x}O{sub 1-y}@ZnO{sub 1-α} coatings. • Light absorption of the coatings was extended to whole visible light region. • Cu{sub x}O{sub 1-y}@ZnO{sub 1-α} coatings showed an excellent response to NO{sub 2} at room temperature. - Abstract: In order to solve the problem that pristine ZnO show little response to NO{sub 2} gas at room temperature, some methods have been used, e.g., introducing narrow-bandgap semiconductors and donor defects into ZnO. In this work, we adopt solution precursor plasma spray to deposit Cu{sub x}O{sub 1-y}@ZnO{sub 1-α} hybrid coatings. Rapid heating and cooling as well as the reducing atmosphere provided by solution precursor plasma spray (SPPS) produce highly concentrated donor defects such as zinc interstitials and oxygen vacancies. X-ray photoelectron spectroscopy, photoluminescence spectroscopy and electron paramagnetic resonance confirmed that rich donor defects were present in the SPPS Cu{sub x}O{sub 1-y}@ZnO{sub 1-α} coatings. Field emission-scanning electron microscopy images exhibited a highly porous nanostructure, and high resolution-transmission electron microscopy showed that there were large amounts of p-n heterojunctions in the nanocomposites. The light absorption of the SPPS Cu{sub x}O{sub 1-y}@ZnO{sub 1-α} hybrids was extended up to the whole visible light region. With assistance of visible light illumination, the nanocomposites exhibited significant response to NO{sub 2} for concentrations below 1 ppm. A sensing mechanism of the Cu{sub x}O{sub 1-y}@ZnO{sub 1-α} sensors was proposed.

Highly selective adsorption of organic dyes containing sulphonic groups using Cu{sub 2}(OH){sub 3}NO{sub 3} nanosheets

Energy Technology Data Exchange (ETDEWEB)

Jia, Jincan; Wang, Honghong; Niu, Helin, E-mail: niuhelin@ahu.edu.cn; Chen, Jingshuai; Song, Jiming; Mao, Changjie; Zhang, Shengyi [Anhui University, College of Chemistry and Chemical Engineering (China); Gao, Yuanhao [Xuchang University, Institute of Surface Micro and Nano Materials (China); Chen, Changle [University of Science and Technology of China, CAS Key Laboratory of Soft Matter Chemistry (China)

2016-09-15

In this study, we report a facile approach to synthesize Cu{sub 2}(OH){sub 3}NO{sub 3} nanosheets via simply sonochemical method, which showed high efficiency and selectivity towards the adsorption of organic dyes containing sulphonic groups. The structure and morphology of the nanosheets were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, N{sub 2} adsorption–desorption isotherms, particle size and zeta potential analysis. The adsorption results indicated that the equilibrium data coincide very well with Langmuir isotherm, and the maximum adsorption capacities for Congo red, methyl blue and methyl orange were 1864, 1270 and 959 mg g{sup −1}, respectively. The kinetic data can be explained by pseudo-second-order model. The Cu{sub 2}(OH){sub 3}NO{sub 3} nanosheets also demonstrated high selectivity towards the adsorption of dyes containing sulphonic groups from mixed dye solutions. The rational mechanism of adsorption was attributed to hydrogen bonding, electrostatic attractions and ion exchanges between the dye molecules and Cu{sub 2}(OH){sub 3}NO{sub 3} in the adsorption process.

Effect of hot band grain size on development of textures and magnetic properties in 2.0% Si non-oriented electrical steel sheet

Energy Technology Data Exchange (ETDEWEB)

Lee, K.M. [Department of Materials Science and Engineering, Korea University, 5-1, Anam-dong, Sungbuk-Gu, Seoul 136-701 (Korea, Republic of); Huh, M.Y., E-mail: myhuh@korea.ac.kr [Department of Materials Science and Engineering, Korea University, 5-1, Anam-dong, Sungbuk-Gu, Seoul 136-701 (Korea, Republic of); Lee, H.J.; Park, J.T.; Kim, J.S. [Electrical Steel Sheet Research Group, Technical Research Laboratories, POSCO, Goedong-dong, Pohang (Korea, Republic of); Shin, E.J. [Korea Atomic Energy Research Institute, Neutron Science Division, Daejeon 305-353 (Korea, Republic of); Engler, O. [Hydro Aluminium Rolled Products GmbH, Research and Development Bonn, P.O. Box 2468, D-53014 Bonn (Germany)

2015-12-15

The effect of hot band grain size on the development of crystallographic texture and magnetic properties in non-oriented electrical steel sheet was studied. After cold rolling the samples with different initial grain sizes displayed different microstructures and micro-textures but nearly identical macro-textures. The homogeneous recrystallized microstructure and micro-texture in the sample having small grains caused normal continuous grain growth. The quite irregular microstructure and micro-texture in the recrystallized sample with large initial grain size provided a preferential growth of grains in 〈001〉//ND and 〈113〉//ND which were beneficial for developing superior magnetic properties. - Highlights: • We produced hot bands of electrical steel with different grain size but same texture. • Hot band grain size strongly affected cold rolling and subsequent annealing textures. • Homogeneous recrystallized microstructure caused normal continuous grain growth. • Irregular recrystallized microstructure led to selective growth of <001>//ND grains. • Hot band with large grains was beneficial for superior magnetic properties.

Intense, pulsed, charged particle beams and associated applications to materials science

Energy Technology Data Exchange (ETDEWEB)

Yatsui, K; Grigoriu, C; Masugata, K; Jiang, W; Sonegawa, T; Nakagawa, Y; Eka Prijono, A C [Nagaoka Univ. of Technology, Niigata (Japan)

1997-03-01

We have demonstrated successful preparation of thin films and nanosize powders by using the technique of intense pulsed ion beam evaporation. In this paper, we review the experimental results of thin film deposition of ZnS, YBa{sub 2}Cu{sub 3}O{sub 7-x}, BaTiO{sub 3}, cBN, ZrO{sub 2}, ITO, and apatite, as well as the experimental results of the synthesis of nanosize powders of Al{sub 2}O{sub 3}. (author)

Transport Barkhausen-like noise in uniaxially pressed Bi{sub 1.65}Pb{sub 0.35}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+{delta}}ceramic samples

Energy Technology Data Exchange (ETDEWEB)

Garcia-Fornaris, I. [Departamento de Ciencias Basicas, Universidad de Granma, Apdo. 21, P.O. Box 85100, Bayamo (Cuba); Govea-Alcaide, E. [Departamento de Fisica, Universidad de Oriente, Patricio Lumumba s/n, P.O. Box 90500, Santiago de Cuba (Cuba); Instituto de Fisica, Universidade de Sao Paulo, CP 66318, 05315-970 Sao Paulo, SP (Brazil); Alberteris-Campos, M. [Departamento de Engenharia Mecanica, Escola Politecnica, Universidade de Sao Paulo, 05508-900 Sao Paulo, SP (Brazil); Mune, P. [Departamento de Fisica, Universidad de Oriente, Patricio Lumumba s/n, P.O. Box 90500, Santiago de Cuba (Cuba); Jardim, R.F., E-mail: rjardim@if.usp.b [Instituto de Fisica, Universidade de Sao Paulo, CP 66318, 05315-970 Sao Paulo, SP (Brazil)

2010-08-01

We report on the detection of the transport Barkhausen-like noise (TBN) in polycrystalline samples of Bi{sub 1.65}Pb{sub 0.35}Sr{sub 2}Ca{sub 2} Cu{sub 3}O{sub 10+{delta}}(Bi-2223) which were subjected to different uniaxial compacting pressures. The transport Barkhausen-like noise was measured when the sample was subjected to an ac triangular-shape magnetic field (f {approx} 1 Hz) with maximum amplitude B{sub max} {approx} 5.5 mT, in order to avoid the flux penetration within the superconducting grains. Analysis of the TBN signal, measured for several values of excitation current density, indicated that the applied magnetic field in which the noise signal first appears, B{sub a}(t{sub i}), is closely related to the magnetic-flux pinning capability of the material. The combined results are consistent with the existence of three different superconducting levels within the samples: (i) the superconducting grains; (ii) the superconducting clusters; and (iii) the weak-links. We finally argue that TBN measurements constitute a powerful tool for probing features of the intergranular transport properties in polycrystalline samples of high-T{sub c} superconductors.