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Superconductivity: Past, present, and future

Description: This paper provides an overview of superconductor research and development activities, with emphasis on the potential of high-{Tc} materials for future applications. Superconductor applications are grouped under the following categories: electronics/instrumentation, bulk material/castings, research devices, industrial/commercial, electric power, and transportation/propulsion. Near-term applications are typically based on thin film and cast forms of high-{Tc} materials, while large-scale applica… more
Date: January 1, 1992
Creator: Uherka, K.L.
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Partner: UNT Libraries Government Documents Department
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(Gamma scattering in condensed matter with high intensity Moessbauer radiation)

Description: This report discusses: quasielastic scattering studies on glycerol; gamma-ray scattering from alkali halides; lattice dynamics in metals; Moessbauer neutron scattering, x-ray diffraction, and macroscopic studies of high {Tc} superconductors containing tungsten; NiAl scattering studies; and atomic interference factors and nuclear Casimir effect.
Date: January 1, 1992
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The influence of anharmonic phonons on the isotope effect in high- Tc oxides

Description: Anharmonic phonons are examined to study the unusual isotope effect exponents for the high-{Tc} oxides. Within a simple model of anharmonicity, the mass dependences of the electron-phonon coupling constant {lambda} and the phonon frequency determine the isotope effect exponent {alpha} as a function of coupling strength. A model in which the outer wells of a multiple-well potential deepen as the orthorhombic/low temperature tetragonal phase transition in La{sub 2-x}M{sub x}CuO{sub 4} is approach… more
Date: January 1, 1992
Creator: Crespi, V.H. & Cohen, M.L.
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Partner: UNT Libraries Government Documents Department
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Recent advances in high-temperature superconductor wire fabrication and applications development

Description: In this paper, recent advances in fabrication of HTS wires are summarized, and detailed discussion is provided for developments in near- and intermediate-term applications. Near-term applications, using presently obtainable current densities, include: liquid-nitrogen depth sensors, cryostat current leads, and magnetic bearings. Intermediate-term applications, using current densities expected to be available in the near future include fault-current limiters and short transmission lines. 25 refs.
Date: January 1, 1992
Creator: Hull, J.R. & Uherka, K.L.
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Partner: UNT Libraries Government Documents Department
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High pressure and synchrotron radiation studies of solid state electronic instabilities

Description: This report discusses Eu and General Valence Instabilities; Ce Problem: L{sub 3} Spectroscopy Emphasis; Bulk Property Emphasis; Transition Metal Compound Electronic Structure; Electronic Structure-Phonon Coupling Studies; High Temperature Superconductivity and Oxide Materials; and Novel Materials Collaboration with Chemistry.
Date: April 1, 1992
Creator: Pifer, J.H. & Croft, M.C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Sintering of Bulk High - Tc Superconductors: Bi-Sr-Ca-Cu-O

Description: Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub x} (2212) and (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (2223) superconductors have orthorhombic crystal structures. They form platelike grains that at high temperatures grow primarily in the a-b planes and not in the c direction. The diffusional properties of Bi-Sr-Ca-Cu-O superconductors are so anisotropic that 2212 and 2223 cannot, in general, be densified by solid-state sintering. Improved densification can be achieved by application of pressure or… more
Date: May 1, 1992
Creator: Goretta, K. C.; Lanagan, M. T.; Kaufman, D. Y.; Biondo, A. C.; Wu, C. T.; Loomans, M. E. et al.
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Partner: UNT Libraries Government Documents Department
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Irreversibility behavior in Ag-sheathed Bi-based superconducting wires

Description: Irreversibility lines for Ag/(Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub y}(2223) wires prepared through a phase formation- decomposition-recovery (PFDR) process and normal annealing process were determined using both AC susceptibility measurements under DC fields and magnetisation measurements. It was found that flux pinning was enhanced in the PFDR processed samples over the normal processed samples, in particular at temperature above 77 K. The PFDR process results in high mass density, gr… more
Date: April 1, 1992
Creator: Dou, S.X.; Liu, H.K.; Guo, Y.C.; Wang, J.; Jin, X.J.; Hu, Q.Y. (New South Wales Univ., Kensington (Australia)) et al.
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Partner: UNT Libraries Government Documents Department
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Assessment study of superconducting fault-current limiters operating at 77K

Description: The possible impact of nitrogen-cooled superconductors on the design and cost of superconducting fault-current limiters is assessed by considering the technical specifications such devices must meet and by comparing material properties of 77-K and 4-K superconductors. The main advantage of operating superconductors at 77 K is that the refrigeration operating cost is reduced by a factor of up to 25, and the refrigeration capital cost is reduced by a factor of up to 10. The heat capacity of 77 K … more
Date: January 1, 1992
Creator: Giese, R. F. & Runde, M.
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YBa sub 2 Cu sub (3-x) Co sub x O sub y : A substrate material for YBCO superconductors

Description: The physical properties of the ceramic YBa{sub 2}Cu{sub (3-x)}Co{sub x}O{sub y} have been investigated in order to evaluate its usefulness as a substrate material for YBCO superconductors. YBa{sub 2}Cu{sub (3-x)}Co{sub x}O{sub y} has been found to be thermally and chemically compatible with 123 and displays adequate electrical properties for a substrate material. A material with the nominal composition of YBa{sub 2}Cu{sub 2.2}Co{sub 0.8}O{sub 7} was investigated, extensively. The mechanical pro… more
Date: April 1, 1992
Creator: Vienna, J.D.; Balachandran, U.; Poeppel, R.B. (Argonne National Lab., IL (United States)); Cermignani, W. & Taylor, J.A. (State Univ. of New York, Alfred, NY (United States). Coll. of Ceramics)
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Partner: UNT Libraries Government Documents Department
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Chemical Technology Division, Annual technical report, 1991

Description: Highlights of the Chemical Technology (CMT) Division's activities during 1991 are presented. In this period, CMT conducted research and development in the following areas: (1) electrochemical technology, including advanced batteries and fuel cells; (2) technology for fluidized-bed combustion and coal-fired magnetohydrodynamics; (3) methods for treatment of hazardous and mixed hazardous/radioactive waste; (4) the reaction of nuclear waste glass and spent fuel under conditions expected for an uns… more
Date: March 1, 1992
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Computer simulation of scattered ion and sputtered species effects in ion beam sputter-deposition of high temperature superconducting thin films

Description: Ion beam sputter-deposition is a technique currently used by many groups to produce single and multicomponent thin films. This technique provides several advantages over other deposition methods, which include the capability for yielding higher film density, accurate stoichiometry control, and smooth surfaces. However, the relatively high kinetic energies associated with ion beam sputtering also lead to difficulties if the process is not properly controlled. Computer simulations have been perfo… more
Date: January 1, 1992
Creator: Krauss, A.R. (Argonne National Lab., IL (United States)) & Auciello, O. (Microelectronics Center of North Carolina, Research Triangle Park, NC (United States))
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Partner: UNT Libraries Government Documents Department
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Ion beam spectroscopy as a means of in-situ monitoring of thin film deposition

Description: Low energy (5--15 keV) pulsed beam Ion Scattering Spectroscopy (ISS) and Direct Recoil Spectroscopy (DRS) are surface analytical tools which possess the ability to provide a remarkably wide range of information directly relevant to the growth of multi-component semiconductor, metal and metal oxide thin films and layered structures. Ion beam methods have not been widely used for this purpose because the design of existing commercial instrumentation is unsuitable in terms of vacuum requirements, … more
Date: January 1, 1992
Creator: Krauss, A. R.; Rangaswamy, M.; Lamich, G.; Gruen, D. M. (Argonne National Lab., IL (United States)); Schultz, J. A. (Ionwerks, Inc., Houston, TX (United States)) & Schmidt, H. (Schmidt Instruments, Inc., Houston, TX (United States))
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Partner: UNT Libraries Government Documents Department
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Microstructure and properties of in-situ rf sputtered YBa sub 2 Cu sub 3 O sub 7 thin films for microwave applications

Description: 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 o… more
Date: January 1, 1992
Creator: 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)
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Partner: UNT Libraries Government Documents Department
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Grain boundary weak links in high- Tc superconductors

Description: The transport critical current density (Jc) for high-{Tc} thin films, bicrystals, and bulk ceramics is shown to be determined by magnetic field penetration into the grain boundaries. The gross grain orientations may not in all cases be an important factor in determining this penetration. The parameter ({lambda}{sub G}/{lambda}{sub J}){sup 2} can characterize the strength of the grain boundary coupling, which depends mainly on the crystal coherence and connectivity at the boundary area.
Date: April 1, 1992
Creator: Shi, D.; Sengupta, S.; Goretta, K.C.; Salem-Sugui, S. Jr. (Argonne National Lab., IL (United States)); Smith, M. & Lwin, Y.N. (Western Illinois Univ., Macomb, IL (United States). Dept. of Physics)
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Partner: UNT Libraries Government Documents Department
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High resolution electron energy loss studies of surface vibrations

Description: New experimental studies of surface vibrational properties of materials with high-resolution electron energy loss spectroscopy (EELS) are reported. This document summarizes recent progress on surface phonon dispersion measurements on copper (001); silver (001) and (111); oxygen adsorption on ultrathin films of cobalt and nickel; aluminum on silicon (111); and copper-oxide based superconductors.
Date: May 1, 1992
Creator: Kesmodel, L.L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Sintering of bulk high- Tc superconductors: Y-Ba-Cu-O

Description: Sintering of bulk YBa{sub 2}Cu{sub 3}O{sub x} (123) samples has been conducted from 850 to 1010{degrees}C in oxygen partial pressures (P{sub O2}) of 2.5 {times} 10{sup 2} to 10{sup 5} Pa. The final grain sizes of the samples were controlled by selective use of (1) liquid phases and (2) partial decomposition of the 123 phase by sintering in a P{sub O2} that was lower than the minimum needed for 123 stability. In nearly fully dense samples, it was found that the grain size could range from about … more
Date: May 1, 1992
Creator: Goretta, K.C.; Chen, N.; Lanagan, M.T.; Wu, W.; Singh, J.P.; Olson, R.A. et al.
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Partner: UNT Libraries Government Documents Department
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Statics and kinetics of oxygen ordering in the oxide superconductor YBa sub 2 Cu sub 3 O sub z

Description: Oxygen ordering in the high-temperature superconductor YBa{sub 2}Cu{sub 3}O{sub z} is well described by a two-dimensional Ising model with anisotropic next-nearest neighbor effective pair interactions, repulsive along the a direction, attractive along b. Monte Carlo simulation shows that this marked anisotropy gives rise, particularly at stoichiometric index z close to 7, to large deviations from unity of the ratio D{sub 11}{sup *}/D{sub 22}{sup *} of tracer diffusion tensor components in the a… more
Date: March 1, 1992
Creator: McCormack, R.; de Fontaine, D. (Lawrence Berkeley Lab., CA (United States)); Ceder, G. (Massachusetts Inst. of Tech., Cambridge, MA (United States)) & Salomons, E. (CEN Saclay, Gif-sur-Yvette, (France))
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Partner: UNT Libraries Government Documents Department
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Structure and flux pinning properties of irradiation defects in YBa sub 2 Cu sub 3 O sub 7-x

Description: We review our investigations of defects produced in YBa{sub 2}Cu{sub 3}O{sub 7-x} by various forms of irradiation. The defect microstructure has been studied by transmission electron microscopy (TEM). Irradiation enhancements of flux pinning have been studied by SQUID magnetometry on single crystals. In many cases the same single crystals were used in both TEM and SQUID investigations. The primary atom recoil spectra for all the irradiations studied have been carefully calculated and used to co… more
Date: June 1, 1992
Creator: Kirk, M.A.
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Partner: UNT Libraries Government Documents Department
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Potential impact of high temperature superconductors on maglev transportation

Description: This report describes the potential impact that high-temperature superconductors (HTSs) may have on transportation by magnetically levitated vehicles. It is not intended as a planning document, but rather as an overview of potential HTS applications to magnetic-levitation (maglev) transportation. The present maglev program in the United States is summarized, and the present status of development of HTSs is described. Areas identified for possible impact on maglev technology are (1) liquid-nitro… more
Date: February 1, 1992
Creator: Hull, J.R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Practical Superconductor Development for Electrical Power Applications, Annual Report: 1992

Description: Annual report for the superconductor program at Argonne National Laboratory discussing the group's activities and research. This report describes the technical progress of research and development efforts aimed at producing superconducting components that are based on the Y-Ba-Cu, Bi-Sr-Ca-Cu, Bi-Pb-Sr-Ca-Cu, and (Tl,Pb)-(Ba,Sr)-Ca-Cu oxide systems including: synthesis and heat treatment of high-Ta superconductors, formation of monolithic and composite wires and tapes, superconductor/metal con… more
Date: October 1992
Creator: Argonne National Laboratory. Materials and Components Technology Division.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Applications of circularly polarized photons at the ALS with a bend magnet source

Description: The purpose of this workshop is to focus attention on, and to stimulate the scientific exploitation of, the natural polarization properties of bend-magnet synchrotron radiation at the ALS -- for research in biology, materials science, physics, and chemistry. The topics include: The Advanced Light Source; Magnetic Circular Dichroism and Differential Scattering on Biomolecules; Tests of Fundamental Symmetries; High {Tc} Superconductivity; Photoemission from Magnetic and Non-magnetic Solids; Studi… more
Date: February 1, 1992
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Partner: UNT Libraries Government Documents Department
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Fine scale mesostructures in superconducting and other materials

Description: We review experimental and theoretical literature on mesoscale features and structures in a variety of displacively transforming materials. These include twinning in martensites and the much finer scale tweed; both may have significant effects on both normal and superconducting properties. Elastic properties are particularly strongly affected. Recent x-ray neutron experiments suggest them in hi-{Tc} materials.
Date: January 1, 1992
Creator: Krumhansl, J.A.
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Oxygen ordering and strain-related morphology in YBa sub 2 Cu sub 3- x O sub 7 systems

Description: Monte Carlo simulations were performed on an anisotropic lattice gas model which represent well the interactions between oxygen atoms in YBa{sub 2}Cu{sub 3}O{sub 7} systems doped with trivalent impurity atoms M such as Fe or Al. Concentration wave amplitudes obtained from these simulations were used to calculate the diffuse X-ray scattering intensity caused by the resulting displacement field using a concentration wave/displacement wave approach, and the results are compared with X-ray and elec… more
Date: January 1, 1992
Creator: Cha, Zhi-Xiong; Zhu, Yimei & Welch, D.O.
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Partner: UNT Libraries Government Documents Department
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