Journal ArticleDOI
High TC superconductors—composite wire fabrication
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In this paper, the authors report preliminary success in the fabrication of fine-wire, composite superconductors consisting of a high-conductivity normal metal shell such as Ag or Cu/Ni/Au and a superconducting core of Ba2YCu3O7 oxide.Abstract:
Commercially useful, bulk superconductors typically require stabilization using a normal metal cladding for reasons of electrical, thermal, and mechanical protection and, in general, need to be drawn into fine fibers and wound into a magnet configuration. The recent discovery of high‐TC superconductor materials such as Ba2YCu3O7 stimulated worldwide interest in the subject, however, with much concern about fabricability of such brittle ceramic materials into desirable fine wire geometry. In this letter, we report preliminary success in the fabrication of fine‐wire, composite superconductors consisting of a high‐conductivity normal metal shell such as Ag or Cu/Ni/Au and a superconducting core of Ba2YCu3O7 oxide. The wire is would into a coil, and then heat treated to produce the desired chemistry in a dense structure. The resistivity of the composite wire is measured to be zero at ≊90 K (in zero field) with a zero‐field critical density of ≊175 A/cm2. Microscopy and x‐ray analysis show that the superconduc...read more
Citations
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Journal ArticleDOI
Grain boundaries in high- T c superconductors
Hans Hilgenkamp,Jochen Mannhart +1 more
TL;DR: In this article, the authors provide a review of grain boundary properties and their applications in high-Tc superconductivity and high-power and electronic device applications, as well as the theoretical models developed to describe grain boundary behavior.
Journal ArticleDOI
High critical currents in iron-clad superconducting MgB2 wires.
TL;DR: The successful fabrication of dense, metal-clad superconducting MgB2 wires is reported, and a transport Jc in excess of 85,000 A cm-2 at 4.2 K is demonstrated, showing that although M gB2 itself does not show the ‘weak-link’ effect characteristic of the high-Tc superconductors, contamination does result in weak-link-like behaviour.
Journal ArticleDOI
Water interaction with the superconducting YBa2Cu3O7 phase
TL;DR: The superconductivity of YBa2Cu3O7 samples is greatly degraded by the interaction with water and humid air as discussed by the authors, which is probably due to the presence of nonequilibrium Cu3+ ions in this compound, but it should not preclude practical application of these materials since it should be possible to protect them with coatings of metal, glass, or plastic.
Journal ArticleDOI
Chemistry. A new twist on molecular shape.
TL;DR: What are the forces that control the twisting and folding of molecules into complex shapes?
Journal ArticleDOI
Superconductivity in the Bi-Sr-Ca-Cu-O compounds with noble metal additions
TL;DR: In this article, the resistivity and magnetic susceptibility measurements on sintered Bi4Sr3Ca2Cu4O16+x containing 20% by weight of Au, Ag, or Pt-group metals indicate that Au and the Ptgroup metals significantly suppress or eliminate the superconducting transition in BiSr•Ca•Cu•O.
References
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Journal ArticleDOI
Possible high Tc superconductivity in the Ba-La-Cu-O system
TL;DR: In this paper, Ba−La−Cu−O system, with the composition BaxLa5−xCu5O5(3−y) have been prepared in polycrystalline form, and samples with x=1 and 0.75,y>0, annealed below 900°C under reducing conditions, consist of three phases, one of them a perovskite-like mixed-valent copper compound.
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Superconductivity at 93 K in a new mixed-phase Y-Ba-Cu-O compound system at ambient pressure
Maw-Kuen Wu,J. R. Ashburn,C. J. Torng,Pei-Herng Hor,R. L. Meng,Li Gao,Z. J. Huang,Yongmei Wang,Ching-Wu Chu +8 more
TL;DR: A stable and reproducible superconductivity transition between 80 and 93 K has been unambiguously observed both resistively and magnetically in a new Y-Ba-Cu-O compound system at ambient pressure.
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Bulk superconductivity at 91 K in single-phase oxygen-deficient perovskite Ba 2 YCu 3 O 9 − δ
Robert J. Cava,Bertram Batlogg,R. B. van Dover,Donald W. Murphy,Steven A. Sunshine,Theo Siegrist,J. P. Remeika,Edward A. Rietman,S. M. Zahurak,G. P. Espinosa +9 more
TL;DR: Observation de la transition supraconductrice a 91 K, sur 1,5 K and determination of the densite de courant critique, de l'effet Meissner, du champ critique, du parametre de Sommerfeld, de parametres GL.
Journal ArticleDOI
Evidence for superconductivity above 40 K in the La-Ba-Cu-O compound system.
TL;DR: An apparent superconducting transition with an onset temperature above 40 K has been detected under pressures in the La-Ba-Cu-O compound system synthesized directly from a solid-state reaction of La/sub 2/O/ sub 3/, CuO, and BaCO/sub 3/ followed by a decomposition of the mixture in a reduced atmosphere.
Journal ArticleDOI
Bulk superconductivity at 36 K in La1.8Sr0.2CuO4.
TL;DR: The results of resistivity and magnetic susceptibility measurements in La/sub 2-//sub x/Sr/sub X/CuO/sub 4/ for x less than or equal to 0.3 were reported in this article.