Effect of Ag on Microstructure and Superconducting Properties of Bi2Sr2CaCu2Ox

  • H. Kumakura
  • T. Hasegawa
  • H. Kobayashi
  • H. Kitaguchi
  • K. Togano
  • H. Maeda
Part of the An International Cryogenic Materials Conference Publication book series (ACRE, volume 40)

Abstract

Transport critical current density Jc of polycrystalline high-Tc oxide superconductors are usually small due to the weak couling of grains. For the Bi-based oxide superconductors, grain coupling is significantly improved by the c-axis grain alignment and high transport Jc was obtained. Especially, for the Bi2Sr2CaCu2OX(Bi-2212), high degree of grain alignment is obtained by the slow cooling and solidification from the partially molten state on Ag substrate.1 By this grain alignment, excellent transport Jc values over 105A/cm2 are attained at 4.2K even in high magnetic fields above 25T. In this solidification process, Ag substrate plays very important roles in the alignment of plate-like Bi-2212 grains.2 During the heat treatment, Bi-2212 decomposes into partially molten state consisting of Bi-free phase, Cu-free phase and liquid phase.3 Ag enhances this decomposition of Bi-2212, and also lowers solidification temperature of Bi-2212 during slow cooling process.4 However, the effect of Ag on the microstructural changes during heating and cooling process is not well investigated yet. Such an investigation is important for the understanding of role of Ag on grain alignment.

Keywords

Oxide Layer Molten State Oxide Superconductor Composite Tape Transport Critical Current Density 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Science+Business Media New York 1994

Authors and Affiliations

  • H. Kumakura
    • 1
  • T. Hasegawa
    • 2
  • H. Kobayashi
    • 2
  • H. Kitaguchi
    • 1
  • K. Togano
    • 1
  • H. Maeda
    • 1
  1. 1.National Research Institute for MetalsTsukuba 305Japan
  2. 2.Showa Electric Wire & Cable Co. Ltd.Kawasaki 210Japan

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