PURPOSE: To obtain a shielding body increased in material strength as well as in the maximum shielding magnetic field by adding and mixing specific amounts of silver into a calcined powder of Y-Ba-Cu oxide superconductor and subjecting the resulting mixture to burning and high temp. treatment under respectively specified conditions.
CONSTITUTION: Silver is add and mixed by about 0.1-2.0 moles into a calcined powder of Y-Ba-Cu oxide superconductor, and the above silver is dispersed by means of burning at a temp. not higher than the melting point of silver and is introduced into the grain boundaries of Y-Ba-Cu-O by means of high temp. treatment at about 1100°C for 30min. By this method, the potential energy of the secondary phase (insulating phase, etc.) of the above grain boundaries can be reduced. Further, by the presence of silver, a Y-Ba-Cu phase in which Y:Ba:Cu=2:1:1 is satisfied and which is capable of being a pinning center can be precipitated in the Y-Ba-Cu-O crystalline grains.
SAKAITANI SHOJI
HIRANO TOSHIMASA
HASUNUMA MASAHIKO
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