| 摘要 |
PROBLEM TO BE SOLVED: To provide a 123 superconductor of rare-earth series which is simple to manufacture and ensures a high irreversible magnetic field. SOLUTION: In the 123 superconductor of rare-earth series which gives the substance represented by the chemical formula of REBa2 Cu3 O7-d (wherein RE is a rare-earth element) as the main element, substituting a portion of RE with Ca ensures the performance that the irreversible magnetic field at the temperature of 77 K is not less than 10 T when applying the magnetic field in the direction of axis C. La, Nd, Sm, Gd or Eu is preferred as RE and in the chemical composition it is preferred that the values of (x) and (y) in RE1-x+y Cax Ba2-y Cu3 O7-d meet the requirements of 0<x<=0.1 and 0<=y<0.1, respectively and more preferably the requirements of 0.01<x<=0.05 and 0<=y<0.1.
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