OXIDE SUPERCONDUCTOR AND ITS PRODUCTION

摘要

PURPOSE:To suppress a mutual substitution of RE and Ba and to produce the superconductor having >=90K critical temp. in a RE-Ba-Cu-O series (RE is La, Nd or Sm.) superconductor. CONSTITUTION:The superconductor is composed of a composition of Re-Ba-Cu-O (RE is at least one element among rare earth elements of La, Nd and Sm.) and has the following structure. That is, a composition in which a ratio of RE:Ba:Cu is 1:2:3 and the ratio of O is 6.8-7.2 is used as a basal phase, and a dispersed phase in which the ratio of RE:Ba:Cu is (1+d):(2-d):3 (0=1% and <=30%. A size of the dispersed phase is <=5mum. In a melting process of the superconductor, at the time of solidifying and forming a superconductive phase from a molten state, an oxygen partial pressure is kept at >=0.00001atm and <=0.1atm. And a temp. of a molten state is kept at 1000-1500 deg.C.