Superconductor and method of producing same

摘要

A high critical temperature and high critical current density superconductor is disclosed which contains a metal oxide expressed by the following formula (I): (R11-x,Bax)Ba2Cu3Od(I) wherein R1 stands for at least one element selected from the group consisting of La, Nd, Sm, Eu and Gd, x is a number greater than 0 but not greater than 0.5 and d is a number between 6.2 and 7.2. Fine phases of RE211, RE422 and/or a metal oxide expressed by the formula (R21-z, Baz) (Ba1-y, R2y)2Cu3Op (R2=La, Nd, Sm, Eu or Gd) may be dispersed in a matrix of the matrix phase of the formula (I). The above superconductor may be obtained by cooling a melt having a temperature of 1,000 DEG -1,300 DEG C. and containing R1, Ba, Cu and O at a cooling rate of 5 DEG C./hour or less under a partial pressure of oxygen of between 0.00001 and 0.05 atm, followed by annealing at 250 DEG -600 DEG C. in an oxygen atmosphere.