N-type oxide superconductor represented by the formula (Ndx(CeyLz)2CuO4-d where L is La, Mg or a mixture of alakaline earth elements

摘要

An oxide superconductor comprises a composition represented by the composition formula: (Ndx-Cey-Lz)2CuO4-d (wherein L is an element selected from Ca and Mg, and x+y+z=1). The compositions of Nd, Ce and L of the oxide superconductor corresponds to a point falling inside an area of Nd-Ce-L ternary diagram surrounded by straight lines (A-B), (B-C), (C-D) and (D-A) connecting point (A) with point (B), point (B) with point (C), point (C) with point (D) and point (D) with point (A), respectively, the points (A), (B), (C) and (D) being points (x=1, y=0, z=0), (x=0.4, y=0.6, z=0), (x=0.4, y=0.3, z=0.3) and (x=0.1, y=0, z=0.9), respectively, in the Nd-Ce-L ternary diagram. Above-described Nd-Ce-L-Cu-O oxides can exhibit superconductivity within a wide range of composition when heat-treated in an atmosphere of nitrogen.