Neodymium-barium-copper-oxide bulk superconductor and process for producing the same

摘要

An Nd-Ba-Cu-O bulk superconductor includes oxide including metallic elements of neodymium (Nd), barium (Ba) and copper (Cu), and has a structure in which fine particles of Nd4Ba2Cu2O10 (i.e., Nd422) are dispersed uniformly in crystalline grains of NdBa2Cu3Ox (i.e., Nd123). It is produced by preparing a mixture powder in which an Nd123 powder and an Nd422 powder are present uniformly, thermally treating the mixture powder in a temperature range where the Nd123 powder melts partially at least but the Nd422 powder hardly melts, and gradually cooling the partially melted mixture powder in a temperature range around a solidifying point of the Nd123 powder. It exhibits an enhanced magnetic-field-trapping capability in the regions of low magnetic field, because of the pinning effect resulting from the fine particles of Nd422 dispersed uniformly in the crystalline grains of Nd123.