Method for production of superconducting oxide tape and superconducting oxide tape produced thereby

摘要

A method for the production of a superconducting oxide tape having a Bi2Sr2Ca2Cu3O10 (Bi-2223) structure interposed between silver sheets, which method consists essentially of preparing a sandwich structure having interposed between silver sheets a molded layer of a superconducting oxide precursor powder consisting essentially of Bi, Pb, Sr, Ca, Cu, and O obtained from a raw material substance composed of, in atomic composition ratio, 1.00 of Bi, 0-0.2 of Pb, 0.9-1.1 of Sr, 0.9-1.1 of Ca and 1.3-1.7 of Cu, and O, heating the sandwich structure in an atmosphere consisting of oxygen and an inert gas, having an oxygen partial pressure in the range of 0-5%, and kept at a temperature in the range of 830-850 DEG C., thereby melting the molded layer, then causing the atmosphere to retain the heating temperature and meanwhile increasing the oxygen partial pressure, thereby inducing precipitation of crystal grains possessing a Bi2Sr2CaCu2O8 (Bi-2212) structure and excelling in orientation, and subsequently maintaining the oxygen partial pressure and temperature at the time of precipitation of the crystal grains, thereby transforming the structure into the (Bi-2223) structure while retaining the particle diameter of the crystal grains and the state of orientation, and superconducting oxide tape produced by the method.