PRODUCTION OF OXIDE SUPERCONDUCTING MATERIAL

摘要

PURPOSE:To obtain the superconducting material having a negative Hall coefficient of a carrier and three-dimensional electric characteristics by treating a specified compd. derived from a perovskite-type copper oxide at high temp. in the mixture of an inert gas and gaseous oxygen. CONSTITUTION:A compd. is synthesized by substituting 16.7-20atom% of the La ion (trivalent) of the perovskite type copper oxide shown by formula I (M is Sr or Ba) for the M ion (bivalent). The compd. is then heat-treated at high temp. in the mixture of an inert gas and 1-20% gaseous O2 to obtain the desired oxide superconducting material. The Fermi level is appropriately positioned by the heat treatment, and the superconducting material having 28K Tc is obtained. The materials obtained by heat-treating the materials shown by formula II (M is Sr and X=0.167''' 0.20) and formula III (M is Ba and X=0.167''' 0.20), etc., in an inert gas contg. 10-20% O2 are exemplified as the oxide superconducting material.