PRODUCTION OF OXIDE SUPERCONDUCTIVE MATERIAL

摘要

PURPOSE:To improve the crystallinity by gradually cooling a specified fused material while allowing it to take oxygen under pressure in an atmosphere composed mainly of oxygen. CONSTITUTION:A raw material containing Y, Ba and Cu and not containing a crystal of formula I (z is 6 to 7) nor a crystal of Y2BaCuO5 is prepared. This raw material is then heated and melted at a melting temperature lower than the decomposition reaction temperature of a peritectic of formula II and higher than the solid-liquid temperature thereof, i.e., at 980 to 1000 deg.C while preventing formation of a crystal of formula I or a crystal of Y2BaCuO5. The resultant molten material is subsequently gradually cooled while allowing it to efficiently take oxygen under application of pressure of >=10atm oxygen partial pressure in an atmosphere composed mainly of oxygen. A rhombic-system single crystal of formula III (x is 6.5 to 7) sufficiently grown in the direction of C axial is then grown while reducing formation of a twin to a low degree, thus producing the oxide superconductive material.