PRODUCTION OF RARE EARTH-BARIUM-COPPER-OXYGEN OXIDE SUPERCONDUCTING MATERIAL

摘要

PROBLEM TO BE SOLVED: To provide a producing method of RE-Ba-Cu-O oxide superconducting material in a large size having characteristics of higher magnetic repulsive force and coercive force. ;SOLUTION: A RE compd., a Ba compd. and a Cu compd. are weighed and mixed in such a manner that each component, by mol%, of the compsn. is included in the region surrounded by lines connecting the points A(35, 25, 40), B(35, 35, 30) C(15, 40, 45) and D(15, 30, 55) in a triangular coordinate which represents the component of RE, Ba and Cu (mol%). The mixture powder is calcined at 900-1500°C to obtain a calcined powder, which is then formed into pellets to obtain a pellet precursor. Then the precursor is heated at 990-1300°C into a coexistence state of solid and liquid and cooled to the temp of a seed crystal. A single crystal of NdGaO₃, Sr₂AlTaO₆ or Sr₂ AlNbO₆ is used as the seed crystal and is brought into contact with the precursor. Then the precursor is gradually cooled to room temp. while temp. gradient by 5-50°C/cm is generated with the seed crystal in the lower temp. side. Thus, a large oriented crystal of RE-Ba-Cu-O oxide superconductive material having the same crystalline direction as that of the seed crystal can be grown from the seed crystal as the base point.;COPYRIGHT: (C)1997,JPO