Melt-textured growth of polycrystalline YBa sub 2 Cu sub 3 0 sub (7-delta) with high J sub C at 77K.

The progress toward major applications of the YBa sub 2 Cu sub 3 0 sub (7-delta) type high T sub c superconductor has been hindered by low critical current densities (J sub c) and their significant deterioration in weak magnetic fields. The present work demonstrates that these problems can successfully be overcome through proper microstructural control using a molten oxide processing. Melt-textured growth of YBa sub 2 Cu sub 3 0 sub (7-delta) from a supercooled melt created an essentially 100% dense structure consisting of locally aligned, long, needle-shaped grains (typically 40-600micron in length). The needles appear to have their long axes parallel to the conduction plane (basal plane) of the orthohombic structure, with a low-angle orientation change between adjacent grains.