ENHANCED FLUX-PINNING BY PHASE DECOMPOSITION IN Y-Ba-Cu-O.

Significantly improved flux-pinning has been achieved in bulk YBa sub 2 Cu sub 3 O sub (7-delta) superconductor ('123' compound) containing fine-scale defects (-50 A thick). The measured J sub c(magn.) of ~10 sup 5 A/cm sup 2 at 77K, H = 0.9T is about ten times higher than the typical values for bulk Y-Ba- Cu-O. The improved structure was produced by rapid decomposition at 920C of the YBa sub 2 Cu sub 4 O sub 8 ('124') precursor. This new and simple processing route could lead to a commercially viable processing technique for flux-pinning enhancement in bulk Y-Ba-Cu-O.