Critical current density of the YBa sub 2 Cu sub 3 0 sub (7-delta) superconductor as affected by microstructural control.

The recent discovery of the YBa sub 2 Cu sub 3 0 sub (7-delta) type high T sub c superconductors stimulated worldwide R&D interest in this field. However, the relatively low critical current density (J sub c) in the polycrystalline, bulk superconductors (as well as its significant deterioration in weak magnetic fields) has been a major roadblock to the rapid technical advancement toward applications. In this paper, we investigated the effect of processing and microstructural control on J sub c of the superconductor. Improved J sub c values of ~3100 A/cm sup 2 at 77K with somewhat reduced field dependence have been obtained through appropriate microstructural modifications.