EFFECT OF Y2BACUO5 INCLUSIONS ON FLUX PINNING IN YBA2CU3O7-DELTA

The effect of Y2BaCuO5 (211) inclusions on flux pinning in the YBa2CU3O7-delta (123) superconductor has been investigated. Intragranular J(c) has been measured on samples containing various amounts of dispersed (211) particles (0%-44%) with various particle sizes ( 1.3-10.4-mu-m). The results clearly show that the presence of (211) particles (at least down to the micron size level) neither significantly enhances the flux pinning nor deteriorates J(c). The observed insensitivity of J(c) to the variation in the total particle surface area indicates that the likelihood of a substantial interface-pinning effect is minimal. While the (211) inclusions appear to assist in the peritectic reactions resulting in better microstructural perfection during melt processing, particle size needs to be controlled to a much finer scale in order for them to serve as efficient pinning centers.