EFFECT OF MECHANICAL GRINDING ON THE TRANSPORT CRITICAL-CURRENT DENSITY AND THE FLUX-PINNING FORCE OF A YBA2CU3OY-AG COMPOSITE SUPERCONDUCTOR

The effect of mechanical grinding (MG) on the physical properties, esp ecially the transport critical current density J(c) and the global pin ning force F-p, of a YBa2Cu3Oy-Ag composite superconductor was examine d. J(c) and F-p increase with the addition of Ag. J(c) of the samples not exposed to MG treatment (no-MG-sample) shows a maximum value at ab out 4 wt.% Ag, while that of the samples which are exposed to MG treat ment (MG-sample) is almost constant, independent of Ag content. F-p of the MG-sample is larger than that of the no- MG-sample. The density o f the grain boundary and the configuration of Ag in the samples seem t o be much affected by MG treatment.