FUNDAMENTAL AND HARMONIC SUSCEPTIBILITIES OF AN OXIDE SUPERCONDUCTOR SYNTHESIZED BY THE POLYMERIZED COMPLEX METHOD

To examine the utility of the Kim-Anderson model for the study of the magentic response of ceramic superconductors, we measured ac complex s usceptibilities chi(n) = chi(n)' - i chi(n)'' (n = 1, 2, 3) of an oxid e superconductor YBa2Cu2.95Co0.05Oy synthesized by the polymerized com plex method, and attempted to simulate the results in the framework of this model. Analyses of chi(n) have shown that generation of the harm onic susceptibilities can be reproduced pretty well by the model, wher e the material parameters k and B-0 involved were determined so as to give the best fit to the observed chi(n). Comparison of k which corres ponds to the pinning force against a flux quantum with those obtained for other ceramic specimens prepared by other methods have revealed th at k well reflects the sample quality in view of critical current dens ity.