TRANSPORT CURRENT-ACTIVATED FLUX-CREEP IN HIGH-T-C SUPERCONDUCTOR THIN-FILMS

This paper discusses the relaxation of a magnetic flux trapped in a su perconducting film under the action of a transport current. The evolut ion of the magnetization after the first jump, at the moment the Loren tz force appears, has been found to obey the creep laws. The effective pinning potential has been obtained as a function of transport curren t. The distribution of the pinning forces is presented and its statist ical properties considered. The standard deviation of the pinning forc es is the same for films prepared using the same technique, while the expectation values characterize the attainable critical current densit y. A criterion for estimating the quality of thin films from the distr ibutions of the pinning forces is formulated.