PARAMAGNETISM AND SCALING BEHAVIOR OF VOLUME FLUX-PINNING FORCE DENSITY IN A GDBA2CU3O6-FILM(X THIN)

Magnetic measurements have been performed on a GdBa2Cu3O6+x supercondu cting thin film. The paramagnetism carried by rare earth Gd3+ ions in the film tilts the magnetic hysteresis loop and broadens the width of the magnetic hysteresis Delta M, then the magnetization critical curre nt density and the volume flux pinning force density based on the Bean critical state model deviate from intrinsic values. Therefore, in ord er to get useful information on the pinning mechanism, correction for the paramagnetism is essential. And after correction for the paramagne tism, a scaling law of the volume flux pinning force density is obtain ed as f(b)=(b/4)(0.5)(1-b/4)(1.5), based on which the possible pinning mechanism in the film is discussed. In the end, deviation from the sc aling law at high fields is interpreted by the collective pinning theo ry. (C) 1995 American Institute of Physics.