AC loss of YBCO coated tape prepared by laser ablation

Abstract

AC transport loss of YBCO coated tape 4 mm wide has been investigated by standard experimental techniques. When used to evaluate the critical current of the tape in an indirect way, the results pointed toward the critical current exceeding 100 A at 77 K and zero superimposed DC field. Taking into consideration the extremely high aspect ratio of the superconducting layer, one would expect to observe the loss behaviour predicted for infinitely thin strip. However, in the case of AC transport, the loss dependence on current follows the formula derived for a strip with elliptical cross-section. The influence of the metal substrate on such behavior was experimentally excluded. To understand this result, additional experiments by field mapping over the sample carrying transport current have been performed. According these results the distribution of the transport current in the cross section of the sample fulfil the elliptical model prediction. © 2006 IOP Publishing Ltd.