AC LOSSES AND CRITICAL CURRENTS IN AG (TL,PB,BI)-1223 TAPE/

The results of AC loss measurements of silver-sheathed (Ti,Pb,Bi)-1223 tapes prepared by the powder-in-tube method are presented. Losses ari sing from an external AC magnetic field are compared with those genera ted by AC transport currents (self-field losses), Experimental results , obtained by both methods, show that energy losses are purely hystere tic in nature in the range of applied frequencies (30-200 Hz). Critica l current densities are derived from the magnetic-loss data and compar ed with those measured by the four-point transport method. Further, th e dependence of the transport critical currents on the external DC mag netic field, for different geometrical configurations of the tapes wit h respect to the field, i.e. field parallel or perpendicular to the pl ane of the sample, are presented. The experimental results are compare d with theoretical predictions based on the critical-state model.