Low magnetic field study of ac losses on monocore Bi-2223 and Tl-1223 silver sheathed tapes

We present the results of a.c. loss measurements of silver clad monocore tapes of Bi-2223 and Tl-1223 prepared by the powder-Zn-tube method. Losses arising from external a.c. magnetic field are compared with those generated by a.c. transport currents (self-field losses). Experimental results, obtained by both methods, show that energy losses are purely hysteretic in nature in the present range of applied frequencies (20-180 Hz). Critical current densities are derived from magnetic loss data and compared with those measured by the four-point transport method. The dependence of the transport current losses on the d.c. magnetic field is also presented. The experimental results are compared with theoretical predictions based on the critical state model. (C) 1997 Published by Elsevier Science Ltd.