LOW MAGNETIC-FIELD STUDY OF AC LOSSES ON MONOCORE BI-2223 AND TL-1223SILVER-SHEATHED TAPES

We present the results of a.c. loss measurements of silver clad monoco re 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 th ose generated by a.c. transport currents (self-field losses). Experime ntal results, obtained by both methods, show that energy losses are pu rely 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 met hod. The dependence of the transport current losses on the d.c. magnet ic field is also presented. The experimental results are compared with theoretical predictions based on the critical state model. (C) 1997 P ublished by Elsevier Science Ltd.