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 arising from an external AC magnetic field are compared with those generated by AC transport currents (self-field losses), Experimental results, obtained by both methods, show that energy losses are purely hysteretic in nature in the range of applied frequencies (30-200 Hz). Critical current densities are derived from the magnetic-loss data and compared with those measured by the four-point transport method. Further, the dependence of the transport critical currents on the external DC magnetic field, for different geometrical configurations of the tapes with respect to the field, i.e. field parallel or perpendicular to the plane of the sample, are presented. The experimental results are compared with theoretical predictions based on the critical-state model.