MEASUREMENT OF SURFACE IMPEDANCE OF BI(PB)-SR-CA-CU-O FILM UNDER A DCMAGNETIC-FIELD

The temperature and DC magnetic field dependence of surface impedance (Z(s)) of high temperature superconducting Bi(Pb)Sr-Ca-Cu-O (BPSCCO) f ilms on MgO substrate were measured at microwave frequency. At a low t emperature, surface resistance (R-s) increases rapidly in the low DC m agnetic field range and gradually in the high-field range. However, th e surface reactance (X-s) also increases rapidly in low fields but har dly changes in high fields. At high temperature, R-s shows only a mono tonic increase vs the field but X-s hardly changes.