EVIDENCE OF DEFECT PINNING IN THE SUPERCONDUCTING BI-(PB)-SR-CA-CU-O SYSTEM

Comparative studies on Bi-2212 single crystal, Bi-2212 tape and 2223 t ape have been carried out using ac susceptibility, magnetization and m agnetoresistivity measurements. It was found that the pinning strength increases with sequence of 2212 single crystal, 2212 tape and 2223 ta pe. This is consistent with results of the pinning potential, U-0, det ermined by using resistance measurements in magnetic fields. The diffe rences in flux pinning are attributable to the different processing co nditions which result in the difference in dislocation density.