ON THE MAGNETIC-BEHAVIOR OF BSCCO(2223) AG TAPES

Pressed and rolled BSCCO(2223) Ag tapes have been widely characterized by SQUID magnetometry with the applied field both parallel and perpendicular to the c-axis. The main results can be summarized as follows: (1) at low temperature (T = 5 K), the anisotropy of the in-plane and out-of-plane current densities J(ab)/J(c) is estimated to be 50; (2) the magnetic response of the tapes indicates that both intergranular (transport) and intragranular contributions to the magnetic moment are present; (3) the samples show a strong degradation; (4) the hysteresis loops show a certain degree of erratic behavior due to frequent jumps; (5) besides this erratic behavior, other anomalies of the hysteresis loops are present: in particular the anomalous field position of the maxima of the magnetization; (6) in bent samples, representing the intragranular magnetization only, all the anomalies disappear and the hysteresis loops are regular; (7) the intergranular magnetization, obtained by subtraction of the magnetic moments measured on the not-bent and bent sample,gives a current density which is irreversible for increasing and decreasing magnetic field, as seen also in transport measurements.