IRREVERSIBLE MAGNETIZATION AND CRITICAL CURRENTS IN SILVER-SHEATHED (BI, PB)(2)SR2CA2CU3O10+Y TAPE

Irreversible magnetization of an Ag-clad Bi(Pb)-Sr-Ca-Cu-O tape has be en measured in the temperature range 7 to 90 K in magnetic field B les s than or equal to 5 T applied perpendicular to the tape plane. Interg ranular (bulk) critical current density J(c)(B), deduced from the low Geld virigin moment m(v), extrapolates well to the transport critical current density J(c) of the same tape measured for T > 77 K. Both J(c) (B) and J(c) follow the same (1 - T/T-c)(n) variation with n approxima te to 1.5. The intragranular critical current density J(c)(G), deduced from the variation of remanent moment m(R) with maximum field H-m, de creases faster with temperature similar to exp(-T/T-0) with T-0 congru ent to 20 K for T less than or equal to 55 K) than J(c)(B) which resul ts in a J(c)(G)/J(c)(B) ratio that decreases with increasing temperatu re. Since J(c)(G)/J(c)(B) approximate to 16 at 77 K this leaves an amp le space for the enhancement of J(c)(B) (approximate to J(c)) in tapes . The temperature dependence of the irreversibility field B-irr is sim ilar to that of J(c)(G).