MAGNETIZATION AND FLUX CREEP IN AG-SHEATHED HIGH-JC TAPE OF BI-PB-SR-CA-CU-O

Magnetic relaxation M(t) for remanent magnetization is studied on the Ag-sheathed tape of Bi-Pb-Sr-Ca-Cu-O with transport J(ct) = 13000 A/cm2 (77K, H = 0 Oe), a nearly-pure high-T(c) phase and highly-oriented microstructure. A correlation between the starting magnetization M(i) = M(t(i)) and the creep rate R = d(4-pi-M)/dlnt appears in the result for H perpendicular-to c, and the empirical relation \R\ is-proportional-to M(i) stands for the full critical-state with a full flux-entry. The field-independent activation energy U(st) in the full critical-state increases linearly with temperature, which is consistent with the relation \R\ is-proportional-to M(i). No difference appears in the temperature dependence of U(st) between H perpendicular-to c and H parallel-to c.