RESISTIVE TRANSITION IN TLBISRCACUO THIN-FILMS IN MAGNETIC-FIELDS

The resistive transition for ac-axis oriented (Tl, Bi)Sr2Ca2Cu3Ox thin film with acritical temperature of 106 K was investigated in magnetic fields up to 9 T. The magnetic field-induced resistive transition shows a considerable anisotropic broadening behavior; a much broader transition in the field perpendicular to the ab-plane than in a parallel field. This behavior is strongly influenced by the magnetic field component perpendicular to the ab-plane. The resistivity in magnetic fields approaches zero exponentially versus temperature. The activation energy U0(0) deduced from the slope of the Arrhenius curve is expressed by the power law of U0 (0) is-proportional-to B - 1. The resistive transition in magnetic fields for (Tl, Bi) Sr2Ca2Cu3Ox is attributed to thermally activated flux creep.