CURRENT-VOLTAGE CHARACTERISTICS AND QUASI-2-DIMENSIONAL VORTEX-GLASS TRANSITION IN EPITAXIAL BI2SR2CA2CU3O(X) FILMS

The existence of a quasi-two-dimensional vortex-glass-liquid transition has been demonstrated in the scaling analysis of non-linear current-voltage characteristics in epitaxial Bi2Sr2Ca2Cu3Ox films in magnetic fields applied parallel to the c-axis. In the vortex-glass regime below the vortex-glass-liquid transition temperature T-g, the linear resistivity rho(lin) = (E/J)(J-->0) appears to vanish, while in the vortex-liquid regime the logE versus logJ curve shows systematic upward curvature and a finite linear resistivity is observed. At T-g a power-law relation E approximate to J(6.5) is, seen. The irreversibility fields B* determined by transport measurements are much higher than the vortex-glass transition fields B-g, implying that finite critical current densities are defined by conventional criteria in the pinned vortex-liquid regime.