Temperature-dependent critical current anisotropy in Bi-2223 tapes

Current-voltage characteristics of Bi-2223 tapes are measured between 4.2 and 100 K in magnetic fields up to 8 T. The transition temperature as obtained by a scaling analysis of the I-V curves is correlated to the anisotropy of the critical current density for two different orientations of the tapes with respect to the magnetic field. In addition the resistivity for low currents exhibits thermally activated behaviour. This implies a decoupling mechanism of the superconducting planes for the degradation of in a magnetic field at elevated temperatures.