2-DIMENSIONAL NATURE OF THE CRITICAL-CURRENT ANISOTROPY IN EPITAXIAL ND1.85CE0.15CUO4-DELTA THIN-FILMS

We report our studies of the angular magnetic field dependence of the critical current density in epitaxial thin films of Nd1.85CuO4-delta i n the temperature range 1.4 K to 14 K. At low temperatures, the critic al current anisotrophy is well described by the 2D model of Josephson- coupled vortices. At temperatures above 10K, we observe deviations fro m the 2D behavior which may be attributed to the temperature dependenc e of the coherence length. The field dependence of the critical curren t density for the field orientation parallel to the CuO2 planes is con sistent with the dimensionality indicated by the angular dependence at all temperatures.