CRITICAL-CURRENT ANISOTROPY IN EPITAXIAL ND1.85CE0.15CUO4-DELTA THIN-FILMS

We report the angular magnetic-field dependence of the critical curren t density in epitaxial thin films of Nd1.85Ce0.15CuO4-delta in the tem perature range 1.4 K to 14 K. At low temperatures, the critical curren t anisotropy is well described by the 2D model of Josephson-coupled la yers. Above 10 K we observe deviations from the 2D behavior which may be attributed to the temperature dependence of the coherence length an d the influence of the anisotropy of the upper critical field. The fie ld dependence of the critical current density for the field orientatio n parallel to the CuO2 planes is consistent with the dimensionality in dicated by the angular dependence.