Critical current anisotropy in epitaxial Nd1.85Ce0.15CuO4−δ thin films

We report the angular magnetic-field dependence of the critical current density in epitaxial thin films of Nd 1.85 Ce 0.15 CuO 4-δ in the temperature range 1.4 K to 14 K. At low temperatures, the critical current anisotropy is well described by the 2D model of Josephson-coupled layers. Above 10 K we observe deviations from the 2D behavior which may be attributed to the temperature dependence of the coherence lenght and the influence of the anisotropy of the upper critical field. The field dependence of the critical current density for the field orientation parallel to the CuO 2 planes is consistent with the dimensionality indicated by the angular dependence.