Anisotropy and field dependence of critical current density in YBa2Cu3O7-delta epitaxial thin film

The critical current density J(c) of the epitaxial YBa2Cu3O7-delta thin film was measured as a function of applied magnetic field H up to 6 T for three special configurations: (1) H parallel to c axis and H perpendicular to J; (2) H perpendicular to c axis and H perpendicular to J; (3) H perpendicular to c axis and H parallel to J. We observed a large anisotropy of J(c)(H) between H parallel to c axis and H perpendicular to c axis with H perpendicular to J, and a very small anisotropy of J(c)(H) between H parallel to J and H perpendicular to J with H perpendicular to c axis. The field dependence of the critical current density can be well described by the modified Kim-Anderson model taking into account the Kramer scaling law. The weak dependence of the transport critical current density on its orientation relative to the applied magnetic field is discussed. (C) 1997 American Institute of Physics.