ab-plane anisotropy of the critical currents in twinned YBa2Cu3O7-delta superconductors

We show that the in-plane critical current density of heavily twinned YBa2Cu3O7-delta thick films is anisotropic, depending on the relative orientation between the transport electrical current and the twin boundary mosaic. We demonstrate that the critical current density in an applied magnetic field can be substantially increased by producing conductors with twin boundaries tilted 45 degrees with respect to the electrical current flow. We show that these findings can be readily incorporated to improve the critical currents of biaxially textured YBa2Cu3O7-delta thick films deposited on metallic substrates. (C) 1996 American Institute of Physics.