ANGLE-RESOLVED CRITICAL TRANSPORT-CURRENT DENSITY OF YBA2CU3O7-DELTA THIN-FILMS AND YBA2CU3O7-DELTA/PRBA2CU3O7-DELTA SUPERLATTICES CONTAINING COLUMNAR DEFECTS OF VARIOUS ORIENTATIONS

Epitaxial YBa2Cu3O7-delta thin films irradiated with swift heavy ions under different directions showed a strongly changed angular dependence of the critical current density J(c) (B, T, theta) in the mixed state. Additional peaks, which dominate the angular dependence of J(c), appear at angles where the magnetic field is parallel to the irradiation direction, due to the strong pinning of the introduced linear defects. Irradiated YBa2Cu3O7-delta/PrBa2Cu3O7-delta superlattices, however, reveal no additional J(c) peaks but an isotropic J(c) enhancement in a wide angular range. This contrary behavior could be explained by flux lines of different dimensionality.