Anisotropy of the critical current density in high quality YBa2Cu3O7-delta thin film

We have investigated the transport critical current density J(c) as a function of the angle theta between the crystallographic c-axis and the applied magnetic field in high quality YBa2Cu3O7-delta thin film. Measurements were performed for various temperature and magnetic field values. Our results show that the critical current density maximum occurs when the applied magnetic field is parallel to the ab planes (theta = 90 degrees)The angular dependence of the critical current density shows the existence of the intrinsic pinning between the CuO2 layers for H parallel to the ab planes and the extrinsic pinning in the configuration where the magnetic field is parallel to the c-axis. We have analyzed our results in the framework of the intrinsic pinning model proposed by Tachiki and Takahachi.