The critical current density and the vortex pinning in high quality YBa2Cu3O7-d thin films

Abstract

We have measured the critical current density J_c of high quality c-axis oriented YBa₂Cu₃O_7-d thin films. Measurements were performed for various magnetic field and temperature values, and as a function of the angle q between the c-axis and the applied magnetic field direction. A maximum of the critical current density was obtained when the flux lines are aligned along the CuO planes (q = 90°); another maximum in J_c was also observed when the magnetic field is adjusted parallel to the c-axis. We attribute these effects to different, intrinsic and extrinsic, pinning mechanisms of vortices in the sample.