Influence of vortex-vortex interaction on critical currents across low-angle grain boundaries in YBa2Cu3O7-δ thin films -: art. no. 014507

Low-angle grain boundaries with misorientation angles theta <5<degrees> in optimally doped thin films of YBa2Cu3O7-delta are investigated by magneto-optical imaging. By using a numerical inversion scheme of Biot-Savart's law, the critical current density across the grain boundary can be determined with a spatial resolution of about 5 mum. Detailed investigation of the spatially resolved flux density and current density data shows that the current density across the boundary varies with varying local flux density. Combining the corresponding flux and current pattern, it is found that there exists a universal dependency of the grain boundary current on the local flux density. Considering the magnetic vortex-vortex interaction in and in the vicinity of the grain boundary, a model is developed that is able to describe the experimental data.