Influence of vortex-vortex interaction on critical currents across low-angle grain boundaries in YBa2Cu3O7-delta 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-o ptical imaging. By using a numerical inversion scheme of Biot-Savart's law, the critical current density across the grain boundary can be determined w ith a spatial resolution of about 5 mum. Detailed investigation of the spat ially resolved flux density and current density data shows that the current density across the boundary varies with varying local flux density. Combin ing the corresponding flux and current pattern, it is found that there exis ts a universal dependency of the grain boundary current on the local flux d ensity. Considering the magnetic vortex-vortex interaction in and in the vi cinity of the grain boundary, a model is developed that is able to describe the experimental data.