Imaging of vortex flow in microstructured high-Tc films by laser scanning microscope

We studied the YBa2Cu3O7 thin films with arrays of antidots by imaging the resistive photoresponse with a laser scanning microscope. The films were initially covered by a thin Au layer, which we removed in order to improve the spatial resolution and imaging contrast. This procedure did not change the superconducting properties of the samples. The improved spatial resolution allowed for visualizing the individual flow channels of vortices. The reported measurements with the laser scanning microscope feature direct measurements of the local critical currents of the samples. We show that minor variations of the bias current leave the spatial distribution of vortex flow channels unchanged.