Comparative study of electron and laser beam scanning for local electricalcharacterization of high-T-c thin films and junctions

The development of spatially resolved methods for an electrical characteriz ation of thin films and junctions is essential for further progress in phys ics and applications of high-temperature superconductors. Two methods, elec tron beam and laser beam scanning, are used to get the high-resolution elec trical images. In this paper we present the results of the comparison of el ectron- and laser-induced responses of the same high-T-c Josephson junction s. Using a laser-beam-induced thermoelectric response at room temperature a nd its odd-symmetric behavior across the grain boundaries, we were able to visualize the grain boundary faceting in bicrystal high-T-c Josephson junct ions with the resolution of similar to 0.1 mu m.