Characterization of superconductors using magnetooptic techniques

Abstract Direct observations and measurements of spatial magnetic flux distributions on the surfaces of YBaCuO superconducting thin films and thin single crystals realized under application of external magnetic field and transport current are accomplished using magneto-optical indicators. These investigations are compared with theoretical calculations yielding critical current densities. Special attention is paid to the influence of defects on the magnetic properties. Furthermore, specific features of flux penetration into flat superconductors are revealed.