Simultaneous micro-characterization of the superconducting and structural properties of high-T(C) superconducting films

Important information on the local values of the critical temperature and the critical current density in high-T(C) superconducting films is obtained by low-temperature scanning electron microscopy (LTSEM). The imaging principle of LTSEM is based on the local beam-induced heating effect and the detection of a voltage response signal in the current-biased specimen film. During the scanning process the sample is mounted on a low-temperature stage the temperature of which is electronically stabilized at some specific value in the range of interest. The local superconducting quantities measured by LTSEM can be correlated with the microstructure of the specimen film investigated by standard techniques. Recently we have studied polycrystalline and epitaxial YBaCuO films on various substrates, and the results are summarized. The spatial resolution of LTSEM has been found to approach 1 μm.