STUDY OF CATHODOLUMINESCENCE IN HIGH-T(C) SUPERCONDUCTORS

We used cathodoluminescence (CL) in the Scanning Electron Microscope ( SEM) for studying different superconducting properties. CL measurement s were used to reveal and identify non-superconducting phases which ex isted in the Y1Ba2Cu3O6+X (YBCO) high T(C) superconducting samples. Th e spectra of the initial YBCO components i.e., Y2O3, BaCO3, CuO, as we ll as that of the commonly found impurity Y2BaCuO5 green phase were ob tained and their relative intensities deduced. The impurity luminescen t phases, which are commonly found in YBCO, had a typical spectra, whi ch distinguished them from one another. The influence of substrate def ects on the morphological and transport properties of YBCO high T(C) s uperconducting thin films was studied as well. The substrate defects w ere characterized by dispersive and nondispersive CL in the SEM. The m orphology of the films was studied by the secondary electrons and was locally compared with the substrate information. Defects in the substr ate induced surface variations in the thin films. The local (1 mum) th icknesses of the thin films were estimated by using CL method in SEM c ombined with image processing analysis. For single phase films, we dem onstrated the possibility to create thickness maps in real time from t he CL pictures. The surface coverage of the film was also deduced.