Preparation and Characterization of Y High Tc Superconducting Thin Fi

For thin film metalorganic chemical vapor deposition (MOCVD), a stoichiometric gas phase can be obtained from a mixture of the precursors in the desired mole ratios, in spite of differences in the volatilities of the individual compounds. Proper film composition is obtained by controlling the velocity of a carriage containing the precursors through the heating zone of a vaporizer. YBaCuO (YBCO) superconducting films were prepared on yttrium stabilized zirconia (YSZ) (001) crystal substrates by single source MOO using a mixture of powders of Y(thd)a, Ba(thd)z and Cu(thd)Z as sources. Nondestructive measurements of resistivity, critical current, composition, and surface morphology were performed on these films. A single crystal film with T,, = 89 K was made under optimum con- ditions. Its homogeneity was investigated by resistivity and T,, measurements and by atomic force microscopy (AFM) at several points of the surface along a diameter of this film. The roughness of the film is higher at the edge than at the center, and this appears to be correlated with the normal state resistivity. The e-axis and u-axis YBCO phases compete with each other at substrate temperatures ranging from 750 to 820°C. The e-axis .vaiv