CROSS-SECTIONAL TEM INVESTIGATIONS OF THE MICROSTRUCTURE AND FILM-SUBSTRATE INTERFACE IN Y-BA-CU-O THIN-FILMS

Superconducting Y-Ba-Cu-O films deposited on yttria-stabilized zirconia (YSZ) and SrTiO3 substrates have been studied by transmission electron microscopy. The films were elaborated by RF diode sputtering, the annealing procedure being performed ex-situ, at temperatures close to 900-degrees-C. Characterization by X-ray diffraction and resistivity measurements shows that the films mainly consist of the desired 123 phase. The c-axis perpendicular orientation has been obtained whatever the substrate orientation with YSZ and with (100) oriented SrTiO3. We report here the results of the cross-sectional TEM investigations of the microstructures and film/substrate interfaces. The presence of a 300 nm thick intermediate layer in films deposited on YSZ is reported while HREM studies clearly show the epitaxial growth of the 123 phase on SrTiO3 (100).