Orientation of thin YBa2Cu3O7-δ/YSZ films characterization by micro-Raman spectroscopy

Micro-Raman scattering of thin YBa2Cu3O7-δ films of various thicknesses, deposited by pulsed laser deposition on the yttrium-stabilized zirconia (001) substrates, was carried out at different scattering geometries. The fraction of c-axis orientation of the films was calculated from the intensity ratio of the O(2,3)-B1g and O(4)-Ag modes. It is shown that it is strongly dependent on the film thickness and the highest fraction of c-axis orientation occurs for film thickness around 80 nm. The lower c-axis fraction for thinner films was explained by the simultaneous growth of a- and c-axis-oriented grains at the interface region, while the lower c-axis fraction for thicker films was due to the faults and voids in the films. Several a- and b-axis in-plane orientations have been identified using polarized Raman spectra. (author)