Spectroscopic ellipsometry studies of YBa sub(2)Cu sub(3)O sub(7- delta ) deposited on SrTiO sub(3)

The dielectric function epsilon = epsilon sub(1) - i epsilon sub(2) of the YBa sub(2)Cu sub(3)O sub(7- delta ) high-T sub(c) superconducting films grown on (100) SrTiO sub(3) (c-axis oriented) and (110) SrTiO sub(3) (ab-oriented) substrate was measured by spectroscopic polarization modulation ellipsometry (SPME) and changes in film orientation were studied by comparing films of various thicknesses. The films deposited on SrTiO sub(3) (100) substrates demonstrated an isotropic epsilon sub(1) that changed with film thickness. It is observed that the decrease in the metallic dielectric behavior associated with the increase in the thickness of the films grown on (100) SrTiO sub(3) substrates is mainly due to a change in the orientation of the films.