DEPOSITION OF CEO2 FILMS INCLUDING AREAS WITH THE DIFFERENT ORIENTATION AND SHARP BORDER BETWEEN THEM

Epitaxial films from one material, with sharp borders between contacti ng regions having different film orientation are grown on one surface of the substrate for the first time. The main reason for the depositio n of thin ceria layers with mixed (001) and (111) orientations on a (< 1(1)over bar 02>) sapphire substrate is determined. We suggest that th is is related to the availability of surface defects which, in thin ne ar-surface layers, deviate from stoichiometric composition. This in tu rn is connected with the loss of oxygen. A technique for influencing C eO2 film orientation is demonstrated. This involves specific prelimina ry processing of the substrate, and the selection of oxygen partial pr essure during the deposition process. High quality thin (30-50 nm) ''p rotective'' (001) CeO2 epitaxial layers are prepared on (<1(1)over bar 02>) Al2O3. Structures comprising two epitaxial protective CeO2 layer s, orientations (001) and (111), are made on the base of (0001) and (< 1(1)over bar 02>) sapphire substrates. The interface between the epita xial layers is <1 000 nm. Preliminary results using this method are de scribed, and the possibility of creating a ''bi-epitaxial'' transition in thin YBa2Cu3O7-x layers is explored.