NEW BUFFER MATERIALS FOR HIGH-TC SUPERCONDUCTING THIN-FILMS

We have tested La2O3, Gd2O3, Y2O3, Dy2O3, and PrO1.82 as new buffer materials for high T(c) superconducting thin films. These oxides are structurally compatible with the superconductors. The cubic phase of La2O3 cannot be stabilized and Nd2O3 films have mixed cubic and hexagonal phases in the temperature and pressure ranges used in the experiment. All other oxides are suitable and also chemically compatible with YBa2Cu3O7-delta superconductor. YBa2Cu3O7-delta thin films on these buffer materials have a superconducting transition temperature of 90 K. (100) oriented films of these oxides were not obtained on R-plane sapphire without a CeO2 seed layer.