RESONANT RUTHERFORD BACKSCATTERING STUDIES OF CERIUM OXIDE THIN-FILMSDEPOSITED BY RF-SPUTTERING

We have studied the stoichiometry of cerium oxide films deposited by R F sputtering on sapphire and MgO as a function of deposition condition s using the resonant Rutherford backscattering method. We found that s ome films have the off-stoichiometry of CeOy with y greater than 2.0. Such an off-stoichiometry cannot be due to a mixture of the known phas es of bulk cerium oxide samples. This may be due to either cerium vaca ncies or interstitial oxygen atomic impurities. The cerium ion x-ray p hotoemission spectra of those films cannot determine the vacancy of th e cerium ions. The c-axis YBaCuo thin flims deposited by sputtering on the CeO3.3 buffer layer on saphhire was found to be epitaxial. The T- c was 86 K with Delta T-c less than 1 K.