OXYGEN-CONTENT AND DISORDER OF A-AXIS YBACUO FILMS WITH VERY HIGH CRYSTALLINITY STUDIED BY RESONANT RUTHERFORD BACKSCATTERING

Highly crystalline a-axis films were deposited by the hybrid sputterin g method, and the conventional DC-template sputtering method. The film s prepared by hybrid sputtering have very low T-c while those prepared by the DC-template method have T-c close to 90 K. The oxygen contents and disorder were studied by the resonant RES method. We found that t he oxygen contents of the films deposited by hybrid sputtering depende d on the deposition temperature. Oxygen deficiency can be the reason f or the poor superconducting properties of those films deposited by hyb rid sputtering. A highly crystalline film deposited by DC template spu ttering had T-c close to 90 K but was found to be off-stoichiometric a nd to have depth-dependent oxygen disorder. The disorder at the Ba and O sublattices of those highly crystalline a-axis films was found to b e uncorrelated.