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 sputtering method, and the conventional DC-template sputtering method. The films 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 the oxygen contents of the films deposited by hybrid sputtering depended on the deposition temperature. Oxygen deficiency can be the reason for the poor superconducting properties of those films deposited by hybrid sputtering. A highly crystalline film deposited by DC template sputtering had T-c close to 90 K but was found to be off-stoichiometric and to have depth-dependent oxygen disorder. The disorder at the Ba and O sublattices of those highly crystalline a-axis films was found to be uncorrelated.