Influence of substrate-film interface engineering on the superconducting properties of YBa2Cu3O7-δ

The atomic stacking sequence at the substrate-film interface plays an essential role in the heteroepitaxial growth of REBa2Cu3O7-delta. During initial growth, the interface configuration influences the surface morphology and structural properties of the film, due to the formation of anti-phase boundaries (APBs) by coalescence of islands with different stacking sequences. In this study, the interface configuration is accurately controlled by both the terminating atomic layer of the SrTiO3 substrate and the stoichiometry of the first unit cell layer. Using this capability the network of APBs and, therefore, the in-plane ordering is tuned, allowing the study of its influence on the structural and electrical properties of the YBa2Cu3O7-delta film. The critical temperature T-c is depressed by increase of the in-plane ordering, which strongly indicates that the presence of APBs in the sample favors the oxygen in-diffusion. (C) 2004 American Institute of Physics.