Novel understanding of the YBa2Cu3O7–x thin film growth

By combining the cross-sectional observation of the randomly oriented film areas and the analyses of the film microstructural influence by the substrate-surface morphology, we achieved a novel understanding of the YBa2Cu3O7–x (YBCO) thin film growth process, which leads to an explanation of different microstructures formed in YBCO thin films. Selective and competitive growth of YBa2Cu3O7–x and Ba–Cu–O/Cu–O was found to occur in the whole film growth process depending on the local surface roughness in which the interfacial energy played a controlling role.