Growth of YBa2Cu3O7−x thin films on sapphire with a cerium-oxide sublayer

The possibility is demonstrated of preparing high-quality films of the high-temperature superconductor YBa2Cu3C7-δ with thicknesses up to 2.6 µm by dc magnetron sputtering. It is found that inclusions consisting of CuO and YBa2Cu3O8 coexist with the growing film and are “sinks” for defects, nonstoichiometric atoms, and mechanical stresses. Using x-ray diffraction and Rutherford backscattering, we find that the structural perfection of the films is improved by increasing the thickness when using the proposed fabrication technique.