Effect of cation composition on the superconducting properties and on the microstructure of YBaCuO thin films

The surface morphology and superconducting properties of YBaCuO epitaxial films prepared through magnetron sputtering from targets of different cation composition were systematically studied. It was shown that small changes in the growth conditions and relatively small variations in the cation composition of the condensate noticeably affect the surface morphology of the films and their structural and superconducting properties, thus offering an efficient way of controlling the YBCO film parameters. It was found that the 90° off-axis configuration of the magnetron sputtering system permits realization of growth conditions in which the grown films do not contain CuO precipitates and exhibit good superconducting properties (T_c≥88 K, j_c(77 K)≥4×10⁶ A/cm²).