SIMS STUDY OF OXYGEN SPIRAL DIFFUSION C-TEXTURED Yba₂Cu₃O_7-\delta/SrTiO₃ EPITAXIAL THIN FILM

Secondary ion mass spectroscopy was used to study the chemical diffusivity of O¹⁸ in c-textured YBa₂Cu₃O_7-\delta/SrTiO₃ epitaxial thin film. By fitting experimental data to the one- dimensional diffusion curve, the apparent diffusivity along the c-axis was obtained to be equal to l.02×10¹⁴cm²/sec when the temperature was 350℃. A computer analysis method was put forward to calculate the "spiral diffusion" process, and the diffusivity anisotopy of films with different mosaic size obtained. For a film of 7000×7000?² mosaic size, Dab was found to be ～3.55×10^-5×exp((-1.03 ev)/kT) cm²/sec. The calculated results reveal that the variation of the results of Dc is not the result of diffusivity anisotropy but of the difference in mosaic size.