Growth of YBa₂Cu₃O_7-δ on vicinally polished MgO substrates

YBaCu₃O_7-δ thin films were grown on vicinally polished MgO [001] substrates. The orientation of the films is strongly influenced by the substrate surface normal, with only very weak alignment to the substrate [001] crystallographic direction. Vicinal angles of 1°, 2.5°, and 5°toward [010] produced films with large mosaic spread parallel to the vicinal angle [as high as 4°full width half maximum (FWHM) for the 5°sample] and with critical current densities as high as films grown on on-axis substrates (e.g., 4.4×10⁷ A/cm²). Samples on 10°and 20°vicinal substrates showed a reduction in mosaic spread but still alignment to the surface normal, and weak and strong reductions of the critical current density, respectively.