Superconducting YBa2Cu3O7-δ textured films on MgO substrates

Thin films of high-Tc superconducting YBa2Cu3O7-δ were prepared by solid-state reaction using (100) MgO substrates and methanol mixtures of Y2O3, Ba(NO3)2, and CuO powder. The paste-coated air dried samples were heated up to 1140 0C in an oxygen flow by three consecutive steps. X-ray diffraction patterns of a 5 μm thick film indicate that the sample consists of single-phase YBa2Cu3O7-δ whose (001) plane is parallel to the (100) MgO substrate and whose lattice constant c is 1.1703 nm. The Meissner effect was confirmed by measuring the temperature dependence of the inductance of the rf coil in which the system film/MgO was placed. The onset temperature and Tcm were found to be about 115 K and 108 K, respectively for films of 5 μm thickness