Y1Ba2Cu3O7-δ thin films grown by a simple spray deposition technique

The preparation of high Tc superconducting thin films of Y1Ba2Cu3O7−δ on (100) single crystals of MgO, ZrO2 with 9% Y2O3 (yttria stabilized zirconia, or YSZ), and SrTiO3 using a simple spray deposition technique is described. Typical film growth procedure involves (a) the spraying of a stoichiometric solution of the nitrate precursors on the heated substrate (180 °C), (b) prebaking in air of the sprayed film (20 min at 500 °C), and (c) oven annealing of the film under flowing O2 (900–950 °C followed by slow cooling to 200 °C in about 3 h). X-ray diffraction analysis of the films after each of the growing steps mentioned above shows primarily the presence of crystalline phases of the nitrates, the oxides, and the orthorhombic superconducting phase, respectively. Resistivity versus temperature measurements show that the onset and completion of the superconductive transition occur at 92 and 87 K, respectively, in films on YSZ substrate; at 95 and 80 K, respectively, in films on SrTiO3 substrate; and at 82 and 77 K, respectively, in films on MgO substrate.