Effects of deposition conditions on the phase formation of YBCO films prepared by spray pyrolysis method

Abstract

YBa2Cu3Oy superconducting films were deposited on LaAlO3(100) single crystal substrates by spray pyrolysis method. Two types of ultrasonic and concentric nebulizer were used in order to generate fine droplets of metal-inorganic precursor solution. c-Axis oriented films were obtained at deposition temperature of 750–850°C and at working pressures of 100Torr and 500Torr. In case of ultrasonic nebulizer, the films showed rough surface morphology due to the presence of enormous droplets, whereas smooth and dense films were obtained for concentric nebulizer. The good c-axis oriented YBCO films were formed at the wide range of the oxygen partial pressure. Oxygen which is generated via the decomposition of nitrate precursors is considered to participate in the formation reaction of YBCO film. Microstructures of YBCO films varied depending on oxygen partial pressure and rod-like grains were appeared when the oxygen partial pressure was lower than 30Torr. YBCO films were deposited epitaxially on LAO(100) substrate. Δϕ of in-plane and Δω of out-of-plane texture were measured as 3.3° and 1.0°, respectively. A transport Jc value of 0.50MA/cm2 at 77K and self-field was achieved for the YBCO film deposited on LaAlO3(100) single crystal substrate.