Preparation and characterization of rf-sputtered Sr-doped lanthanum cuprate thin films on yttria-stabilized zirconia substrates

The LSCu thin film was deposited on a YSZ substrate by rf sputtering under a pressure of 5 mTorr with a 120 W rf power. A single tetragonal perovskite phase was obtained when the sample was subjected to heat-treatment at more than 500 °C in air for 2 h. However, a second phase was formed when the specimen was heat-treated at 800 °C. The electrical conductivity of LSCu film was about 131 S/cm when the specimen was heat-treated at 500 °C. The structure of LSCu was identified by X-ray diffraction (XRD). The chemical composition of LSCu films was analyzed using inductively coupled plasma-atomic emission spectrometry (ICP-AES), and X-ray photoelectron spectroscopy (XPS). The surface morphologies and the thicknesses of the LSCu films were examined by scanning electron microscopy (SEM). The electrical conductivities were investigated by four-point probe technique.