Preparation And Properties Of La_0.5Sr_0.5CoO₃and Ce_0.8Gd_0.2O_1.9-δ Buffer Layers

In recent years, conductive buffer layers have been involved to joint metal substrate and superconductive YBCO layer, which can transfer current from YBCO layer to metalic substrate so that the stability of electricity transmission can be increased. Developed countries have already done detailed research in conductive buffer layer, but domestically it is just in the starting stage. Metal organic deposition (MOD) method is popular in practice because it has many advantages such as low cost, no requirement of vacuum, uniform thickness of prepared films and easy operation of production devices.In this paper, La0.sSr0.5CoO3and Ce0.8Gd0.2O1.9-δ buffers were produced by MOD method. The XRD, SEM were adopted to study the crystal structure and surface morphology of films. Further, the influences of different precursor solution, heat treatment and atmosphere conditions on the properties of films were discussed.La0.5Sr0.5CoO3conductive buffer was produced on the surface of LaAlO3single crystal substrate by MOD. The heat-treatment process was determined by thermal analysis. The best concentration of precursor solution was0.6mol/L by comparing different precursor solutions. The produced La0.5Sr0.5CoO3film was single oriented, uniform thickness and no crack or pore. It was further tested the relation between temperature and electrical resistance of La0.5Sr0.5CoO3film, using a standard four-point probe technique. Electrical resistance of La0.sSr0.5CoO3film was still1.0×10-4Ω·m at liquid nitrogen temperature, which showed great conductivity.La0.5Sr0.5CoO3buffer which crystallized adequately on Ni-W was produced by MOD. La0.5Sr0.5CoO3film produced a single-orientation and cracks on the surface.In producing Ce0.8Gd0.2O1.9-δ buffer on Ni-W by MOD, it was determined that1.2mol/L was the best one by comparing with different concentrations of precursor solution. The excellent craft was to coating for60s with rotate speed of 3000r/min. In atmosphere of Ar+4%H2, Ce0.8Gd0.2O1.9-δ film produced in1100℃was single-orientation. Using φ scan of XRD, it was observed that Ce0.8Gd0.2O1.9-δ film and Ni-W exhibited epitaxial growth by in-plane rotation45°. The film had the dense and uniform microstructure.