Electrochemical Characterization of La0.9Sr0.1Ga0.8Mg0.2O3-δ Thin Film Electrolyte Deposited by Radio Frequency Magnetron Sputtering

To reveal the mechanism of the conductivity change of La0.9Sr0.1Ga0.8Mg0.2O3-delta (LSGM) thin film from the bulk, the LSGM thin films with different thickness deposited on sapphire substrate by radio frequency magnetron sputtering was studied. The grains in thick (1.8 mu m similar to) film had a nearly sphere shape and approximately 0.3 mu m in size. The grains in thin (similar to 0.6 mu m) film had a nearly spatulate and approximately 0.1 mu m in size. The lattice constant of the 0.6 mu m thickness film was decreased from that of the bulk by the influence of the substrate. The conductivity values in 3.0 and 0.6 mu m thickness film at 700 degrees C were 2.3x10(-3) and 1.1x10(-3) Scm(-1), respectively. Their activation energy were 1.07 and 1.26 eV, respectively. The thicker the film is, the conductivity increases and the activation energy decreases. This should be caused by the smaller bulk resistivity than the grain boundary resistivity.