Electrochemical Characterization of La_(0.9)Sr_(0.1)Ga_(0.8)Mg_(0.2)O_(3-δ) Thin Film Electrolyte Deposited by Radio Frequency Magnetron Sputtering

摘要

To reveal the mechanism of the conductivity change of La_(0.9)Sr_(0.1)Ga_(0.8)Mg_(0.2)O_(3-δ) (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 μm～) film had a nearly sphere shape and approximately 0.3 μm in size. The grains in thin (～0.6 μm) film had a nearly spatulate and approximately 0.1 μm in size. The lattice constant of the 0.6 μm thickness film was decreased from that of the bulk by the influence of the substrate. The conductivity values in 3.0 and 0.6 μm thickness film at 700 ℃ were 2.3×10~(-3) and 1.1 × 10~(-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.