A.C. electrical properties of defect-perovskite LaTa3O9 were measured in the temperature range between 423 and 1073K under oxygen partial pressures (PO(2)) from 10Pa to 0.1MPa. Complex impedance spectra showed three dispersions associated with bulk, surface layer and a diffusion (Warburg) process. The conductivity of bulk was independent of PO(2) and its activation energy was 0.40 to 0.48eV. The capacitance of bulk was 5 to 8pF and independent of temperature. The conductivity of surface layer (σ2) increased with increasing PO(2) as expressed by σ2 ∝ PO(2)n (n = 0.14 to 0.18). The capacitance of surface layer increased from 3 to 20nF and increased with increasing temperature. The ionic transport number measured with an oxygen concentration cell was nearly 1 at 750K, and decreased with increasing temperature.
|Number of pages||4|
|Journal||Journal of the Ceramic Society of Japan. International ed.|
|Publication status||Published - 1995 Jan 1|
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