Oxygen surface exchange and diffusion in the new perovskite oxide ion conductor LaGaO{sub 3}
- Oita Univ. (Japan)
- Imperial College of Science, Technology, and Medicine, London (United Kingdom)
One of the aims of these experiments was to verify that the oxygen ion is the majority carrier in LaGaO{sub 3}-based materials, as they are thought to exhibit p-type conductivity in the high oxygen partial pressure range. Specifically, we have investigated oxygen surface exchange and diffusion in La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3-x} by {sup 18}O isotopic exchange and SIMS at high partial pressures of oxygen (0.1 MPa). In conclusion, these results show that bulk oxygen diffusion in LSGM is very rapid. By a comparison of the oxygen self-diffusivity obtained from tracer and ionic conductivity, the electrical conductivity observed is ionic in the temperature range we have measured. The surface exchange coefficients are anomalous when compared to other perovskite oxides. The activation enthalpy for surface exchange is higher than that for self diffusion coefficient, a finding observed for two other solid oxide electrolytes with the fluorite structure. This behavior is thought to originate in the low electron concentrations found in these electrolyte materials, particularly at the lowest temperatures. 13 refs., 2 figs.
- OSTI ID:
- 484484
- Journal Information:
- Journal of the American Chemical Society, Vol. 119, Issue 11; Other Information: PBD: 19 Mar 1997
- Country of Publication:
- United States
- Language:
- English
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