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Study on the electrical conductivity and oxygen diffusion of oxide-ion conductors La{sub 2}Mo{sub 2-x}T {sub x}O{sub 9-{delta}} (T = Al, Fe, Mn, Nb, V)

Journal Article · · Materials Research Bulletin
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  1. Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, 230031 Hefei (China)
  2. Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, 230031 Hefei (China) and Nanchang Institute of Aeronautical Technology, 330034 Nanchang (China)
In this paper, the influence of cationic substitutions at Mo site with Al{sup 3+}, Fe{sup 3+}, Mn{sup 4+}, Nb{sup 5+} and V{sup 5+} ions on the structure, oxygen ion diffusion and electrical properties in La{sub 2}Mo{sub 2}O{sub 9} oxide-ion conductors have been investigated by X-ray diffraction method, dielectric relaxation technique and direct current conductivity measurement. Except for V{sup 5+} substitution all of these substitutions up to 5% cannot suppress the phase transition in La{sub 2}Mo{sub 2}O{sub 9}. In the dielectric measurement, one prominent relaxation peak is observed in temperature spectrum as well as in frequency spectrum, which is associated with the short-distance diffusion of oxygen vacancies. The activation energy for oxygen ion diffusion is deduced as in the range of 1-1.1 eV for Al, Fe, Mn and Nb doped samples and 1.4-1.5 eV for V doped samples. All substituted samples have a higher conductivity than the un-doped compound. In the Al, Fe, Mn and Nb substituted materials the phase transition is not suppressed; however, K substitution at the La site can completely suppress the transition and maintains high conductivity at low temperature.
OSTI ID:
21000652
Journal Information:
Materials Research Bulletin, Journal Name: Materials Research Bulletin Journal Issue: 6 Vol. 42; ISSN MRBUAC; ISSN 0025-5408
Country of Publication:
United States
Language:
English