B-Site cation diffusivity of Mn and Cr in perovskite-type LaMnO3 with cation-deficit nonstoichiometry

文献情報

出版日 2009-03-13

DOI 10.1039/B901208G

インパクトファクター 3.676

著者

Shogo Miyoshi, Manfred Martin

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要旨

The Mn tracer diffusivity and Cr impurity diffusivity in LaMnO3+δ were studied for the regime of cation-deficient nonstoichiometry with radio-isotope techniques. The effective Mn diffusion coefficient in polycrystalline LaMnO3+δ was successfully measured in the temperature range 1423 ≤T/K ≤ 1523 and oxygen partial pressure range 0.008 ≤PO2/bar ≤ 1. The estimated bulk diffusion coefficient of Mn in LaMnO3+δ is quite high compared with the other perovskite oxides reported in literature, which is regarded to reflect the high cation vacancy concentration of LaMnO3+δ. The Mn diffusivity shows a weak temperature dependence with an apparent activation energy of 0.6 eV and a strong PO2 dependence. Both dependencies may indicate a Mn diffusion mechanism by means of B-site vacancies which is, however, facilitated by the presence of A-site vacancies; that is, the Mn diffusivity depends on the vacancy concentrations not only at the B-sites but also at the A-sites. The Cr impurity diffusivity is significantly smaller than the Mn tracer diffusivity.

掲載誌

Physical Chemistry Chemical Physics

CiteScore: 5.5

自己引用率: 10.3%

年間論文数: 3036

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