Cation self-diffusion in disordered VOx

S. Kumarakrishnan, N. L. Peterson, Thomas O Mason

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The diffusion of 48V in disordered VOx, crystals has been measured by a serial-sectioning technique as a function of temperature (1100-1500°C) over the homogeneity range 0.78 <x <1.28. The temperature dependence of the cation tracer diffusivity at each fixed composition is characterized by an Arrhenius behavior in the temperature range 1100-1500°C. The Arrhenius parameters decrease rather sharply near the stoichiometric composition as the composition increases from the metal-rich to the metal-deficient regime; the activation energy for diffusion decreases from ~71 kcal mole to ~48 kcal mole, and the frequency factor decreases by nearly two orders of magnitude (from ~5 cm2 s to ~0.05 cm2 s). It is concluded that the significant difference in the cation self-diffusion behavior between the metal-rich and the metal-deficient VOx may be attributed to the significant differences in the defect structures of the two regimes. The various possible diffusion mechanisms are explored, and comparisons of the cation diffusion behavior in VOx, with that of the related transition-metal monoxides TiOx and Fe1-δO are made. It is concluded that the experimental results for the entire composition range are consistent with the process of diffusion occurring by the migration of monovacancies in equilibrium with defect clusters, the nature of the clusters being different for x <1 and x #62;; 1.

Original languageEnglish
Pages (from-to)1007-1014
Number of pages8
JournalJournal of Physics and Chemistry of Solids
Volume46
Issue number9
DOIs
Publication statusPublished - 1985

Keywords

  • defect clusters
  • diffusion mechanisms
  • point defects
  • self-diffusion
  • VO

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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