Order-disorder enhanced oxygen conductivity and electron transport in Ruddlesden-Popper ferrite-titanate Sr3Fe2-xtixO6+δ

Y. A. Shilova, M. V. Patrakeev, E. B. Mitberg, I. A. Leonidov, V. L. Kozhevnikov*, K. R. Poeppelmeier

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

47 Scopus citations

Abstract

The Ruddlesden-Popper ferrite Sr3Fe2O6+δ and its titania-doped derivatives Sr3Fe2-xTixO6+δ, where 0<x≤2, have been characterized by X-ray powder diffraction and thermogravimetry. The changes in oxygen content and crystal lattice parameters are consistent with titanium ions entering the solid solution in 4+ oxidation state with octahedral oxygen coordination. Electronic conductivity measurements on polycrystalline Sr3Fe2O6+δ and Sr3Fe0.8Ti1.2 O6+δ in the temperature range 750-1000°C and oxygen partial pressures (pO2) varying between 10-20 and 0.5 atm revealed that the predominant partial conductivity of electrons is proportional to pO2-1/4 in the low pO2 region, while the predominant partial contribution of holes to the conductivity is proportional to pO2+1/4 in the high pO2 range. The pressure-independent oxygen ion conductivity is found to decrease with the increase in titanium content. A possible pathway for oxygen ion migration is discussed in relation to disorder in the oxygen sublattice and titanium doping.

Original languageEnglish (US)
Pages (from-to)275-283
Number of pages9
JournalJournal of Solid State Chemistry
Volume168
Issue number1
DOIs
StatePublished - Oct 2002

Funding

We acknowledge partial support of this work by the Russian Foundation for Basic Research (Grant 01-03-96519) and by sixth competition of the RAS young scientists (Grant 192). One of us (K.R.P.) is grateful to the EMSI program of the National Science Foundation and the US Department of Energy Office of Science (CHE-9810378) at the Northwestern University Institute for Environmental Catalysis.

Keywords

  • Electron conductivity
  • Oxygen conductivity
  • Oxygen transfer
  • Ruddlesden-Popper ferrite
  • Thermopower

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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