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 language | English (US) |
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Pages (from-to) | 275-283 |
Number of pages | 9 |
Journal | Journal of Solid State Chemistry |
Volume | 168 |
Issue number | 1 |
DOIs | |
State | Published - 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