Abstract
Measurements of the equilibrium oxygen content, electrical conductivity and thermopower in the perovskite-like solid solution La0.7Sr 0.3Co1-zMnzO3-δ (z=0 and 0.25) as a function of the temperature and oxygen partial pressure are used to determine the temperature dependence of the conductivity and thermopower at different values of the oxygen deficiency. A model for a hopping conductor with screened charge disproportionation is applied for the data analysis in combination with trapping reactions of n- and p-type carriers on local oxygen vacancy clusters and manganese cations, respectively. Changes in the ratio of n-type to p-type mobility are due to variations in oxygen vacancy concentration and manganese content, while the energetic parameters governing charge disproportionation of the trivalent cobalt cations and formation of vacancy associates are shown to be essentially invariable. These calculated charge carrier site occupancies are used to model temperature variations of the electrical properties in La0.7Sr0.3Co1-zMn zO3-δ in favorable correspondence with experimental observations.
Original language | English (US) |
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Pages (from-to) | 296-304 |
Number of pages | 9 |
Journal | Journal of Solid State Chemistry |
Volume | 172 |
Issue number | 2 |
DOIs | |
State | Published - May 2003 |
Funding
This research was supported by the International Association (INTAS) of the European Community under Contract No. 2000-00728. The partial support from the US Civilian Research and Development Foundation (CRDF, Grant No. REC 005) is greatly appreciated. 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. We are particularly grateful to the reviewer who attracted our attention to publication [17] .
Keywords
- Cobaltite
- Electrical conductivity
- Hopping conductor
- Manganite
- Oxygen content
- Perovskite
- Thermopower
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry