Abstract
For LaMnO3+δ with oxygen-excess nonstoichiometry, in situ X-ray diffractometry was performed under high temperatures and precisely controlled oxygen partial pressures, PO2. A rhombohedral phase was observed under most experimental conditions. With temperature rising, the lattice volume increased linearly in a low temperature region; the coefficient of linear thermal expansion (CTE) was 1.06×10-5K-1. In a high temperature region, the temperature dependence of the lattice volume upwardly deviated from the linearity, indicating that the unit cell expanded upon decrease in excess oxygen. The nonstoichiometry coefficient of the linear isothermal expansion was calculated at 5×10-2 using literature data on δ(T, PO2). The rhombohedral distortion escalated with temperature and PO2 decreasing. The dependence of cell volume and distortion on nonstoichiometry is well interpreted as the effect of variation in the ionic radius and tolerance factor.
Original language | English |
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Pages (from-to) | 383-386 |
Number of pages | 4 |
Journal | Solid State Ionics |
Volume | 175 |
Issue number | 1-4 |
DOIs | |
Publication status | Published - 2004 Nov 30 |
Event | Fourteenth International Conference on Solid State Ionics - Monterey, CA., United States Duration: 2003 Jun 22 → 2003 Jun 27 |
Keywords
- Expansion upon reduction
- In situ XRD
- LaMnO
- Oxygen-excess nonstoichiometry
- Solid oxide fuel cell
- Thermal expansion
ASJC Scopus subject areas
- Chemistry(all)
- Materials Science(all)
- Condensed Matter Physics