In situ XRD study on oxygen-excess LaMnO3

Shogo Miyoshi, Atsushi Kaimai, Hiroshige Matsumoto, Keiji Yashiro, Yutaka Nigara, Tatsuya Kawada, Junichiro Mizusaki

Research output: Contribution to journalConference articlepeer-review

15 Citations (Scopus)

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 languageEnglish
Pages (from-to)383-386
Number of pages4
JournalSolid State Ionics
Volume175
Issue number1-4
DOIs
Publication statusPublished - 2004 Nov 30
EventFourteenth International Conference on Solid State Ionics - Monterey, CA., United States
Duration: 2003 Jun 222003 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

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