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Journal of Materials Science

, Volume 28, Issue 17, pp 4689–4692 | Cite as

Study of La1−xMnO3−δ non-stoichiometry and defect structure using ESR and iodometry

  • M. Ippommatsu
  • S. Otoshi
  • H. Sasaki
  • H. Ohnishi
  • T. Higuchi
  • M. Miyayama
  • H. Yanagida
Papers

Abstract

The oxidation states of manganese in the La1−xMnO3−δ (x = 0.09–0.11) were investigated by electron spin resonance (ESR) and iodometry. The ESR analysis carried out at room temperature for the samples prepared in air revealed the presence of broad peaks at g = 2.0, considered to be relevant to Mn2+. It was also found that the intensity of the peak increased as lanthanum vacancy content increased. The average valence state of manganese, determined by iodometry, was approximately 3.2, and decreased by 1 as the lanthanum vacancy increased by 1. Similar trends were observed with the samples prepared at Po2 = 1×10−7. The results indicated that Mn2+ is stably present in the La1−xMnO3−δ having an average valence number exceeding 3.0. A series of experimental results with respect to the non-stoichiometry of La1−xMnO3−δ can be explained by assuming that Mn2+ is stabilized after forming a complex with a lanthanum vacancy and two oxygen vacancies.

Keywords

Oxidation Oxygen Polymer Manganese Electron Spin Resonance 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Chapman & Hall 1993

Authors and Affiliations

  • M. Ippommatsu
    • 1
  • S. Otoshi
    • 1
  • H. Sasaki
    • 1
  • H. Ohnishi
    • 1
  • T. Higuchi
    • 2
  • M. Miyayama
    • 2
  • H. Yanagida
    • 2
  1. 1.Fundamental Research LaboratoriesOsaka Gas Co., Ltd.OsakaJapan
  2. 2.Faculty of EngineeringUniversity of TokyoTokyoJapan

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