Study of (Ln,Sr)(Fe,Co)O3-δ type CMR materials by 57 Co emission Mössbauer spectroscopy

Z. Homonnay, Z. Klencsár, E. Kuzmann, Z. Németh, P. Rajczy, K. Kellner, G. Gritzner, A. Vértes

Research output: Contribution to journalConference article

2 Citations (Scopus)

Abstract

Emission Mössbauer experiments on La0.8Sr0.2CoO3-δ, Eu0.8Sr0.2CoO3-δ, and La0.8Sr0.257Fe0.05Co0.95O 3.δ were carried out using 57Co dopant in order to see how the spectra may be interpreted on the basis of the results of transmission Mössbauer studies on the same or similar compounds. It was found that when the material contains a small amount of iron, the emission and transmission Mössbauer spectra match each other at room temperature, which lead to the conclusion that iron does not form clusters in the cobaltate perovskite but is rather monoatomically dispersed in the lattice. The iron free cobaltates showed lower isomer shifts than the ones containing iron, which is proposed to be due to the very low concentration of nucleogenic 57Fe, tending to acquire an oxidation state higher than +3, and to the different electric transport properties of the host material. The difference between magnetic structures observed at low temperatures in transmission and emission experiments as well as in La- and Eu-containing materials were attributed to different oxygen defect structures. It is generally concluded that in the investigated materials, the 57Fe probe formed by an EC decay of 57Co in an emission Mössbauer experiment serves as a normal 57Fe probe having the oxygen coordination number of the mother 57Co.

Original languageEnglish
Pages (from-to)165-170
Number of pages6
JournalSolid State Phenomena
Volume90-91
Publication statusPublished - Jan 1 2003
EventProceedings of the 5th International Conference on Solid State - Bratislava, Slovakia
Duration: Jul 7 2002Jul 12 2002

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Keywords

  • Colossal magnetoresistance
  • Emission Mössbauer spectroscopy
  • Europium-strontium-co baltate
  • Lanthanum-strontium-cobaltate
  • Perovskite

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Condensed Matter Physics

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