Valence-state mixing and separation in SmBaFe2O5+w

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Journal Title
Journal ISSN
Volume Title
School of Chemical Technology | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
1999
Major/Subject
Mcode
Degree programme
Language
en
Pages
15251-15260
Series
Physical Review B, Volume 60, Issue 22
Abstract
A mixed-valence state, formally denoted as Fe2.5+, is observed in the 300 K Mössbauer spectra of the most reduced samples of SmBaFe2O5+w. Upon cooling below the Verwey-type transition temperature (TV≈200K), the component assigned to Fe2.5+ separates into a high-spin Fe3+ state and an Fe2+ state with an unusually low internal field. The separation of the mixed-valence state at TV is also confirmed by magnetic susceptibility measurements and differential scanning calorimetry. A model is proposed which accounts for the variation of the amount of the mixed-valence state with the oxygen content parameter w.
Description
Keywords
mixed-valence states, Fe2.5+, SmBaFe2O5+w
Other note
Citation
Lindén, J. & Karen, P. & Kjekshus, A. & Miettinen, J. & Pietari, T. & Karppinen, Maarit. 1999. Valence-state mixing and separation in SmBaFe2O5+w. Physical Review B. Volume 60, Issue 22. 15251-15260. ISSN 1550-235X (electronic). DOI: 10.1103/physrevb.60.15251.