High temperature Mössbauer spectroscopy of some SrFeO3−y phases
1987; Elsevier BV; Volume: 62; Issue: 4 Linguagem: Inglês
10.1016/0038-1098(87)90803-9
ISSN1879-2766
AutoresL. Fournès, Yves Potin, Jean‐Claude Grenier, G. Demazeau, Michel Pouchard,
Tópico(s)High-pressure geophysics and materials
ResumoTwo terms of the SrFeO3−y solid solution (y = 0.17; 0.25) have been investigated by Mössbauer spectroscopy at high temperature under controlled atmosphere. A first order transition has been observed respectively at 670 K and 570 K : the high temperature spectra show an average valence state of iron related to an electron hopping fast enough for not discerning oxidation states (III) and (IV). At room temperature the SrFeO2.75 spectrum characterizes distinct Fe3+ (50%) and Fe4+ (50%) cations both with high spin configuration, while in SrFeO2.83 iron exhibits both an average valence state implying a short range electron hopping (Fe3+ + Fe4+ + Fe4+ + Fe3+) and a Fe4+ state similar to that of SrFeO3 in which electron delocalization appears.
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