Structural aspects of Pr1-xSrxFeO3-w

Marit Stange, Johan Lindén, Arne Kjekshus, Norman Binsted, Mark T. Weller, Bjørn C. Hauback, Helmer Fjellvåg*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

17 Citations (Scopus)

Abstract

Structural aspects of the distorted perovskite ABO3 phase Pr1-xSrxFeO3-w,x=0.00-0.80,w=0.000-0.332, were studied by powder X-ray diffraction, powder neutron diffraction, 57Fe Mössbauer spectroscopy, and Fe K-, Sr K-, and Pr LIII-edge EXAFS techniques. The diffraction data revealed no indications for ordering of Pr and Sr at the A site, nor for oxygen vacancy ordering at O sites for heavily reduced samples. Mössbauer spectroscopy showed octahedral, square pyramidal, and tetrahedral Fe coordinations with relative amounts closely following the predictions for a binomial distribution of oxygen vacancies. In addition to Fe3+ and Fe4+, also Fe5+ appears at 77 K for (G-type) antiferromagnetic samples with high average Fe valence. This suggests dynamic 2 Fe4+↔Fe3++Fe5+ fluctuations. At 296 K, a mixed valence Fe(3+n)+ component significantly improved the fit of Mössbauer spectra for the most oxidized paramagnetic samples. The qualitative EXAFS study shows that the local environments for Fe, Pr, and Sr strongly depend on x and w. The local Pr- and Sr-site geometries differ significantly from the cubic average structure for Pr0.50Sr0.50FeO2.746.

Original languageEnglish
Pages (from-to)148-163
Number of pages16
JournalJournal of Solid State Chemistry
Volume173
Issue number1
DOIs
Publication statusPublished - Jun 2003
MoE publication typeA1 Journal article-refereed

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