Structural aspects of Pr1-xSrxFeO3-w

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

*Korresponderande författare för detta arbete

Forskningsoutput: TidskriftsbidragArtikelVetenskapligPeer review

19 Citeringar (Scopus)

Sammanfattning

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.

OriginalspråkEngelska
Sidor (från-till)148-163
Antal sidor16
TidskriftJournal of Solid State Chemistry
Volym173
Utgåva1
DOI
StatusPublicerad - jun 2003
MoE-publikationstypA1 Tidskriftsartikel-refererad

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