TY - JOUR
T1 - Structural aspects of Pr1-xSrxFeO3-w
AU - Stange, Marit
AU - Lindén, Johan
AU - Kjekshus, Arne
AU - Binsted, Norman
AU - Weller, Mark T.
AU - Hauback, Bjørn C.
AU - Fjellvåg, Helmer
PY - 2003/6
Y1 - 2003/6
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=0038617832&partnerID=8YFLogxK
U2 - 10.1016/S0022-4596(02)00116-0
DO - 10.1016/S0022-4596(02)00116-0
M3 - Article
AN - SCOPUS:0038617832
SN - 0022-4596
VL - 173
SP - 148
EP - 163
JO - Journal of Solid State Chemistry
JF - Journal of Solid State Chemistry
IS - 1
ER -