Evolution of Oxygen-Vacancy Ordered Crystal Structures in the Perovskite Series SrnFenO3n−1 (n=2, 4, 8, and ∞), and the Relationship to Electronic and Magnetic Properties
Over the oxygen composition range 2.5≤x≤3.0, the SrFeOx system exists as four distinct compounds with the nominal composition SrnFenO3n−1 (n=2, 4, 8, and ∞). The end member SrFeO3 (n=∞) possesses a simple cubic perovskite crystal structure, whereas the oxygen-deficient (n=2, 4, and 8) members each a...
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Published in | Journal of solid state chemistry Vol. 151; no. 2; pp. 190 - 209 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
San Diego, CA
Elsevier Inc
01.05.2000
Elsevier |
Subjects | |
Online Access | Get full text |
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Summary: | Over the oxygen composition range 2.5≤x≤3.0, the SrFeOx system exists as four distinct compounds with the nominal composition SrnFenO3n−1 (n=2, 4, 8, and ∞). The end member SrFeO3 (n=∞) possesses a simple cubic perovskite crystal structure, whereas the oxygen-deficient (n=2, 4, and 8) members each adopt a different vacancy-ordered perovskite crystal structure. Using time-of-flight neutron powder diffraction, we show that previously proposed structures for the Sr4Fe4O11 (n=4) and Sr8Fe8O23 (n=8) compounds are incorrect. We determine the correct crystal structures for Sr4Fe4O11 (orthorhombic, space group Cmmm, a=10.974(1) Å, b=7.702(1) Å, and c=5.473(1) Å) and Sr8Fe8O23 (tetragonal, space group I4/mmm, a=10.929(1) Å and c=7.698(1) Å) through comparisons of the goodness of fit for Rietveld refinements of candidate models and bond-length distributions for each model. Using the correct crystal structures, we are able to assign valence states to the Fe crystallographic sites and to achieve consistency with published Mössbauer results for the same compounds. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 OGA ANL/MSD/JA-33919 USDOE Office of Science (SC) DE-AC02-06CH11357 USDOD |
ISSN: | 0022-4596 1095-726X |
DOI: | 10.1006/jssc.1999.8640 |