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Title
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Coupled anion and cation ordering in (R=Y, Ho, Dy) anion-deficientperovskites
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Author
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Abstract
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| The Sr3RFe4O10.5 (R=Y, Ho, Dy) anion-deficient perovskites were prepared using a solid-state reaction in evacuated sealed silica tubes. Transmission electron microscopy and 57Fe Mössbauer spectroscopy evidenced a complete A-cations and oxygen vacancies ordering. The structure model was further refined by ab initio structure relaxation, based on density functional theory calculations. The compounds crystallize in a tetragonal a≈2√2ap≈11.3 Å, с≈4сp≈16 Å unit cell (ap: parameter of the perovskite subcell) with the P42/mnm space group. Oxygen vacancies reside in the (FeO5/4□3/4) layers, comprising corner-sharing FeO4 tetrahedra and FeO5 tetragonal pyramids, which are sandwiched between the layers of the FeO6 octahedra. Smaller R atoms occupy the 9-fold coordinated position, whereas the 10-fold coordinated positions are occupied by larger Sr atoms. The Fe sublattice is ordered aniferromagnetically up to at least 500 K, while the rare-earth sublattice remains disordered down to 2 K. |
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Language
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English
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Source (journal)
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Journal of solid state chemistry. - London
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Publication
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London
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2010
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ISSN
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0022-4596
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DOI
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10.1016/J.JSSC.2010.09.039
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Volume/pages
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183
:12
(2010)
, p. 2845-2854
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ISI
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000285431100014
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Full text (Publisher's DOI)
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