Title
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Oxygen vacancy ordering in the double-layered Ruddlesden-Popper cobaltite
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Author
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Abstract
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A new oxygen-deficient Ruddlesden−Popper (RP) cobaltite Sm2BaCo2O7−δ (δ ≈ 1.0) has been synthesized and the crystal structure elucidated by Rietveld analysis of X-ray powder diffraction (XRD) data and transmission electron microscopy (TEM). The phase crystallizes in a primitive orthorhombic unit cell, with lattice parameters a = 5.4371(4) Å; b = 5.4405(4) Å and c = 19.8629(6) Å, and space group Pnnm. Contrary to other oxygen-deficient cobalt RP phases, the oxygen vacancies are located in the equatorial positions of the [CoO] layers to give an intralayer structure similar to Sr2Mn2O5, which is not usually observed for cobalt-containing materials. The Sm3+ and Ba2+ cations show a strong preference for distinct sites, with the majority of the larger Ba2+ cations situated in the perovskite block layers and Sm3+ cations predominantly in the rock salt layers. Magnetic susceptibility data demonstrate the strong antiferromagnetic (AFM) character of Sm2BaCo2O7−δ. |
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Language
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English
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Source (journal)
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Chemistry of materials / American Chemical Society. - Washington, D.C., 1989, currens
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Publication
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Washington, D.C.
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2008
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ISSN
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0897-4756
[print]
1520-5002
[online]
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DOI
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10.1021/CM8010138
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Volume/pages
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20
:19
(2008)
, p. 6231-6237
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ISI
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000259871500038
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Full text (Publisher's DOI)
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