Oxygen Ordered Phases in LaxSr1−xMnOy (0 ≤ x ≤ 0.2, 2.5 ≤ y ≤ 3): An In situ Neutron Powder Diffraction

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• 作者：Leopoldo Suescun ; Bogdan Dabrowski ; James Mais ; Steven Remsen ; James W. Richardson Jr. ; Evan R. Maxey ; James D. Jorgensen
• 刊名：Chemistry of Materials
• 出版年：2008
• 出版时间：February 26, 2008
• 年：2008
• 卷：20
• 期：4
• 页码：1636 - 1645
• 全文大小：4504K
• 年卷期：v.20,no.4(February 26, 2008)
• ISSN：1520-5002

文摘

In situ neutron powder diffraction experiments have been performed on samples of SrMnO_y, La_0.1Sr_0.9MnO_y, and La_0.2Sr_0.8MnO_y (2.5 ≤ y ≤ 3) to determine the existence of oxygen-vacancy ordering and study order–disorder transformations in the La_xSr_1−xMnO_y system. The vacancy ordered monoclinic Sr₇Mn₇O₁₃, tetragonal (La_xSr_1−x)₅Mn₅O₁₃ and orthorhombic (La_xSr_1−x)₂Mn₂O₅ (x = 0, 0.1, and 0.2) phases have been observed, together with already described La_0.1Sr_0.9MnO_2.55. Reversible vacancy order–disorder transitions have been observed for the La-containing (La_xSr_1−x)₅Mn₅O₁₃ phases. Oxygen-vacancy disordered cubic or pseudocubic phases have also been observed with increasing stability range in y with increasing x. Preliminary phase diagrams of the system have been derived as a function of temperature and oxygen content.