Effect of Mn valence on crystal structure of La–Mn–O perovskite oxides
Effect of Mn valence on crystal structure of La–Mn–O perovskite oxides
复制标题
Mn价态对La-Mn-O钙钛矿氧化物晶体结构的影响
DOI：
10.1557/jmr.1995.1079
复制
发表时间：
1995
影响因子：
2.7
通讯作者：
T. Kokubo
中科院分区：
文献类型：
--
作者：
T. Yao;T. Ito;T. Kokubo
氧化镧和碳酸锰的La：Mn = 1：1混合物在1400 °C或1300 °C下在各种氧分压下进行热处理。通过化学分析测定了样品中Mn的价态，并通过粉末X射线衍射和Rietveld分析对晶体结构进行了细化。在低氧分压下热处理，形成了一种新的正交钙钛矿相，属于Pbnm空间群，含有- Mn^2+离子。结构非常接近立方对称。据推测，Mn^2+离子的微观杨-特勒效应几乎相互抵消。
La:Mn = 1:1 mixtures of lanthanum oxide and manganese carbonate were heat-treated under various oxygen partial pressures at 1400 °C or 1300 °C. The Mn valence of the samples was measured by a chemical analysis, and the crystal structures were refined by the powder x-ray diffraction and the Rietveld analysis. A novel orthorhombic perovskite phase, belonging to the space group Pbnm and containing - Mn^2+ ions, was formed by heat-treatment under low oxygen partial pressures. The structure was very close to a cubic symmetry. It is supposed that the micro Jahn-Teller effects of Mn^2+ ions were nearly canceled by one another.