Key role of the charge distribution in the properties of the Ba2FeMo1−xRexO6 double perovskites
Key role of the charge distribution in the properties of the Ba2FeMo1−xRexO6 double perovskites
复制标题
电荷分布对 Ba2FeMo1−xRexO6 双钙钛矿性能的关键作用
DOI：
10.1016/s0304-8853(02)00370-0
复制
发表时间：
2002
影响因子：
2.7
通讯作者：
B. Raveau
中科院分区：
文献类型：
--
作者：
F. Sriti;N. Nguyen;C. Martin;A. Ducouret;B. Raveau
合成了Ba 2FeMo 1 − xRexO 6固溶体，其尺寸为0 <$x <$1，并通过X射线衍射进行了表征。该系列样品的磁性能是显著的：当x=0.50时，Tc达到最大值，达到370 K。穆斯堡尔研究表明了电荷分布在这些性质中的重要作用。主要的铁状态接近Fe 2+，相当于80%，而剩余的20%对应于混合价Fe（3−δ）+状态。这表明Fe 3 +-Mo 5 +/Fe 2 +-Mo 6+和Fe 3 +-Re 5 +/Fe 2 +-Re 6+态的简并和杂化形成窄带，这将是这些材料中双交换型机制的原因。根据Mo ~（6+）/Mo ~（5+）和Re ~（6+）/Re ~（5+）电对之间的氧化还原反应讨论了x=0.50时TC的优化。这些陶瓷的输运性质也被提出。
The solid solution Ba2FeMo1−xRexO6has been synthesized for 0⩽x⩽1 and characterized by X-ray diffraction. The magnetic properties of this series are remarkable: TCgoes to a maximum reaching 370K for x=0.50. The Mössbauer study shows the important role of the charge distribution in those properties. The main iron state is close to Fe2+which corresponds to 80%, whereas the 20% remaining corresponds to a mixed valent Fe(3−δ)+state. This suggests degeneracy and hybridization of the Fe3+–Mo5+/Fe2+–Mo6+and Fe3+–Re5+/Fe2+–Re6+states forming a narrow band which would be responsible for the double exchange type mechanism in these materials. The optimization of TCfor x=0.50 is discussed in terms of redox reaction between Mo6+/Mo5+and Re6+/Re5+couples. The transport properties of these ceramics are also presented.