Charge ordering in transition metal oxides
Charge ordering in transition metal oxides
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DOI：
10.1016/j.solidstatesciences.2005.02.011
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发表时间：
2006-08-01
影响因子：
3.5
通讯作者：
Attfield, J. Paul
中科院分区：
文献类型：
--
作者：
Attfield, J. Paul
许多氧化物中存在两种过渡金属电荷(氧化)态的长程有序。综述了几种半掺杂锰氧化物(Pr0.5Ca0.5MnO_3、TbBaMn2O6、YBaMn2O6)和磁铁矿(Fe3O4)的粉末中子衍射研究的直接结构证据。在所有情况下，电荷有序都伴随着向低(单斜或三斜)对称性的微妙扭曲。半掺杂的锰氧化物显示出电荷和Mn3+轨道有序排列的多晶性。用键价和估计这些氧化物和其他氧化物的电荷分离程度只有理想差异的20%-80%。从目前的数据来看，这种效应的来源尚不清楚。(C)2006年爱思唯尔公司。版权所有。
Long range ordering of two transition metal charge (oxidation) states occurs in many oxides. Direct structural evidence from powder neutron diffraction studies on several half-doped manganites (Pr0.5Ca0.5MnO3, TbBaMn2O6, YBaMn2O6) and magnetite (Fe3O4) is reviewed. Charge ordering is accompanied by subtle distortions to low (monoclinic or triclinic) symmetry in all cases. The half-doped manganites reveal polymorphism of both charge and Mn3+ orbital ordered arrangements. The degree of charge separation estimated by bond valence sums for these and other oxides is only 20-80% of the ideal difference. The origin of this effect is not clear from present data. (c) 2006 Elsevier SAS. All rights reserved.