Charge and Orbital Ordering Structure of Fe3O4 in the Low-Temperature Phase as Deduced from NMR Study
Charge and Orbital Ordering Structure of Fe3O4 in the Low-Temperature Phase as Deduced from NMR Study
复制标题
NMR 研究推导出低温相 Fe3O4 的电荷和轨道有序结构
DOI：
10.1143/jpsj.70.2333
复制
发表时间：
2001
影响因子：
1.7
通讯作者：
M. Mizoguchi
中科院分区：
文献类型：
--
作者：
M. Mizoguchi
用核磁共振方法研究了4.2K下球形Fe 3 O 4中Fe离子的超精细场。从谐振频率对外磁场的角度依赖性，A -和B -站点上的不等价站点的数量被确定为分别只有8和16。超精细领域的A -网站的各向异性表明，在高温相的镜像对称性之一仍然是不完整的。提出了一种电荷和轨道有序结构，这与低温相Fe 3 O 4的晶体学和电子学性质一致。还提出了一个模型的金属-绝缘体转变温度T MI以上的电荷密度波。通过冻结铁离子晶格点处的电荷密度波，构造了T MI以下的电荷有序。两种机制被假定在冻结时稳定轨道有序。一个是最近的电子云之间的库仑排斥力...
The hyperfine fields of Fe ions in Fe 3 O 4 have been investigated for a spherically shaped specimen at 4.2 K using NMR. From the angular dependence of the resonance frequencies on an external magnetic field, the numbers of the inequivalent sites on A - and B -sites are determined to be just eight and sixteen, respectively. The anisotropy in the hyperfine fields of A -sites reveals that one of the mirror symmetries in the high-temperature phase remains incomplete. A charge and orbital ordering structure, which is consistent with the crystallographic and electronic properties of Fe 3 O 4 in the low-temperature phase, is proposed. A model of charge density waves above the metal-insulator transition temperature T MI is also proposed. The charge ordering below T MI is constructed by freezing the charge density waves at the lattice points of Fe ions. Two mechanisms are postulated to stabilize orbital ordering at the time of freezing. One is the repulsive Coulomb force between the electron clouds of the nearest...