Polarized Raman scattering and lattice eigenmodes of antiferromagnetic NdFeO3
Polarized Raman scattering and lattice eigenmodes of antiferromagnetic NdFeO3
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DOI：
10.1002/jrs.1923
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发表时间：
2008-07
影响因子：
2.5
通讯作者：
M. Singh;H. Jang;H. C. Gupta;R. Katiyar
中科院分区：
文献类型：
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作者：
M. Singh;H. Jang;H. C. Gupta;R. Katiyar
利用偏振拉曼散射和晶格动力学计算（LDC）研究了正交晶系Pbnm NdFeO3单晶中的一阶和二阶喇曼激活声子。利用两种平行偏振态X ′（ZZ）X ′和Z（X ′ X ′）Z进行偏振拉曼散射实验，区分了Ag对称的带心声子和B1 g本征模.在LDC的帮助下，我们能够分配大多数观察到的拉曼激活模式，包括声子的B2g和B3g对称性。LDC的结果表明，在所采用的16个力常数中，对应于在FeO 6八面体单元中的中心Fe阳离子和轴向氧原子之间的伸缩振动的力常数具有最大值。这表明，B位Fe阳离子是更紧密地结合到轴向O1离子比其他两个赤道O2离子。进一步表明，在较高波数下，氧原子的位移对区心振动起主导作用。版权所有© 2008约翰威利父子有限公司。
The first- and second-order Raman-active phonons in the orthorhombic Pbnm NdFeO3 single crystals were studied by means of polarized Raman scattering and lattice dynamics computations (LDC). The zone-center phonons of Ag symmetry were distinguished from the B1g eigenmodes by performing polarized Raman scattering experiments using two parallel polarization configurations, X′(ZZ)X′ and Z(X′X′)Z. With the help of LDC, we were able to assign most of the observed Raman-active modes, including phonons of B2g and B3g symmetry. The LDC results indicated that among the 16 force constants employed, the one corresponding to the stretching vibration between the central Fe cation and the axial oxygen atom in a FeO6 octahedron unit had the largest value. This suggests that the B-site Fe cation is more tightly bound to the axial O1 ion than the other two equatorial O2 ions. It was further shown that at higher wavenumbers, the displacement of oxygen atoms contributed dominantly to the zone-center vibrations. Copyright © 2008 John Wiley & Sons, Ltd.