Rao Mala N, Kaur Nupinderjeet, Chaplot S L, Gaur N K, Singh R K
Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085, India.
J Phys Condens Matter. 2009 Sep 2;21(35):355402. doi: 10.1088/0953-8984/21/35/355402. Epub 2009 Aug 10.
The lattice dynamics of yttrium manganite (YMnO(3)) has been investigated by means of a shell model with pair-wise interionic interaction potential. The experimental data of crystal structure and Raman and infrared frequencies compare well with the lattice dynamical calculations. The phonon dispersion curves found along three high symmetry directions and the density of states of YMnO(3) have also been calculated from this model. The computed phonon density of states is used to derive the macroscopic thermodynamic quantities like the Debye temperature and specific heat. The crystal structure data computed from this model are in good agreement with the available experimental data measured by neutron powder diffraction. We have made a comparative study of the structures derived from the potential model calculations for both LaMnO(3) and YMnO(3). Symmetry vectors obtained through group theoretical analysis at the zone centre point were employed to classify the phonon frequencies obtained into their irreducible representations. The computed Raman and infrared frequencies have shown good agreement with the measured data.
利用具有离子间成对相互作用势的壳层模型研究了钇锰氧化物（YMnO₃）的晶格动力学。晶体结构以及拉曼和红外频率的实验数据与晶格动力学计算结果吻合良好。还从该模型计算了沿三个高对称方向的声子色散曲线以及YMnO₃的态密度。计算得到的声子态密度用于推导德拜温度和比热等宏观热力学量。从该模型计算得到的晶体结构数据与通过中子粉末衍射测量得到的现有实验数据高度吻合。我们对由势模型计算得出的LaMnO₃和YMnO₃的结构进行了比较研究。利用在区域中心点通过群论分析获得的对称矢量，将得到的声子频率分类为它们的不可约表示。计算得到的拉曼和红外频率与测量数据显示出良好的一致性。
