Structural properties of Bi_(1-x)La_xFeO_3 studied by micro-Raman scattering  

作　　者：杨洋 刘玉龙 朱恪 张丽艳 马树元 刘洁 将毅坚 

机构地区：[1]Institute of Physics,Chinese Academy of Sciences [2]College of Physical Science and Technology,Guangxi University [3]College of Laser Engineering,Beijing University of Technology

出　　处：《Chinese Physics B》2010年第3期551-556,共6页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (Grant Nos. 10674171 and 10874236)

摘　　要：This paper reports that La-doped BiFeO3 （Bil-xLaxFeO3, x = 0, 0.1, 0.2, 0.3, 0.6, 0.8 and 1.0） were studied by using micro-Raman spectroscopy and x-ray diffraction （XRD）. The XRD patterns indicate that the structure of Bi1-xLaxFeO3 changes from rhombohedral BiFeO3 to orthorhombic LaFeO3. The results of Raman spectroscopy show good agreement with the XRD results. Strikingly, the phonon peak at around 610 cm^-1 and the two-phonon peaks in the high frequency range exist in all compounds and enhance with increasing La substitution. The increasing intensity of the 610 cm-1 peak is attributed to the changes in the FeO6 octahedron during the rhombohedral-orthorhombic phase transition. The enhancements of the two-phonon peaks are associated with the breakdown of the cycloid spin configuration with the appearance of the orthorhombic structure. These results indicate the existence of strong spin phonon coupling in Bi1-xLaxFeO3, which may provide useful information for understanding the effects of La content on the structural and magnetic properties of Bi1 -xLaxFeO3.This paper reports that La-doped BiFeO3 （Bil-xLaxFeO3, x = 0, 0.1, 0.2, 0.3, 0.6, 0.8 and 1.0） were studied by using micro-Raman spectroscopy and x-ray diffraction （XRD）. The XRD patterns indicate that the structure of Bi1-xLaxFeO3 changes from rhombohedral BiFeO3 to orthorhombic LaFeO3. The results of Raman spectroscopy show good agreement with the XRD results. Strikingly, the phonon peak at around 610 cm^-1 and the two-phonon peaks in the high frequency range exist in all compounds and enhance with increasing La substitution. The increasing intensity of the 610 cm-1 peak is attributed to the changes in the FeO6 octahedron during the rhombohedral-orthorhombic phase transition. The enhancements of the two-phonon peaks are associated with the breakdown of the cycloid spin configuration with the appearance of the orthorhombic structure. These results indicate the existence of strong spin phonon coupling in Bi1-xLaxFeO3, which may provide useful information for understanding the effects of La content on the structural and magnetic properties of Bi1 -xLaxFeO3.

关 键 词：Bi1-xLaxFeO3 Raman scattering phase transition spin phonon coupling 

分 类 号：O614.532[理学—无机化学]