不同La掺杂浓度的BiFeO_3的结构性质的显微拉曼光谱研究  

Effects of La-Doping on the Structure of BiFeO_3 Studied by Micro-Raman Scattering

作　　者：杨洋[1] 张丽艳[1] 朱恪[1] 马树元[2] 刘玉龙[1] 

机构地区：[1]中国科学院物理研究所,北京100190 [2]广西大学物理科学与技术学院,南宁530004

出　　处：《光散射学报》2010年第2期147-150,共4页The Journal of Light Scattering

基　　金：国家自然科学基金(1067417110874236)

摘　　要：使用显微拉曼散射技术研究不同的La掺杂浓度对BiFeO3(Bi1-xLaxFeO3,x=0,0.1,0.2,0.3,0.6,0.8和1.0)的结构性质的影响。拉曼光谱的变化证明了在Bi1-xLaxFeO3中,随着La含量的增加,其结构从三方相变成正交相。引人注目的是,位于610 cm-1附近的拉曼峰和它的二阶峰依然存在,并且随着La掺杂量的增加发生明显的增强。这一现象与BiFeO3在三方相结构存在的螺旋自旋结构被破坏有关。我们的实验证实了在Bi1-xLaxFeO3材料中存在着强烈的自旋-声子相互作用,这对于理解Bi1-xLaxFeO3材料的结构与物性之间的关系提供有用的信息。La-doped BiFeO3 （Bi1-xLaxFeO3, x=0, 0.1, 0.2, 0.3, 0.6, 0.8 and 1.0） were studied by using micro-Raman spectroscopy. The distinct changes in the Raman spectra indicated that the structure of Bi1-xLaxFeO3 changes from the rhombohedral BiFeO3 to the orthorhombic LaFeOa. Strikingly, the phonon peak at around 610 cm^-1 and its corresponding two-phonon peak existed in all compounds and were enhanced with increasing La- substitution. Such phenomena were associated with breakdown of the cycloid spin configuration in the rhombohedral BiFeO3. Our results indicate the existence of strong spin-phonon coupling in Bi1-xLaxFeO3, which may provide useful information for understanding the correlation between the structural and magnetic properties of Bi1-xLaxFeO3.

关 键 词：拉曼光谱 La-掺杂 Bi1-xLaxFeO3 相变 

分 类 号：O657[理学—分析化学]