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 LaFeO3. 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.