论文标题
压力诱导的LACRO3结构相变的拉曼散射研究
Raman scattering investigation of the pressure induced structural phase transition in LaCrO3
论文作者
论文摘要
我们报告了使用拉曼散射探测的稀土（R）正交物质（RCRO3）中钙钛矿畸变的压力依赖性，以研究LACRO3中从正交PNMA到菱形r-3c相的结构过渡的起源。八面体倾斜模式的压力诱导的变化表明，LACRO3抑制了倾斜变形，并且在RCRO3家族的其余成员中得到了增强。两个相反的压力行为之间的交叉发生在1.20Å的临界R-ION半径下。我们试图通过分别探测对CR-O和R-O的平均键强度敏感的Raman Phonon模式，以建立CR和R-Sites的这种异常交叉和可压缩性之间的关系。最后，我们研究了CRO6和RO12 Polyhedra的键长分裂，以确定多面体自我失真在确定钙钛矿扭曲的压力依赖性演化中的作用。
We report the pressure dependence of perovskite distortions in rare-earth (R) orthochromites (RCrO3) probed using Raman scattering in order to investigate the origin of structural transition from orthorhombic Pnma to rhombohedral R-3C phase in LaCrO3. The pressure induced changes in octahedral tilt modes demonstrates that tilt distortions are suppressed in LaCrO3 and are enhanced in the remaining members of RCrO3 family. This crossover between the two opposite pressure behaviors occurs at a critical R-ion radius of 1.20 Å. We attempted to establish the relation between this unusual crossover and compressibility at Cr- and R-sites by probing Raman phonon modes sensitive to the mean bond strength of Cr-O and R-O respectively. Finally, we study the bond-length splitting of both CrO6 and RO12 polyhedra to ascertain the role of polyhedral self distortion in determining the pressure dependent evolution of perovskite distortions.
