High-pressure x-ray diffraction and Raman spectroscopy of phase transitions in Sm2O3
High-pressure x-ray diffraction and Raman spectroscopy of phase transitions in Sm2O3
复制标题
Sm2O3 相变的高压 X 射线衍射和拉曼光谱
DOI：
10.1063/1.4795504
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发表时间：
2013-03-21
影响因子：
3.2
通讯作者：
Li, Yanchun
中科院分区：
文献类型：
--
作者：
Jiang, Sheng;Liu, Jing;Li, Yanchun
用高压同步辐射角色散X射线衍射和拉曼散射研究了Sm 2 O3在40.1 GPa和41.0 GPa压力下的结构相变。X射线衍射数据表明，单斜和立方相开始转变为六方相，分别在2.5和4.2 GPa。六方相在至少40.1GPa下是稳定的，并且不能淬火到环境条件。这些相变也被拉曼光谱所证实。基于所观察到的压力-体积数据的三阶Birch-Murnaghan拟合产生了立方相、单斜相和六方相的零压力体积模量B-0 = 149（2）、153（7）和155（5）GPa，当它们的一阶压力导数（B '（0））固定为4时。还得到了拉曼峰的压力系数和不同拉曼模式的模式Gruneisen参数。结合前人的研究结果，我们得出结论：中等稀土倍半氧化物从立方相和单斜相到六方相的转变压力随阳离子半径的减小而增大。(C)2013年美国物理学会。[http：//dx.doi.org/10.1063/1.4795504]
The structural phase transitions in Sm2O3 with mixed phases of cubic and monoclinic as starting material were studied by in situ high-pressure synchrotron angle dispersive x-ray diffraction and Raman scattering measurements up to 40.1 GPa and 41.0 GPa, respectively. The x-ray diffraction data indicate that the monoclinic and cubic phases begin to transform to a hexagonal phase at 2.5 and 4.2 GPa, respectively. The hexagonal phase is stable up to at least 40.1 GPa and could not be quenched to ambient conditions. These phase transitions have also been confirmed by Raman spectroscopy. A third-order Birch-Murnaghan fit based on the observed pressure-volume data yields zero pressure bulk moduli B-0 = 149(2), 153(7), and 155(5) GPa for cubic, monoclinic, and hexagonal phases, respectively, when their first pressure derivatives (B'(0)) were fixed as 4. The pressure coefficients of Raman peaks and the mode Gruneisen parameters of different Raman modes were also obtained. Coupled with previous results, we conclude that the transition pressure of medium rare-earth sesquioxides from the cubic and monoclinic to the hexagonal phase increase with the decreasing of the cation radius. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4795504]