Pressure-induced disappearance of the local rhombohedral distortion in BaTiO3
Pressure-induced disappearance of the local rhombohedral distortion in BaTiO3
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DOI：
10.1209/epl/i2006-10020-2
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发表时间：
2006-05
期刊：
影响因子：
1.8
通讯作者：
J. Itié;B. Couzinet;A. Polian;A. Flank;P. Lagarde
中科院分区：
文献类型：
--
作者：
J. Itié;B. Couzinet;A. Polian;A. Flank;P. Lagarde
在金刚石对顶砧装置上，用X射线吸收谱研究了BaTiO_3在室温下Ti K边的X射线吸收谱。在Ti K边缘处观察到的边缘前特征对压力敏感。结果表明，在2GPa以上获得的高压立方相类似于高温相，钛不在氧八面体的中心。在2和10 GPa之间，前边缘特征的强度减小，表明Ti原子正向氧八面体的中心移动。在10 GPa以上，特征不再改变，表明Ti原子位于氧八面体的中心。没有观察到Ti原子位置和压力下的拉曼活性之间的相关性。
BaTiO3 has been studied by X-ray absorption spectroscopy at the Ti K edge up to 19 GPa in a diamond anvil cell at room temperature. The pre-edge features observed at the Ti K edge are sensitive to the pressure. It is shown that the high-pressure cubic phase obtained above 2 GPa is similar to the high-temperature one, with titanium out of the centre of the oxygen octahedron. Between 2 and 10 GPa the intensity of the pre-edge features decreases indicating that the Ti atom is moving toward the centre of the oxygen octahedron. Above 10 GPa, the features do not change anymore, showing that the Ti atom is at the centre of the oxygen octahedron. No correlation between the Ti atom position and the Raman activity under pressure is observed.