CeO_2纳米八面体高压结构相变的Raman研究(英文)

High-pressure Raman Study on the Structural Stability of CeO_2 Nano-octahedrons

利用高压原位拉曼光谱技术研究了非静水条件对CeO2纳米八面体高压结构相变的重压影响。研究表明:在非静水条件下(无传压介质),当压力达到26 GPa时,CeO2纳米八面体发生由立方萤石型结构到正交α-PbCl2型结构的可逆结构相变,相变压力低于相应的体材料(30 GPa)。相反,在准静水压条件下,CeO2纳米八面体的相变压力为33 GPa,高于其体材料。研究表明,实验条件对CeO2纳米八面体结构稳定性具有重要影响。

The effect of nonhydrostatic conditions on high pressure phase transition on CeO2 nano- octahedrons were studied using in situ high-pressure Raman spectroscopy. Under non-hydrostatic conditions （with no pressure medium） the CeO2 nano-octahedrons underwent a reversible phase transition from fluorite phase to a-PbC12 phase at 26 GPa, which is lower than the bulk counterpart. In contrast, the CeO2 nano-octahedrons under hydrostatic conditions are shown to be more stable than the bulk. The transition pressure from cubic to orthorhombic phase is approximately 3 GPa higher than bulk materials. These results show that experimental conditions have an important ef- fect on the structural stability of CeO2 nano-octahedrons.