微区Raman光谱在TiO_2高压结构相变研究中的应用

本文以金红石单晶TiO2和锐钛矿多晶TiO2为研究对象,应用金刚石小压机和原位拉曼光谱测量技术,系统研究了室温高压下TiO2的结构相变。原位拉曼测量表明,金红石单晶TiO2在压力达到12.91GPa时开始发生由金红石结构向斜锆石结构(MI)的相变,当压力达到14.16 GPa时,相变完成;继续加压到21.65 GPa,没有发现进一步的相变;卸压时由斜锆石结构转变为PbO2结构,相变发生在大约7.11 GPa处。锐钛矿多晶TiO2在压力达到4.26 GPa时开始向PbO2结构转变,当压力达到8.34 GPa时相变完成;继续加压到12.94 GPa,样品开始发生由PbO2结构向斜锆石结构的相变,当压力达到18.74 GPa时相变完成;继续加压到21.39 GPa,没有发现进一步的相变;卸压时也由斜锆石结构转变为PbO2结构,起始相变压力点应高于8 GPa。

Raman Study of the Phase Transformations of TiO2 under Static High-Pressure

In this paper,the phase transformations of the single crystal of rutile and polycrystalline anatase TiO2 have been studied by in-situ Raman spectroscopy at static high pressures using diamond anvil cell(DAC) at room temperature.The Raman measurement results show that single crystal of rutile TiO2 begins to transform into baddeleyite structure(MI) at about 12.91 GPa,and the phase transition is finished at about 14.16 GPa.The next phase transition is not found until about 21.65 GPa.On decompression to 7.11 GPa,the MI transforms into α-PbO2 structure(TiO2Ⅱ).The polycrystalline anatase TiO2 begins to transform into αPbO2 structure at about 4.26 GPa,the transition is finished at about 8.34 GPa.The α-PbO2 begins to transform into MI at about 12.94 GPa,and the phase transition is finished at about 18.74 GPa.There are not other transitions until 21.39 GPa.On decompression to 7.94 GPa,the MI transforms into α-PbO2 structure.