Structural transition of BaF_2 nanocrystals under high pressure  

作　　者：王婧姝 马春丽 祝洪洋 武晓鑫 李冬妹 丛日东 刘景 石蕊 崔啟良 

机构地区：[1]Jilin Normal University [2]State Key Laboratory of Superhard Materials, Jilin University [3]Institute of High Energy Physics, Chinese Academy of Sciences

出　　处：《Chinese Physics C》2013年第8期76-79,共4页中国物理C（英文版）

基　　金：Supported by National Natural Science Foundation of China (11074089, 51172087);National Basic Research Program of China (2011CB808204)

摘　　要：The structural transition of BaF2 nanocrystals is studied by in situ high pressure synchrotron radiation X-ray diffraction measurements up to about 21.2 GPa at ambient temperature. Two phase transformations were observed at 5.8 and 14.4 GPa, and the two high pressure phases are identified as orthorhombic （Pnma） phase and hexagonal （P63/mmc） phase by Rietveld refinement. Upon decompression, the 0c-PbC12-type metastable phase is retained when the pressure is released. Two phase transformations of the BaF2 nanocrystals are higher than that in bulk BaF2. It is proposed that the size effects are found to influence the BaF2 nanocrystals high-pressure behaviors and the surface energy plays a significant role in the structural stability.The structural transition of BaF2 nanocrystals is studied by in situ high pressure synchrotron radiation X-ray diffraction measurements up to about 21.2 GPa at ambient temperature. Two phase transformations were observed at 5.8 and 14.4 GPa, and the two high pressure phases are identified as orthorhombic （Pnma） phase and hexagonal （P63/mmc） phase by Rietveld refinement. Upon decompression, the 0c-PbC12-type metastable phase is retained when the pressure is released. Two phase transformations of the BaF2 nanocrystals are higher than that in bulk BaF2. It is proposed that the size effects are found to influence the BaF2 nanocrystals high-pressure behaviors and the surface energy plays a significant role in the structural stability.

关 键 词：NANOCRYSTALS BaF2 synchrotron radiation phase transition 

分 类 号：O521.2[理学—高压高温物理]