HR: 1340h
AN: MR43C-1516    [Abstracts]
TI: Synchrotron x-ray diffraction studies for zincite and ceria under high pressure conditions
AU: * Wang, L
EM: luhong1@hit.edu.cn
AF: Harbin Institute of Technology, Research Academy of Science and Technology, Science Park, Harbin, 150080, China
AU: Liu, H
EM: haozhe@hit.edu.cn
AF: Harbin Institute of Technology, Research Academy of Science and Technology, Science Park, Harbin, 150080, China
AU: Sinogeikin, S
AF: Carnegie Institution of Washington, Geophysical Laboratory, Washington DC, DC 20015, United States
AU: Shu, J
AF: Carnegie Institution of Washington, Geophysical Laboratory, Washington DC, DC 20015, United States
AU: Mao, H
AF: Carnegie Institution of Washington, Geophysical Laboratory, Washington DC, DC 20015, United States
AB: Certificated by National Institute of Standards & Technology (NIST), the ZnO and CeO2 powders are intended for use as internal standards for quantitative x-ray diffraction (XRD) analysis, and as external standards for checking the intensity response of x-ray diffraction instruments. For the current high pressure XRD beamlines in synchrotron sources, these oxide powders are normally used as calibration standards at ambient conditions. It is also possible to use these standards as internal standards via their well measured equation of state (EoS). For example, use the wurtzite phase of ZnO to calibrate the wavelength and the distance between sample and detector at ambient conditions. Then use its well-known wurtzite-to-rocksalt type phase transition at 9.3 GPa as fixed point. Its simple rocksalt structure could support such calibrations since we observed its structural stability to high pressure from 10 GPa to at least 215 GPa. A series of synchrotron XRD experimental results will be presented: CeO2 in helium pressure medium up to phase transition pressure; ZnO at high pressure conditions in various pressure media, and the rocksalt phase stability above 200 GPa. High pressure and low temperature down to 15K XRD experiments were also performed for ZnO to fulfill its wurtzite-to-rocksalt type phase transition boundary at low temperature domain. The internal atomic pre-transition distortion effect at low temperature and high pressure will be discussed combine the first-principles calculations results.
DE: 3620 Mineral and crystal chemistry (1042)
DE: 3924 High-pressure behavior
DE: 3954 X-ray, neutron, and electron spectroscopy and diffraction
DE: 3994 Instruments and techniques
SC: Mineral and Rock Physics [MR]
MN: 2007 Fall Meeting