在下地幔压力条件下对方铁矿和镁方铁矿的单晶同步辐射X射线衍射研究。

Single-crystal synchrotron X-ray diffraction study of wüstite and magnesiowüstite at lower-mantle pressures.

作者信息

Jacobsen Steven D, Lin Jung Fu, Angel Ross J, Shen Guoyin, Prakapenka Vitali B, Dera Przemyslaw, Mao Ho-kwang, Hemley Russell J

机构信息

Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road NW, Washington, DC 20015, USA.

出版信息

J Synchrotron Radiat. 2005 Sep;12(Pt 5):577-83. doi: 10.1107/S0909049505022326. Epub 2005 Aug 16.

DOI:10.1107/S0909049505022326

PMID:16120980

Abstract

This study demonstrates the use of monochromatic synchrotron X-ray radiation of 40 keV for high-precision equation-of-state studies on sets of single crystals analysed individually in the same diamond-anvil pressure cell. Angle-dispersive zone-axis diffraction patterns were obtained from crystals of wustite-Fe0.93O and magnesiowüstite-(Mg0.73Fe0.27)O to 51 GPa in a hydrostatic helium pressure medium. The rhombohedral phase of Fe0.93O was observed above 23 GPa, and its isothermal bulk modulus (K0) was determined to be 134 (+/-4) GPa, assuming K'=4. The rhombohedral phase of Fe(0.93)O is more compressible than B1-structured Fe0.93O, with K0=146 (+/-2) GPa. Magnesiowüstite-(Mg0.73Fe0.27)O remains cubic over the experimental pressure range, and has a bulk modulus of 154 (+/-3) GPa with K'=4.0 (+/-0.1).

摘要

本研究展示了利用40 keV的单色同步加速器X射线辐射，对在同一金刚石对顶砧压力室中单独分析的单晶组进行高精度状态方程研究。在静水压氦压力介质中，从方铁矿-Fe0.93O和镁方铁矿-(Mg0.73Fe0.27)O晶体获得了角度色散区轴衍射图案，压力高达51 GPa。在23 GPa以上观察到Fe0.93O的菱面体相，假设K' = 4，其等温体积模量(K0)确定为134(±4)GPa。Fe(0.93)O的菱面体相比B1结构的Fe0.93O更易压缩，B1结构的Fe0.93O的K0 = 146(±2)GPa。镁方铁矿-(Mg0.73Fe0.27)O在实验压力范围内保持立方相，其体积模量为154(±3)GPa，K' = 4.0(±0.1)。