Stability and equation of state of MgGeO3 post-perovskite phase

Kei Hirose, Katsuyuki Kawamura, Yasuo Ohishi, Shigehiko Tateno, Nagayoshi Sata

Research output: Contribution to journalArticle

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Abstract

A phase transition of MgGeO3 perovskite was examined at high-pressure and -temperature using synchrotron X-ray diffraction measurements. The results demonstrate that it transforms to a CaIrO 3-type post-perovskite phase above 63 GPa at 1800 K. The density increase is 1.5% at the transition pressure. These observations confirm that MgGeO3 is a low-pressure analogue to MgSiO3, for which a similar phase transition was recently found above 125 GPa and 2500 K. The unit-cell parameters of MgGeO 3 post-perovskite phase obtained at 300 K during decompression from 79 to 6 GPa show that the b-axis is significantly more compressible than are the a- and c-axes, which could be due to the GeO6-octahedral sheet stacking structure along b. The bulk modulus was determined to be K0 = 192(±5) GPa with a fixed pressure derivative of the bulk modulus, K', of 4.

Original languageEnglish
Pages (from-to)262-265
Number of pages4
JournalAmerican Mineralogist
Volume90
Issue number1
DOIs
Publication statusPublished - Jan 2005
Externally publishedYes

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perovskite
bulk modulus
Equations of state
equation of state
equations of state
phase transition
transition pressure
pressure reduction
synchrotrons
low pressure
Elastic moduli
Phase transitions
analogs
decompression
stacking
transform
cells
Synchrotrons
X-ray diffraction
diffraction

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

Cite this

Hirose, K., Kawamura, K., Ohishi, Y., Tateno, S., & Sata, N. (2005). Stability and equation of state of MgGeO3 post-perovskite phase. American Mineralogist, 90(1), 262-265. https://doi.org/10.2138/am.2005.1702

Stability and equation of state of MgGeO3 post-perovskite phase. / Hirose, Kei; Kawamura, Katsuyuki; Ohishi, Yasuo; Tateno, Shigehiko; Sata, Nagayoshi.

In: American Mineralogist, Vol. 90, No. 1, 01.2005, p. 262-265.

Research output: Contribution to journalArticle

Hirose, K, Kawamura, K, Ohishi, Y, Tateno, S & Sata, N 2005, 'Stability and equation of state of MgGeO3 post-perovskite phase', American Mineralogist, vol. 90, no. 1, pp. 262-265. https://doi.org/10.2138/am.2005.1702
Hirose, Kei ; Kawamura, Katsuyuki ; Ohishi, Yasuo ; Tateno, Shigehiko ; Sata, Nagayoshi. / Stability and equation of state of MgGeO3 post-perovskite phase. In: American Mineralogist. 2005 ; Vol. 90, No. 1. pp. 262-265.
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