High pressure and high temperature phase transitions of FeO

Motohiko Murakami, Kei Hirose, Shigeaki Ono, Taku Tsuchiya, Maiko Isshiki, Tetsu Watanuki

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43 Citations (Scopus)


We investigated the phase transitions of FeO at high pressure and high temperature up to 87 GPa and 1730 K by in situ synchrotron X-ray diffraction measurements in a laser-heated diamond anvil cell (DAC). The results demonstrated that the NaCl-type (B1) structure of FeO undergoes transition to the NiAs-type (B8) structure above 70 GPa at 1600 K. The density increase across this transition is about 2%. Present B1-B8 transition pressure is consistent with the previous shock-induced transition pressure. The relative intensities of diffraction peaks of the B8 phase may suggest a polytype normal/inverse NiAs structure, which has a metallic nature that could promote the oxygen incorporation into the iron-rich core. Transition to the metallic B8 phase above 70 GPa is also consistent with the earlier electrical resistance measurements. The hexagonal close-packed (hcp) ε-phase of Fe coexisted with FeO both at room temperature and high temperatures above 44-87 GPa.

Original languageEnglish
Pages (from-to)273-282
Number of pages10
JournalPhysics of the Earth and Planetary Interiors
Issue number1-2
Publication statusPublished - 2004 Aug 16


  • FeO
  • In situ X-ray measurement
  • Laser-heated DAC
  • NiAs (B8) structure
  • Phase transition

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Geophysics
  • Physics and Astronomy (miscellaneous)
  • Space and Planetary Science

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    Murakami, M., Hirose, K., Ono, S., Tsuchiya, T., Isshiki, M., & Watanuki, T. (2004). High pressure and high temperature phase transitions of FeO. Physics of the Earth and Planetary Interiors, 146(1-2), 273-282. https://doi.org/10.1016/j.pepi.2003.06.011