Spin crossover, structural change, and metallization in NiAs-type FeO at high pressure

Haruka Ozawa, Kei Hirose, Kenji Ohta, Hirofumi Ishii, Nozomu Hiraoka, Yasuo Ohishi, Yusuke Seto

    Research output: Contribution to journalArticlepeer-review

    35 Citations (Scopus)


    We report high-spin to low-spin crossover of iron in NiAs (B8)-type Fe 0.96O (FeO hereafter) at high pressure by a combination of in-situ x-ray emission spectroscopy (XES) and x-ray diffraction (XRD) measurements. The XES spectra show a loss of spin in B8-type FeO approximately above 119 GPa at 300 K, consistent with the ∼2.5% volume reduction around 120 GPa. The high-temperature XRD study also demonstrates a similar volume decrease at 1560-1780 K under the same pressure condition. While the crystal structure of FeO remains to be B8 type across such volume reduction, the atomic arrangements of Fe and O change from inverse to normal NiAs form with considerable decrease in c/a axial ratio. With recent electrical resistance measurements, these suggest that iron spin crossover, inverse-normal structural change, and insulator-metal transition occur concurrently in B8 FeO around 120 GPa.

    Original languageEnglish
    Article number134417
    JournalPhysical Review B - Condensed Matter and Materials Physics
    Issue number13
    Publication statusPublished - Oct 14 2011

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics


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