High-pressure experiments on phase transition boundaries between corundum, Rh2O3(II)-and CaIrO3-type structures in Al 2O3

Jinya Kato, Kei Hirose, Haruka Ozawa, Yasuo Ohishi

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    9 Citations (Scopus)

    Abstract

    Phase transitions in Al2O3 between corundum Rh 2O3(II)-type and CaIrO3-type (post-perovskitetype)phases were examined at high pressure and high temperature in a laser-heated diamond-anvilcell (DAC) based on in situ X-ray diffraction measurements. The locations of corundum-Rh2O3(II)and Rh2O3(II)-CaIrO3 boundaries were precisely determined by conducting both forward and backwardreaction experiments. The results demonstrate that corundum undergoes a phase transition toRh 2O3(II)-type structure above 106 GPa at 1800 K with a negative Clapeyron slope of -6.5 ± 1.5MPa/K, generally consistent with earlier experimental and theoretical works. The Rh2O 3(II)-typephase further transforms into CaIrO3-type above 170 GPa at 2300 K, indicating the transition pressuremuch higher than earlier experimental work but in agreement with reported GGA calculations. TheClapeyron slope of this phase transition was found to be high negative (-20 ± 5 MPa/K).

    Original languageEnglish
    Pages (from-to)335-339
    Number of pages5
    JournalAmerican Mineralogist
    Volume98
    Issue number2-3
    DOIs
    Publication statusPublished - 2013

    Keywords

    • Corundum
    • High pressure
    • Phase transition
    • Post-perovskite

    ASJC Scopus subject areas

    • Geophysics
    • Geochemistry and Petrology

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