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Shock-induced phase transitions in the MgO-FeO system to 200 GPa |
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| Authors: | Li Zhang Zizheng Gong Yingwei Fei |
| Affiliation: | a Institute of High Pressure and High Temperature Physics, Southwest Jiaotong University, Chengdu 610031, China b Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015, USA c Beijing Institute of Spacecraft Environment Engineering, Beijing 100094, China |
| Abstract: | We report new shock-compression data for single-crystal MgO at 114 and 192 GPa. Our data together with the existing shock-wave data revealed a volume discontinuity at 170±10 GPa along with the MgO Hugoniot. The discontinuity gives a volume increase of 1.9%, indicating a possible phase transition from a rock-salt structure (B1) to a high-temperature phase along with the MgO Hugoniot. We re-examined the Hugoniot data on polycrystalline sample (Mg0.6, Fe0.4)O up to 200 GPa [M.S. Vassiliou, T.J. Ahrens, The equation of state of Mg0.6Fe0.4O to 200 GPa, Geophys. Res. Lett. 9 (1982) 127-130], which showed similar discontinuity with a 2.2% volume increase at 135±10 GPa. Our results add to fundamental understandings of the behavior of MgO and the lower mantle mineral magnesiowüstite (Mg, Fe)O at ultrahigh pressure and temperature. |
| Keywords: | A. Oxides C. High pressure D. Phase transitions |
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