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High pressure Raman spectroscopic study of spinel MgCr2O4 |
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| Authors: | Z Wang H.S.C O'NeillP Lazor S.K Saxena |
| Affiliation: | a Center for Study of Matter at Extreme Conditions (CeSMEC), Florida International University, VH 150, University Park, Miami, FL 33199, USA b Research School of Earth Sciences, Australian National University, Canberra, ACT 2000, Australia c Institute of Earth Sciences, Uppsala University, S-752 36, Uppsala, Sweden |
| Abstract: | An in situ Raman spectroscopic study was conducted to investigate the pressure induced phase transformation of MgCr2O4 spinel up to pressures of 76.4 GPa. Results indicate that MgCr2O4 spinel undergoes a phase transformation to the CaFe2O4 (or CaTi2O4) structure at 14.2 GPa, and this transition is complete at 30.1 GPa. The coexistence of two phases over a wide range of pressure implies a sluggish transition mechanism. No evidence was observed to support the pressure-induced dissociation of MgCr2O4 at 5.7-18.8 GPa, predicted by the theoretical simulation. This high pressure MgCr2O4 polymorphism remains stable upon release of pressure, but at ambient conditions, it transforms to the spinel phase. |
| Keywords: | C. Raman spectroscopy A. Ceramics C. X-ray diffraction |
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