High-pressure Raman scattering and x-ray diffraction studies of MgTa2O6

High-pressure Raman scattering and angle dispersive synchrotron x-ray diffraction studies have been carried out on magnesium tantalate (MgTa2O6) up to 41 GPa at room temperature. A pressure-induced phase transition at pressures above 10 GPa accompanied by softening of the internal ν11 (Eg) modes has...

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Bibliographic Details
Published in:AIP advances 2020-06, Vol.10 (6), p.065324-065324-7
Main Authors: Jia, Shufan, Zhou, Qiang, Huang, Fengxian, Li, Fangfei, Hu, Yuxin, Huang, Litong, Li, Liang, Li, Yining, Cui, Tian
Format: Article
Language:English
Subjects:
Bulk modulus
Crystals
Equations of state
Lattice vibration
Low pressure
Magnesium
Phase transitions
Raman spectra
Room temperature
Structural stability
Synchrotron radiation
Vibration mode
X-ray diffraction
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Summary:High-pressure Raman scattering and angle dispersive synchrotron x-ray diffraction studies have been carried out on magnesium tantalate (MgTa2O6) up to 41 GPa at room temperature. A pressure-induced phase transition at pressures above 10 GPa accompanied by softening of the internal ν11 (Eg) modes has been observed. Another phase transition took place at 20.2 GPa, which indicates that the edge shared TaO6 octahedra are distorted. The equation of state for MgTa2O6 in low pressure phase I was obtained by the second-order Birch–Murnaghan method, yielding a zero-pressure bulk modulus B0 of 205.8 ± 8.4 GPa. The pressure dependencies of the lattice vibration mode were extracted, and it is suggested that the instability of the trirutile structure at high pressure is related to the strong deformation of the TaO6 octahedra. Decompression measurements suggest that the pressure-induced transformation is irreversible.
ISSN:2158-3226
2158-3226
DOI:10.1063/5.0009821