Pressure-induced phase transition study of magnesiochromite (MgCr₂O₄) by Raman spectroscopy and X-ray diffraction

详细信息    查看全文

• 作者：Wenjun Yong^a ; ^{wyong4@uwo.ca} ; Sanda Botis^a ; Sean R. Shieh^a ; ^b ; Weiguang Shi^a ; Anthony C. Withers^c
• 关键词：Phase transition ; Magnesiochromite ; Spinel ; Raman ; X-ray diffraction ; High pressure
• 刊名：Physics of the Earth and Planetary Interiors
• 出版年：2012
• 出版时间：April, 2012
• 年：2012
• 卷：196-197
• 期：Complete
• 页码：75-82
• 全文大小：593 K

文摘

Pressure-induced phase transition in magnesiochromite (MgCr₂O₄) was studied by in situ Raman spectroscopy and X-ray diffraction to 50 and 60 GPa, respectively. A polymorphic phase transition from cubic structure to tetragonal I4₁/amd structure was observed at pressures above 20 GPa and this transition is complete at 23.5 GPa. The volume data for magnesiochromite fitted to Birch-Murnaghan equation of state (EOS) yield K₀ = 189(2) GPa, and V₀ = 578.68(4) ?³, consistent with theoretical calculations. The EOS of the high pressure tetragonal phase was also obtained as K₀ = 191(8) GPa and V₀ = 279(1) ?³ when  = 4 (fixed). The volume reduction at phase transition is about 4.4 % . The high pressure phase is unquenchable and transformed back to magnesiochromite with little hysteresis upon release of pressure.