Garnet-to-Perovskite Transition in Gd3Sc2Ga3O12 at High Pressure and High Temperature

详细信息    查看全文

• 作者：Chuanlong Lin ; Jing Liu ; Jung-Fu Lin ; Xiaodong Li ; Yanchun Li ; Qingli Zhang ; Lun Xiong ; Rui Li
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：January 7, 2013
• 年：2013
• 卷：52
• 期：1
• 页码：431-434
• 全文大小：269K
• 年卷期：v.52,no.1(January 7, 2013)
• ISSN：1520-510X

文摘

The structural phase transition of gadolinium鈥搒candium鈥揼allium garnet (Gd₃Sc₂Ga₃O₁₂, GSGG) has been studied at high pressure and high temperature using the synchrotron X-ray diffraction technique in a laser-heated diamond anvil cell. The GSGG garnet transformed to an orthorhombic perovskite structure at approximately 24 GPa after laser heating to 1500鈥?000 K. The garnet-to-perovskite phase transition is associated with an 8% volume reduction and an increase in the coordination number of the Ga³⁺ or Sc³⁺ ion. The orthorhombic perovskite GSGG has bulk modulus B₀ = 194(15) GPa with B₀鈥?= 5.3(8), exhibiting slightly less compression than the cubic garnet structure of GSGG with B₀ = 157(15) GPa and B₀鈥?= 6.5(10). Upon compression at room temperature, the cubic GSGG garnet became amorphous at 65 GPa. Coupled with the amorphous-to-perovskite phase transition in Y₃Fe₅O₁₂ and Gd₃Ga₅O₁₂ at high-pressure鈥搕emperature conditions, we conclude that amorphization should represent a new thermodynamic state resulting from hindrance of the garnet-to-perovskite phase transition, whereas the garnet-to-amorphous transition in rare-earth garnets should be kinetically hindered at room temperature.