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

• DOI: 10.1021/ic302245x
• Publication Date: 2012-12-14T13:33:07Z
• Authors: Chuanlong Lin; Jing Liu; Jung-Fu Lin; Xiaodong Li; Yanchun Li; Qingli Zhang; Lun Xiong; Rui Li
• Keywords: Orthorhombic crystal system; Diamond anvil cell

The structural phase transition of gadolinium-scandium-gallium garnet (Gd(3)Sc(2)Ga(3)O(12), GSGG) has been studied at high pressure and temperature using the synchrotron X-ray diffraction technique in a laser-heated diamond anvil cell. GSGG transformed to an orthorhombic perovskite structure approximately 24 GPa after laser heating 1500-2000 K. garnet-to-perovskite is associated with ∼8% volume reduction increase coordination number Ga(3+) or Sc(3+) ion. bulk modulus B(0) = 194(15) B(0)' 5.3(8), exhibiting slightly less compression than cubic 157(15) 6.5(10). Upon room temperature, became amorphous ∼65 GPa. Coupled amorphous-to-perovskite Y(3)Fe(5)O(12) Gd(3)Ga(5)O(12) high-pressure-temperature conditions, we conclude that amorphization should represent new thermodynamic state resulting from hindrance transition, whereas garnet-to-amorphous rare-earth garnets be kinetically hindered temperature.