In situ observation of a garnet/perovskite transition in CaGeO3
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We used an in situ measurement method to investigate the phase transition of CaGeO3 polymorphs under high pressures and temperatures. A multi-anvil high-pressure apparatus combined with intense synchrotron X-ray radiation was used. The transition boundary between a garnet and a perovskite phase at T = 900–1,650 K and P = 3–8 GPa was determined as occurring at P (GPa) = 9.0−0.0023 × T (K). The transition pressure determined in our study is in general agreement with that observed in previous high-pressure experiments. The slope, dP/dT, of the transition determined in our study is consistent with that calculated from calorimetry data.
KeywordsCalcium germinate Phase transition Garnet Perovskite
The authors thank A. Suzuki, K. Mibe, and T. Kawamoto for their help in carrying out the experiments. The synchrotron radiation experiments were performed at the NE7A, KEK (Proposal No. 2009G508) and BL04B1, SPring-8 (Proposal No. 2008A1090). This work was partially supported by Grants-in-Aid for Scientific Research from JSPS and the Earthquake Research Institute cooperative research program, Japan.
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