High-pressure behavior of MnGeO3 and CdGeO3 perovskites and the post-perovskite phase transition
High-pressure behavior of MnGeO3 and CdGeO3 perovskites and the post-perovskite phase transition
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DOI：
10.1007/s00269-005-0049-7
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发表时间：
2005
影响因子：
1.4
通讯作者：
Shigehiko Tateno;K. Hirose;N. Sata;Y. Ohishi
中科院分区：
文献类型：
--
作者：
Shigehiko Tateno;K. Hirose;N. Sata;Y. Ohishi
基于激光加热金刚石砧池中高压和高温下的原位同步加速器 X 射线衍射测量，检查了 MnGeO3 和 CdGeO3 中钙钛矿结构的稳定性和高压行为。结果表明，随着压力的增加，正交晶系MnGeO3钙钛矿的结构畸变增强，并在1800K、60GPa以上时发生相变，形成CaIrO3型后钙钛矿结构。后钙钛矿相的摩尔体积比同等压力下的钙钛矿小1.6%。相比之下，随着压力的增加，CdGeO3钙钛矿的结构与理想立方钙钛矿结构的畸变程度越来越小，即使在110 GPa和2,000 K下也很稳定。这些结果表明，随着压力的增加，钙钛矿结构的大幅畸变诱导了向后钙钛矿的相变。
The stability and high-pressure behavior of perovskite structure in MnGeO3and CdGeO3were examined on the basis of in situ synchrotron X-ray diffraction measurements at high pressure and temperature in a laser-heated diamond-anvil cell. Results demonstrate that the structural distortion of orthorhombic MnGeO3perovskite is enhanced with increasing pressure and it undergoes phase transition to a CaIrO3-type post-perovskite structure above 60 GPa at 1,800 K. A molar volume of the post-perovskite phase is smaller by 1.6% than that of perovskite at equivalent pressure. In contrast, the structure of CdGeO3perovskite becomes less distorted from the ideal cubic perovskite structure with increasing pressure, and it is stable even at 110 GPa and 2,000 K. These results suggest that the phase transition to post-perovskite is induced by a large distortion of perovskite structure with increasing pressure.