Space group and crystal structure of the Perovskite CaTiO3 from 296 to 1720K
Space group and crystal structure of the Perovskite CaTiO3 from 296 to 1720K
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DOI：
10.1016/j.jssc.2005.06.027
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发表时间：
2005-09-01
影响因子：
3.3
通讯作者：
Yashima, M
中科院分区：
文献类型：
--
作者：
Ali, R;Yashima, M
利用高温中子Rietveld分析和x射线粉末衍射数据，研究了钛酸钙钙钛矿CaTiO3在296 ~ 1720k温度范围内的结构相变。结果表明，该化合物在1498 +/- 25 K和1634 +/- 13 K下分别表现出正交pbm -四边形I4/mcm和I4/mcm -立方Pm(3)的可逆相变。在Pbnm和I4/mcm结构之间没有观察到Cmcm相的证据。晶格参数在Pbnm-I4/mcm转变点处不连续变化，而在14/mcm- pm (3) over barm转变点处连续变化。这些结果表明，Pbnm-I4/mcm的转变是一级的，而I4/mcm- pm (3) over barm的转变是二级或更高一级的。(c) 2005爱思唯尔公司版权所有。
The structural phase transitions of the calcium titanate perovskite CaTiO3 were investigated by the Rietveld analysis of high-temperature neutron and X-ray powder diffraction data in the temperature range of 296-1720K. The present work demonstrates that the compound exhibits two reversible phase transitions of orthorhombic Pbnm-tetragonal I4/mcm and of I4/mcm\-cubic Pm (3) over barm at 1498 +/- 25 K and 1634 +/- 13 K, respectively. No evidence of Cmcm phase is observed between the Pbnm and I4/mcm structures. The lattice parameters discontinuously change at the Pbnm-I4/mcm transition point, while a continuous change is observed for the 14/mcm-Pm (3) over barm transformation. These results indicate that the Pbnm-I4/mcm transition is of first order and that the I4/mcm-Pm (3) over barm transformation is of either second or higher order. (c) 2005 Elsevier Inc. All rights reserved.