Coupling of Jahn-Teller and tilting distortions in high temperature structural phase transition of the Ca_0.2Sr_0.6Nd_0.2Mn_{1鈭?span style='font-style: italic'>x}Cr_xO₃; 0聽鈮ぢ?span style='fon

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• 作者：Teck-Yee Tan^a ; Qingdi Zhou^a ; Brendan J. Kennedy^a ; ^{b.kennedy@chem.usyd.edu.au} ; Qinfen Gu^b ; Justin A. Kimpton^b
• 关键词：Perovskite ; Cooperative Jahn&ndash ; Teller distortion ; Manganite ; Phase transition ; Orbital ordering
• 刊名：Solid State Sciences
• 出版年：2012
• 期刊代码：98_12932558
• 类别：ch
• 出版时间：April, 2012
• 卷：14
• 期：4
• 页码：506-514
• 文件大小：2053 K

摘要

The manganite perovskites Ca_0.2Sr_0.6Nd_0.2Mn_1鈭?em>xCr_xO₃, 0聽鈮ぢ?em>x聽鈮ぢ?.2, have been synthesized by solid state methods, and their room temperature structures determined using synchrotron X-ray powder diffraction. At room temperature, the oxides have a tetragonal structure in space group I4/mcm. Whereas the BO₆ groups in the x聽=聽0 sample are noticeably distorted those in the x聽=聽0.2 sample are more regular as a consequence of the progressive removal of the Jahn-Teller type distortion. High temperature diffraction measurements of the x聽=聽0, 0.1 and 0.2 samples reveal that Cr doping has little effect on the transition to the cubic structure that occurs around 450聽掳C. Cr doping does however significantly alter the spontaneous strains in the oxides as a consequence of the cooperative Jahn-Teller distortion.