A variable temperature structural study of the Jahn-Teller distortion in Ba2CuUO6 |
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| Authors: | Qingdi Zhou |
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| Institution: | School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia |
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| Abstract: | The structure of the ordered double perovskite Ba2CuUO6 has been investigated between room temperature and 800 °C using synchrotron X-ray powder diffraction. At room temperature Ba2CuUO6 is tetragonal, space group I4/m, a=8.82331(13) c=8.82330(13) Å, the structure being characterized by a large Jahn-Teller distortion of the CuO6 octahedra and small out-of-phase tilts of the BO6 octahedra. This Jahn-Teller distortion is also evident in the UV-Vis spectra. Analysis of the spontaneous tetragonal strain reveals a continuous ferroelastic phase transition near 420 °C. This appears to be related to the loss of the tilts whilst maintaining the Jahn-Teller distortion, so that the high temperature structure is in space group I4/mmm. |
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| Keywords: | A Oxide C Neutron scattering C X-ray diffraction D Crystal structure D Phase transition |
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