Anion Disorder in Lanthanoid Zirconates Gd2鈥?i>xTbxZr2O7

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• 作者：Emily Reynolds ; Peter E. R. Blanchard ; Brendan J. Kennedy ; Chris D. Ling ; Samuel Liu ; Max Avdeev ; Zhaoming Zhang ; Gabriel J. Cuello ; Anton Tadich ; Ling-Yun Jang
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：August 5, 2013
• 年：2013
• 卷：52
• 期：15
• 页码：8409-8415
• 全文大小：350K
• 年卷期：v.52,no.15(August 5, 2013)
• ISSN：1520-510X

文摘

The pyrochlore鈥揹efect fluorite order鈥揹isorder transition has been studied for a series of oxides of the type Gd_2鈥?i>xTb_xZr₂O₇ by a combination of diffraction and spectroscopy techniques. Synchrotron X-ray diffraction data suggest an abrupt transition from the coexistence of pyrochlore and defect fluorite phases to a single defect fluorite phase with increasing Tb content. However neutron diffraction data, obtained at 位 鈮?0.497 脜 for all Gd-containing samples to minimize absorption, not only provide evidence for independent ordering of the anion and cation sublattices but also suggest that the disorder transition across the pyrochlore鈥揹efect fluorite boundary of Ln₂Zr₂O₇ is rather gradual. Such disorder was also evident in X-ray absorption measurements at the Zr L₃-edge, which showed a gradual increase in the effective coordination number of the Zr from near 6-coordinate in the pyrochlore rich samples to near 7-coordinate in the Tb rich defect fluorites. These results indicate the presence of ordered domains throughout the defect fluorite region, and demonstrate the gradual nature of the order鈥揹isorder transition across the Gd_2鈥?i>xTb_xZr₂O₇ series.