X-ray multi-beam resonant diffraction analysis of crystal symmetry for layered perovskite YBaCuFeO₅

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• 作者：Wen-Chung Liu ; Yu-Zhan Zheng ; Yu-Chieh Chih ; Yen-Chung Lai ; Yi-Wei Tsai ; Yan-Zong Zheng ; Chao-Hung Du ; Fang-Cheng Chou ; Yun-Liang Soo and Shih-Lin Chang
• 关键词：X-ray multiple diffraction ; diffraction anomalous fine structure ; DAFS ; dynamical X-ray diffraction theory ; crystal symmetry ; YBaCuFeO5
• 刊名：Journal of Applied Crystallography
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：49
• 期：5
• 页码：1721-1725
• 全文大小：996K
• ISSN：1600-5767

文摘

The open question of crystal symmetry for YBaCuFeO₅, still under debate, is resolved by using diffraction anomalous fine structure and resonant multi-beam X-ray diffraction at the Fe and Cu K edges. The different asymmetric intensity distributions observed at 7, 7.1305 and 8.9945 keV give direct evidence that the space group of YBaCuFeO₅ should be P4/mmm with the distance between Cu and apical O atoms longer than that between Fe and O atoms. This approach provides a direct way to resolve detailed structural symmetry which is indeterminate in conventional Bragg diffraction.