Investigating the Local Structure of Lanthanoid Hafnates Ln2Hf2O7 via Diffraction and Spectroscopy

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• 作者：Peter E. R. Blanchard ; Sam Liu ; Brendan J. Kennedy ; Chris D. Ling ; Max Avdeev ; Jade B. Aitken ; Bruce C. C. Cowie ; Anton Tadich
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：February 7, 2013
• 年：2013
• 卷：117
• 期：5
• 页码：2266-2273
• 全文大小：363K
• 年卷期：v.117,no.5(February 7, 2013)
• ISSN：1932-7455

文摘

The lanthanoid hafnates Ln₂Hf₂O₇ (Ln = La, Pr, Nd, Sm鈥揟m) were studied using a combination of synchrotron X-ray and neutron powder diffraction together with X-ray absorption and Raman spectroscopy. Spectroscopic methods revealed a gradual increase in disorder from the ideal pyrochlore structure to the defect fluorite structure as the size of the Ln cation increases. The line shape of the Hf L₃-edge X-ray absorption near edge spectra which is sensitive to the local coordination environment changed with increasing disorder. The general line shape of the O K-edge XANES and Raman spectra also indicated an increase in disorder across the Ln₂Hf₂O₇ series. Differences in the diffraction and spectroscopy analysis reflect the greater sensitivity of the spectroscopy techniques to local ordering.