Exploring cation disorder in mixed?metal pyrochlore ceramics using 17 O NMR spectroscopy and first?principles calculations

نویسندگان

چکیده

Characterising the local structures (e.g., cation distribution) of mixed-metal ceramics by NMR spectroscopy is often challenging owing to unfavourable properties (low ?, large quadrupole moment and/or low abundance) many metal nuclei. 17 O an attractive option prevalence oxygen within ceramics. The moderate ? and small mean that greatest barrier accessing information available from this nucleus isotopic enrichment. We explore challenges ensuring uniform enrichment with O2 (g) for pyrochlore solid solutions, Y2 Snx Ti2-x O7 , La2 Zr2-x Hf2-x demonstrating high temperatures (900?°C 12?hr) are required. In addition, sites very symmetry (such as tetrahedral OY4 OLa4 CQ ???0 present here), we demonstrate quantitative spectra require correction differing contributions centreband satellite transitions, which can be a factor ~3.89. It common use first-principles calculations aid in interpreting disordered solids. Here, ensemble modelling approach ensure all possible arrangements modelled minimum number calculations. By combining enrichment, comprehensive computational approach, able show distribution essentially random, whereas OLa2SnZr OLa2SnHf slightly energetically disfavoured, leading weak preference clustering like cations.

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ژورنال

عنوان ژورنال: Magnetic Resonance in Chemistry

سال: 2021

ISSN: ['0749-1581', '1097-458X']

DOI: https://doi.org/10.1002/mrc.5140