Probing the validity of the spinel inversion model: a combined SPXRD, PDF, EXAFS and NMR study of ZnAl2O4

Autor: Eiji Nishibori, Jørgen Skibsted, Espen Drath Bøjesen, Sanna Sommer, Nina Lock, Bo B. Iversen, Hidetaka Kasai
Rok vydání: 2020
Předmět:
Zdroj: Sommer, S, Bøjesen, E D, Lock, N, Kasai, H, Skibsted, J, Nishibori, E & Iversen, B B 2020, ' Probing the validity of the spinel inversion model : a combined SPXRD, PDF, EXAFS and NMR study of ZnAl 2 O 4 ', Dalton Transactions, vol. 49, no. 38, pp. 13449-13461 . https://doi.org/10.1039/d0dt02795b
Dalton transactions 49(38), 13449-13461 (2020). doi:10.1039/D0DT02795B
ISSN: 1477-9234
1477-9226
DOI: 10.1039/d0dt02795b
Popis: Dalton transactions 49(38), 13449 - 13461 (2020). doi:10.1039/D0DT02795B
Spinels are of essential interest in the solid-state sciences with numerous important materials adopting this crystal structure. One defining feature of spinel compounds is their ability to accommodate a high degree of tailorable point defects, and this significantly influences their physical properties. Standard defect models of spinels often only consider metal atom inversion between octahedral and tetrahedral sites, thereby neglecting other defects such as interstitial atoms. In addition, most studies rely on a single structural characterization technique, and this may bias the result and give uncertainty about the correct crystal structure. Here we explore the virtues of multi-technique investigations to limit method and model bias. We have used Pair Distribution Function analysis, Rietveld refinement and Maximum Entropy Method analysis of Powder X-ray Diffraction data, Zn edge Extended X-ray Absorption Fine Structure, and solid-state $^{27}$Al Nuclear Magnetic Resonance to study the structural defects in ZnAl$_2$O$_4$ spinel samples prepared by either microwave hydrothermal synthesis, supercritical flow synthesis, or spark plasma sintering. In addition, the samples were subjected to thermal post treatments. The study demonstrates that numerous synthesis dependent defects are present and that the different synthesis pathways allow for defect tailoring within the ZnAl$_2$O$_4$ structure. This suggests a pathway forward for optimization of the physical properties of spinel materials.
Published by Soc., London
Databáze: OpenAIRE
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