TY - JOUR
T1 - Probing the validity of the spinel inversion model
T2 - a combined SPXRD, PDF, EXAFS and NMR study of ZnAl2O4
AU - Sommer, Sanna
AU - Bøjesen, Espen Drath
AU - Lock, Nina
AU - Kasai, Hidetaka
AU - Skibsted, Jørgen
AU - Nishibori, Eiji
AU - Iversen, Bo Brummerstedt
PY - 2020/10
Y1 - 2020/10
N2 - 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-state27Al Nuclear Magnetic Resonance to study the structural defects in ZnAl2O4spinel 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 ZnAl2O4structure. This suggests a pathway forward for optimization of the physical properties of spinel materials.
AB - 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-state27Al Nuclear Magnetic Resonance to study the structural defects in ZnAl2O4spinel 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 ZnAl2O4structure. This suggests a pathway forward for optimization of the physical properties of spinel materials.
UR - http://www.scopus.com/inward/record.url?scp=85092218432&partnerID=8YFLogxK
U2 - 10.1039/d0dt02795b
DO - 10.1039/d0dt02795b
M3 - Journal article
C2 - 32966463
AN - SCOPUS:85092218432
SN - 1477-9226
VL - 49
SP - 13449
EP - 13461
JO - Dalton Transactions
JF - Dalton Transactions
IS - 38
ER -