Structure evolution upon chemical and physical pressure in (Sr1−xBax)2FeSbO6
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Here we demonstrate the gradual structural transformation from the monoclinic I2/m to tetragonal I4/m, cubic Fm-3m and hexagonal P63/mmc structure upon the isovalent larger-for-smaller A-site cation substitution in the B-site ordered double-perovskite system (Sr1−xBax)2FeSbO6. This is the same transformation sequence previously observed up to Fm-3m upon heating the parent Sr2FeSbO6 phase to high temperatures. High-pressure treatment, on the other hand, transforms the hexagonal P63/mmc structure of the other end member Ba2FeSbO6 back to the cubic Fm-3m structure. Hence we may conclude that chemical pressure, physical pressure and decreasing temperature all work towards the same direction in the (Sr1−xBax)2FeSbO6 system. Also shown is that with increasing Ba-for-Sr substitution level, i.e. with decreasing chemical pressure effect, the degree-of-order among the B-site cations, Fe and Sb, decreases.
|Number of pages||7|
|Journal||Journal of Solid State Chemistry|
|Publication status||Published - 1 Feb 2017|
|MoE publication type||A1 Journal article-refereed|
- Cation order, Chemical pressure, Crystal structure, Double perovskite, High-pressure synthesis