Structure evolution upon chemical and physical pressure in (Sr{sub 1−x}Ba{sub x}){sub 2}FeSbO{sub 6}

Journal Article · Wed Feb 15 00:00:00 EST 2017 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2016.11.033· OSTI ID:22658189

Tiittanen, T.

Here we demonstrate the gradual structural transformation from the monoclinic I2/m to tetragonal I4/m, cubic Fm-3m and hexagonal P6{sub 3}/mmc structure upon the isovalent larger-for-smaller A-site cation substitution in the B-site ordered double-perovskite system (Sr{sub 1−x}Ba{sub x}){sub 2}FeSbO{sub 6}. This is the same transformation sequence previously observed up to Fm-3m upon heating the parent Sr{sub 2}FeSbO{sub 6} phase to high temperatures. High-pressure treatment, on the other hand, transforms the hexagonal P6{sub 3}/mmc structure of the other end member Ba{sub 2}FeSbO{sub 6} 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 (Sr{sub 1−x}Ba{sub x}){sub 2}FeSbO{sub 6} 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. - Graphical abstract: In the (Sr{sub 1−x}Ba{sub x}){sub 2}FeSbO{sub 6} double-perovskite system the gradual structural transformation from the monoclinic I2/m to tetragonal I4/m, cubic Fm-3m and hexagonal P6{sub 3}/mmc structure is seen upon the isovalent larger-for-smaller A-site cation substitution. High-pressure treatment under 4 GPa extends stability of the cubic Fm-3m structure within a wider substitution range of x. - Highlights: • Gradual structural transitions upon A-cation substitution in (Sr{sub 1−x}Ba{sub x}){sub 2}FeSbO{sub 6.} • With increasing x structure changes from I2/m to I4/m, Fm-3m and P6{sub 3}/mmc. • Degree of B-site order decreases with increasing x and A-site cation radius. • High-pressure treatment extends cubic Fm-3m phase stability for wider x range. • High-pressure treatment affects bond lengths mostly around the A-cation.

• OSTI ID: 22658189
• Journal Information: Journal of Solid State Chemistry, Vol. 246; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANTIMONATES
BARIUM COMPOUNDS
BOND LENGTHS
CATIONS
HCP LATTICES
IRON COMPOUNDS
MONOCLINIC LATTICES
PHASE STABILITY
PRESSURE DEPENDENCE
PRESSURE RANGE MEGA PA 10-100
STRONTIUM COMPOUNDS
TEMPERATURE RANGE 0400-1000 K
TETRAGONAL LATTICES
TRANSFORMATIONS