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Title: Structural and magnetic study of Yb{sup 3+} in the perovskites Sr{sub 2}YbMO{sub 6} (M=Nb, Ta, Sb)

The compounds Sr{sub 2}YbNbO{sub 6}, Sr{sub 2}YbTaO{sub 6} and Sr{sub 2}YbSbO{sub 6} have been prepared using solid state methods by heating pelleted reagents in air at temperatures up to 1400 °C. Rietveld refinement against room temperature neutron powder diffraction data show that all three compounds crystallise with a cation-ordered variant of the perovskite structure in the P2{sub 1}/n space group. Complete cation ordering occurs between M{sup 5+} and Yb{sup 3+} over two octahedrally-coordinated sites in the structure and all compounds are stoichiometric in oxygen. The Sb–O bond lengths are similar to related perovskite compounds but differ slightly from those indicated by bond valence sums. Magnetic susceptibility data resemble Curie–Weiss paramagnetic behaviour, but can be better understood as arising from the effect of the octahedral crystal field on the {sup 2}F{sub 5/2} ground state of Yb{sup 3+} leading to a temperature dependent magnetic moment on this ion below 100 K. - Graphical abstract: The magnetic susceptibility of the face-centred cubic Yb{sup 3+} lattice is dominated by the temperature dependent single-ion moment below 100 K. - Highlights: • Cation-ordered perovskites are studied using neutron diffraction and magnetometry. • Yb{sup 3+} cations form a pseudo face centred cubic lattice in a distorted structure.more » • Sb{sup 5+} cation is slightly overbonded as observed in related perovskites. • Crystal field splitting of 4f{sup 13} Yb{sup 3+} giving a temperature dependent moment. • Magnetic susceptibility reproduces theoretical predictions below 100 K.« less
Authors:
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Publication Date:
OSTI Identifier:
22443527
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 221; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANTIMONY IONS; BOND LENGTHS; CATIONS; CRYSTAL FIELD; FCC LATTICES; GROUND STATES; MAGNETIC MOMENTS; MAGNETIC SUSCEPTIBILITY; MONOCLINIC LATTICES; NEUTRON DIFFRACTION; OXYGEN; PARAMAGNETISM; PEROVSKITE; RARE EARTHS; SOLIDS; SPACE GROUPS; TEMPERATURE DEPENDENCE; YTTERBIUM IONS