Thermal low spin-high spin equilibrium of Fe(II) in thiospinels CuFe{sub 0.5}(Sn{sub (1-x)}Ti{sub x}){sub 1.5}S{sub 4} (0{<=}x{<=}1)

Journal Article · Fri Apr 15 00:00:00 EDT 2011 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.01.038· OSTI ID:21494255

Womes, M ^[1]; Reibel, C ^[1]; Mari, A ^[2]; Zitoun, D ^[1]

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1. Universite Montpellier II, Institut Charles Gerhardt (UMR CNRS 5253), CC015, Place E. Bataillon, 34095 Montpellier Cedex 5 (France)
2. Laboratoire de Chimie de Coordination (UPR CNRS 8241), 205 route de Narbonne, 31077 Toulouse Cedex 04 (France)

A series of spinel compounds with composition CuFe{sub 0.5}(Sn{sub (1-x)}Ti{sub x}){sub 1.5}S{sub 4} (0{<=}x{<=}1) is analysed by X-ray diffraction, measurements of magnetic susceptibilities and {sup 57}Fe Moessbauer spectroscopy. All samples show a temperature-dependent equilibrium between an electronic low spin 3d(t{sub 2g}){sup 6}(e{sub g}){sup 0} and a high spin 3d(t{sub 2g}){sup 4}(e{sub g}){sup 2} state of the Fe(II) ions. The spin crossover is of the continuous type and extends over several hundred degrees in all samples. The Sn/Ti ratio influences the thermal equilibrium between the two spin states. Substitution of Sn(IV) by the smaller Ti(IV) ions leads to a more compact crystal lattice, which, in contrast to many metal-organic Fe(II) complexes, does not stabilise the low spin state, but increases the residual high spin fraction for T{yields}0 K. The role played by antiferromagnetic spin coupling in the stabilisation of the high spin state is discussed. The results are compared with model calculations treating the effect of magnetic interactions on spin state equilibria. -- Graphical Abstract: Comparison of fractions of high spin Fe(II) from Moessbauer spectra (circles) with plots of {chi}{sub m}T (dots) versus T. Discrepancies between both methods indicate anti-ferromagnetic spin coupling. Display Omitted Research highlights: {yields} Many Fe(II) complexes show thermally induced high spin-low spin crossover. {yields} Spin crossover in spinel compounds is extremely scarce. {yields} Usually, lattice contraction favours the low spin state in Fe(II) complexes. {yields} In these spinels, lattice contraction favours the high spin state. {yields} The stabilisation of the high spin state is explained by spin-spin interactions.

• OSTI ID: 21494255
• Journal Information: Journal of Solid State Chemistry, Vol. 184, Issue 4; Other Information: DOI: 10.1016/j.jssc.2011.01.038; PII: S0022-4596(11)00049-1; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANTIFERROMAGNETISM
COPPER COMPLEXES
CRYSTAL LATTICES
EXCHANGE INTERACTIONS
IRON COMPLEXES
IRON IONS
J-J COUPLING
MAGNETIC SUSCEPTIBILITY
MOESSBAUER EFFECT
ORGANOMETALLIC COMPOUNDS
SPIN
SPINELS
SULFIDES
THERMAL EQUILIBRIUM
TITANIUM IONS
X-RAY DIFFRACTION
ANGULAR MOMENTUM
CHALCOGENIDES
CHARGED PARTICLES
COHERENT SCATTERING
COMPLEXES
COUPLING
CRYSTAL STRUCTURE
DIFFRACTION
EQUILIBRIUM
INTERACTIONS
INTERMEDIATE COUPLING
IONS
MAGNETIC PROPERTIES
MAGNETISM
MINERALS
ORGANIC COMPOUNDS
OXIDE MINERALS
PARTICLE PROPERTIES
PHYSICAL PROPERTIES
SCATTERING
SULFUR COMPOUNDS
TRANSITION ELEMENT COMPLEXES