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Title: Spin-lattice coupling in iron jarosite

Abstract

We have studied the magnetoelectric coupling of the frustrated triangular antiferromagnet iron jarosite using Raman spectroscopy, dielectric measurements and specific heat. Temperature dependent capacitance measurements show an anomaly in the dielectric constant at T{sub N}. Specific heat data indicate the presence of a low frequency Einstein mode at low temperature. Raman spectroscopy confirms the presence of a new mode below T{sub N} that can be attributed to folding of the Brillouin zone. This mode shifts and sharpens below T{sub N}. We evaluate the strength of the magnetoelectric coupling using the symmetry unrestricted biquadratic magnetoelectric terms in the free energy. - Graphical abstract: Sketch of two connected triangles formed by Fe{sup 3+} spins (red arrows) in the hexagonal basal plane of potassium iron jarosite. An applied magnetic field (H) below the antiferromagnetic ordering temperature induces shifts of the hydroxy ligands, giving rise to local electrical dipole moments (blue arrows). These electric displacements cancel out in pairwise fashion by symmetry. Ligand shifts are confined to the plane and shown by shadowing. Highlights: Black-Right-Pointing-Pointer Evidence has been found for spin-lattice coupling in iron jarosite. Black-Right-Pointing-Pointer A new optical Raman mode appears below T{sub N} and shifts with temperature. Black-Right-Pointing-Pointer The magnetodielectric coupling ismore » mediated by superexchange. Black-Right-Pointing-Pointer Symmetry of Kagome magnetic lattice causes local electrical dipole moments to cancel.« less

Authors:
;  [1];  [2]; ;  [1];  [1]
  1. Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands)
  2. Max Planck Institute for Chemical Physics of Solids, Noethnitzer Str. 40, 01187 Dresden (Germany)
Publication Date:
OSTI Identifier:
22149884
Resource Type:
Journal Article
Journal Name:
Journal of Solid State Chemistry
Additional Journal Information:
Journal Volume: 195; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0022-4596
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANTIFERROMAGNETISM; BRILLOUIN ZONES; COUPLING; DIELECTRIC MATERIALS; DIPOLE MOMENTS; FREE ENERGY; IRON; LIGANDS; MAGNETIC FIELDS; MAGNETIC PROPERTIES; PERMITTIVITY; POTASSIUM; RAMAN SPECTROSCOPY; SPECIFIC HEAT; TEMPERATURE DEPENDENCE

Citation Formats

Buurma, A.J.C., Handayani, I.P., Mufti, N., Blake, G.R., Loosdrecht, P.H.M. van, and Palstra, T.T.M., E-mail: t.t.m.palstra@rug.nl. Spin-lattice coupling in iron jarosite. United States: N. p., 2012. Web. doi:10.1016/J.JSSC.2012.03.011.
Buurma, A.J.C., Handayani, I.P., Mufti, N., Blake, G.R., Loosdrecht, P.H.M. van, & Palstra, T.T.M., E-mail: t.t.m.palstra@rug.nl. Spin-lattice coupling in iron jarosite. United States. doi:10.1016/J.JSSC.2012.03.011.
Buurma, A.J.C., Handayani, I.P., Mufti, N., Blake, G.R., Loosdrecht, P.H.M. van, and Palstra, T.T.M., E-mail: t.t.m.palstra@rug.nl. Thu . "Spin-lattice coupling in iron jarosite". United States. doi:10.1016/J.JSSC.2012.03.011.
@article{osti_22149884,
title = {Spin-lattice coupling in iron jarosite},
author = {Buurma, A.J.C. and Handayani, I.P. and Mufti, N. and Blake, G.R. and Loosdrecht, P.H.M. van and Palstra, T.T.M., E-mail: t.t.m.palstra@rug.nl},
abstractNote = {We have studied the magnetoelectric coupling of the frustrated triangular antiferromagnet iron jarosite using Raman spectroscopy, dielectric measurements and specific heat. Temperature dependent capacitance measurements show an anomaly in the dielectric constant at T{sub N}. Specific heat data indicate the presence of a low frequency Einstein mode at low temperature. Raman spectroscopy confirms the presence of a new mode below T{sub N} that can be attributed to folding of the Brillouin zone. This mode shifts and sharpens below T{sub N}. We evaluate the strength of the magnetoelectric coupling using the symmetry unrestricted biquadratic magnetoelectric terms in the free energy. - Graphical abstract: Sketch of two connected triangles formed by Fe{sup 3+} spins (red arrows) in the hexagonal basal plane of potassium iron jarosite. An applied magnetic field (H) below the antiferromagnetic ordering temperature induces shifts of the hydroxy ligands, giving rise to local electrical dipole moments (blue arrows). These electric displacements cancel out in pairwise fashion by symmetry. Ligand shifts are confined to the plane and shown by shadowing. Highlights: Black-Right-Pointing-Pointer Evidence has been found for spin-lattice coupling in iron jarosite. Black-Right-Pointing-Pointer A new optical Raman mode appears below T{sub N} and shifts with temperature. Black-Right-Pointing-Pointer The magnetodielectric coupling is mediated by superexchange. Black-Right-Pointing-Pointer Symmetry of Kagome magnetic lattice causes local electrical dipole moments to cancel.},
doi = {10.1016/J.JSSC.2012.03.011},
journal = {Journal of Solid State Chemistry},
issn = {0022-4596},
number = ,
volume = 195,
place = {United States},
year = {2012},
month = {11}
}