Helical bunching and symmetry lowering inducing multiferroicity in Fe langasites
Résumé
In the chiral Ba3(Nb,Ta)Fe3Si2O14 langasites, the triangle-based helical magnetic order is revisited. It follows from the observation by neutron scattering of additional magnetic satellites and gaps in the spin waves spectra. These so-far undetected features are explained by a bunching of the magnetic helices due to single-ion anisotropy, and by a departure of the in-plane magnetic moments from the 120° arrangement due to a structural loss of the 3-fold axis. These weak modulations of the crystallographic and magnetic structures are shown to be responsible for a spin-induced electric polarization in zero and finite magnetic field, thus ascertaining the multiferroicity of these attractive materials.
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satellites.pdf (3.14 Mo)
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Supplemental_Material_satellites.pdf (1.43 Mo)
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| Origine | Fichiers produits par l'(les) auteur(s) |
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