Spin-Wave and Electromagnon Dispersions in Multiferroic MnWO4 as Observed by Neutron Spectroscopy: Isotropic Heisenberg Exchange versus Anisotropic Dzyaloshinskii-Moriya Interaction

Abstract

High resolution inelastic neutron scattering reveals that the elementary magnetic excitations in multiferroic MnWO4 consist of low energy dispersive electromagnons in addition to the well-known spin-wave excitations. The latter can well be modeled by a Heisenberg Hamiltonian with magnetic exchange coupling extending to the 12th nearest neighbor. They exhibit a spin-wave gap of 0.61(1) meV. Two electromagnon branches appear at lower energies of 0.07(1) meV and 0.45(1) meV at the zone center. They reflect the dynamic magnetoelectric coupling and persist in both, the collinear magnetic and paraelectric AF1 phase, and the spin spiral ferroelectric AF2 phase. These excitations are associated with the Dzyaloshinskii-Moriya exchange interaction, which is significant due to the rather large spin-orbit coupling.

arXiv comment8 pages, 6 figures, accepted for publication in Physical Review B

References in corpus (28)

• Spin current and magneto-electric effect in non-collinear magnets
• Ferroelectricity in spiral magnets
• Multiferroic materials and magnetoelectric physics: symmetry, entanglement, excitation, and topology
• Magnetically driven ferroelectric order in Ni${}_3$V${}_2$O${}_8$
• Possible evidence for electromagnons in multiferroic manganites
• Inversion symmetry breaking in noncollinear magnetic phase of a triangular lattice antiferromagnet CuFeO2
• Ferroelectric polarization flop in a frustrated magnet MnWO${}_4$ induced by magnetic fields
• Spin-polarization coupling in multiferroic transition-metal oxides
• Dynamical magneto-electric coupling in helical magnets
• Ferroelectricity induced by acentric spin-density waves in YMn${}_2$O${}_5$
• A New Multiferroic Material: MnWO4
• Dynamics of Multiferroic Domain Wall in Spin-Cycloidal Ferroelectric DyMnO${}_3$
• Magnetic and magnetoelectric excitations in TbMnO${}_3$
• Long-Range Magnetic Interactions in the Multiferroic Antiferromagnet $\mathrm{MnW}{\mathrm{O}}_4$
• Local symmetry and magnetic anisotropy in multiferroic MnWO4 and antiferromagnetic CoWO4 studied by soft x-ray absorption spectroscopy
• Robust Ferroelectric State in Multiferroic Mn${}_{1-x}$Zn${}_x$WO${}_4$
• Electromagnons in the spin collinear state of a triangular lattice antiferromagnet
• The Suppression and Recovery of the Ferroelectric Phase in Multiferroic $MnW{O}_4$
• Magnetic orders and spin-flop transitions in the cobalt doped multiferroic $\mathrm{M}{\mathrm{n}}_{1-\mathrm{x}}\mathrm{C}{\mathrm{o}}_{\mathrm{x}}\mathrm{W}{\mathrm{O}}_4$
• Magnetic switching and phase competition in the multiferroic antiferromagnet $\mathrm{M}{\mathrm{n}}_{1-\mathrm{x}}\mathrm{F}{\mathrm{e}}_{\mathrm{x}}\mathrm{W}{\mathrm{O}}_4$
• Magnetic digital flop of ferroelectric domain with fixed spin chirality in a triangular lattice helimagnet
• Critical slowing down near the multiferroic phase transition in MnWO${}_4$
• Magnetic structure and ferroelectric polarization of MnWO4 investigated by density functional calculations and classical spin analysis
• Origin of Multiferroicity in MnWO4
• Directional magnetoelectric effects in MnWO4: magnetic sources of the electric polarization
• Electronic structure and anomalous band-edge absorption feature in multiferroic MnWO4: An optical spectroscopic study
• Crystal structure, incommensurate magnetic order and ferroelectricity in mn${}_{1-x}$cu${}_x$wo${}_4$ (x=0-0.19)
• Magnetic order and electromagnon excitations in DyMnO3 studied by neutron scattering experiments

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