Selection rules and dynamic magnetoelectric effect of the spin waves in multiferroic BiFeO${}_3$

Abstract

We report the magnetic field dependence of the THz absorption and non-reciprocal directional dichroism spectra of BiFeO${}_3$ measured on the three principal crystal cuts for fields applied along the three principal directions of each cut. From the systematic study of the light polarization dependence we deduced the optical selection rules of the spin-wave excitations. Our THz data, combined with small-angle neutron scattering results showed that i) an in-plane magnetic field rotates the $\mathbf{q}$ vectors of the cycloids perpendicular to the magnetic field, and ii) the selection rules are mostly determined by the orientation of the $\mathbf{q}$ vector with respect to the electromagnetic fields. We observed a magnetic field history dependent change in the strength and the frequency of the spin-wave modes, which we attributed to the change of the orientation and the length of the cycloidal $\mathbf{q}$ vector, respectively. Finally, we compared our experimental data with the results of linear spin-wave theory that reproduces the magnetic field dependence of the spin-wave frequencies and most of the selection rules, from which we identified the spin-polarization coupling terms relevant for the optical magnetoelectric effect.

References in corpus (31)

• Weak ferromagnetism and magnetoelectric coupling in bismuth ferrite
• Multiferroic materials and magnetoelectric physics: symmetry, entanglement, excitation, and topology
• Dynamical magneto-electric coupling in helical magnets
• Observation of electromagnon excitations in the BiFe0${}_3$ spiral magnet
• Giant directional dichroism of terahertz light in resonance with magnetic excitations of the multiferroic oxide BaCo${}_2$Ge${}_2$O${}_7$
• Chirality of Matter Shows Up via Spin Excitations
• Structure and spin dynamics of multiferroric BiFeO${}_3$
• Four-coloured Spin-wave Excitations in Multiferroic Materials
• Non collinear magnetism and single ion anisotropy in multiferroic perovskites
• Magnetic dispersion and anisotropy in multiferroic BiFeO3
• Optical coupling to spin waves in the cycloidal multiferroic BiFeO3
• Spin wave measurements over the full Brillouin zone of multiferroic BiFeO3
• Symmetry Conditions for Non-reciprocal Light Propagation in Magnetic Crystals
• Optical diode effect in the room-temperature multiferroic BiFeO$_3
• High-temperature terahertz optical diode effect without magnetic order in polar FeZnMo${}_3$O${}_8$
• Long wavelength magnetic and magnetoelectric excitations in the ferroelectric antiferromagnet BiFeO3
• Terahertz spectroscopy of spin waves in multiferroic BiFeO${}_3$ in high magnetic fields
• The Spin State and Spectroscopic Modes of Multiferroic BiFeO3
• Magnetoelectric memory function with optical readout
• Theory of spin-orbit enhanced electric-field control of magnetism in multiferroic BiFeO3
• Field dependence of the Spin State and Spectroscopic Modes of Multiferroic BiFeO${}_3$
• Spin-Induced Polarizations and Non-Reciprocal Directional Dichroism of Multiferroic BiFeO${}_3$
• Direct coupling of ferromagnetic moment and ferroelectric polarization in BiFeO${}_3$
• Magnetic field control of cycloidal domains and electric polarization in multiferroic BiFeO${}_3$
• Spin excitations of magnetoelectric LiNiPO${}_4$ in multiple magnetic phases
• Quantum Dynamics of Multiferroic Helimagnets: a Schwinger-Boson Approach
• Directional dichroism in the paramagnetic state of multiferroics: a case study of infrared light absorption in Sr2CoSi2O7 at high temperatures
• Magnetic resonances of multiferroic TbFe${}_3$(BO${}_3$)${}_4$
• Magnetic anisotropy and exchange paths for octa- and tetrahedrally coordinated Mn${}^{2+}$ ions in the honeycomb multiferroic Mn${}_2$Mo${}_3$O${}_8$
• The Magnetoelastic Distortion of Multiferroic BiFeO${}_3$ in the Canted Antiferromagnetic State
• In-situ electric field control of THz non-reciprocal directional dichroism in the multiferroic Ba${}_2$CoGe${}_2$O${}_7$

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