2024/02/02 by B. Tóth, Tóth, B., D. G. Farkas +16
Engineering · Materials Science · Physics and Astronomy · #FOS: Physical sciences #Magneto-Optical Properties and Applications #Materials Science (cond-mat.mtrl-sci) #Multiferroics and related materials #Physics of Superconductivity and Magnetism
paper · pdf · doi:10.48550/arxiv.2402.01417
openalex publication_date 2024/02/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Although BiFeO3 is one of the most studied multiferroic materials, recent magnetization and neutron scattering studies have revealed a new magnetic phase in this compound - the transverse conical phase. To study the collective spin excitations of this phase, we performed THz spectroscopy in magnetic fields up to 17 T at and above room temperature. We observed five spin-wave branches in the magnetic phase with long wavelength conical modulation. Using a numerical spin dynamics model we found two kinds of excitations with magnetic moments oscillating either along or perpendicular to the static fields. Remarkably, we detected strong directional dichroism, an optical manifestation of the magnetoelectric effect, for two spin-wave modes of the conical phase. According to our experiments, the stability of the conical state is sensitive to the magnetic field history and it can become (meta)stable at or close to zero magnetic field, which may allow exploiting its magnetoelectric properties at room temperature.