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Free keywords:
Chirality; Electric fields; Ion exchange; Neutron scattering; Spin waves; Dynamic chirality; Exchange ions; Multiferroic phase; Multiferroics; Nearest-neighbor interactions; Nearest-neighbour; Neutron scattering experiments; Spin waves calculations; Time-of flight; Wave dispersion; Dispersion (waves)
Abstract:
Inelastic neutron scattering experiments combining time-of-flight and polarized techniques yield a comprehensive picture of the magnon dispersion in multiferroic Formula Presented including the dynamic chirality. Taking into account only Formula Presented moments, spin-wave calculations including nearest-neighbor interactions, frustrating next-nearest neighbor exchange, as well as single-ion anisotropy and antisymmetric terms describe the energy dispersion and the distribution of neutron scattering intensity in the multiferroic state very well. Polarized neutron scattering reveals strong dynamic chirality of both signs that may be controlled by external electric fields in the multiferroic phase. Also above the onset of long-range multiferroic order in zero electric field, a small inelastic chiral component can be inverted by an electric field. The microscopic spin-wave calculations fully explain also the dynamic chirality of magnetic excitations, which is imprinted by the static chirality of the multiferroic phase. The ordering of Formula Presented moments at lower temperature reduces the broadening of magnons but also renders the magnon dispersion more complex. © 2023 American Physical Society.
