Competing Magnetic Energy Scales in the Topological Ferrimagnet TbMn<sub>6</sub>Sn<sub>6</sub>
ORAL
Abstract
TbMn6Sn6 is a metallic ferrimagnet displaying signatures of topological electrons and topological magnons arising from ferromagnetism and spin-orbit coupling within the Mn kagome layers. We present inelastic neutron scattering data showing strong ferromagnetic (FM) interactions within a Mn layer and reveal a magnetic bandwidth of ∼ 230 meV. The low-energy magnetic excitations are characterized by strong FM Mn-Mn and antiferromagnetic (AFM) Mn-Tb nearest-neighbor interlayer exchange, as well as weaker and competing longer range FM and AFM Mn-Mn interlayer exchange similar to those driving helical AFM order in YMn6Sn6. When these measurements are combined with density-functional theory calculations, we find that competing Mn-Mn interlayer magnetic interactions occur in all RMn6Sn6 compounds with R = Y, Gd-Lu. This results in magnetic instabilities and tunability when Mn-R interactions are weak. In the case of TbMn6Sn6, the strong AFM Mn-Tb coupling ensures a highly stable three-dimensional ferrimagnet.
*Work at the Ames Laboratory was supported by the Department of Energy, Basic Energy Sciences under Contract No. DE-AC02-07CH11358. Measurements at the Spallation Neutron Source at ORNL are sponsored by the User Facilities division of DOE BES.
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Publication: S.X.M. Riberolles et al., Phys. Rev. X 12, 021403 (2022).
Presenters
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Benjamin G Ueland
- Ames National Laboratory