Low-Temperature Competing Magnetic Interactions in the Topological RMn6Sn6 Kagome Metals

ORAL

Abstract



The RMn6Sn6 (R166, R = rare earth) hexagonal kagome metals show intriguing topological and magnetic properties which depend on the choice of R. Here, we present inelastic neutron scattering (INS) studies of R166 for R = Tb, Ho and Er. All three compounds exhibit ferrimagnetic order at low-temperature, but Er166 has an intermediate temperature triple-spiral phase with an incommensurate antiferromagnetic (AFM) propagation vector. Our INS data show that all three compounds have strong ferromagnetic (FM) interactions within individual Mn layers but differing temperature-dependent magnetic anisotropies. Strong FM interactions within a Mn layer determines the overall magnetic bandwidth of ∼ 230 meV. The low-energy magnetic excitations are characterized by strong FM Mn-Mn and AFM Mn-R nearest-neighbor interlayer exchange, as well as weaker and competing longer range FM and AFM Mn-Mn interlayer exchange. Competition between the interlayer interactions and also between the Mn easy-plane and R uniaxial anisotropies reveals itself with changing temperature as an energy shift of the R magnon band associated with the thermal population of R crystalline-electric-field levels. Our data confirm density-functional-theory calculations, which find that competing Mn-Mn interlayer magnetic interactions occur in all R166 compounds with R = Y, Gd-Lu, which in turn results in magnetic instabilities and tunability when Mn-R interactions are weak.



* Work at the Ames National Laboratory was supported by the Department of Energy, Basic Energy Sciences under Contract No. DE-AC02-07CH11358. This work was also supported by the Center for the Advancement of Topological Semimetals (CATS), an Energy Frontier Research Center at the Ames National Laboratory. A portion of this research used resources at the Spallation Neutron Source, which is a U.S. DOE Office of Science User Facility operated by the Oak Ridge National Laboratory.

–

Publication: [1] Riberolles, S. X. M. et al, Low-temperature competing magnetic energy scales in the topological Ferrimagnet TbMn6Sn6, Phys. Rev.X 12, 021043 (2022).
[2] Riberolles, S. X. M. et al, Orbital character of the spin-reorientation transition in TbMn6Sn6, Nat Commun 14, 2658 (2023).

Presenters

  • Fei Li

    Ames National Laboratory

Authors

  • Fei Li

    Ames National Laboratory

  • Tianxiong Han

    Iowa State University, Ames National Laboratory, Iowa State University, Ames National Lab

  • Simon X Riberolles

    Ames National Laboratory, Ames Lab

  • Tyler J Slade

    Ames National Lab, Ames National Laboratory

  • Douglas L Abernathy

    Oak Ridge National Lab

  • Garrett E Granroth

    Oak Ridge National Lab, ORNL

  • Bing Li

    Argonne National Laboratory

  • Yongbin Lee

    Iowa State University

  • Paul C Canfield

    Iowa State University, Ames National Laboratory/Iowa State University

  • Benjamin G Ueland

    Ames National Laboratory/Iowa State University, Ames National Laboratory

  • Liqin Ke

    Ames National Laboratory

  • Robert J McQueeney

    Ames National Laboratory/Iowa State University, Iowa State University, Ames National Laboratory and Iowa State University