Evolution of spin structure in Kagome metal Sc_0.8Hf_0.2Mn₆Sn₆ under magnetic field

Much interest has been drawn to the magnetic Kagome materials because of the presence of rich phases including quantum spin liquid, flat electronic bands and topological electronic behavior. In particular, a topological Hall effect in the absence of crystallographic inversion symmetry breaking is observed in the Kagome-net magnet YMn₆Sn₆ near room temperature (240 K) with in-plane magnetic field applied (µ₀H > 2 Tesla). Such effect is believed to associated with noncollinear spin structures like the double-fan spin structure [1] or transverse conical spiral configuration [2,3]. Similar behavior has been observed in the Hf-doped Sc_0.8Hf_0.2Mn₆Sn₆ except with a much-reduced critical field. We have used single crystal neutron diffraction to investigate the evolution of the complex spin configuration with magnetic field applied both in in-plane and along the c-axis. The detailed modification in spin structure is discussed in the context of the competitions between exchange interactions and magnetic anisotropies.

[1] Q. Wang et al., Phys. Rev. B 103, 014416 (2021).

[2] N. J. Ghimire et al., Sci. Adv. 6, eabe2680 (2020).

[3] R. L. Dally et al., Phys. Rev. B 103, 094413 (2021).