Large Hall Signal due to Electrical Switching of an Antiferromagnetic Weyl Semimetal State

The electrical manipulation of a topological state is crucial for utilizing the robust properties of topological materials in electronic devices ^[1,2]. Recently, such manipulation is realized in the antiferromagnetic Weyl semimetal Mn₃Sn through the readout signal of anomalous Hall effect in the Mn₃Sn/heavy metal (Pt, W) heterostructures ^[3]. Here, we reported that the switching of Hall signal of Mn₃Sn/heavy metal multilayer can be significantly enhanced by: (i) changing the crystal orientation of Mn₃Sn by removing Ru buffer layer, and (ii) changing the interfacial condition by annealing at the interface between Mn₃Sn and the heavy metal. Compared to the reported switching Hall signal in Ru/Mn₃Sn/Pt multilayers, the switching Hall resistance becomes one order larger, ~0.35 Ω, in the Mn₃Sn/W devices. The readout voltage can be increased to mV order by increasing the read current. Moreover, by investigating the thickness dependence of Mn₃Sn layer, we found that the effective switching thickness in Mn₃Sn layer could go up to 40nm, which is much thicker than ferromagnetic materials.

[1] S. Nakatsuji, N. Kiyohara, T. Higo, Nature 527, 212-215 (2015).

[2] T. Higo, et al. APL 113, 202402 (2018).

[3] H. Tsai, T. Higo, et al. Nature 580, 608–613 (2020).