Sn*

Antiferromagnetic (AF) materials have garnered significant attention for their favorable properties in device applications, including very small stray fields and ultrafast spin dynamics [1]. Among antiferromagnets (AFMs), those with macroscopic time-reversal symmetry breaking (TRSB) with non-trivial spin structure have been extensively studied for their potential to detect and control spontaneous responses akin to ferromagnets. The non-collinear AFM Mn₃Sn [2], a prominent example of such TRSB AFMs, is a magnetic Weyl semimetal with unique chiral AF ordering hosting cluster magnetic octupoles and topological band structures, which lead to large transverse responses induced by the momentum-space Berry curvature [2,3]. The research targets are shifting fundamental studies, which have yielded fruitful results discussed above, towards exploring spintronics properties, focusing on cross-coupling effects such as spin-electron and -lattice coupling.

This presentation focuses on our studies involving heterointerfaces based on Mn₃Sn. We have successfully manipulated the chiral AF order in bilayer films composed of polycrystalline Mn₃Sn and heavy metals, demonstrating the potential for spin-orbit torque (SOT) [4]. This research extends to bilayer films comprising epitaxial Mn₃Sn and heavy metals [5,6], where we have achieved SOT-induced perpendicular magnetic recording for the first time in AFMs [6], leveraging high-quality Mn₃Sn films fabricated by MBE methods. Additionally, we have observed magnetoresistance effects at room temperature in an AF tunnel junction composed of Mn₃Sn/MgO/Mn₃Sn multilayers [7]. These results offer promising avenues for the development of chiral AF spintronics.

[1] Jungwirth et al., Nat. Nano. 11, 231 (2016). [2] Nakatsuji, Kiyohara, & TH, Nature 527, 212 (2015); Nakatsuji and Arita, Annu. Rev. Condens. Matter. Phys. 13, 119 (2022). [3] Kuroda, Tomita et al., Nat. Mater. 16, 1090 (2017). [4] Tsai, TH et al., Nature 580, 608 (2020). [5] Takeuchi et al., Nat. Mater. 20, 1364 (2021). [6] TH, Kondou et al., Nature 607, 474 (2022). [7] Chen, TH, Tanaka et al., Nature 613, 490 (2023).