Magnetic properties of Mn₃Sn thin films depending on annealing condition

In recent years, antiferromagnets have rapidly attracted attention because it shows several advantages such as no stray field, ultrafast spin dynamics, and current-induced phenomena, compared to ferromagnets. In particular, the non-collinear antiferromagnets (NC-AFM) based on D0₁₉ (space group=194, P6₃/mmc) hexagonal Mn₃X (X=Ga, Ge, and Sn) is an important template in antiferromagnetic spintronics owing to nontrivial magnetic properties which are a giant anomalous Hall effect, magnetic spin Hall effect, magnetic Wely fermions, and chiral anomaly. Among the compounds, the magnetic Weyl semimetal Mn₃Sn is a prime representative of NC-AFM. In Mn₃Sn, the Mn atoms form a triangular sublattice in the c-plane (0001) called Kagome lattice, and their net magnetic moments are disclosed from non-collinear 120° ordered chiral spin structure. This spin texture leads to the existence of Weyl point with opposite chirality in Mn3Sn due to breaking time-reverse symmetry.

In this work, we study the spin-orbit torque (SOT) switching properties of the Mn₃Sn depending on the annealing condition. The Mn₃Sn thin films were prepared on MgO (110) substrates with different annealing conditions using an UHV magnetron sputtering system. We found that the annealing process gives rise to tensile strain in the ( direction in the Mn₃Sn layer. The strain also enhances SOT-induced switching property of the Mn­₃Sn film. Our work provides further scientific and technological advances in antiferromagnetic spintronics based on Mn₃Sn.