Topological Spin Textures in a Non-Collinear Antiferromagnet System.

Topologically protected magnetic "whirls" such as skyrmions in antiferromagnetic materials have recently attracted extensive interest due to their nontrivial band topology and potential application in antiferromagnetic spintronics. However, room-temperature skyrmions in natural metallic antiferromagnetic materials with merit of probable convenient electrical manipulation have not been reported. Here, room-temperature skyrmions are realized in a non-collinear antiferromagnet, Mn Sn, capped with a Pt overlayer. The evolution of spin textures from coplanar inverted triangular structures to Bloch-type skyrmions is achieved via tuning the magnitude of interfacial Dzyaloshinskii-Moriya interaction. Beyond that, the temperature can induce an unconventional transition from skyrmions to antiferromagnetic meron-like spin textures at ≈220 K in the Mn Sn/Pt samples. Combining with the theoretical calculations, it is found that the transition originates from the temperature dependence of antiferromagnetic exchange interaction between kagome sublayers within the Mn Sn crystalline unit-cell. These findings open the avenue for the development of topological spin-swirling-based antiferromagnetic spintronics.