Giant Topological Hall Effect Across a Broad Temperature Window in Co‐Doped Mn ₃ Sn Noncoplanar Antiferromagnets

ABSTRACT The interplay between magnetism and topology in a geometrically frustrated noncollinear kagome lattice generate a real‐space Berry curvature and produce a topological Hall effect (THE). However, the absence of a room‐temperature THE severely hinders its application in spintronics. Here, a intrinsic THE is showed up to ∼1.64 µΩ·cm for x = 0.42 in Mn _{3− x} Co _x Sn at 2 K with the field applied along H // z , ∼ 9 times of the reported maximum value in other noncoplanar antiferromagnetic materials. Such a THE across a broad wide temperature window up to 300 K, where it reaches a value of 0.45 µΩ·cm, ∼ 5 times of the reported maximum value in other noncoplanar antiferromagnetic materials. We attribute this giant THE to a robust intrinsic scalar spin chirality induced by magnetic Co doping. Our findings establish Co‐doped Mn ₃ Sn as a unique platform for tailoring noncoplanar spin textures via doping to yield an unprecedented THE. This thereby enables the application of robust topological spin textures near room temperature, highlighting their significant potential in antiferromagnetic spintronics.