An ordinary Hall effect in a conductor arises due to the Lorentz force acting on the charge carriers. In ferromagnets, an additional contribution to the Hall effect, the anomalous Hall effect (AHE), appears proportional to the magnetization. It is also known that the AHE can arise in non-collinear and non-coplanar antiferromagnets due to scalar spin chirality. However, recently a large AHE was observed in a collinear antiferromagnet CoNb₃S₆ [1]. More recent theories have indicated that the AHE in CoNb₃S₆ may be inherently related to the chirality associated with the crystal structure [2,3]. The presence of a small ferromagnetic component plays an important role in revealing the AHE in CoNb₃S₆ which was limited to a narrow temperature range just below the Néel temperature. Here we will show that partial substitution of Co by Fe widens the temperature range and that the AHE in Co_1-xFe_xNb₃S₆ saturates at lower temperatures. We will discuss the importance of this observation in the context of recent theories of the AHE in collinear antiferromagnets.

[1] Ghimire et al. Nat. Commun. 9, 3975 (2018).
[2] Šmejkal et al. arXiv:1901.00445 (2019).
[3] Zhang et al. arXiv:909.13338 (2019).