Tuning topological Hall effect in Co1/3NbS2 single crystals through Fe doping

Antiferromagnets Co1/3MS2 (M = Nb, Ta) have attracted great interest recently due to their large spontaneous Hall resistivity, attributed to the topological Hall effect (THE). In this work, we successfully manipulate the magnetic structures to tune THE by replacing Co with Fe in Co1/3NbS2 single crystals, i.e., (FexCo1−x)1/3NbS2. The evolution of the crystal lattice parameter c caused by the increase in Fe-doping levels is consistent with the change in composition. With increasing x, the main magnetic transition temperature gradually increases from 23.5 to 31.5 K. Enhanced topological Hall resistivity (∼3.04 µΩ cm at 2 K under zero field), meta-magnetic transition, and butterfly-shaped magnetoresistance are observed in the x = 0.12 single crystal. The x = 0.18 single crystal shows similar behaviors to the x = 0.12 sample, but a shrinkage of the topological Hall resistivity. While in x = 0.40 single crystal, THE disappears as magnetization changes from weak ferromagnetism in x = 0.12 and 0.18 to antiferromagnetism along the c axis, and instead, a field-induced hysteresis and topological Hall effect are observed. Our work provides a promising route to tune the THE by manipulating the spin orientation.