Significant composition dependence of the anomalous Hall effect in the metallic triangular lattice antiferromagnet Co_1/3TaS₂

This presentation reports that metallic triangular antiferromagnet Co_1/3TaS₂ exhibits a substantial anomalous Hall effect (AHE) tunable by cobalt composition. We have synthesized single-crystal Co_xTaS₂ with a range of Co composition (0.299 < x < 0.34) and characterized their bulk properties. For 0.299 < x < 0.325, Co­_xTaS₂ undergoes two antiferromagnetic phase transitions at T_N1 = 38 K and T_N2 = 26.5 K. It exhibits the anomalous Hall effect as large as conventional ferromagnets (σ_xy(H = 0) ~ 70 Ω^-1 cm^-1) below T_N2, together with a weak ferromagnetic moment along the c-axis (M_z(H = 0) ~ 0.01μ_B). Surprisingly, such bulk properties vary significantly with x, even though the investigated range does not deviate much from the ideal value of x = 1/3. Most importantly, the weak ferromagnetic moment (M_z(H = 0)) and the AHE (σ_xy(H = 0)) are absent for x > 0.325. Based on the similar composition dependence observed in isostructural material Fe_1/3NbS₂ [1] and our neutron diffraction data, we discuss the origin of the tunable AHE in Co_xTaS₂.



[1] S. Wu et. al., Phys. Rev. X 12, 021003 (2022)