Magnetic phase dependence of the anomalous Hall effect in Mn3Sn single crystals

Thermodynamic and transport properties are reported on single crystals of the hexagonal antiferromagnet Mn3Sn grown by the Sn flux technique. Magnetization measurements reveal two magnetic phase transitions at T1 = 275 K and T2 = 200 K, below the antiferromagnetic phase transition at TN ≈ 420 K. The Hall conductivity in zero magnetic field is suppressed dramatically from 4.7 Ω−1 cm−1 to near zero below T1, coincident with the vanishing of the weak ferromagnetic moment. This illustrates that the large anomalous Hall effect arising from the Berry curvature can be switched on and off by a subtle change in the symmetry of the magnetic structure near room temperature.