Preparation, magnetic and transport properties of Mn3Sn single crystals

Abstract

Topological antiferromagnetic Mn₃Sn crystals exhibit notable magnetic and transport properties, comparable to ferromagnets, and undergo various intriguing magnetic phase transitions during heating or cooling. The spin structures of Mn₃Sn crystals are highly influenced by growth conditions and the stoichiometric ratio of Mn and Sn, which in turn affect the phase transition temperature and the transport signatures. In this work, we employed the flux method, carefully controlling factors such as melting temperature, cooling rate, sampling temperature, vacuum, and composition, and fabricated Mn_2.991Sn_1.009 bulk single crystals successfully. The size of the resulting single crystal after cutting is 6 × 5 × 3 mm³. The microstructure, magnetic and transport properties of the prepared single crystals were characterized parallel to and perpendicular to the z-axis. A strong and a weak magnetic phase transition were observed at 200 K and 280 K, respectively. Our results indicate that the magnetic phase transition of Mn₃Sn crystals at 200 K involves a switch in the easy-axis of magnetization from in-plane to out-of-plane, corresponding to the anomalous Hall resistance peak at 200 K. These results show a clear correlation between the spin structure and Berry curvature in Mn₃Sn crystals, which significantly affect the magnitude of the anomalous Hall effect.