Abnormal Negative Magnetoresistance and Exceptional Hall Component in Magnetic Weyl Semimetal Co₃Sn₂S₂ Nanodevices

Recently, the first magnetic Weyl semimetal Co₃Sn₂S₂ has been discovered[1-3]. For topological related spintronics applications in low dimensions, the growth and physical researches of Co₃Sn₂S₂ thin films are highly desired. In this work, we synthesized single-crystalline Co₃Sn₂S₂ nanoflakes with thickness from 100 to 30 nm by chemical vapor method. The nanodevices were prepared by using microfabrication. The nanoflakes show stable Curie temperature around 181 K, high anomalous Hall conductivity of 800 S cm^-1, large coercive force up to 5.5 T, and high quality with RRR up to 20. At low temperatures, the decreased resistance is observed when the external magnetic field is lower than the coercive field and antiparallel to the internal magnetization, showing an abnormal negative magentoresistance. Meanwhile, an exceptional Hall component, after subtracting the normal and anomalous Hall, is also found before the magnetic domain is switched. A value of this component is observed up to three times larger than the anomalous Hall contribution. Exotic behaviors were observed in magnetic Weyl semimetal Co₃Sn₂S₂ nanodevices.
1. E. K. Liu et al. Nat. Phys. 14, 1125 (2018).
2. D. F. Liu et al. Science 365, 1282 (2019).
3. N. Morali et al. Science 365, 1286 (2019).