Unconventional anomalous Hall effect in magnetic topological insulator MnBi4Te7 device

Applied Physics Letters, Volume 118, Issue 8, February 2021. The natural intrinsic magnetic topological insulator MnBi2Te4(Bi2Te3)n is a platform for studying intriguing transport phenomena and provides an essential chance for the fundamental understanding of the combination of magnetism and topology. Here, we fabricated MnBi4Te7 thin film devices and carried out the transport measurement. It shows the unconventional anomalous Hall effect in the devices with the hysteresis anomaly and hump-like behavior. The gate-controlled sign reversal is also an interesting feature. With the modulation of gate voltage and temperature, we suggest that the unconventional anomalous Hall effect is due to the coexistence of the antiferromagnetic component and ferromagnetic component, which may result from the inhomogeneous spatial variation. Our work provides a resourceful insight into the study of the material family.