Fully micromagnetic analysis of voltage-controlled magnetization switching in magnetic-topological-insulator-based devices

We numerically investigate magnetization switching behavior in voltage-controlled magnetic-topological-insulator-based (VC-MTI) devices by means of the fully micromagnetic simulation. First, the influence of domain in VC-MTI devices was investigated. When the device size is larger than 1 µm, multidomain structure might appear. However, these domains disappear when the gate voltage and source-drain electric field are applied, which is the refresh operation of the actual VC-MTI device. The switching behaviors of a 100-nm-size VC-MTI device in the fully micromagnetic simulation are in agreement with those of the macrospin model although the gate pulse width is slightly different from that of the macrospin model. When the device is less than 1 µm, the macrospin model is adequate for the investigation of switching behavior in VC-MTI devices and the magnetization switching occurs in rotation mode. Therefore, for the VC-MTI device with less-than-100 nm size, the macrospin model is a good approach for the analysis of device operation and write-error rate.