Impact of Unconventional Torque on the Performance of Weyl-Semimetal-Based SOT-MTJ: A Micromagnetic Study

Effective spin manipulation is one of the fundamental aspects of spin-orbit torque (SOT) magnetic tunnel junction (MTJ) for low-power logic and memory applications. The performance of the Transitional-Metal dichalcogenides (TMD) based SOT-MTJ is examined in this work in relation to the out-of-plane spin momentum in Weyl semimetal (WS). Micromagnetic simulations have been performed to evaluate the characteristics of the device performance under the interfacial Dzyaloshinskii–Moriya interaction (DMI) effect and random thermal field. By modeling the modified LLGS equation in the macromagnetic modeling framework, the field-free switching condition resulting from unconventional torque from the WS has been verified by this investigation without considering any external magnetic field (EMF). The micromagnetic investigation reveals that the out-of-plane torque modulates the device performance in a substantial way. The combined action of conventional and unconventional torque results in the deterministic switching of magnetization in the absence of an EMF. When compared to the conventional SOT-MTJ, the critical current density drops to 3.5% of its initial value, with the effective Spin-Hall efficiency of TMD ranging from 0.1 to 3.5. However, the magnetization switching speed of the device is impacted when the out-of-plane torque outweighs the in-plane component. Yet, the switching speed is decreased by a factor of
$\sim 0.5\times - 0.7\times $
thanks to the stochastic temperature effects. Furthermore, we demonstrate the significance of out-of-plane torque in optimizing power dissipation density (PDD) in TMD-based SOT-MTJ.