Spin–orbit torque true random number generator with thermal stability

Abstract

Interfacial Dzyaloshinskii–Moriya interaction (DMI) plays a pivotal role in spin–orbit torque (SOT)-induced magnetization switching, notably seen in deterministic switching even in the absence of an external magnetic field at 0 K. However, in SOT devices operating at room temperature, thermal fluctuations contribute significantly to magnetization switching due to the altered energy profile caused by DMI. In this work, we unveil that unlike the deterministic magnetization switching observed at 0 K, SOT-induced magnetization switching assisted by DMI is highly stochastic. Following the SOT-induced nucleation of a domain wall (DW), thermal fluctuations can induce rapid back-and-forth DW motion under the influence of a current pulse, resulting in stochastic switching. Furthermore, our findings indicate that the switching probability remains stable as the temperature increases. These results illustrate that SOT-induced magnetization switching assisted by DMI is well-suited for a true random number generator with robust thermal stability.