Bayesian Reasoning Enabled by Spin-Orbit Torque Magnetic Tunnel Junctions

The rapid development of artificial intelligence (AI) over the past few decades has been nourished by advancements in machine learning algorithms, increased computational power, and availability of vast amounts of data[1], which has in turn revolutionized numerous fields including but not limited to medical science and healthcare, information technologies, finance, transportation, and more. This regenerative feedback between AI and its applications leads to a further explosive growth of data and expansion of model scales, which calls for a paradigm shift toward efficient and speedy computing and memory technologies, especially, advanced algorithms and emerging AI hardware enabled by nonvolatile memories[2]. In this aspect, the emerging memory technologies, such as magnetic random-access memories[3], ferroelectric random-access memories[4], resistive random-access memories[5, 6] and phase-change random-access memories[7], have been implemented to accelerate AI computing, for instance, the matrix multiplication[8]. Thanks to their high energy-efficiency, fast speed, long endurance, and versatile functionalities, spin-tronic devices based on spin-orbit torques as one prominent example among emerging memories, have shown great potential in the aspect of hardware-accelerated true random number generation (TRNG)[9-18] besides of the matrix multiplication. For instance, the high quality true random number generators with stable and reconfigurable probability-tunability have been demonstrated using SOT -MTJs [19-21].