Prospect of Spintronics in Neuromorphic Computing

Abstract

Neuromorphic computing emulates a biological brain at different levels of the computer hierarchy by exploiting brain‐inspired principles in designing novel devices, algorithms, and architectures. It is believed to have a lower power budget and a higher efficiency in performing cognitive tasks, and is arguably the most promising approaches for next‐generation artificial intelligence. Despite the potentials, progress of neuromorphic computing is constrained by a lack of dedicated hardware. Spintronics is a fast‐evolving discipline that exploits the spin degree of freedom in electronics. The interplay of magnetic and electrical properties of spintronic devices gives rise to a wide range of amazing phenomena, which are both intrinsically conducive to neuromorphic computing and highly compatible with conventional manufacturing technologies. Here, the development of neuromorphic computing with reference to spintronics is reviewed. The state‐of‐the‐art spintronic technologies, such as the magnetic tunnel junction, spin–orbit torque, domain wall propagation, magnetic skyrmions, and antiferromagnet, are highlighted and how they can used for artificial neurons and synapses in different artificial neural networks are discussed. The technical challenges to be overcome for realizing more powerful all‐spin artificial neural networks are also evaluated.

Perpendicular Magnetization Switching Driven by Spin‐Orbit Torque for Artificial Synapses in Epitaxial Pt‐Based Multilayers

“…The magnetization switching driven by spin‐orbit torque (SOT) has attracted a lot of attention with tremendous potential applications in magnetic random‐access memory, [ 1 ] oscillators, [ 2 ] and neuromorphic computing, [ 3 ] due to its low energy consumption, nonvolatility, and reversibility. [ 4 ] Enhanced SOT efficiency is of great importance to reduce the critical switching current density and hence the operation power of the devices.…”

Emerging Low‐Dimensional Heterostructure Devices for Neuromorphic Computing

“…[36,39,40] Spintronic devices based on the low-dimensional heterostructures [19,41,42] are also promising for neuromorphic computing. [22,[43][44][45][46][47][48] Magnetic tunnel junction based on ferromagnetic metal/oxide/ferromagnetic metal heterostructure has been regarded as one of promising candidates for nonvolatile memory and computing applications. [41,[49][50][51] Magnetization dynamics in the spin-torque oscillators based on magnetic tunnel junction gives rise to nonlinear I-V characteristics and finite magnetization relaxation time and have been employed to implement reservoir computing.…”

Skyrmions Under Control—FIB Irradiation as a Versatile Tool for Skyrmion Circuits

“…[7,8] Numerous proposals have been made using skyrmionsas a data carrier in Boolean or new, alternative computing systems. [9][10][11][12][13] However, the number of experimental realizations of these systems is still lacking behind. Reasons for this are the delicate interplay of magnetic energies which stabilizes skyrmions and the difficulties in controlling their nucleation, motion, and annihilation.…”