Leaky-Integrate-Fire Neuron via Synthetic Antiferromagnetic Coupling and Spin-Orbit Torque

TL;DR

This paper presents a spintronic neuron device that combines leaky-integrate-fire functions using synthetic antiferromagnetic coupling and spin-orbit torque, advancing neuromorphic computing hardware.

Contribution

It introduces a domain wall neuron with integrated leaky and fire functionalities achieved through synthetic antiferromagnetic coupling and spin-orbit torque.

Findings

Maximum domain wall velocity of 2500 μm/s during leaky process

Device utilizes materials compatible with CMOS and STT-MRAM fabrication

Achieves leaky-integrate-fire functions in a single spintronic device

Abstract

Neuromorphic computing (NC) is a promising candidate for artificial intelligence applications. To realize NC, electronic analogues of brain components, such as synapses and neurons, must be designed. In spintronics, domain wall (DW) based magnetic tunnel junctions - which offer both synaptic and neuronal functionalities - are one of the promising candidates. An electronic neuron should exhibit leaky-integrate-fire functions similar to their biological counterparts. However, most experimental studies focused only on the integrate-and-fire functions, overlooking the leaky function. Here, we report on a domain wall neuron device that achieves integration using spin-orbit torque-induced domain wall motion and a leaky function via synthetic antiferromagnetic coupling. By fabricating Hall bar devices in a special geometry, we could achieve these two functionalities. During the leaky process, the maximum DW velocity achieved was 2500 {\mu}m/s. The proposed design utilizes materials used in STT-MRAM fabrication and is compatible with CMOS fabrication. Therefore, this neuron can be readily integrated into NC.