Antiferromagnetic skyrmion based shape-configured leaky-integrate-fire neuron device

Abstract

Spintronic devices based on antiferromagnetic skyrmion (AFM) motion on the nanotracks have gained significant interest as a key component of neuromorphic data processing systems. AFM skyrmions are favorable over the ferromagnetic skyrmions as they follow the straight trajectories and prevent its annihilation at the nanotrack edges. In this paper, the AFM skyrmion-based neuron device that exhibits the leaky-integrate-fire (LIF) functionality is proposed for the first time. It exploits the current-driven skyrmion dynamics on the shape-configured nanotracks that are linearly decreasing and exponentially decaying. The device structure creates the regions from lower to higher energy states for the AFM skyrmions during its motion from the wider to narrower region. This causes the repulsion force from the nanotrack edges to act on the AFM skyrmion thereby, drifting it in the backward direction in order to minimize the system energy. This provides the leaking functionality to the neuron device without any external stimuli and additional hardware cost. The average velocities during the integration and leaky processes are in the order of 103 and 102 m/sec, respectively for the linearly and exponentially tapered nanotracks. Moreover, the energy of the skyrmion is in the order 10-20 J. Hence, the suggested device opens up the path for the development of high-speed and energy-efficient devices in antiferromagnetic spintronics for neuromorphic computing.

Antiferromagnetic skyrmion-based high speed diode

“…Owing to the insensitivity of AFM skyrmions towards external magnetic elds, they are more robust against magnetic eld perturbations, thus improving the stability and reliability of AFM skyrmion-based devices. 26,27 The velocity of these skyrmions is around tens of order in magnitude greater than that of FM skyrmions. 23 Furthermore, AFM materials are more abundant in nature, which include metals comprising Mnbased alloys, insulators, and semiconductors.…”

Biskyrmion-based artificial neuron

“…Besides their potential for conventional spintronic devices, skyrmions are attractive for neuromorphic computing [14][15][16][17][18][19][20]. This promising approach is oriented at our brain's operational mode.…”

Room temperature ferromagnetic skyrmion-based artificial neuron device

“…But, the induced Magnus force deflects the FM skyrmion from the straight path and this effect is commonly known as skyrmion hall effect (SkHE), this can lead to annihilation of the skyrmion [12][13]. This is a serious issue where the straight motion of skyrmions are necessary [14][15]. The SkHE can be eliminated by various means such as manipulation of synthetic antiferromagnetic (SAF) skyrmion in coupled bilayer-ferromagnetic [16].…”