Neuromorphic Memory Rings based on Artificial Antiferromagnetic Neurons

Antiferromagnetic (AFM) spin Hall oscillators driven by an external sub-threshold current can create ultra-short spikes (with duration on the order of a few ps) in response to a weak external stimulus and therefore can be used as ultra-fast artificial neurons [1, 2]. One of specific features of AFM neurons is an effective inertia that originates from exchange coupling between two magnetic sublattices [3]. Inertial effects allow one to develop AFM-based neural networks with new functionalities not possible with conventual artificial neurons. Here we investigate the dynamical behavior of neuromorphic memory rings – periodic pulse generators formed by several AFM neurons coupled in a ring structure. We show, that spike generation in a neuromorphic ring can be initiated by applying an external spike to any single neuron in the ring. Dynamic suppression of the spike propagation can be achieved by embedding an additional inhibitor circuit in the ring, thus turning a ring structure into a fully controllable neuromorphic memory device.

[1] R. Khymyn, I. Lisenkov, J. Voorheis, et al., Sci. Rep. 8, 15727 (2018).
[2] O. Sulymenko, O. Prokopenko, I. Lisenkov, et al., J. Appl. Phys. 124, 152115 (2018).
[3] R. Khymyn, I. Lisenkov, V. Tiberkevich, et al., Sci. Rep. 7, 43705 (2017).