Fixed Magnetic Skyrmion Based Resonate and Fire Neurons

The membrane potential of resonate and fire neurons oscillate in a subthreshold damped fashion and fire when excited by an input frequency that nearly equals to their Eigen frequency[1]. We model such neurons by utilizing the magnetization dynamics of a fixed magnetic skyrmion in the free layer of a magnetic tunnel junction. To realize firing of a neuron, we propose to employ voltage generated strain or voltage control of magnetic anisotropy as input spike which modulates the magnetic anisotropy. This evokes continual expansion and shrinkage motion (i.e. breathing) of the skyrmion that mimics the subthreshold oscillation. Any subsequent input pulse having interval equal to the breathing period drives this motion into resonance. An annular electrode is used to identify if a threshold value is surpassed which is assumed as firing of the neuron. By rigorous micromagnetic simulation, we investigate the interspike timing dependence and response to different excitatory and inhibitory incoming input pulse such as doublet, triplet and bursts.
1. Izhikevich et al Neural Networks 14, no. 6-7 (2001): 883–894.