Energy Efficient Voltage Controlled Domain Wall Neuron and Synapse*

We present micromagnetic simulation of voltage-controlled spintronic neuron and synapse by utilizing domain wall (DW) motion in the free layer of a Magnetic Tunnel Junction (MTJ). The free layer is a soft ferromagnet (CoFeB) exchange coupled to a magnetostrictive Rare Earth Iron Garnet (REIG) racetrack with perpendicular magnetic anisotropy (PMA) deposited on a heavy metal layer. The whole stack is fabricated on a piezoelectric substrate. Chiral domain walls can be introduced in the free layer due to PMA and Dzyaloshinskii-Moriya Interaction (DMI) [1, 2], translated with spin orbit torque by applying a current pulse to the heavy metal layer and arrested at specific location along the racetrack domain by tuning the bulk PMA of the magnetic layer using a highly localized voltage-generated strain from the piezoelectric layer. Micromagnetic simulations with realistic defects and thermal noise will be presented for an energy efficient neuron and non-volatile programmable synapse using this device.

Refrences:
[1] C. O. Avci, et al., Nature Materials, 16, 309, 2017.
[2] E.R. Rosenberg, et al., Physical Review Materials, 2, 094405, 2018.