In this work we present the creation, annihilation and dynamics of a topologically protected magnetic structure, a skyrmion, for neuromorphic computing application. We study the effect of Dzyaloshinskii Moriya interaction (DMI) and surface anisotropy on the skyrmion density. The relation between skyrmion annihilation threshold anisotropy Kth and DMI coefficient is evaluated. Furthermore, the skyrmion diameter dependence on these two parameters is studied. Using MOKE analysis we study the effect of external magnetic field on the skyrmion density and predict the threshold magnetic field for the transition of magnetic texture from Labriynth domains to skyrmions. These results are further supported by the MuMax simulations. The spin orbit torque SOT manipulation of skyrmion size and density is also presented for skyrmion applications in the race-track memory and neuromorphic computing. Motivated by the results, we propose a Skyrmionic neuromorphic device and using SOT switching mechanism, show its applicability as spintronic synapse and neuron. The MuMax simulations are coupled to the Non- Equilibrium Green’s Function formalism to model the neuron and synapse behavior. Finally, we conclude with the possibility of using these devices for pattern recognition and other unconventional computing paradigms.

The present work discusses the proposal of a spintronic neuromorphic system with spin orbit torque driven domain wall motion-based neuron and synapse. We propose a voltage-controlled magnetic anisotropy domain wall motion based magnetic tunnel junction neuron. We investigate how the electric field at the gate (pinning site), generated by the voltage signals from pre-neurons, modulates the domain wall motion, which reflects in the non-linear switching behaviour of neuron magnetization. For the implementation of synaptic weights, we propose 3-terminal MTJ with stochastic domain wall motion in the free layer. We incorporate intrinsic pinning effects by creating triangular notches on the sides of the free layer. The pinning of domain wall and intrinsic thermal noise of device lead to the stochastic behaviour of domain wall motion. The control of this stochasticity by the spin orbit torque is shown to realize the potentiation and depression of the synaptic weight. The micromagnetics and spin transport studies in synapse and neuron are carried out by developing a coupled micromagnetic Non-Equilibrium Green’s Function (MuMag-NEGF) model. The minimization of the writing current pulse width by leveraging the thermal noise and demagnetization energy is also presented. Finally, we discuss the implementation of digit recognition by the proposed system using a spike time dependent algorithm.