Tunable magnetic domain walls for therapeutic neuromodulation at cellular level: Stimulating neurons through magnetic domain walls

Cellular-level neuron stimulation has attracted much attention in the areas of prevention, diagnosis, and treatment of neurological disorders. Herein, we propose a spintronic neurostimulator based on the domain wall movement inside stationary magnetic nanostructures driven by the spin transfer torques. The electromotive forces generated by the domain wall motion can serve as highly localized stimulation signals for neuron cells. Our simulation results show that the induced electric field from the domain wall motion in permalloy nanostructures can reach up to 14 V / m, which is well above the reported threshold stimulation signal for clinical applications. The proposed device operates on a current range of several microamperes that is 10³ times lower than the current needed for the magnetic stimulation by microcoils. The duration and amplitude of the stimulating signal can be controlled by adjusting the applied current density, the geometry of the nanostructure, and the magnetic properties of the material.