A multi-state memory device based on the Manipulation of a single skyrmion using spin-polarized current

Towards a multistate skyrmionic device, Firstly, the motion of a single skyrmion under spin-transfer-torque (STT) is studied in the conventional and constricted wire the study reveals the possibility to pin, depin and annihilate skyrmion. Later, a stepped nano-track with bottom and top confinements has been proposed, to stabilize the skyrmion in each confinement. The adjustment of the current density magnitude and its duration enabled the displacement of the skyrmion at any position. More interestingly, it was observed that only one skyrmion can be stabilized in each confinement when a large number is displaced by current pulses. These results open the way for large-capacity memory devices and neuromorphic computing.