Skyrmion nucleation via localized spin current injection in confined nanowire geometry in low chirality magnetic materials

Magnetic skyrmions have been the focus of intense research with promising applications in memory, logic and interconnect technology. Several schemes have been proposed to nucleate skyrmions. However, they either result in an uncontrolled skyrmion bubble production or are mostly targeted towards integration with racetrack memory device. We propose a novel scheme for a controlled single skyrmion nucleation in a confined nanowire geometry with sub-100 nm width using a generalized approach of “localized spin current injection” technique in material systems exhibiting low Dzyaloshinskii–Moriya interaction (DMI). Our proposed nucleation mechanism follows a pathway involving the creation of a reversed magnetic domain containing vertical Bloch line (VBL) pairs that form an edge domain wall as the VBLs get annihilated at the edge of the nanowire. However, pinning of the edge domain walls within a narrow gap using notches or anti-notches results in the creation of a magnetic bubble with defect-free domain wall that relaxes into a skyrmion structure. Our simulations predict that the proposed mechanism allows skyrmion nucleation on sub-ns timescale, shows robustness to variations like local pinning sites and is applicable for any skyrmion-based logic, memory and interconnect application.