Dynamics of chiral domain walls under applied current in cylindrical magnetic nanowires

Abstract

The dynamics of two types of chiral magnetic domain walls in magnetic cylindrical nanowires under spin-polarized current are investigated by means of micromagnetic simulations. We show that Bloch point domain walls with chirality identical to that of the Oersted field can propagate without dynamical instabilities with velocities ∼300 m/s. The domain wall width is shown to widen at larger current densities limiting the velocity increase. For domain walls with opposite chirality, we observed a new pinning mechanism created by the action of the Oersted field, limiting their propagation distance even after chirality switching. Vortex–antivortex domain walls transform into Bloch point domain walls, and after that they can unexpectedly propagate either along or against the direction of the current. Our findings demonstrate that domain wall dynamics under current in cylindrical magnetic nanowires can result in a plethora of different behaviors that will have important implications for future 3D spintronic devices.