Nucleation of magnetic textures in stripe domain bifurcations for reconfigurable domain wall racetracks

TL;DR

This study uses micromagnetic simulations to analyze how magnetic textures nucleate and transform in stripe domain-based reconfigurable racetrack memory, highlighting topological charge exchanges that enable controlled vortex dynamics.

Contribution

It introduces a detailed analysis of topological transformations and nucleation processes in magnetic stripe textures for racetrack memory applications.

Findings

Topological charge exchanges govern vortex/antivortex pair formation.

Magnetization reversal involves nucleation of vortices, antivortices, Bloch lines, and Bloch points.

Controlled vortex propagation is achieved through topological transformations.

Abstract

Within the racetrack memory paradigm, systems exploiting magnetic guiding potentials instead of geometrical ones, allow for enhancing the versatility of the final devices adding magnetic reconfigurable capabilities. Hard/soft magnetic multilayers with stripe domain configurations fulfill these requirements. In these systems, the topology of the generated textures that would act as information carriers, is strongly conditioned by the stripe lattice configuration. Micromagnetic simulations have been used to study the magnetization reversal process in NdCo$_5$/Py reconfigurable racetracks. By using skyrmionic charges and magnetic vorticity lines, the topological transformations controlling the nucleation of vortices, antivortices, Bloch lines and Bloch points has been analyzed. It has been shown that magnetic topological charge exchanges between textures rule the formation of vortex/antivortex pairs with opposite polarities, key for the guided propagation through the stripe pattern.