Micromagnetic study of Brownian motion in chiral magnetic structures

A magnetic skyrmion is a type of vortex magnetic structure that is stabilized by its topological structure. An example of this type of spin structure can be found in thin magnetic films with perpendicular magnetic anisotropy and Dzyaloshinski-Moriya interactions. It has a size range between nanometers and microns, and a variety of excitation mechanisms can be used to modulate its dynamics, including electric current and electric fields. Novel spintronic storage devices can be constructed with magnetic skyrmions as a form of information carrier. Hence, magnetic bimerions can be seen as the in-plane topological counterpart of magnetic skyrmions. Despite this, there are few studies that have been able to use systematic research into spin topological features to explain their random thermal motions. In this project, a micro�magnetic method based on the Landau-Lifshitz-Gilbert equation has been used to study the dynamics of bimeron in magnetic nanodots under the influence of thermal effects. An investigation was conducted to determine the impact of anisotropy, DMI, damping, and geometric size on the Brownian motion of bimerons. According to our results, the thermal Brownian motion of the magnetic bimeron under thermal effects is different from the thermal Brownian motion of the magnetic skyrmion with symmetry protected topological states (SPT). The thermal stability of bimeron is lower than that of magnetic skyrmion as a result of its lack of topology protection and rotational symmetry. This study contributes to the understanding of the dynamics of topological magnetic structures and provides some recommendations for the development and application of spintronic devices in the future.