Effects Of The Graphene Induced DM Interaction On Skyrmions And Vortices In Ferromagnetic Metals

Magnetic skyrmions are topologically protected spin structures,which have nanoscale dimensions and can be manipulated by the ultra-low electric current.These properties make them become potential information carriers in data storage,processing and transmission devices.Graphene with a single-layer atomic structure has adjustable spin properties and can be doped with other atoms or combined with other 2D materials to form composites,which is an ideal candidate for spintronic applications.In order to combine the advantages of both the magnetic skyrmions and graphene materials,the models of magnetic racetrack and nanodisk with graphene layers on the surface are proposed in this thesis.Previous studies have demonstrated that the Dzyaloshinsky-Moriya interaction(DMI)is mainly found at the interface between the magnetic material and the heavy metal due to the large spin-orbit coupling(SOC).Researches show that the Gr/Co interface can also induce DMI as a result of the Rashba effect,increasing the types of materials to produce DMI.Using the micromagnetic simulation software OOMMF(the Object Oriented Micro Magnetic Framework),we study the nucleation and dynamic behavior of skyrmions in the racetrack and nanodisk.The results demonstrate that the skyrmions can be created and driven in the proposed nanoscale racetrack with a more stable structure owing to the protection from the graphene.The vortex,radial vortex,multi-domain state and other magnetic structures are found in both nanodisks with monolayer model and bilayer model magnetic films.The results of this thesis show that when the total value of the DMI vector is fixed,we can obtain the same magnetic structure in the bilayer structure.In addition,the graphene can enhance the perpendicular magnetic anisotropy(PMA)of the magnetic crystal so that the transitions between vortex,radial vortex and skyrmion can be achieved by adjusting material parameters,which can give a good guide for the design of graphene-based magnetic converter.The results of this thesis provide helps for the design of new spintronic devices and have certain research significance.