Influence Of Magnetic Domain Structure On The Magnetization Dynamics Of Striped Domain Thin Films

Soft magnetic thin films have the characteristics of high saturation magnetization,high permeability and low coercivity,and are widely used in various magnetic devices,such as magnetic sensors,reluctance random access memories and inductive cores.Magnetic components are also developing towards miniaturization,high frequency and integration to adapt to the development trend of electronic devices.We put forward higher requirements for permeability and resonance frequency of magnetic films(especially soft magnetic films)which can be used in high frequency band.The magnetization dynamics of soft magnetic film is actually the magnetization dynamics of magnetic moment,domain and domain wall in the film.Therefore,the distribution of magnetic moment and the structure of magnetic domain in the films are of great significance to the study of their high frequency microwave magnetism.In this paper,the influence of magnetic domain structure on the magnetization dynamics of soft magnetic films with stripe domain structure is studied:1.Influence of surface pinning on the domain and high-frequency microwave magnetic properties in Permalloy striped domain films.(1)Explore the influence of surface pinning caused by substrate roughness on the magnetization dynamics in Permalloy films with stripe domain structure.The experimental results show that the regularity and homogeneity of the stripe domains are significantly affected even by small changes of substrate roughness.Both the resonance frequency and intensity of the stripe domain which is greatly affected are reduced,and the excitation of acoustic mode,optical mode and spin waves are suppressed due to large pinning.(2)Explore the influence of Permalloy film thickness on surface pinning in stripe domain structure.The experimental results show that for the same substrate roughness,the thinner the film is,the more obvious effect caused by roughness on the regular and homogeneity of the stripe domain structure is.The decrease in the resonance frequency and intensity of the stripe domains is also more pronounced in the thinner films.2.Influence of antiferromagnetic layer on the stripe domain and its high-frequency microwave magnetic properties.(1)Explore the influence of antiferromagnetic layer thickness on the magnetization dynamics of antiferromagnetic/ferromagnetic double-layer films with striped domain structure.The experimental results show that the regularity and homogeneity of the stripe domain are weakly affected by the increase of the thickness of the antiferromagnetic layer.The addition of antiferromagnetic Ir Mn increases the saturation magnetization of the film,and the resonance frequency of all films show a slight upward trend.(2)Explore the influence of heat treatment temperature on the magnetization dynamics of antiferromagnetic/ferromagnetic double-layer films with striped domain structure.The experimental results show that the stripe domain becomes wider with the increase of heat treatment temperature,and finally it is difficult to observe.The coercive field H_c of the film decreases with the increase of heat treatment temperature,and the remanence ratio M_r/M_s is on the contrary.Saturation magnetization 4?M_s of heat-treated sample decreased significantly,while the anisotropic field H_k increased obviously.3.Influence of ferromagnetic layer on the stripe domain film and its high-frequency microwave magnetic properties.(1)Explore the influnece of composition gradient on the domain structure and high-frequency microwave magnetic properties of Co Zr films.The experimental results show that as the content of the magnetic element Co decreases,the domain width of dendritic stripes decreases until the magnetic striped domain structure disappears.When the domain width decreases,the coercive field increases gradually,and when the stripe domain structure disappears,the coercive field decreases greatly.With the increase of Co sputtering power,the film thickness decreases and the peak intensity of resonance peak increases.(2)Explore the influence of ferromagnetic layer thickness on the magnetization dynamics of ferromagnetic/ferromagnetic bilayers.The experimental results show that the change in ferromagnetic layer thickness has a weak effect on the regularity and homogeneity of magnetic domain.The effective saturation magnetization first increases and then decreases as the ferromagnetic layer thickness increases,while the effective anisotropy field first decreases and then increases.