Micromagnetic Study On Magnetic Regulation Of Micro And Nano Magnetic Materials

In recent years,micromagnetic simulation has become one of the important means to investigate magnetic materials.It has been widely used in studying the relationship between the macroscopic magnetism and microstructure of magnetic materials as well as exploring the interaction between magnetic materials.Based on the potential application value of modulated nanowires in the field of information storage and the influence of magnetic dipolar interaction on the practical application of magnetic materials.In this paper,modulated nanowires and cobalt-based amorphous wire arrays are simulated by using OOMMF micromagnetic software.The main contents are as follows:(1)The study of nanowires with one modulated structure and two modulated structures shows that the remanence ratio and coercive field of nanowires can be effectively controlled by changing the thickness,composition and position of the modulated structure.By analyzing the magnetization reversal process of the modulated nanowires,it is found that no matter how many modulated structures the nanowire contains,the nanowire starts forming vortex magnetization configuration at the modulated structure,and then the entire magnetization reversal process is completed by the propagation of the vortex domain wall.The difference is that for nanowires containing only one modulated structure,the chirality of the vortex at both ends of the modulated structure is opposite,while for nanowires containing two modulated structures,the chirality of the vortex at both ends of the modulated structure is the same.(2)By analyzing the axial hysteresis loops of N(1?N?4)parallel cobalt-based amorphous wire arrays,it is found that the hysteresis loops exhibit N steps and N-1plateaux as the number of wires increases,and the external magnetic field corresponding to the first magnetization reversal process of the amorphous wire array gradually moves to the lower field,the external magnetic field corresponding to the last magnetization reversal process of the amorphous wire array gradually moves to the higher field.The results also show that the plateaux width of the hysteresis loop decreases as the length of the wires increases or the distance between them increases.The above phenomenon is attributed to the effect of the magnetic dipolar field around the wire during demagnetization.