Micromagnetic Simulation Of Cerous Rare Earth Permanent Magnet Materials

Rare earth permanent magnetic materials are a kind of high-performance permanent magnetic materials with rare earth elements as the main component.Because of their good magnetic properties and thermal stability,they are widely used in various fields,including electric vehicles,wind power generation,maglev train,aerospace,computer hard disks,medical equipment,etc.However,the high cost of traditional rare earth materials has brought many limitations to the development of rare earth permanent magnet materials.Magnesium doped CeCo₃ has received considerable attention due to its strong ferromagnetism,high magnetic anisotropy,and low cost.But the magnetic properties of Ce_1-xMg_xCo₃ magnets are not good enough to be widely used.The exchange-coupling composite magnet structure can significantly improve the magnetic properties of single-phase magnets.This study employs micromagnetic simulation methods to investigate several composite magnet structure models incorporating exchange-coupling effects.Their magnetic behaviors are simulated,and their hysteresis loops and magnetic moments during magnetization are analyzed.These findings provide basis for the preparation of high magnetic Ce magnet structure in the future.We first established a micromagnetic model of multilayer exchange-coupled gradient films.This model has six layers,five of which are composed of hard magnetic materials,and the magneto crystalline anisotropy constants between the layers are gradient distribution,while the other layer is composed of soft magnetic materials.We study the effect of different magnetic crystal anisotropy gradients on the magnetic performance of the model and analyze the magnetic moment changes during the magnetization process.The simulation results show that the coercivity and residual magnetization of magnets can be effectively improved,and the magnetic energy product can be enhanced so as to improve the magnetic properties when the anisotropy gradient of magnetic crystal is reduced and the anisotropy difference at the interface is increased,During the magnetization process,a vortex state distribution of magnetic moment will be generated,and the formation and disappearance of this vortex state is accompanied by the accumulation and dissipation of energy.We also simulate a cross elliptical magnetic nano disk structure model,which consists of two elliptical disks of the same size arranged vertically,one composed of hard magnetic materials and the other composed of soft magnetic materials.We study the influence of the variation of the semi-minor axis of the elliptic disk on the coercivity of the model and the variation of magnetic moment during magnetization.The simulation results indicate that when the semi-minor axis is half of the semi-major axis,the coercivity of the model can reach the maximum value.During the magnetization process,the model will experience both the movement of magnetic vortex states and the movement of magnetic domain walls.