Micromagnetic Simulation Of Magnetic Property Of Double Main Phases NdFeN/CeFeB Permanent Magnetic Film

As a major development direction of China’s strategic emerging industries,rare-earth permanent magnetic materials play a pivotal role in the application of zero-energy magnetic fields,such as clean energy,efficient green power output.In the long-term development and utilization process,the utilization of rare earth resources is extremely unbalanced.The demand for scarce resources such as Nd and Dy is large,while the utilization rate of rich resources such as Ce and La is extremely low,which makes the further development and use of rare earth elements with high abundance become a focus of current research.In this paper,the hysteresis loops of out-plane and in-plane double-main-phase Nd₂Fe₁₄B/Ce₂Fe₁₄B multilayers were calculated by the three-dimensional calculation software OOMMF on the basis of the theory of micro-magnetism method.The hysteresis loops,the coercivity and the changes of the energy in the process of magnetization reversal process are discussed.The coercivity mechanism is analyzed to provide a theoretical basis for increasing the utilization of Ce and the magnetic property.The main researches are as follows:The models of out-plane and in-plane double-main-phase Nd₂Fe₁₄B/Ce₂Fe₁₄B bilayers were established.The hysteresis loops and magnetic reversal mechanisms were systematically investigated.The simulation results show that the magnetic reversal of Nd₂Fe₁₄B/Ce₂Fe₁₄B bilayers system is mainly dominated by nucleation.When the thickness of two main phase layers increases at the same time,the coercivity of the system gradually decreases,the maximum magnetic energy product of the system reduces.When the thickness of Nd₂Fe₁₄B layer remains unchanged and the thickness of Ce₂Fe₁₄B layer increases,the coercivity and remanence decrease,which has a great influence on the maximum magnetic energy product.By studying the exchange coupling interaction at the interface of two phases,the strong exchange coupling at the interface can avoid the decoupling phenomenon of two phases and help to increase the maximum magnetic energy product of magnets.The models of in-plane double-main-phase Nd₂Fe₁₄B/Ce₂Fe₁₄B/Nd₂Fe₁₄B trilayers are established.The influences on the magnetic property of the structure of Nd₂Fe₁₄B layers and the Ce₂Fe₁₄B layer thickness were systematically investigated.Simulation results show that the magnetic reversal of the double-main-phase Nd₂Fe₁₄B/Ce₂Fe₁₄B/Nd₂Fe₁₄B trilayers is mainly dominated by nucleation.The study on the structural distribution changes of Nd₂Fe₁₄B layers shows that when the thickness of the two main phases is certain,the use of symmetrical sandwich structure and the pinning interaction at the two interfaces of the two main phases can effectively improve the coercivity and the maximum magnetic energy product of the magnets.When the thickness of Ce₂Fe₁₄B layer increases with the adoption of symmetrical sandwich structure,the coercivity and the maximum magnetic energy product of the system decrease.