界面原子扩散对SmCo/Fe交换弹簧双层膜磁性能影响的微磁学研究  

Micromagnetic studies of influence of interface atomic diffusion on magnetic properties of SmCo/Fe exchange-spring bilayers

作　　者：何鑫鑫 赵倩 He Xin-Xin;Zhao Qian(College of Science,Inner Mongolia University of Science and Technology,Baotou 014010,China)

机构地区：[1]内蒙古科技大学理学院,包头014010

出　　处：《物理学报》2021年第19期180-189,共10页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51861030);内蒙古自治区自然科学基金(批准号:2019MS01002)资助的课题。

摘　　要：本文通过三维微磁学数值模拟,研究了界面处原子扩散形成的界面层对易轴平行和垂直膜面取向SmCo/Fe双层膜磁性能的影响.当易轴取向平行膜面时,体系成核在第二象限.随着界面层厚度的增加,尽管剩磁逐渐减小,而成核场和钉扎场逐渐增加,以致最大磁能积先增加后减小,直至体系由交换弹簧磁体过渡到刚性磁体.当易轴取向垂直膜面时,随着界面层厚度的增加,体系成核由第一象限逐渐过渡到第二象限,虽然钉扎场从减小、不变到略有增加,但成核场和剩磁逐渐增加,导致最大磁能积逐渐增加.在退磁过程中,膜面内自旋偏转:易轴平行膜面取向系统显示了flower态和C态的产生与消失的过程;而易轴垂直膜面取向系统显示了vortex态的产生与消失的过程.随着易轴平行膜面SmCo/Fe双层膜界面层中SmCo原子扩散比例的增加,成核场和钉扎场增加但剩磁减小,最大磁能积先增加后降低.当易轴两种取向时,对任一界面层厚度,成核场随界面交换耦合常数的增大而增大,这表明界面层的存在增强了硬磁/软磁层之间的交换耦合作用.本文建立的模型很好地模拟了相关的实验结果[2007 Appl.Phys.Lett.91072509].In this paper,based on three-dimensional micromagnetic numerical simulation,the influences of the interface layer formed by the atomic diffusion at the interface on magnetic properties in parallel SmCo/Fe bilayer and perpendicular SmCo/Fe bilayer are investigated.For the parallel system,whose nucleation occurs in the second quadrant,as the interface layer thickness increases,the nucleation field and the pinning field increase gradually though the remanence decreases gradually,hence the maximum energy product first goes up and then comes down.As a result,in the system there occurs the transition from the exchange-spring to the rigid magnet.For the perpendicular system,with the increase of the interface layer thickness,a gradual transition from the first quadrant to the second quadrant happens to its nucleation.Although the pinning field experiences the changes from decreasing to unchanging and to increasing,the nucleation field and remanence both rise gradually.Therefore,the energy product is enhanced gradually.During the demagnetization,there appears a spin deviation within the film plane:the parallel system shows a progress of generation and disappearance of the flower and C states;however,the perpendicular system shows a progress of generation and disappearance of the vortex state.With the increase of the ratio of the SmCo atomic diffusion in the interface layer of parallel SmCo/Fe bilayers,the nucleation and pinning field go up,but the remanence decreases,and hence the maximum energy product first rises and then drops.For the two easy axis orientations and any interface layer thickness,the nucleation field rises with the increase of interface exchange energy constant,indicating that the existence of an interface layer between the soft layer and hard layer enhances the exchange coupling interaction between them.The model in this paper well simulates the relevant experimental results[2007 Appl.Phys.Lett.91072509].

关 键 词：微磁学数值模拟 界面层 成核场 磁能积 

分 类 号：O484.43[理学—固体物理]