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本文通过三维微磁学数值模拟,系统地计算了CoPt/Co磁性双层膜与CoPt/Co/CoPt三层膜结构中的自旋分布.计算结果表明,当三层膜的硬磁相和软磁相厚度分别为8nm和16nm左右时,在三层膜的每一层均会出现斯格明子(Skyrmion)结构.特别是,我们首次发现,当双层膜的硬软磁层厚度均在8nm左右时,在硬磁相和软磁相中均会出现斯格明子结构,即双斯格明子态.双层膜软磁相出现斯格明子的厚度要比三层膜小很多,其对应的斯格明子数只比三层膜小约8%.斯格明子数对硬磁相和软磁相的磁晶各向异性常数K和交换作用常数A都比较敏感,随着K和A的变化,体系硬磁相和软磁相的自旋分布会在涡旋(Vortex)态和斯格明子态之间相互转化,而界面耦合常数对斯格明子数影响不大.
In this paper, the three-dimensional micro-magnetic numerical simulation systemically calculated the spin distribution of CoPt / Co magnetic bilayers and CoPt / Co / CoPt three-layer structure.The calculated results show that when the three layers of hard magnetic phase and soft When the thickness of the magnetic phase is about 8 nm and about 16 nm, the Skyrmion structure appears in each layer of the three-layer film. In particular, we first found that when the thicknesses of the hard and soft layers of the double-layer film are both 8 nm Or so, the Schmidt structure, ie, the bi-sigma sub-state, appears in both the hard magnetic phase and the soft magnetic phase, and the thickness of the schmidyon in the bilayer membrane soft magnetic phase is much smaller than that of the trilayer membrane, and the corresponding The Schmid number is only about 8% smaller than that of the three-layer film.Schuginger number is sensitive to the magnetocrystalline anisotropy constant K and exchange constant A of the hard magnetic phase and the soft magnetic phase.With the changes of K and A , The spin distribution of the hard phase and the soft phase in the system can be transformed into each other in the Vortex state and the Schmittium state, while the interface coupling constant has little effect on the Schiegon number.