MnFeCoGe六方磁体中自旋序依赖的斯格明子稳定化
Spin order dependent skyrmion stabilization in MnFeCoGe hexagonal magnets
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中文总结 AI 辅助
本研究结合理论与实验探究MnFe1-xCoxGe体系中磁基态对斯格明子稳定化的影响，发现易轴共线基态下可形成稳定六方斯格明子晶格，非共线或易锥相时则为非拓扑II型磁泡，揭示了面内磁矩/各向异性的阻碍作用，为调控偶极斯格明子稳定性提供新途径。
中文摘要 AI 辅助
中心对称系统中的拓扑磁性斯格明子在螺旋度上具有更高的自由度，因此在包括基于斯格明子的量子计算在内的先进自旋电子学中具有巨大潜力。然而，中心对称磁体也会与拓扑斯格明子一同出现非拓扑平庸磁泡。因此，研究不同磁基态及其内在相互作用对中心对称磁体中磁性斯格明子稳定化的影响是当务之急。本文结合理论与实验，研究了非共线磁基态在一系列交换阻挫非共线铁磁体系MnFe1-xCoxGe中对斯格明子稳定化的作用。借助中子衍射（ND）和洛伦兹透射电子显微镜（LTEM）研究，我们发现仅当底层磁基态为具有易轴各向异性的共线态时，六方斯格明子晶格才会作为稳定的场致态出现。相比之下，在具有部分面内各向异性的非共线磁有序情况下，非拓扑II型磁泡是稳定态。此外，我们还发现当系统经历从易轴铁磁相到易锥铁磁相的自旋重取向转变时，斯格明子会转变为非拓扑磁泡。我们的结果明确证实了面内磁矩/各向异性在共线和非共线磁体中均会阻碍斯格明子稳定性的重要作用。因此，本研究为通过改变材料的本征特性来调控偶极斯格明子的稳定性提供了广泛的可能性。
英文摘要
Topological magnetic skyrmions in centrosymmetric systems exhibit a higher degrees of freedom in their helicity, hence possess a great potential in the advanced spintronics including skyrmion based quantum computation. However, the centrosymmetric magnets also display non-topological trivial bubbles along with the topological skyrmions. Hence it is utmost priority to investigate the impact of different magnetic ground states and their underlying interactions on the stabilization of magnetic skyrmions in cetrosymmetric magnets. Here, we present a combined theoretical and experimental study on the role of non-collinear magnetic ground state on the skyrmion stabilization in a series of exchange frustrated non-collinear ferromagnetic system MnFe1-xCoxGe. With the help of neutron diffraction (ND) and Lorentz transmission electron microscopy (LTEM) studies, we show that hexagonal skyrmions lattice emerges as a stable field driven state only when the underlying magnetic ground state is collinear with easy-axis anisotropy. In contrast, non-topological type-II bubbles are found to be stable state in the case of non-collinear magnetic ordering with partial in-plane anisotropy. Furthermore, we also find that the skyrmions transform to the non-topological bubbles when the system undergoes a spin reorientation transition from the easy-axis to easy-cone ferromagnetic phase. Our results categorically establish the significant role of in-plane magnetic moment/anisotropy that hinders the stability of skyrmion both in the case of collinear and non-collinear magnets. Thus, the present study offers a wide range of opportunities to manipulate the stability of dipolar skyrmions by changing the intrinsic characteristics of the materials.
