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arXiv 2402.13751cond-mat.mtrl-sci
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中心对称磁体中半子(meron)与斯格明子晶体之间的多步拓扑转变

Multi-step topological transitions among meron and skyrmion crystals in a centrosymmetric magnet

H. Yoshimochi, R. Takagi, J. Ju, N. D. Khanh, H. Saito, H. Sagayama, H. Nakao, S. Itoh, Y. Tokura, T. Arima, S. Hayami, T. Nakajima, S. Seki

AI总结:

该研究在中心对称磁体GdRu2Ge2中实验发现半子与斯格明子晶体间的多步拓扑转变,并通过散射、输运测量和RKKY竞争模型揭示了2.7 nm纳米准粒子的磁场调控机制。

摘要:

诸如斯格明子和半子(meron)之类的拓扑涡旋自旋织构,近来作为高密度磁性信息器件的独特构建单元而备受关注。在不同类型的此类准粒子之间实现可控转变是一项重要挑战,而此前这仅在少数以Dzyaloshinskii-Moriya相互作用为特征的非中心对称体系中实现。在此,我们报道了在中心对称磁体GdRu2Ge2中多种半子晶体态与斯格明子晶体态之间发生多步拓扑转变的实验发现。通过基于共振X射线散射和中子散射实验以及电子输运测量开展详细的磁结构分析,我们发现该化合物随外磁场变化而承载着椭圆斯格明子、半子/反半子对以及圆形斯格明子的周期性晶格。这些对象的直径小至2.7 nm,比典型的非中心对称磁体几乎小两个数量级。这种错综复杂的拓扑磁转变方式可由一个考虑了不等价波矢处RKKY相互作用之间竞争的理论模型很好地再现。本研究结果表明,即便是具有竞争相互作用的简单中心对称磁体,也可成为一种很有前景的材料平台,用于实现种类更丰富、具有独特对称性和拓扑性质的纳米磁性准粒子,而且其稳定性或许可通过多种外部刺激进行调控。

英文摘要:

Topological swirling spin textures, such as skyrmions and merons, have recently attracted much attention as a unique building block for high-density magnetic information devices. The controlled transformation among different types of such quasi-particles is an important challenge, while it was previously achieved only in a few non-centrosymmetric systems characterized by Dzyaloshinskii-Moriya interaction. Here, we report an experimental discovery of multi-step topological transitions among a variety of meron and skyrmion crystal states in a centrosymmetric magnet GdRu$_2$Ge$_2$. By performing the detailed magnetic structure analysis based on resonant X-ray and neutron scattering experiments as well as electron transport measurements, we have found that this compound hosts periodic lattice of elliptic skyrmions, meron/anti-meron pairs, and circular skyrmions as a function of external magnetic field. The diameter of these objects is as small as 2.7 nm, which is almost two orders of magnitude smaller than typical non-centrosymmetric magnets. Such an intricate manner of topological magnetic transitions are well reproduced by a theoretical model considering the competition between RKKY interactions at inequivalent wave vectors. The present findings demonstrate that even a simple centrosymmetric magnet with competing interactions can be a promising material platform to realize a richer variety of nanometric magnetic quasi-particles with distinctive symmetry and topology, whose stability may be tunable by various external stimuli.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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