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MA: Fachverband Magnetismus

MA 41: Poster III

MA 41.31: Poster

Donnerstag, 20. März 2025, 15:00–17:30, P3

Sliding Through Topology: Unlocking the Tunable Hopf Index — Maria Azhar, •Sandra Chulliparambil Shaju, Ross Knapman, Alessandro Pignedoli, and Karin Everschor-Sitte — Faculty of Physics and CENIDE, University of Duisburg-Essen, 47057 Duisburg, Germany

Recently, there has been growing interest in three-dimensional magnetic structures [1-3], especially regarding their intriguing topological properties and the calculation of their topological index [4]. In this study, we introduce a new approach to determine the Hopf index of magnetic textures, focusing on contributions from both the self-linking and cross-linking of flux tubes [5]. This alternative perspective provides deeper insight into the topological nature of magnetic textures, particularly those exhibiting non-integer topological indices, which we interpret as states of ``mixed topology". We emphasize the critical role of the background magnetization in these three-dimensional textures, which influences whether the Hopf index is an integer or not. To illustrate these concepts, we present examples of three-dimensional magnetic textures within various backgrounds, including ferromagnetic, helical, and screw-dislocation configurations.

References:

[1] P. Sutcliffe, Phys. Rev. Lett. 118 (2017).

[2] F. Zheng, et al., Nature 623 (2023).

[3] M. Azhar, et al., Phys. Rev. Lett. 128 (2022).

[4] R. Knapman, et al., arXiv:2410.22058 (2024).

[5] M. Azhar, Sandra. C. Shaju, et al., arXiv:2411.06929 (2024).

Keywords: Magnetic Hopfions; Topological spin structures; Hopf Index; Screw dislocations; Fractional Hopfions