Dresden 2026 – scientific programme

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MA: Fachverband Magnetismus

MA 37: Non-Skyrmionic Magnetic Textures

MA 37.4: Talk

Wednesday, March 11, 2026, 15:45–16:00, POT/0351

Fractional Hopfions in Composite Magnets — •Sanjay Ashok and Jan Masell — Karlsruhe Institute of Technology (KIT), Karlsruhe

Hopfions are three dimensional magnetization textures studied due to their unique physical-, topological properties and their functionalization prospects [1]. These textures are usually doughnut shaped and classified by their integer topological winding number called Hopf index. In our work, we demonstrate that hopfions with fractional Hopf index, called fractional hopfions [2, 3], can be stabilized in composite magnets. We identify a two-slab composite magnet with slab-dependent Dzyaloshinskii-Moriya interaction (DMI) as a suitable material platform for stabilizing fractional Hopfions. We further distinguish the role of Bloch-, Neel- and Antiskyrmion-type DMI in composite magnets and their effect on the winding of fractional hopfions [4]. By studying the phase diagram of fractional hopfions we predict the range of external magnetic field and uniaxial anisotropy where these textures can be found.

[1] Zheng et al., Nature 623, 7988 (2023); [2] Knapman et al., Comm. Phys. 7, 1 (2024); [3] Yu et al., Adv. Mat. 35, 20 (2023); [4] Ashok and Masell, in preparation

Keywords: Hopfions; 3D magnetism; Topological Textures