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arXiv · 2601.16704

Control of helix orientation in chiral magnets via lateral confinement

Maurice Colling·Mariia Stepanova·Mario Hentschel·Somasree Bhattacharjee·Erik Lysne·Kasper Hunnestad·Naoya Kanazawa·Yoshinori Tokura·Jan Masell·Dennis Meier
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Abstract

Helimagnetic materials offer a versatile platform for spin-based device concepts owing to their long-range, tunable spiral order. Here, we demonstrate controlled manipulation of the helimagnetic propagation vector q by geometrical confinement, using FeGe as a model DMI-driven chiral magnet. Micromagnetic simulations based on the nonlinear sigma model reveal that open boundaries give rise to a chiral surface twist acting as an effective surface anisotropy, which dictates the preferred helix orientation in the absence of magnetostatic shape effects. This geometry-induced anisotropy is quantitatively captured by an analytical model derived from the DMI boundary condition. Magnetic force microscopy measurements on focused-ion-beam structured FeGe confirm the predicted orientation behavior and establish geometry-controlled helimagnetic order as a robust, tunable mechanism for steering DMI-stabilized spin-spiral states. The concept provides a general route toward device-level control of chiral magnetic order in of non-centrosymmetric systems.

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Maurice Colling, Mariia Stepanova, Mario Hentschel, Somasree Bhattacharjee, Erik Lysne, Kasper Hunnestad, Naoya Kanazawa, Yoshinori Tokura, Jan Masell, Dennis Meier. 2026-01-23. Control of helix orientation in chiral magnets via lateral confinement. https://arxiv.org/abs/2601.16704

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