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.
@article{arxiv.2601.16704,
title = {Control of helix orientation in chiral magnets via lateral confinement},
author = {Maurice Colling and Mariia Stepanova and Mario Hentschel and Somasree Bhattacharjee and Erik Lysne and Kasper Hunnestad and Naoya Kanazawa and Yoshinori Tokura and Jan Masell and Dennis Meier},
journal= {arXiv preprint arXiv:2601.16704},
year = {2026}
}