Confinement Driven Spin‐Texture Evolution in Directly Written Nanomagnets

Abstract In low‐dimensional magnetic structures, magnetostatic energy minimization yields a uniform spin‐texture, resembling that of a macroscopic bar magnet, thereby limiting their scope for applications. Here, the formation of non‐collinear spin‐textures such as Néel‐type domain walls with perpendicular core magnetization, stable under ambient conditions, in magnetic nanostructures with dimensions reduced to ≈25 nm, is experimentally demonstrated. A single‐step magnetic writing process is deployed, wherein a nano‐focused beam of penetrating ions displaces atoms locally and converts a short‐range ordered precursor alloy that is paramagnetic to a strain‐relaxed lattice that is ferromagnetic, thus manifesting a controllable spin‐texture evolution. Simulations show that the spin‐textures rely on the presence of symmetry breaking due to crystallographic misalignments within the confined geometries. Theoretical considerations yield the critical dimension below which perpendicular Néel walls are stabilized. These results provide a direct route to implementing spatially confined non‐collinear spin‐textures generating local perpendicular magnetic fields, that are necessary in applications such as spin‐transport and spin‐based quantum sensing.