Curvature engineered unconventional 3D spin textures in amorphous Fe_0.58Ge_0.42  thin films

Curvature-induced Dzyaloshinskii–Moriya interaction (DMI) provides a powerful means to create chiral spin textures, enabling studies of topology in nanomagnets and the design of skyrmion-based devices on flexible or patterned materials. We report the first observation of curvature-induced, localized skyrmionic textures in amorphous Fe₀.₅₈Ge₀.₄₂ (a-Fe-Ge) thin films, deposited by DC magnetron co-sputtering onto flat TEM grids and toroidally curved Si₃N₄ membranes patterned by e-beam lithography. Using magnetic soft X-ray nanotomography at MISTRAL/ALBA with XMCD contrast (~30 nm resolution) at RT, we found that flat substrates host conventional stripe domains, while curved regions with nonzero Gaussian curvature nucleate skyrmions coexisting with stripes elsewhere. Target skyrmions—precursors to hopfions—were observed. Micromagnetic simulations confirm curvature–magnetization coupling even in disordered materials, revealing geometry as a tool to engineer nanoscale magnetic landscapes and potentially generate higher-order topological spin states via designed curvature.