Curvature Induced Magnetism in 3D Magnetic Nanostructures

Three-dimensional (3D) nanomagnetic structures provide a fertile ground for stabilizing unconventional spin configurations. In particular, curvature can intricately modify the energy landscape and govern magnetic characteristics, including topology and chirality. We have explored curvature-induced modification of magnetic configuration in a Co/Pd multilayer thin film with perpendicular magnetic anisotropy (PMA), deposited on an interconnected network of Cu NWs [1]. The resulting sample contained both planar and curved regions, allowing a comparative study of curvature-induced effects on spin textures. In the curved regions, the magnetization was found to deviate from the out-of-plane direction, aligning instead with the local surface normal. The overall domain orientation was also influenced by the underlying NW-defined curvature and the domains preferentially aligned along the long axis of the NWs. Furthermore, the chirality of the domain walls (DWs) was strongly affected by curvature. In particular, Néel DWs were promoted, and the effective DMI contribution was found to be approximately 1/3 of the intrinsic DMI of the Co/Pd multilayer.



We have also realized a prototypical 3D topological nanostructure, magnetic Möbius bands, using two-photon polymerization, followed by sputtering of magnetic films [2]. Magnetometry and first-order reversal curve (FORC) analysis reveal a strong preference for vortex formation in the vertical section of the band, with vortex polarity intrinsically determined by the band’s handedness. The vortices can be repositioned or reconfigured by applied magnetic fields. These behaviors arise from curvature-induced modifications to the exchange energy, which also drive the fragmentation of larger domains into more complex textures. Our results are supported by magnetometry, micromagnetic simulations, and soft X-ray nanotomography.



These studies demonstrate the potentials of using 3D nanomagnetic systems to explore how geometry influences domain structure and spin configurations. This work is done in collaboration with D. Bhattacharya, C. Langton, B. J. Fugetta, D. Raftrey, S. Satapathy, O. Bezsmertna, A. Sorrentino, D. Makarov, G. Yin, P. Fischer.