Curvature induced modifications of chirality and magnetic configuration in perpendicular magnetized films

TL;DR

This study demonstrates how curvature in 3D magnetic nanostructures influences magnetic domain configurations and induces a Dzyaloshinskii-Moriya interaction, offering new pathways for designing advanced spintronic devices.

Contribution

It provides the first experimental evidence of curvature-induced DMI in curved Co/Pd multilayer nanostructures and explores its effects on magnetic domain stability.

Findings

Curvature modifies magnetic domain structures in nanowires.

Curvature induces a measurable DMI, about one-third of the intrinsic value.

Curvature enhances stability of Neel-type domain walls.

Abstract

Designing curvature in three-dimensional (3D) magnetic nanostructures enables controlled manipulation of local energy landscapes, allowing for the modification of noncollinear spin textures relevant for next-generation spintronic devices. In this study, we experimentally investigate 3D magnetization textures in a Co/Pd multilayer film, exhibiting strong perpendicular magnetic anisotropy (PMA), deposited onto curved Cu nanowire meshes with diameters as small as 50nm and lengths of several microns. Utilizing magnetic soft X-ray nanotomography, we achieve reconstructions of 3D magnetic domain patterns at approximately 30nm spatial resolution. This approach provides detailed information on both the orientation and magnitude of magnetization within the film. Our results reveal that interfacial anisotropy in the Co/Pd multilayers drives the magnetization towards the local surface normal. In contrast to typical labyrinth domains observed in planar films, the presence of curved nanowires significantly alters the domain structure, with domains preferentially aligning along the nanowire axis in close proximity, while adopting random orientations farther away. We report direct experimental observation of a curvature-induced Dzyaloshinskii-Moriya interaction (DMI), which is quantified to be approximately one-third of the intrinsic DMI in Co/Pd stacks. The curvature induced DMI enhances stability of Neel-type domain walls. These experimental observations are further supported by micromagnetic simulations. Altogether, our findings demonstrate that introducing curvature into magnetic nanostructures provides a powerful strategy for tailoring complex magnetic behaviors, paving the way for the design of advanced 3D racetrack memory and neuromorphic computing devices.