Curved Three-Dimensional Cobalt Nanohelices for Use in Domain Wall Device Applications

Three-dimensional fabrication of nanostructures opens unique possibilities to understand not only the fundamental effects of the shape of and interactions between the nanostructures but also technological applications. This is of particular importance for magnetic nanostructures, where curvilinear geometry can lead to the emergence of topological effects and spin excitations. In this work, we used the focused electron beam ion deposition (FEBID) method to fabricate three-dimensional magnetic cobalt nanohelices with controlled geometry such as chirality and curvature. Using a combination of off-axis electron holography and electron tomography, we are able to determine the way in which the quantitative nanoscale magnetization distribution is related to the 3D morphology and curvature of the nanohelices. These results pave a way forward for development of future 3D magnetic nanostructures to explore novel physics as well as for applications based on domain walls such as magnetic memory and magnetic field sensors.