Three dimensional magnetic systems promise significant opportunities for applications, for example providing higher density devices and new functionality associated with complex topology and greater degrees of freedom [1,2]. For the experimental realisation of these new properties, appropriate characterisation techniques are required to determine both the three-dimensional magnetic structure at the nanoscale, and its response to external excitations.
To obtain access to the three-dimensional magnetic configuration at the nanoscale, we exploit X-ray magnetic nanotomography [3]. In particular, we have determined the complex magnetic structure within the bulk of a micrometre-sized soft magnetic pillar and identified the magnetic configuration of nanoscale topological objects such as vortex rings, as well as Bloch point singularities [3,4].
In addition to the magnetic structure, the dynamic response of the 3D magnetic configuration to excitations is key to our understanding of both fundamental physics, and applications. With our recent development of X-ray magnetic laminography [5], it is now possible to determine the magnetisation dynamics of a three-dimensional magnetic system [5] with spatial and temporal resolutions of 50 nm and 70 ps, respectively.
These new experimental capabilities of X-ray magnetic imaging open the door to the elucidation of complex three-dimensional magnetic structures, and their dynamic behavior.
[1] Fernández-Pacheco et al., “Three-dimensional nanomagnetism” Nat. Comm. 8, 15756 (2017)
[2] Donnelly and V. Scagnoli, “Imaging three-dimensional magnetic systems with X-rays” J. Phys. D: Cond. Matt. (2019).
[3] Donnelly et al., “Three-dimensional magnetization structures revealed with X-ray vector nanotomography” Nature 547, 328 (2017).
[4] Donnelly et al., “Experimental observation of vortex rings in a bulk magnet” Nat. Phys. 17, 316 (2021)
[5] Donnelly et al., “Time-resolved imaging of three-dimensional nanoscale magnetization dynamics”, Nature Nanotechnology 15, 356 (2020).