Claire Donnelly
Extending nanomaterials to three dimensions results in opportunities for increased density and interconnectivity, with the possibility to go beyond the physics of planar systems [1,2]. This has recently been exemplified by nanomagnetism, where advances in methodologies have driven breakthroughs in our physical understanding, leading to the discovery of exotic spin textures, non-reciprocal dynamics and curvature-induced effects.
In this talk we address the challenge of mapping 3D order at the nanoscale. We start by considering ferromagnets, for which we have developed X-ray magnetic tomography and laminography [3,4], to map 3D magnetic configurations [3], and their GHz dynamics [4,5]. In this way, we gain insight into textures such as nanoscale magnetic vortex rings and Bloch point singularities [3,6]. With X-ray magnetic tomography established for ferromagnets, we next develop new imaging capabilities for a wider range of materials. By harnessing coherent X-rays, we exploit phase dichroism to open up the study of previously inaccessible ferromagnetic systems [7]. We go beyond ferromagnets by establishing linear dichroic tomography, gaining access to 3D orientation fields in a variety of systems: from crystallographic defects in catalysts [8], to 3D antiferromagnetic configurations.
With these new experimental techniques, it is now possible to investigate three dimensional textures in magnetic systems – and beyond. This new understanding and control of 3D topological textures paves the way not only for enhanced understanding of these systems, but also towards the next generation of technological devices.
[2] C. Donnelly and V. Scagnoli, J. Phys. D: Cond. Matt. 32, 213001 (2020).
[3] C. Donnelly et al., Nature 547, 328 (2017).
[4] C. Donnelly et al., Nat. Nano. 15, 356 (2020).
[5] S. Finizio, CD et al., Nano Lett. (2022)
[6] C. Donnelly et al., Nat. Phys. 17, 316 (2020)
[7] J. Neethirajan, CD et al., Phys. Rev. X 14, 031028 (2024)
[8] A. Apseros, CD et al., Nature 636, 345 (2024)