Three dimensional magnetic systems promise significant opportunities for both fundamental physics, and technological applications, for example providing higher density devices and new functionalities associated with complex topology and greater degrees of freedom [1,2].
In this lecture, I will describe recent advances in both characterization and nanofabrication techniques that allow us to explore the physics of three dimensional magnetic systems experimentally. In particular, harnessing recent advances in X-ray magnetic tomographic imaging, it is now possible to map both the static configuration [3,4], and dynamical behaviour [5,6], of topological magnetic structures [3-6]. This new insight, combined with recent advances in analytical techniques [7] have led to first experimental observations of 3D magnetic solitons such as nanoscale magnetic vortex rings [7,8].
As well as existing within bulk and thin film systems, 3D spin textures can be introduced via the patterning of complex 3D magnetic nanostructures [9]. Such textures are not limited to the magnetization: recently it has been discovered that highly coupled curvilinear nanosystems can lead to the formation of topological textures within the magnetic stray field [10].
These new experimental capabilities for 3D magnetic systems open the door to complex three-dimensional magnetic structures, and their dynamic behaviour.
References
[1] Fernández-Pacheco et al., Nature Communications 8, 15756 (2017).
[2] C. Donnelly and V. Scagnoli, J. Phys. D: Cond. Matt. 32, 213001 (2020).
[3] C. Donnelly et al., Nature 547, 328 (2017).
[4] K. Witte, et al., Nano Letters 20, 1305 (2020).
[5] C. Donnelly et al., Nature Nanotechnology 15, 356 (2020).
[6] S. Finizio et al., Nano Letters (2022)
[7] C. Donnelly et al., Nat. Phys. 17, 316 (2020)
[8] N. Cooper, PRL. 82, 1554 (1999).
[9] L. Skoric et al., Nano Letters 20, 184 (2020).
[10] C. Donnelly et al., Nature Nanotechnology 17, 136 (2022)