SPICE Workshop on Quantum Functionalities of Nanomagnets, June 17th - 19th 2025
Thorsten Hesjedal
Magnetic skyrmions, topologically protected spin textures, exhibit unique winding numbers that are crucial for understanding their stability and interactions. While skyrmions are not inherently quantum objects, their integer winding number represents a quantized topological property with significant implications for spintronic applications. In this talk, I will present our advancements in directly determining the topological winding number of skyrmions using resonant elastic X-ray scattering (REXS) [1]. This technique enables high-precision measurements of skyrmion topology in bulk materials such as Cu2OSeO3, overcoming limitations of traditional imaging methods [2]. Moreover, by leveraging the energy-dependent probing depth of REXS, we have been able to re-solve the depth-dependent evolution of skyrmion tubes, providing direct insights into their near-surface twisting and internal structural variations in 3D [3].
Beyond static topology, our mode-resolved detection of magnetization dynamics provides direct insight into skyrmion resonances, revealing how different excitation modes couple to the topologi-cal properties of these magnetic textures [4]. Using X-ray diffractive ferromagnetic resonance (DFMR), we can selectively probe dynamic spin modes linked to the periodic structure of skyrmi-ons, offering a powerful tool for studying their real-space dynamics [4].
References
[1] S. L. Zhang et al., Direct experimental determination of the topological winding number of skyrmions in Cu2OSeO3, Nat. Commun. 8, 14619 (2017).
[2] S. L. Zhang et al., Resonant elastic X-ray scattering from the skyrmion lattice in Cu2OSeO3, Phys. Rev. B 93, 214420 (2016).
[3] S. Zhang et al., Reciprocal space tomography of 3D skyrmion lattice order in a chiral mag-net, PNAS 115, 6386–6391 (2018).
[4] D. M. Burn et al., Mode-Resolved Detection of Magnetization Dynamics Using X-ray Diffrac-tive Ferromagnetic Resonance, Nano Lett. 20, 345−352 (2020).