Speaker
Description
The extension of nanomagnetism into three dimensions and curvilinear geometries opens new frontiers for spintronic applications, offering additional degrees of freedom beyond conventional planar thin films [1]. This talk presents recent advances in understanding and controlling topological magnetic states such as skyrmions and vortices on curved surfaces.
In the first part of my talk, I will show how the curvature can indirectly assist skyrmion formation on self-assembled polystyrene particles coated with Pt/Co/Ta multilayers [2]. Using magnetic force microscopy (MFM), we demonstrate that the confined spiraling 3D stripe states can be transformed into metastable skyrmions at the apex of spherical particles through local magnetic field stimuli from the MFM tip, despite negligible curvature induced DMI.
On the other hand, spin waves in magnonic systems offer energy-efficient alternatives to conventional electronics [3], with low-frequency magnetic vortex resonances being particularly relevant for microwave applications. While planar magnetic vortices have been extensively studied, their dynamics in three-dimensional curvilinear architectures remain largely unexplored.
In the second part of my talk, I will focus on our latest results on the direct experimental observation of vortex core gyration on a 3D curvilinear surface [4]. Using a stripline antenna on a SiN membrane, we excite self-assembled polystyrene spheres coated with NiFe, which host a vortex lattice state at remanence. Time-resolved scanning transmission X-ray microscopy (TR-STXM) at BESSY II [5] captures real-space, time-resolved dynamics, revealing complex spin-wave modes due to curvature-induced field gradients.
References
[1] Fernández-Pacheco, A. et al. Nature Communications 8, 15756 (2017).
[2] Koraltan, S. et al. arXiv:2511.22557 (2025).
[3] Chumak, Andrii V., et al. Nature physics 11.6 (2015): 453-461.
[4] Koraltan, Sabri, et al. In Preparation (2026).
[5] Koraltan, Sabri, et al. Science Advances 10.39 (2024): eado8635.