Berlin 2018 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 2: Focus Session: Nanomagnetism in the x-ray spotlight

MA 2.2: Hauptvortrag

Montag, 12. März 2018, 10:00–10:30, H 1012

Time-resolved imaging of nanoscale spin textures and spin waves — •Jörg Raabe, Simone Finizio, and Sebastian Wintz — Paul Scherrer Institut, Villigen, Schweiz

The direct imaging of nanoscale spin textures and their dynamics represents a key demand in magnetism research. Scanning transmission x-ray microscopy (STXM) using soft x-rays [e.g. 1] provides unique means for high-resolution, element-selective magnetic imaging, by exploiting diffractive lenses and the x-ray magnetic circular dichroism (XMCD) effect [2]. In particular, time-resolved STXM offers an ultimate combination of spatial and stroboscopic temporal resolution, down to Δ r ∼ 10 nm, Δ t ∼ 10 ps. In this contribution, we will present three examples of state of the art dynamic STXM imaging. In the first example, magnetoelastic coupling is used to control the intrinsic anisotropy of a vortex spin texture. This control results in drastic changes of the vortex core gyration frequency and orbit which were directly imaged in the experiment [3]. In the second part, we will show dynamic imaging of a remnant topological bubble at room temperature in a low-pinning iron-nickel alloy with weak perpendicular magnetic anisotropy. Finally, we will present how such topological spin textures can be exploited as natural antennas for the coherent excitation of nanoscale spin waves, which have also been directly observed [4].

[1] J. Raabe et al. Rev. Sci. Instrum. 79, 113704 (2008).

[2] G. Schütz et al. Phys Rev. Lett. 58, 737 (1987).

[3] S. Finizio et al. Phys. Rev. B 96, 054438 (2017).

[4] S. Wintz et al. Nat. Nanotechnol. 11, 948 (2016).