Berlin 2024 – scientific programme

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MA: Fachverband Magnetismus

MA 46: Poster II

MA 46.2: Poster

Thursday, March 21, 2024, 15:00–18:00, Poster C

Skyrmion flow in a periodically modulated channel — •Klaus Raab, Maurice Schmidt, Maarten A. Brems, Jan Rothörl, Fabian Kammerbauer, Peter Virnau, and Mathias Kläui — Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany

We investigate the non-equilibrium flow behaviour of skyrmions, magnetic whirls with non-trivial real space topology, driven by spin-torques in modulated channel geometries. Poiseuille-like velocity flow-profiles of liquids usually occur due to no-slip boundary conditions, meaning moving particles do interfere with the boundary e.g. the wall of the confining geometry, reducing the velocity of particles closest to a wall1. Skyrmions on the other hand should experience slip at the boundaries due to the repulsive nature of the skyrmion-edge and skyrmion-skyrmion interaction. Adding structured obstacles along the boundary may lead to partial or even no-slip behaviour and thus to Poiseuille-like flow profiles while skyrmions are forced through a wire due to spin-torques. Influence of channel width and edge geometry modulation were optimized and tested using simulations and compared with experimental measurements of straight and modulated channels. Understanding flow dynamics and velocity profiles of skyrmions, their interaction with each other and their harbouring geometry is essential for skyrmionic applications like the racetrack memory2. 1. Sutera, S. P. & Skalak, R. The History of Poiseuille*s Law. Annu. Rev. Fluid Mech. 25, 1-20 (1993). 2. Fert, A., Cros, V. & Sampaio, J. Skyrmions on the track. Nat. Nanotechnol. 8, 152-156 (2013).

Keywords: Skyrmion flow; Spin-orbit torque; Diffusion; Confinement; Experiment