SKM 2021 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 15: Posters Magnetism IV

MA 15.13: Poster

Donnerstag, 30. September 2021, 13:30–16:30, P

Nutational switching in ferromagnets and antiferromagnets — •Lucas Winter, Levente Rózsa, Sebastian Großenbach, and Ulrich Nowak — University of Konstanz , Konstanz, Germany

For magnetic memory devices, precessional switching is a promising new way of writing data. However, on ultra-short timescales, recent research[1] indicates that the magnetization does not only exhibit precession but also nutation. Here, we investigate how nutation can contribute to spin switching. We use analytic theory and atomistic spin simulations to discuss the behavior of ferromagnets and antiferromagnets in high-frequency magnetic fields. In ferromagnets, linearly polarised fields align the magnetization perpendicular to the external field, enabling 90^∘ switching. For circularly polarized fields in the xy plane, the magnetization tilts to the z direction. During this tilting, it rotates around the z axis, allowing 180^∘ switching. In antiferromagnets, external fields with frequencies higher than the nutation frequency align the order parameter parallel to the magnetic field direction, while for lower frequencies it is oriented perpendicular to the field.

The switching frequency increases with higher magnetic field strengths, but it deviates from the Larmor frequency characteristic for precessional switching. High field strengths are required to outpace precessional switching. Furthermore, nutational switching requires low temperatures to be observable.

[1] K. Neeraj et al., Nat. Phys. 17, 245 (2021).