SKM 2021 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 15: Posters Magnetism IV

MA 15.45: Poster

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

Domain Walls in a Row-Wise Antiferromagnetic Monolayer — Jonas Spethmann, Martin Grünebohm, Roland Wiesendanger, Kirsten von Bergmann, and •André Kubetzka — Department of Physics, University of Hamburg

We investigate magnetic domain walls in a row-wise antiferromagnetic (AFM) system, the fcc-stacked manganese monolayer on Re(0001) [1], employing spin-polarized STM, atom manipulation, and spin dynamics simulations [2]. In contrast to traditional AFM domain walls, which can be described by a coherent spin rotation, we find that the low symmetry of the row-wise AFM state facilitates a new type of domain wall which connects rotational domains by a transient 2Q state [3], a non-collinear spin texture with characteristic 90^∘ angles in the wall center. Surprisingly, the wall width of about 2 nm is determined by a balance of Heisenberg and higher-order exchange interactions and independent of crystal anisotropy. Based on the mathematical equivalence of uniaxial anisotropy and fourth-order exchange interactions, we can establish simple formulas for domain wall width and energy. Furthermore, magnetic atom manipulation is used to image the domain wall structure with atomic spin-resolution and to modify wall positions, opening new possibilities to investigate AFM systems and prepare AFM spin configurations.

[1] J. Spethmann, et al., Phys. Rev. Lett. 124, 227203 (2020).

[2] J. Spethmann, et al., Nature Commun. 12, 3488 (2021).

[3] P. Kurz, PhD thesis, Aachen, Germany (2000).