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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 6: Skyrmions I (joint session MA/KFM)

KFM 6.9: Talk

Wednesday, September 29, 2021, 12:15–12:30, H5

Emergence of Magnetic Skyrmions in Ultrathin Films of Manganese on W(001) at High Magnetic Fields — •Reiner Brüning, Kirsten von Bergmann, André Kubetzka, and Roland Wiesendanger — Festkörper- und Nanostrukturphysik, Hamburg, Deutschland

Topological spin textures like skyrmions with diameters on the order of a few nanometers are promising objects for the application in the field of spintronics. Whereas typical skyrmion systems like Pd/Fe bilayers on Ir(111) [1] have a hexagonal crystal symmetry, here, we investigate a monolayer of Mn on the square lattice of W(001) using spin-polarized scanning tunneling microscopy at 4.2 K. In absence of an external magnetic field, the known magnetic ground state of a 2.2 nm spin spiral is observed [2]. Between 90^∘ rotational domains two types of magnetic domain walls can be identified.

The measurements at 9 T show that the external magnetic field leads to a decrease in the size of the domains and initializes the transition from the spin spiral to small skyrmion areas which results in a coexistence state of the spin spiral and skyrmion phase. Inside the small skyrmionic areas, the skyrmions arrange in a hexagonal-like order, in agreement with recent simulations [3]. By high voltage pulses of 1-2 V, we can locally induce transitions between spiral phase and skyrmion phase.

[1] N. Romming et al., Science, 341, (2013)

[2] P. Ferriani et al., Phys. Rev. Lett. 101, 027201 (2008)

[3] A. K. Nandy et al., Phys. Rev. Lett. 116, 177202 (2016)