SKM 2021 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 17: Skyrmions II (joint session MA/KFM)

MA 17.6: Vortrag

Freitag, 1. Oktober 2021, 11:30–11:45, H5

Non-linear Magnetic Response of Topological Spin Textures in Helimagnetic FeGe — Mariia Stepanova^1,2, •Jan Masell³, Erik Lysne^1,2, Peggy Schoenherr⁴, Laura Köhler⁵, Michael Paulsen⁶, Alireza Qaiumzadeh², Naoya Kanazawa⁷, Achim Rosch⁸, Yoshinori Tokura^3,7, Arne Brataas², Markus Garst⁵, and Dennis Meier^1,2 — ¹NTNU, Trondheim, Norway — ²Center for Quantum Spintronics, NTNU, Trondheim, Norway — ³RIKEN, Wako, Japan — ⁴UNSW, Sydney, Australia — ⁵KIT, Karlsruhe, Germany — ⁶PTB, Berlin, Germany — ⁷University of Tokyo, Tokyo, Japan — ⁸Universität zu Köln, Köln, Germany

Chiral magnets possess a periodic layered structure which is similar to cholesteric liquid crystals, forming a wide variety of non-trivial topological defects. Using magnetic force microscopy (MFM), we resolve 1D and 2D topological defects in the near-room temperature helimagnet FeGe, including disclinations and dislocations with nonzero topological winding number, as well as three fundamental types of helimagnetic domain walls. Interestingly, in addition to their non-trivial structure, all topological defects in FeGe exhibit a pronounced non-linear magnetic response in MFM, which is not observed in regions with perfect lamellar-like order. This magnetic signature is reminiscent of the "lines of flare" that arise in cholesteric liquid crystals, suggesting local variations in magnetic susceptibility. By combining MFM and micromagnetic simulations, we investigate the origin of the magnetic signature of the topological defects and discuss possibilities to utilize the anomalous local response as read-out signal in spintronics devices.