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MA: Fachverband Magnetismus
MA 40: Skyrmions III (joint session MA/TT)
MA 40.8: Vortrag
Mittwoch, 18. März 2020, 17:00–17:15, POT 6
Observation of unusual magnetic response at topological defects in FeGe — •Mariia Stepanova1,2, Erik Lysne1,2, Peggy Schoenherr3, Jan Masell4, Laura Köhler5, Achim Rosch6, Naoya Kanazawa7, Yoshinori Tokura4,7, Markus Garst5,8, Alireza Qaiumzadeh2, Arne Brataas2, and Dennis Meier1,2 — 1NTNU, Trondheim, Norway — 2QuSpin, NTNU, Trondheim, Norway — 3ETH Zurich, Zürich, Switzerland — 4RIKEN, Wako, Japan — 5Technische Universität Dresden, Dresden, Germany — 6Universität zu Köln, Köln, Germany — 7University of Tokyo, Tokyo, Japan — 8Karlsruhe Institute of Technology, Karlsruhe, Germany
Lamellar textures do not just arise in liquid crystals and biological systems, they are also observed in helimagnets. Analogous to cholesteric liquid crystals, chiral magnets possess a periodic layered structure and form different types of non-trivial topological defects. Using magnetic force microscopy (MFM) on the near-room temperature helimagnet FeGe, we resolve 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 an unusual MFM response, which is not observed in regions with perfect lamellar-like order. This magnetic signature is similar to the so-called "lines of flare" in cholesteric liquid crystals, suggesting local variations in magnetic susceptibility. We investigate the origin of the magnetic signature of the topological defects and discuss the possibility to use the local MFM response as a read-out signal in device applications.