Dresden 2017 – scientific programme
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MA: Fachverband Magnetismus
MA 3: Magnetic Textures: Statics and experimental imaging
MA 3.5: Talk
Monday, March 20, 2017, 10:30–10:45, HSZ 101
Observation of topological magnetic defects in helimagnetic FeGe — •Peggy Schönherr1, Jan Müller2, Laura Köhler3, Naoya Kanazawa4, Manfred Fiebig1, Yoshi Tokura4,5, Achim Rosch2, Markus Garst3, and Dennis Meier1,6 — 1ETH Zürich, Switzerland — 2Universität zu Köln, Germany — 3Technische Universität Dresden, Germany — 4University of Tokyo, Japan — 5Riken, Japan — 6Norwegian University of Science and Technology, Norway
Complex spin textures, like helical spin spirals with a fixed wavelength, can occur due to chiral magnetic interactions. Chiral magnets are a striking nanoscopic analog to liquid crystals, possessing lamellar phases and ordered topological defects. Defects are of great importance as they strongly influence order and mobility of the spin system. Here we present the experimental observation of such 1D and 2D objects with non-trivial topology in the helimagnetic phase of FeGe using magnetic force microscopy. We show that the depinning and subsequent motion of edge dislocations govern the local magnetization dynamics. Moreover, the defects can form chains and build topological domain walls, which are distinctly different from classical antiferro- and ferromagnets. Experimentally, three main types of domain walls are found depending on the angle between neighboring domain orientations. The domain walls can also carry a skyrmion charge, which implies a coupling to spin currents and contributions to the topological Hall effect. Thus, going beyond skyrmions, chiral magnets reveal a zoo of magnetic nano-objects with non-trivial topology.