Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 22: Superconductivity: Topological Defects in Superconductors and Magnets (joint session TT/MA)
TT 22.2: Vortrag
Montag, 12. März 2018, 15:15–15:30, HFT-FT 101
Nanoscale imaging of magnetic topological defects in helimagnetic FeGe — •Peggy Schönherr1, Jan Müller2, Laura Köhler3, Achim Rosch2, Naoya Kanazawa4, Yoshi Tokura4,5, Manfred Fiebig1, Markus Garst3, and Dennis Meier6 — 1ETH Zürich, Switzerland — 2Universität zu Köln, Germany — 3Technische Universität Dresden, Germany — 4University of Tokyo, Japan — 5Riken, Japan — 6NTNU Trondheim, 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 magnetic force microscopy measurements in combination with micromagnetic simulations, discussing the dynamics and interactions of 1D and 2D objects with non-trivial topology in the helimagnetic phase of FeGe. We show that the local magnetization dynamics are strongly influenced by depinning and subsequent motion of edge dislocations (1D). Their motion is part of a slow relaxation process, having profound impact on the formation of the helical ground state. Other 1D objects that play an important role for the micromagnetism are so-called π disclinations, which can form chains and build domain walls that are distinctly different from classical antiferro- and ferromagnetic domain walls. Thus, our microscopy data reveal a new multitude of magnetic nano-objects with non-trivial topology going beyond the previously discussed skyrmions.