Berlin 2024 – wissenschaftliches Programm
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 15: Multiferroics and Magnetoelectric Coupling (joint session MA/KFM)
KFM 15.8: Vortrag
Mittwoch, 20. März 2024, 17:00–17:15, EB 407
Non-trivial Spin Structures And Multiferroic Properties Of The DMI-Compound Ba2CuGe2O7 — •Korbinian Fellner1, Sebastian Mühlbauer1, Peter Wild1, Michal Dembski-Villalta1, Tommy Kotte2, Markus Garst3, Alexandra Turrini4, and Bertrand Roessli4 — 1Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Garching, Germany — 2Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany — 3Karlsruhe Institute of Technology (KIT), Karlsruhe. Germany — 4Paul Scherrer Institut (PSI), Villigen, Switzerland
Incommensurate spiral magnets have raised tremendous interest in recent years, mainly motivated by their wealth of spin structures, such as skyrmions. A second field of interest is multiferroicity: Helical spin structures are in general ferroelectric, enabling the coupling of the electric and magnetic properties. Ba2CuGe2O7, featuring a quasi-2D structure with Dzyaloshinskii-Moriya interactions (DMI), is a material that is interesting in both of these regards and combines them with a third one: a variety of unconventional magnetic phase transitions. Neutron diffraction is used for an examination of the distribution of critical fluctuations in reciprocal space, associated with the paramagnetic to helimagnetic transition of Ba2CuGe2O7. It's reduced dimensionality prompts a transition from incommensurate antiferromagnetic fluctuations to 2D antiferromagnetic Heisenberg fluctuations, showcasing a varied array of magnetic phase transitions in spiral textures. Recently, a new phase with a vortex-antivortex magnetic structure has been theoretically described and experimentally confirmed.
Keywords: Multiferroics; DMI; 2D; Vortex; Incommensurate AFM