Dresden 2026 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 57: Thin Films: Magnetic Coupling Phenomena / Exchange Bias and Magnetic Anisotropy
MA 57.4: Vortrag
Freitag, 13. März 2026, 10:15–10:30, POT/0112
Large Microstructure-Dependent Magneto-Ionic Effects in Nanocrystalline Fe-Ni alloys — •Anna Ullrich1, Florin Leo Hambeck1, Raphael Kohlstedt2,3, Sandra Schiemenz4, Daniel Wolf4, and Karin Leistner1,3,4 — 1Institute of Chemistry, Chemnitz University of Technology, Germany — 2Institute of Physics, Chemnitz University of Technology, Germany — 3Research Center MAIN, Chemnitz University of Technology, Germany — 4Leibniz IFW Dresden, Germany
Magneto-ionic effects offer voltage-driven, energy-efficient control of magnetic properties via electrochemical reactions or ion migration.[1] Most studies focus on Co- or Fe-based systems,[2] recent research has reported similar effects in Ni,[3] prompting exploration in industrial relevant Fe-Ni alloys. We investigated magneto-ionic control in electrodeposited Fe-Ni thin films across the full compositional range using in situ MOKE microscopy.[4] Near-equiatomic films with mixed fcc/bcc phase and ultrafine grains show up to −90 % coercivity reduction at ∼1 V. In situ Raman spectroscopy and structural characterization attribute the effect to dense grain boundaries and heterogeneous surface oxides, facilitating voltage-induced surface oxide reduction and magnetic softening. Our findings highlight the importance of microstructure in enhancing magneto-ionic functionality, providing guidelines for designing materials for sensing, actuation, and neuromorphic computing. [1] Leighton, Nat. Mater. 2019, 18, 13-18., [2] Nichterwitz et al., APL Mater. 2021, 9, 030903., [3] Kutuzau et al., Phys. Rev. Mater. 2025, 9, 114408., [4] Ullrich et al., Adv. Electron. Mater. 2025, e00654.
Keywords: Magneto-ionic; Fe-Ni alloys; Nanocrystalline; Voltage-control of Magnetism