Dresden 2017 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 41: Micromagnetism / Computational Magnetics

MA 41.6: Vortrag

Mittwoch, 22. März 2017, 16:30–16:45, HSZ 101

Shell-ferromagnetism of nano-precipitate in a Ni-Mn-In off-stoichiometric Heusler alloy by ferromagnetic resonance — •Franziska Scheibel¹, Detlef Spoddig¹, Ralf Meckenstock¹, Asli Çakir², Michael Farle¹, and Mehmet Acet¹ — ¹Faculty of Physics and CENIDE, University Duisburg-Essen, 47057 Duisburg, Germany — ²Department of Metallurgical and Materials Engineering, Muğla Sitki Koçman University, 48000 Muģla, Turkey

Previous studies have shown that the off-stoichiometric Ni-Mn-based Heusler alloys decompose into a ferromagnetic (FM) Ni₅₀Mn₂₅X₂₅ Heusler alloy and the antiferromagnetic Ni₅₀Mn₅₀ alloy during temper-annealing [1]. Annealing of Ni₅₀Mn_45.1In_4.9 in a field of 5 T leads to an alignment of the magnetic moments at the interface of the nano-precipitates along the field direction, leading to a vertical shift of the magnetic hysteresis which is stable up to 9 T and 500 K. The hard magnetic shell can only be reversed in a field of 12 T, which makes this material interesting for permanent magnetic memory application. We studied the coupling mechanism and interface exchange energy by ferromagnetic resonance (FMR). Bidirectional FMR measurements in the range −1.1 ≤ µ₀H ≤ 1.1 T at 400 K show a corresponding signal to the decomposed FM phase, indicating a shape anisotropy. FMR studies up to 12 T shows that the FMR of the hard magnetic shell appears at the same resonance field as the FMR of the soft magnetic core but is only present after saturation at 12 T. Work supported by the Deutsche Forschungsgemeinschaft (SPP 1599).
A. Çakir et al., Sci. Rep. 6 , 28931 (2016)