Regensburg 2019 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 19: Miscellaneous: Biomaterials, Magnetic Shape Memory Alloys, Sensors and Actuators (joint session MM/MA)
MM 19.1: Vortrag
Dienstag, 2. April 2019, 14:15–14:30, H46
Magnetic and chemical microstructures of Mn-based Heusler compounds studied by small-angle neutron scattering — •Ulrike Zweck, Michael Leitner, Pascal Neibecker, and Winfried Petry — Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Garching
Ni2MnZ based Heusler compounds have attracted a considerable amount of attention due to their various appealing properties such as the ferromagnetic shape-memory effect or the magnetocaloric effect. Since the magnetic properties are very sensitive to the degree of structural order in these systems [1], understanding the correlation of these two ordering parameters is crucial.
The magnetic moments are mainly carried by the Mn atoms, which interact ferromagnetically in the L21-ordered state. However, it has been found that at structural anti-phase domain boundaries the magnetization tends to reverse, leading to atomically sharp ferromagnetic domain walls [2]. To study this interplay of magnetic and structural order as well as the mechanism of coupling of ferromagnetic domains across APD boundaries, we have investigated Ni2MnAl and Ni2MnAl0.5Ga0.5 powder samples in distinct ordering states via temperature-dependent small-angle neutron scattering (SANS), giving access to the magnetization microstructure. Further, we reproduce the correlation between structural and magnetic order by Monte Carlo simulations.
[1] P. Neibecker et al., Appl. Phys. Lett. 105, 261904 (2014).
[2] H. Ishikawa et al., Acta Mater. 56, 4789 (2008).