SKM 2021 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 15: Posters Magnetism IV
MA 15.28: Poster
Donnerstag, 30. September 2021, 13:30–16:30, P
Exploration of the magnetic structure of the shape-memory Heusler alloy Mn2NiGa — •Alistair Cameron1, Sanjay Singh2, Robert Cubitt3, and Dmytro Inosov1 — 1Institut fuer Festkoerper- und Materialphysik, Technische Universitaet Dresden, D-01069 Dresden, Germany — 2IIT, Banaras Hindu University, Varanasi, India — 3Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, F-38042 Grenoble Cedex 9, France
The material Mn2NiGa is an example of one of the shape-memory Heusler alloys which have been predicted to show a skyrmion lattice. The Mn2YZ Heusler compounds undergo a cubic to tetragonal phase transition with decreasing temperature, and while most of these compounds possess a centrosymmetric low-temperature phase, this phase in Mn2NiGa is noncentrosymmetric. This opens up the possibility of the presence of the anisotropic Dzyaloshinskii-Moriya interaction, which can lead to the formation of skyrmion lattices. Both simulations and AC susceptibility measurements predicted the presence of a skyrmion lattice in this system, and so we performed small-angle neutron scattering measurements in order to search for this. The lattice was predicted to emerge below the Martensitic transition, and in a field of up to 1 T. However, while we saw a clear redistribution of spectral weight, we did not see any sign of a skyrmion lattice across a large range in temperature, field and scattering vector beyond those predicted for this lattice. We conclude that other magnetic behaviour dominates this material within the noncentrosymmetric tetragonal phase.