Large topological Hall effect and in situ observation of magnetic domain structures in the Mn2FeSn compound. (December 2022) - Liu, J.
Abstract: The search for novel topological magnetic domain structures such as magnetic skyrmions, bubbles and vortices, and relative physical effect has always been the focus of spintronics devices. Here, the magnetism, transport properties and magnetic domain structures of the polycrystalline hexagonal Mn2 FeSn compound are studied in detail. We find the strong texture along c-axis in this bulk compound owing to large temperature gradient between the bottom and top of the ingot during the preparation process. The resistivity resulting from topological Hall effect reaches about 5.19 μΩ cm at 50 K in the sample of compound obtained by cutting along perpendicular texture direction. Spontaneous nanoscale magnetic bubbles have directly been observed at low temperature due to the competition among the magnetocrystalline anisotropy, antiferromagnetic, and ferromagnetic exchange interactions as decreasing temperature. It is the formation of non-collinear or non-coplanar spin configuration that causes the obvious topological Hall effect. Additionally, the biskyrmion-like state can be obtained with evolution of stripe domains under an appropriate magnetic field. Based on these results, this study of Mn2 FeSn magnet may be beneficial to the development for exploring novel magnetic spin textures. Graphical abstract: Image 1 Highlights: Non-metal behavior is presented in hexagonal Mn2 FeSn alloy. The magnitude of resistivity stemming from large topological Hall effect reaches about 5.19 μΩ cm at 50 K. Spontaneous nanoscale magnetic bubbles are directly observed at low temperature. The biskyrmion-like state can be regulated under an external magnetic field.