Magnetic, Magnetotransport, and Anomalous Hall Effect Behavior in Polycrystalline Hexagonal Mn₂FeSn Thin Films

Manganese-based Heusler alloys are interesting due to their topology, tunability, and potential application in next-generation spintronic devices. Here, we present the magnetic, magnetoresistance, and anomalous Hall Effect behavior in hexagonal D0₁₉ polycrystalline Mn₂FeSn thin films grown using the magnetron co-sputtering method. A saturation magnetization of 3.5 mB is observed at 2 K, which is higher than the Slater-Pauling value of 2 mB. The resistivity shows a non-metallic behavior that does not fit with the thermally activated behavior of semiconductors, the variable range hopping conduction mechanism, or their combination. Magnetization vs temperature behavior shows evidence of an antiferromagnetic phase transition near 210 K and a Ferromagnetic transition near 270 K. We observe a large exchange bias behavior peaking at 50 K, which gradually disappears by 150 K. On the other hand, Magnetization vs field and Hall effect data show that the coercivity and Hall resistivity peaking at 150 K. We report a peak Hall angle of 12°, anomalous Hall angle of 10°, anomalous Hall resistivity of 63 μΩ cm and anomalous Hall conductivity of 562 [Ω cm]^-1 at150 K, while the coercivity is almost 0.6 T at 150 K. We observe the anomalous Hall resistivity to scale linearly with resistivity squared below 150 K implying an intrinsic Berry curvature contribution at low temperatures. Detailed analysis will be presented to understand the origins of observed behavior, including possible topological Hall effect and spin-glass-type behavior.