Crystal structure and magnetism of Pt-doped Fe₂MnGa compounds

Materials with non-collinear magnetic structures are of interest due to their unique magnetic and electrical transport properties, as well as their potential to exhibit non-trivial topological states. We have investigated one such compound, Fe₂MnGa, doped with Pt. Samples with compositions Fe_1-xPt_xMnGa (x = 0, 0.2, 0.3, 0.4) were synthesized in a face-centered cubic structure using arc melting followed by annealing. The parent compound, Fe₂MnGa, exhibits antiferromagnetic behavior at room temperature with a Néel temperature (T_N) of 434 K. However, as the temperature increases, the material transitions into a ferrimagnetic state with a Curie temperature (T_c) of 760 K. Above room temperature, the Pt-doped samples also exhibit ferrimagnetic behavior, with T_c and high field magnetization [M_3T], values of 724 K and 60 emu/g; 810 K and 59 emu/g; and 782 K and 57 emu/g for Fe_1.8Pt_0.2MnGa, Fe_1.7Pt_0.3MnGa, and Fe_1.6Pt_0.4MnGa, respectively. Interestingly, when the temperature is decreased below room temperature, these doped samples demonstrate spin compensation behavior, with compensation temperatures of 241 K, and 254 K for Fe_1.7Pt_0.3MnGa, and Fe_1.6Pt_0.4MnGa, respectively. The results of this research are interesting, as non-colinear magnetic structures may lead to non-trivial topological states with potential applications in next generation spintronic devices.