Formation and magnetic properties of hexagonal DO19 phase in Fe2MnGa: An experimental and theoretical investigation

The formation and magnetic properties of Fe2MnGa hexagonal DO19 phase were investigated in detail. Hexagonal Fe2MnGa can be stabilized by furnace cooling, while the FCC phase can be obtained by quenching from high temperature. Strong ferromagnetic character is identified in Fe2MnGa DO19 phase. Its saturation magnetic moment Ms at 5 K is as large as 4.40 μB/f.u. and Curie temperature TC is 563 K. First-principles calculations indicate that Fe and Mn atoms tend to occupy the 6h sites randomly in the DO19 lattice. The DO19 type Fe2MnGa shows a normal ferromagnetic metal character in its electronic structure. Similar to the experimental results, the calculated total magnetic moment is also quite large and mainly comes from the contributions of Fe and Mn spin moments. Both of them are larger than 1.8 μB and are parallel coupled. These properties are quite different from the antiferromagnetic character in FCC Fe2MnGa. •Fe2MnGa DO19 hexagonal phase has been synthesized and investigated.•Large saturation magnetization Ms and high TC were observed in DO19 Fe2MnGa.•Structure optimization was performed, electronic/magnetic properties were calculated.•Ferromagnetic coupling between Fe and Mn results in the large Ms of Fe2MnGa.