Fe2MnGe: A hexagonal Heusler analogue

• Published in: Journal of alloys and compounds 2019-01, Vol.771, p.793-802
• Main Authors: Keshavarz, S., Naghibolashrafi, N., Jamer, M.E., Vinson, K., Mazumdar, D., Dennis, C.L., Ratcliff, W., Borchers, J.A., Gupta, A., LeClair, P.
• Format: Article
• Language: English
• Subjects: Heusler; Magnetic; Neutron diffraction
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2018.07.298

We synthesized bulk polycrystalline samples of Fe2MnGe using arc-melting and vacuum annealing. Our experimental investigations revealed that Fe2MnGe crystallizes in a hexagonal DO19 phase at room temperature, in analogy with its “parent” compound Fe3Ge. We find a large saturation magnetization, even larger than that predicted for the tetragonal phase, of approximately 5μB/f.u. at T = 5 K, with a Curie temperature of Tc∼505 K. The large moment and magnetocrystalline anisotropy, along with the possibility of half-metallicity presents Fe2MnGe as a strong candidate for spin-transfer-torque RAM and other spintronic applications. We do not find evidence for the cubic or tetragonal phases predicted by first-principles theory during these investigations. However, our neutron diffraction investigations were suggestive of a low temperature structural transformation. •Bulk Fe2MnGe was made using arc-melting and vacuum annealing.•It is a strongly ferromagnetic metal crystallizing in the hexagonal DO19 structure.•Neutron diffraction suggested a low temperature cubic phase.•Our results suggest large magnetocrystalline anisotropy, potentially useful for spintronic applications.