The origin of complex magnetic phases in Fe based binary Fe3Ga4 compound

The Fe3Ga4 inter-metallic and magnetic compound has recently witnessed interests because of close competition between magnetic states resulting in magnetic phase transitions easily accessible via variations in temperature or magnetic field. Experimentally this compound has been found to have different magnetic states at different temperatures. In its unit cell, Fe3Ga4 presents a complex base-centered monoclinic structure with eighteen Fe atoms per unit cell occupying four non-equivalent sites. The presence of different Fe atoms in the compound with a large number of nonequivalent nearest-neighbor and next-nearest-neighbor interactions exhibits a complicated magnetic behavior in this compound. To the best of our knowledge, magnetic behavior of Fe3Ga4 is not well understood either experimentally or theoretically. Based on our density functional theory calculations and a phenomenological model Hamiltonian, we try to elucidate the origin of different magnetic interactions and magnetic ordering in this compound. Besides, an intermediate magnetic state may host a topological Hall effect induced in this compound. The authors acknowledge support from DOE through grant DE-SC-0021089.