First-Principles Calculations of the Structural, Magnetic, and Electronic Properties of Fe_2MgB Full-Heusler Alloy

The structural, magnetic, and electronic properties of a new Fe_2MgB full-Heusler alloy were calculated using a first-principles approach based on density functional theory. The conventional Cu_2MnAl -type and inverse Hg_2CuTi -type structures in nonmagnetic and ferromagnetic states were considered for the full-Heusler alloy. The ferromagnetic Hg_2CuTi -type structure was found to be the most energetically favourable. Fe_2MgB with ferromagnetic structure has a molecular magnetic moment of 3.000 μ _B at the equilibrium lattice constant of 5.562 Å. The molecular magnetic moment originates from the alloy’s two Fe atoms and obeys the Slater–Pauling rule. The majority-spin channels are metallic, whereas the minority-spin electrons exhibited a semiconducting behaviour with an indirect narrow gap of 0.179 eV in the equilibrium state. The ferromagnetic Hg_2CuTi -type Fe_2MgB is proven to be a potential half-metallic material suitable for use in spintronics.