Influence of Si substitution on structural, electronic and magnetic properties of Fe2MnGa Heusler compound

摘要

We investigate the electronic and magnetic properties of Fe2MnGa1-xSix alloy (x = 0, 0.25, 0.5, 0.75, and 1) using first-principles density functional theory within the generalized gradient approximation method. The lattice constant decreases linearly whereas bulk modulus increases with increasing Si content. The total magnetic moment varies linearly with increasing Si content, which follows the Slater-Pauling rule. Electronic band structure calculations indicate that the Fe2MnGa1-xSix exhibits half-metallic character for all the concentrations studied and the spin polarization and the spin-down band gap both increase with the Si content. Based on the magnetic properties calculations, the Heisenberg exchange coupling parameters give Fe-Mn ferromagnetic coupling and Mn-Mn antiferromagnetic coupling. The TC first decreases and then increases with Si content, which is in well agreement with the experimental results.