Crystal field splitting, half metallic ferromagnetism, structural, mechanical and magneto-electronic properties of spinels type structure compounds MgX2O4 (X\u2009=\u2009Fe and Co) for spintronic applications

Abstract

First-principle study has been conducted using the full potential linearized augmented plane wave plus local orbital method (FPLAPW\u2009+\u2009LO) within the scope of density functional theory with generalized gradient approximation (GGA) and Generalized Gradient Approximation plus Hubbard parameters U (GGA\u2009+\u2009U) as exchange correlation potentials to study the mechanical, structural, electronic and magnetic properties of two spinels type structure compounds MgX2O4 (X\u2009=\u2009Fe and Co). The structural parameters evaluated from the solution of equation of state with GGA are consistent with experiment. For the calculation of electronic as well as magnetic properties of these compounds, we have used the GGA\u2009+\u2009U formalism to treat the d state of transition metals Fe and Co more efficiently. Moreover, the crystal fields splitting for both of the compounds are also explored. The electronic band structure and density of states predicts the half metallic/metallic nature of MgFe2O4 and MgCo2O4, respectively. The spin polarized total magnetic moments of the compounds under investigation reveal the ferromagnetic behavior of these compounds. Moreover, the elastic properties of these compounds are also calculated with GGA and compared with available calculations. These compounds are founds to be elastically stable and ductile in nature. Half metallic/metallic ferromagnetic nature of MgFe2O4 and MgCo2O4, respectively, predicts the important of these spinels in spintronic devices.