Assessment of magnetism and magnetocrystalline anisotropy of (Mn[Formula: see text]Fe[Formula: see text])[Formula: see text]P[Formula: see text]Si[Formula: see text] (x,y = 0 or 1/3) compounds for permanent magnets.

In order to calculate the prospects for new transition-metal rich and rare-earth free permanent magnets, we have investigated the electronic and magnetic properties of Fe[Formula: see text]P and related Mn- or/and Si-substituted compounds using full potential linearized augmented plane wave (FPLAPW) method under generalized gradient approximation (GGA) exchange-correlation (XC) functional. In agreement with the experiment, our calculated total magnetic moment and magnetocrystalline anisotropy (MCA) for Fe[Formula: see text]P are found to be 3.03 μ [Formula: see text]/f.u. and 538 μeV/f.u. (2.58 MJ/m[Formula: see text]), respectively. We find that the substitution of Mn or/and Si in Fe[Formula: see text]P not only enhances the magnetization but also boosts the maximum energy product by preserving the hard magnetic behavior. Our theoretical predictions provide useful insights to enhance magnetization with tolerable loss of MCA for Mn or/and Si substituted Fe[Formula: see text]P. Thus, we propose rare-earth free prospective candidates for permanent magnets through Fe[Formula: see text]P based compounds.