Mechanical, structural, electronic, magnetic, and thermomagnetic properties of the full-Heusler Fe2MnAs1-xSix alloy using DFT and Monte Carlo simulation

The thermomagnetic, electronic, structural, and mechanical properties of the Fe2MnAs1-xSix (x = 0, 0.25, 0.5, 0.75, and 1.0) full Heusler alloys were investigated using Monte Carlo simulation (MCs) and density functional theory (DFT). Both the pure and doped structures exhibit the L21 prototype, and there is a noticeable decline in the lattice parameter as the Si concentration increases. Electronic analysis was performed using Wien2k and the calculations were conducted using the full-potential linearized augmented plane wave (FP-LAPW) method implementing various approximations including GGA-PBE, mBJ-GGA, GGA + U, and PBEsol (GGAsol). Studying exchange coupling parameters revealed that ferromagnetic states primarily arise from the interactions between Fe-Mn and Fe-Fe in both pure and doped structures. The resultant Curie temperature ranged from 215 to 490 K by investigating the magnetic properties. Additionally, different mechanical properties such as Poisson's ratio, linear compressibility, anisotropy parameter, shear, bulk, and Young's modulus were examined for all the structures.