Probing electronic, magnetic and thermal properties of NiMnSb Half-Heusler alloy for spintronics as an environmentally friendly energy resource: A DFT+U and Monte Carlo study

Abstract

The NiMnSb Half-Heusler alloy has a high Curie temperature (Tc = 720 K) and high spin polarization (P = 100%), which makes it one of the good magnetic materials with exceptional structural, electrical, magnetic, and thermo-elastic properties. Using Density Functional Theory with Hubbard correction and Monte Carlo methods, we have probed the electronic, magnetic and thermal properties of NiMnSb. The computational study found a lattice parameter of 5.91Å and an integer value of total moment magnetic equal to 4μB using GGA method. However, using the Hubbard correction, these values increased by 0.17% and 9.25% to the experimental results, respectively, which also resulted in the destruction of the Half-metallic behavior. The high total magnetic moment is preserved despite bulk and axial strain by varying the relative change of lattice parameter and c/a ratio. The variation of spin polarization against the change of lattice parameter to experimental value reveals a very strong spin polarization between -2.2% and 0.2%. The thermal properties show that the alloy under probing is more stable, both thermodynamically and thermo-mechanically. The Monte Carlo simulation shows that NiMnSb’s strong ferromagnetic property stays its high as the temperature rises to 720 K. Above 720 K, NiMnSb joins the group of paramagnetic materials.