Phase stability and structural properties of the K$_{x}$Ca$_{1-x}$N novel ferromagnetic alloy from first-principles

Abstract

We study the structural properties and phase stability of the K$_{x}$Ca$_{1-x}$N alloy using the regular-solution model based on the total energy of the mixing. The pseudopotential approach was used along with PBE functional of Perdew, Burke, and Ernzerhof (PBE). We investigated the bond-lengths distribution as a function of composition $x$. We also predicted the phase separation of the two partially miscible components and calculated the enthalpy $\Delta H$ using the interaction parameter $\Omega$. We observe an asymmetry about $x=0.46$ in the phase diagram due to the $x$-dependant interaction parameter $\Omega=12.69-1.32x$ kcal/mole. The equilibrium solubility limit, known as the miscibility gap is found to be around 3033 K.