High Spin Polarization of Ferrimagnetic Half-Heusler Compounds FeCrZ and MnYZ (Y = Mn, Cr; Z = IIIb, IVb, Vb Elements)

We have studied the electronic and magnetic properties of the half-Heusler compounds FeCrZ and MnYZ (Y = Mn, Cr; Z = Al, Si, P, Ga, Ge, As, In, Sb, Sn) by first-principles total-energy calculations. The results show that, among the paramagnetic, ferromagnetic, and ferrimagnetic states, the ferrimagnetic state is the most stable in all the compounds apart from MnCrP and FeCrZ (Z = Si and Ge). It is found that ten among 24 ferrimagnetic compounds have high spin polarization. The origin of the band gap in the present compounds is also explained by the the strong hybridization between the d orbitals (t(2g) or e(g)) of the X and Y atoms as a ferromagnetic and half-metallic XYZ with a half-Heusler structure.