First-principle investigation of half-metallic ferromagnetism in octahedrally bonded Cr-doped rock-salt SrS, SrSe, and SrTe

We have investigated the electronic structure and half-metallic ferromagnetism of Sr(1-x)Cr(x)Z (Z = S, Se, and Te) in rock-salt structure at concentrations x (x = 0.125, 0.25, 0.5, 0.75 and 0.875) of Cr, using first-principles calculations of density functional theory. The electronic and magnetic properties show that Sr(1-x)Cr(x)Z (Z = S and Se) at x = 0.125, 0.25, 0.5, 0.75 and SSr1-xCrxTe at all concentrations are half-metallic ferromagnets (HMF) with spin polarization of 100% and total magnetic moments of 4 mu B per Cr atom, whereas the HMF character destroyed for Sr(1-x)Cr(x)Z (Z = S and Se) at x = 0.875. The integrals Bohr magneton of total magnetic moments confirm the half-metallic ferromagnetic behavior of Sr(1-x)Cr(x)Z. We have found that the ferromagnetic state is stable by the 3d-eg (Cr) partially filled states associated with the double-exchange mechanism. Therefore, the Sr1-xCrxS, Sr1-xCrxSe, and Sr1-xCrxTe at low concentration are predicted to be new potential candidates for spintronic applications.