Induced half-metallicity in Cr-based ferromagnetic chalcospinels with anion substitutions: CuCr2S(Se)4-xEx (E=F, Cl, Br), Cu(Cd)Cr2S(Se)4-x, and CdCr2S(Se)4-xDx (D=N, P, As)

First-principles calculations of the electronic structures of chalcogenide spinels with anion vacancy and substitutions are presented. Our calculations predict that Cu(Cd)Cr2S(Se)(4-x), CuCr2S(Se)(4-x)E-x (E=F, Cl, Br), and CdCr2S(Se)(4-x)D-x (D=N, P, As) can be half-metallic over a range of concentrations. The magnetic moment is found to scale approximately linearly on adding or withdrawing electrons and varies between 5.0 and 6.0 mu(B)/f.u.