First-principles study of half-metallic properties of the Heusler alloy Ti2CoGe

First-principles calculations have been performed on the electronic structures and magnetic properties of a new Ti2Co-based full-Heusler alloy Ti2CoGe. The calculations predict the Ti2CoGe is a half-metallic ferromagnet at the equilibrium lattice constant with the minority-spin energy gap of 0.60 eV. It is found that the total magnetic moment (M-t) and the number of valence electrons (Z(t)) in Ti2CoGe obey a new Slater-Pauling (SP) rule of M-t=Z(t)-18 and the rule also can be applied to other Ti2Co-based half-metallic full-Heusler alloys. The Ti2CoGe alloy keeps a 100% polarization at Fermi level and maintains the half-metallic character for lattice constants ranging between 6.05 and 6.67 angstrom. (C) 2012 Elsevier B.V. All rights reserved.