First-principles study of the Hf-based Heusler alloys: Hf2CoGa and Hf2CoIn.

The electronic structures and magnetic properties of the new Heusler alloys Hf 2 CoGa and Hf 2 CoIn have been studied by using the first-principles projector augmented wave (PAW) potential within the generalized gradient approximation (GGA). Both Hf 2 CoGa and Hf 2 CoIn Heusler alloys have the half-metallic character and completely (100%) spin polarization at the Fermi level ( E F ) and the indirect band gaps of 0.733 eV and 0.654 eV, respectively, in the minority spin channel. The total magnetic moments µ t are all 2 µ B per formula unit, linearly scaled with the total number of valence electrons ( Z t ) by µ t = Z t −18 and the atomic magnetic moments have localized character due to less affected by deformations. The origin of the indirect band gaps for these two new Heusler alloys is well understood. These two new Heusler alloys are the ideal candidates for spintronic devices. [ABSTRACT FROM AUTHOR]