Ab initio prediction of half-metallic properties for the ferromagnetic Heusler alloys Co2MSi (M=Ti,V,Cr)

By means of density functional calculations, the magnetic and electronic properties and phase stabilities of the Heusler compounds Co2MSi (with M=Ti,V,Cr,Mn,Fe,Co,Ni) were investigated. Based on the calculated results, we predict the ferromagnetic phases of the compounds Co2TiSi, Co2VSi, and Co2CrSi to be half metals. Of particular interest is Co2CrSi because of its high density of majority-spin states at Fermi energy in combination with a reasonably high estimated Curie temperature of 747 K. The compounds Co2TiSi and Co2VSi are thermodynamically stable, whereas Co2CrSi is of a metastable phase which might be stabilized by suitable experimental techniques. (c) 2006 American Institute of Physics.