Electronic and Magnetic Properties of Fe2−xCoxTiSi (x = 0, 0.5, 1, 1.5, 2) Heusler Alloys.

The first principles calculations are carried out to understand the half metallic and ferromagnetic properties of Fe_2−xCo_xTiSi (x = 0, 0.5, 1, 1.5, 2) full Heusler alloys. The stable structure is predicted as L2₁ structure (Cu₂MnAl phase). The lattice constant value of Fe_2−xCo_xTiSi Heusler compounds increases as the value of x increases. These alloys exhibit half metallic ferromagnetism (except Fe₂TiSi) with small spin flip gap at the minority spin state. At high pressure, semiconductor to metallic phase transition is observed in Fe₂TiSi while half metallic to metallic phase transition is observed in Fe_1.5Co_0.5TiSi, Fe_1.0 Co_1.0TiSi, Fe_0.5Co_1.5TiSi and Co₂TiSi. The spin polarization of these compounds (except Fe₂TiSi) is 100%. Hence, these compounds are suitable for spin injection devices in spintronics. [ABSTRACT FROM AUTHOR]