Investigation of half-metallic and magnetic phase transition in Co2TiZ (Z = Al, Ga, In) Heusler alloys.

The half-metallic and ferromagnetic properties of Co₂TiZ (Z = Al, Ga, In) Heusler alloys are investigated. The structural stability is analyzed among the two possible structures, namely, L2₁ (Cu₂MnAl phase) and XA (Hg₂CuTi phase) structures. It is found that these alloys are stable in L2₁ (Cu₂MnAl phase) structure. The electronic structure of Co₂TiZ reveals that these alloys exhibit half-metallic ferromagnetism with small spin-flip gap at the minority spin state. As the pressure is increased, ferromagnetic to non-magnetic phase transition is observed at the pressures of 380.9, 363.0 and 317.8 GPa for Co₂TiAl, Co₂TiGa and Co₂TiIn, respectively. Half-metallic to metallic phase transition occurs in Co₂TiAl, Co₂TiGa and Co₂TiIn at the pressures of 76.5 GPa, 73.1 GPa and 63.9 GPa respectively. [ABSTRACT FROM AUTHOR]