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]