Investigations on the electronic, structural, magnetic properties related to shape-memory behavior in Ti₂CoX (X=Al, Ga, In)

Highlights: • The analysis of phase stability trend is studied for Ti₂CoX(X = Al, Ga, In). • Ti₂CoGa is more suitable as shape memory alloy. • Total magnetic moments disappear with a increase of c/a ratio for all systems. • Density of states at the Fermi level are also shown. - Abstract: Using the full-potential local orbital minimum-basis method, we have performed a systematic investigations on the electronic, structural, and magnetic properties related to shape memory applications for Ti₂CoX (X=Al, Ga, In) alloys. Our results confirm that these alloys are half-metallic ferromagnets with total magnetic moment of 2μ_B per formula unit in austenite phase, and undergo a martensitic transformation at low temperatures. The relative stabilities of the martensitic phases differ considerably between Ti₂CoX (X=Al, Ga, In). Details of the electronic structures suggest that the differences in hybridizations between the magnetic components are responsible for trends of phase. Quantitative estimates for the energetics and the magnetizations indicate that Ti₂CoGa is a promising candidate for shape memory applications