Electronic structures and magnetic properties of near-equiatomic Co-Ti alloys

The magnetic properties of near-equiatomic CoTi alloys were studied by using the first-principles electronic structure calculations. A formation of the antistructure Co atom and its cluster plays an important role to determine the ferromagnetic behavior of the disordered equiatomic alloy or off-stoichiometric Co-rich alloys. A small but considerable amount of charge transfer from the Ti to Co atom is crucial to the structural stability and the magnetic properties of the alloy system. A sharp peak in the calculated density-of-states curve near the Fermi level grows as the Ti concentration decreases, indicating a strong localization of the states, which gives a better understanding of the change in physical properties upon an order→disorder transition