Preparation of Co–Ti–N nanocomposite films

In this work, Co–Ti–N nanocomposite films were prepared by the reactive sputtering method. Depending on N2 partial pressure in the Ar and N2 mixture during sputter deposition, two different structures were formed. At an N2 partial pressure of 6.7×10−4 Pa, the as-deposited film is composed of TiN and an amorphous CoTiN phase. After thermal annealing at 400 °C, Co was separated out to form a Co–TiN structure. The saturation magnetization increases substantially after thermal annealing. On the other hand, when the film was deposited at an N2 partial pressure of 6.7×10−3 Pa, both Ti and Co were nitrided. A complex nitride of Ti and Co, (TiCo)N was formed in the film. In this circumstance, thermal annealing at 400 °C had almost no effect on the structure and magnetic properties of the film.