Amorphous Ni–Al underlayer-accelerated L10 ordering transition of FePt thin films

In the present study, we succeeded in accelerating the L10 ordering transition of FePt thin films by employing amorphous Ni–Al as underlayers. The coercivity Hc = 5 kOe and ordering parameter S = 0.67 of FePt thin films deposited on a Ni–Al underlayer with a thickness of ∼5 nm after 380 °C annealing for 30 min are significantly higher than those Hc = 0.4 kOe and S = 0.35 of the films without the Ni–Al underlayer. The L10 ordering process of and the coercivity of FePt thin films can be significantly tuned by varying the thickness of the Ni–Al underlayer.