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.