It was noted that understanding the ordering transition from A1 to L10 structure in FePt thin films was of great importance in developing L10-FePt films as ultra-high density magnetic recording media. Here, the L10-ordering transition of FePt films was investigated based on activation volume measurements. A large activation volume ΔV∗ = 10–11Å3 = (0.75–0.8)Ω, where Ω was average atomic volume of FePt, was determined for atomic diffusions in the L10-ordering transition, indicating a thermal-vacancy-assisted phase transition. This transition was suggested to be predominantly dependent on the diffusion of Fe atoms. These findings have direct implications for yielding L10-FePt films at low temperatures and optimizing their microstructures.

Thermal-Vacancy-Assisted Phase Transition in FePt Thin Films. X.H.Li, F.Q.Wang, B.T.Liu, D.F.Guo, X.Y.Zhang: Applied Physics Letters, 2011, 98[14], 141912