Presentation Information
[10a-E208-3]Competing Kinetics of L10 Chemical Ordering and Solid-State Dewetting in Epitaxial FePd/SrTiO3(001) Films
H. K. Dara1, S Vergara5, Mitsuharu Uemoto2, Tomoya Ono2, S Gorfman1, I Goldfarb1, 〇Hiroshi Naganuma3,4, A Kohn1 (1.Tel Aviv Univ., 2.KobeUniv, 3.ToyamaUniv, 4.Nagoya Univ., 5.UnivParisSaclay)
Keywords:
L10-FePd,STEM
L10-ordered FePd exhibits large perpendicular magnetocrystalline anisotropy suitable for spintronic applications. In this work, epitaxial equiatomic FePd thin films (~26 nm) were sputter-deposited on SrTiO3(001) substrates, and the kinetics of L10 chemical ordering and solid-state dewetting were investigated by varying the substrate temperature Ts from 150 to 600 degrees C. With increasing Ts, a single-variant L10- tetragonal phase formed with the c-axis perpendicular to the substrate, and the long-range order parameter S increased from 0.16 to 0.76. The magnetization easy axis correspondingly rotated from in-plane to out-of-plane. At an intermediate temperature range (ITR) of Ts = 300-400 degrees C, local degradation of ordering, reduced crystal coherence length, and simultaneous void nucleation were observed, pointing to a coupled structural transition and onset of dewetting. First-principles DFT calculations revealed that the {101} plane of L10 FePd possesses the lowest surface free-energy density (gamma = 1.60 J/m2), governing facet formation during dewetting. These results clarify how ordering kinetics and surface energetics jointly determine the structural and magnetic properties of epitaxial FePd films.