[10a-E208-1~11] 10.1 Emerging materials in spintronics and magnetics (including fabrication and characterization methodologies)

9:30 AM - 9:45 AM JST(12:30 AM - 12:45 AM UTC)

[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 Naganuma^3,4, 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 T_s from 150 to 600 degrees C. With increasing T_s, 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 T_s = 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.