Influence of stoichiometry and growth temperature on the crystal structure and magnetic properties of epitaxial L10 Fe-Pd (001) films

To investigate the crystallographic structure and the magnetic properties as a function of chemical composition (40–62 at. %) and substrate temperature (Ts = 300–550 °C), we fabricated epitaxial FePd films of thickness 20 ± 2 nm by sputtering on MgO (100) single-crystal substrates. The ordering parameter, measured by x-ray diffraction with synchrotron radiation, and the perpendicular anisotropy of the Fe54Pt46 films increased with increasing substrate temperature. For FePd films (Ts = 550 °C) with varied Fe content, a direct correlation between the ordering parameter and the magnetocrystalline anisotropy field is found. The greatest ordering parameter, 0.84, and magnetocrystalline anisotropy field, ∼20 kOe, were obtained for FePd films of Fe concentration 54 at. %, indicating that an off-stoichiometric L10 FePd might be preferable for engineering and applications