Elastic stiffness of L1₀ FePt thin film studied by picosecond ultrasonics

The elastic stiffness of epitaxial and polycrystalline L 10 FePt films is studied by picosecond ultrasonics coupled with x-ray reflectivity analysis, and we find that C33 of L 10 FePt is 309 GPa. The morphology of FePt films shows dependence on the film thickness; as the film thickness increases the mazelike structure changes to a continuous film. The elastic stiffness correlates with the morphology change, and it increases as the film thickness increases. When the film thickness exceeds 40 nm, the elastic stiffness becomes independent of the film thickness, and we define the saturated value as C33 of L 10 FePt. © 2011 American Institute of Physics.Nakamura N., Uranishi A., Wakita M., et al. "Elastic stiffness of L 10 FePt thin film studied by picosecond ultrasonics", Applied Physics Letters, 98(10), 101911 (2011) https://doi.org/10.1063/1.3562031