[en] Full text: With the rapid developments of wireless communications and high-frequency microwave applications, soft magnetic films have attracted lots of interest because of their applications in microwave devices, communications and magnetic recording [1,2,3]. Low-damping magnetic materials are highly desirable for high frequency, and full Heusler compounds in this respect provide interesting properties. Here, we present a study of the magnetic dynamics of Co₂FeAl films with a Gilbert damping constant as low as 3.1×10-4 for thickness of 100 nm. The in-plane as well as out-of-plan ferromagnetic resonance (FMR) were measured on different thicknesses of Co₂FeAl films grown on Si(100), all samples were capped with a 5 nm thick Ti layer. The thickness dependencies of the magnetic anisotropy and inhomogeneous broadening of the linewidth are good indicators of crystal quality and magnetic uniformity. The damping parameter is investigated as a function of thickness using broad-band ferromagnetic resonance (VNA-FMR). We found that the saturated magnetic damping constant αo decreasing continuously with the Co₂FeAl thickness t_CFA. Furthermore, the structural investigation of these films was performed by X-ray diffraction, AFM, selected area electron diffraction (SAED) and HR-TEM. The columnar grains were observed for 100 nm thick films, while an island grains were observed for 5 nm thick films. It was found that the type of growth for CFA could influence the damping. References: [1] Xiong L L and Adeyeye A O Appl. Phys. Lett. 108 262401(2016) [2] Godsell J F, Kulkarni S, O’Donnell T and Roy S J. Appl. Phys. 107 033907 (2010) [3] Liu X M, Ding J, Kakazei G N and Adeyeye A O Appl. Phys. Lett. 103 062401 (2013). (author)