  The determination of Lande's g-factor and the damping constant is central to
extracting crucial information about the spin-spin and spin-orbit interactions
in magnetically ordered systems. In insulating compounds based on 3d elements,
the spin-orbit interaction can be effectively probed by investigating the
ground state of the corresponding free 3d ion within the crystalline
environment. For metallic systems, the problem is non-trivial because of
additional band structure effects. Here, we investigate the anisotropic
magnetization dynamics in bulk single crystalline Fe5GeTe2, a van der Waals 2D
itinerant ferromagnet at room temperature, using broadband ferromagnetic
resonance spectroscopy. Strikingly, contrary to the results of ab-initio
calculations, we do not observe any intrinsic anisotropy of magnetization
damping close to room temperature, suggesting diminished role of spin-orbit
interaction. However, there is a sizable anisotropy in the Lande's g factor
near room temperature which is attributed to anisotropic critical spin
fluctuations.
