Sub-THz High Spin Precession Frequency in van der Waals Ferromagnet FeGaTe.

The 2D magnet FeGaTe has received considerable attention for its high Curie temperature (), robust intrinsic ferromagnetism, and significant perpendicular magnetic anisotropy (PMA). In this study, the dynamic magnetic properties of FeGaTe are systematically investigated using an all-optical pump-probe technique. We find that the spin precession frequency () is as high as 351.2 GHz at = 10 K under a field of = 70 kOe. However, it decreases to 242.8 GHz at 300 K, mainly due to the reduced effective PMA field (). The Gilbert damping factor (α) is modest, which increases from 0.039 (10 K) to 0.075 (300 K) owing to the enhanced scattering rate. Interestingly, when FeGaTe is coupled with 2 nm of Co, the , , and α just decrease slightly, highlighting the dominant influence of FeGaTe. These findings substantially deepen our understanding of FeGaTe, promoting the development of spintronic devices based on advanced 2D magnetic materials.