Sub-THz High Spin Precession Frequency in van der Waals Ferromagnet Fe 3 GaTe 2 .

The 2D magnet Fe ₃ GaTe ₂ has received considerable attention for its high Curie temperature ( T _C ), robust intrinsic ferromagnetism, and significant perpendicular magnetic anisotropy (PMA). In this study, the dynamic magnetic properties of Fe ₃ GaTe ₂ are systematically investigated using an all-optical pump-probe technique. We find that the spin precession frequency ( f ) is as high as 351.2 GHz at T = 10 K under a field of H = 70 kOe. However, it decreases to 242.8 GHz at 300 K, mainly due to the reduced effective PMA field ( H _keff ). 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 Fe ₃ GaTe ₂ is coupled with 2 nm of Co, the H _keff , f , and α just decrease slightly, highlighting the dominant influence of Fe ₃ GaTe ₂ . These findings substantially deepen our understanding of Fe ₃ GaTe ₂ , promoting the development of spintronic devices based on advanced 2D magnetic materials.