Anisotropic spin dynamics in the intrinsic ferromagnet <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msub> <mml:mi>Fe</mml:mi> <mml:mn>3</mml:mn> </mml:msub> <mml:msub> <mml:mrow> <mml:mi>Ga</mml:mi> <mml:mi>Te</mml:

The van der Waals material ${\mathrm{Fe}}_{3}{\mathrm{Ga}\mathrm{Te}}_{2}$ (F3GaT) is a promising candidate for spintronic applications due to its high Curie temperature (${T}_{C}$) and strong perpendicular magnetic anisotropy (PMA). In this study, we thoroughly investigate the spin dynamics of F3GaT single crystals using electron spin resonance (ESR) techniques. The temperature-dependent ESR spectra reveal a significant range of magnetic fluctuations from ${T}_{C}\ensuremath{\sim}362$ K to ${T}^{\phantom{\rule{0.1em}{0ex}}\ensuremath{\ast}}\ensuremath{\sim}410$ K. Furthermore, the angle-dependent resonance field ${H}_{r}$ of the ESR demonstrates strong PMA, with the maximum ${H}_{r}$ in the $ab$ plane indicating the hard direction, while the minimum along the $c$ axis suggesting the easy orientation. Meanwhile, the angle-dependent ESR spectra reveal distinct anisotropic spin couplings. For $H//ab$, spin-spin relaxation predominates between ${T}_{C}$ and ${T}^{\phantom{\rule{0.1em}{0ex}}\ensuremath{\ast}}$, whereas spin-lattice relaxation prevails above ${T}^{\phantom{\rule{0.1em}{0ex}}\ensuremath{\ast}}$. In contrast, for $H//c$, the Korringa mechanism, arising from the interaction between localized spins and conduction electrons, dominates above ${T}_{C}$. Our findings elucidate the anisotropic spin dynamics in F3GaT, providing insights into its potential application in microwave-based spintronic devices.