Giant Magneto-Optical Effect in van der Waals Room-Temperature Ferromagnet Fe₃GaTe₂

Abstract The discovery of ferromagnetic two-dimensional (2D) van der Waals (vdWs) materials provides an opportunity to explore intriguing physics and to develop innovative spin electronic devices. However, the main challenge for practical applications of vdWs ferromagnetic crystals lies in the weak intrinsic ferromagnetism and small perpendicular magnetic anisotropy (PMA) above room temperature. Here, we report the intrinsic vdWs ferromagnetic crystal Fe₃GaTe₂, synthesized by the self-flux method, exhibiting a Curie temperature (T_C) of 370 K, a high saturation magnetization of 33.47 emu/g, and a large PMA energy density of approximately 4.17 × 10⁵ J/m³. Furthermore, the magneto-optical effect is systematically investigated in Fe₃GaTe₂. The doubly degenerateE_2g (Γ) mode reverses the helicity of incident photons, indicating the existence of pseudoangular-momentum (PAM) and chirality. Meanwhile, the non-degenerate non-chiralA_1g(Γ) phonon exhibits a significant magneto-Raman effect under an external out-of-plane magnetic field. These results lay the groundwork for studying phonon chirality and magneto-optical phenomena in 2D magnetic materials, providing the feasibility for further fundamental research and applications in spintronic devices.