Robust ferromagnetism in wafer-scale FeGaTe above room-temperature.

The discovery of ferromagnetism in van der Waals (vdW) materials has enriched the understanding of two-dimensional (2D) magnetic orders and opened new avenues for fundamental physics research and next generation spintronics. However, achieving ferromagnetic order at room temperature, along with strong perpendicular magnetic anisotropy, remains a significant challenge. In this work, we report wafer-scale growth of vdW ferromagnet FeGaTe using molecular beam epitaxy. The epitaxial FeGaTe films exhibit robust ferromagnetism, exemplified by high Curie temperature (T = 420 K) and large perpendicular magnetic anisotropy (PMA) constant K = 6.7 × 10J/m at 300 K for nine-unit-cell film. Notably, the ferromagnetic order is preserved even in the one-unit-cell film with T reaching 345 K, benefiting from the strong PMA (K = 1.8×10J/m at 300 K). In comparison to exfoliated FeGaTe flakes, our epitaxial films with the same thickness show the significant enhancement of T, which could be ascribed to the tensile strain effect from the substrate. The successful realization of wafer-scale ferromagnetic FeGaTe films with T far above room temperature represents a substantial advancement (in some aspects or some fields, e.g. material science), paving the way for the development of 2D magnet-based spintronic devices.