Seeded Vapor Phase Growth of Fe-Intercalated Fe3GeTe2 Nanoplates with Large Coercive Field.

Two-dimensional (2D) magnets provide a versatile platform for exploring emergent quantum phases and developing next-generation spintronic devices. Despite this potential, high-throughput chemical vapor deposition (CVD) of ternary phase 2D magnets remains a significant challenge and is rarely explored. Here, we report a seeded-CVD method to synthesize nanoplates of a 2D magnetic material, Fe3GeTe2 (FGT), with lateral sizes of 10 μm and thicknesses of 20-80 nm. Synthesized nanoplates exhibit high Curie temperature (Tc ∼ 206 K) and large coercive field (∼1 T) based on reflective magnetic circular dichroism (RMCD) measurements. Cross-sectional scanning transmission electron microscopy and multislice electron ptychography directly reveal widespread and 3D-inhomogeneous Fe intercalation within the vdW gaps that is quantified to be Fe3+xGeTe2 with x ≈ 0.4, which resolves the atomic structural origins of the magnetic enhancement. These results enable a scalable route to synthesize 2D ternary magnet Fe3GeTe2 directly for property studies and device integration.