Fe₅₋ₓGeTe₂

An Fe-rich member of the Fe_nGeTe₂ family with variable Fe occupancy, space group R3̄m. It hosts two-dimensional ferromagnetism with a near-room-temperature Curie temperature (~270–310 K), higher than Fe₃GeTe₂, along with complex, site-dependent Fe ordering and spin reorientation transitions. Its high T_c retained at few-layer thickness and tunable magnetic anisotropy make Fe₅₋ₓGeTe₂ an important platform for room-temperature van der Waals magnetism and spintronic heterostructures.