A planar Fe₂B monolayer with room temperature antiferromagnetism

The design of two-dimensional materials with antiferromagnetic properties above room temperature is crucial for the preparation of next-generation nano-scale spintronic devices. Based on first-principles calculation combined swarm-intelligence structural prediction methods, we propose a novel planar Fe₂B monolayer material. In this structure, Fe atoms form a graphene-like honeycomb pattern sublattice, with B atoms occupying the centers of Fe₆ hexagons in a hexagonal lattice. The Fe₂B monolayer is predicted to be kinetically, thermally, thermodynamically, and mechanically stable. Notably, it exhibits strong intrinsic antiferromagnetism arising from both superexchange and direct exchange interactions between Fe atoms. Monte Carlo simulations estimate a high Néel temperature of 608 K, indicating robust magnetic order well above room temperature. Interestingly, its above room-temperature antiferromagnetism and easy axis of magnetization can be well preserved under biaxial strains from -5% to +5%. The Fe₂B monolayer is a promising candidate material for high-performance, strain-tolerant spintronic devices and offers valuable guidance for the research of nanoscale magnetic materials.