Above-Room-Temperature Strong Ferromagnetism in 2D MnB Nanosheet

Two-dimensional (2D) room-temperature (RT) ferromagnetic materials have amassed considerable interest in the field of fundamental physics for applications in next-generation spintronic devices owing to their physical properties. However, realizing strong RT ferromagnetism and a high Curie temperature (T_C) in these 2D magnetic materials remains challenging. Herein, we develop a 2D MnB nanosheet for known 2D ferromagnets that demonstrates strong RT ferromagnetism and a record-high above-RT T_C of ∼585.9 K. Through magnetic force microscopy, clear evidence of ferromagnetic behavior is observed at room temperature. Structural characterization and density functional theory calculations further reveal that (i) after exfoliation of bulk, -OH functional groups were introduced in addition to Mn-B bonds being formed, which increases MnB nanosheet T_C to 585.9 K and (ii) the d³↑ spin configuration of Mn mainly contributed to the magnetic moment of MnB, and the hybridization between the d (d) and d orbitals of the Mn atom provides a large contribution to magnetic anisotropy, which stabilizes the magnetic property of MnB. Our findings establish a strong experimental foundation for 2D MnB nanosheets as ideal materials for the construction of spintronic devices.