Strong Room-Temperature Ferromagnetism in Ultrathin NiOOH Nanosheets through Surfactant Manipulation

Two-dimensional (2D) ferromagnetic (FM) materials with nanoscale thickness and spontaneous net magnetization have emerged as a promising class of functional materials for applications in next-generation spintronics, quantum processing, and data storage devices. However, most 2D materials exhibit weak FM even at low temperatures, limiting their potential applications in many technological fields. The fabrication of strong room-temperature FM 2D materials is highly desirable for the development of practical applications. Here, we demonstrate an ionic layer epitaxy strategy to synthesize few-layered NiOOH nanosheets with strong room-temperature FM and a saturation magnetization up to 409.86 emu cm^-3 at 300 K. The results are consistent with the ab initio predictions of a stable FM NiOOH nanolayer structure with an FM configuration. The FM strength of the NiOOH nanosheets can be tuned by controlling the surfactant monolayer density and annealing. This work offers a promising strategy for achieving strong high-temperature FM in 2D materials for spintronic applications.