Ultrathin nanosheets of feroxyhyte: a new two-dimensional material with robust ferromagnetic behavior

Abstract

Two dimensional (2D) nanosheets have shown great potential for their applications in next-generation nanoelectronic devices. However, developing 2D nanosheets for next-generation spintronics has been blocked due to their lack of robust intrinsic ferromagnetic behavior. Here, we highlight the robust ferromagnetic behavior in a 2D inorganic graphene-like structure. δ-FeOOH ultrathin nanosheets, as a new 2D material, exhibit an unprecedented high saturation magnetization value of 7.5 emu g⁻¹ at room temperature, which is the highest value among graphene and graphene analogues. Atomic-scale topochemical transformation ensures the formation of 2D δ-FeOOH ultrathin nanosheets from intermediate Fe(OH)₂ nanosheets. Moreover, the δ-FeOOH ultrathin nanosheet is found to be a semiconductor with a direct band gap of 2.2 eV. Owing to the advantages of robust ferromagnetism in semiconductors, δ-FeOOH ultrathin nanosheets are promising candidates for the construction of next-generation spintronics.