Room-temperature ferromagnetic CoSe2 nanoplates synthesized by chemical vapor deposition.

Among novel two-dimensional (2D) materials, transition metal dichalcogenides (TMDs) with 3d magnetic elements have been extensively researched owing to their unique magnetic, electric, and photoelectric properties. As an important member of TMDs, CoSe2 is an interesting material with controversial magnetic properties, hitherto there are few reports related to the magnetism of CoSe2 materials. Here, we report the synthesis of CoSe2 nanoplates on Al2O3 substrates by chemical vapor deposition (CVD). The CVD-grown CoSe2 nanoplates exhibit three typical morphologies (regular hexagonal, hexagonal, and pentagonal shapes) and their lateral sizes and thickness of CoSe2 nanoplates can reach up to hundreds of microns and several hundred nanometers, respectively. The electric-transport measurement shows a metallic feature of CoSe2 nanoplates. Furthermore, the slanted hysteresis loop and nonzero remnant magnetization of the CoSe2 nanoplates confirm the ferromagnetism in the temperature range of 5 to 400 K. This work provides a novel platform for designing CoSe2-based spintronic devices and studying related magnetic mechanisms.