Room-temperature ferromagnetism enhancement in Fe-doped VSe2 nanosheets synthesized by a chemical method

Two-dimensional (2D) few-layer VSe2, V1−xFexSe2 nanosheets have been synthesized by a high-temperature organic solution-phase method. The thickness of VSe2 nanosheets can be tuned from 12 to 5 layers by decreasing the precursor concentrations. The few-layer VSe2 nanosheets show the room-temperature ferromagnetism. The coercivity and magnetization reach 0.024 T and 0.036 mA·m2·g−1 at room temperature. The charge-density wave behavior is also confirmed in VSe2 by the hysteresis loops and zero-field-cooling curve. V1−xFexSe2 nanosheets can be obtained by doping Fe(acac)3 in the reaction process. The room-temperature coercivity and magnetization of V0.8Fe0.2Se2 nanosheets are 5 times higher than those of the pure VSe2 nanosheets without destroying the structures. The enhancement of magnetization is due to the coupling interaction of 3d orbits between V and Fe atoms. Higher Fe concentration is beneficial to improve the coercivity, which is attributed to the formation of the second phase Fe3Se4. This simple chemical preparation method can be extended to prepare the other 2D materials.