Top‐Down Preparation and Magnetic Properties of MnSe₂ Nanoparticles

Nanostructured transition metal dichalcogenide MnSe 2 has attracted much attention due to its fascinating magnetic properties. In this article, a series of MnSe 2 nanoparticles with different particle sizes are successfully prepared by a facile top‐down method of solid‐state reaction combined with ball milling, and the effects of ball milling on the phase composition, microstructure and magnetic properties of the MnSe 2 are systematically studied. The results show that pure MnSe 2 microparticles are obtained by the solid‐state reaction, however, partial MnSe 2 is decomposed after ball milling for 16 h. The average particle size of the MnSe 2 gradually decreases with the increase of milling time. MnSe 2 nanoparticles with average particle size approximately 65 nm are obtained after milling for 40 h. After milling, the antiferromagnetic MnSe 2 nanoparticles exhibit weak ferromagnetic characteristics due to the surface effect and the microstrain induced by ball milling. The residual magnetization ( M r ) and coercivity ( H c ) of the sample gradually increase as the particle size decreases. The M r and H c of the sample milled for 40 h reach 70.13 × 10 −4 emu g −1 and 67.47 Oe, respectively.