Synthesis and characterization of cobalt nanoparticles

Well-dispersed Co nanoparticles were synthesized successfully by using simple solution reduction method. In this reaction system, PVP serves as surface modified reagent, and hydrazine plays as reduced reagent. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and superconducting quantum interference device (SQUID) system. The results show that the product was h-Co nanostructure. The saturation magnetization determined at high field is about 153 emu/g, which is roughly 1.62 μB/Co. This amounts to 95% of the bulk value, -1.72 μB/Co, which has a coercivity of -65 Oe at 300 K. The advantages of the method are mild, low-cost, well-repeatable, high-yield and easily controllable.