Magnetic properties of carbon coated Fe, Co and Ni nanoparticles

Carbon coated Fe, Co and Ni nanoparticles (Fe@C, Co@C and Ni@C) have been fabricated by an efficient solid-state route using melamine as carbon source. The structure and morphology of Fe@C, Co@C and Ni@C nanoparticles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). It is shown that the structure and morphology of Fe@C are different from those of Co@C and Ni@C. The crystallinity of carbon in Fe@C, Co@C and Ni@C nanoparticles was examined by Raman spectroscopy. The results indicate that the graphitization degree of carbon decreases in the order Fe@C > Co@C > Ni@C. Additionally, the reactions involved in the syntheses are speculated. The magnetic properties of Fe@C, Co@C and Ni@C nanoparticles were tested by VSM at room temperature. The variations of magnetic properties of Co@C and Ni@C with the increase of reactive temperatures are discussed respectively.

► Fe@C, Co@C and Ni@C nanoparticles have been fabricated by an efficient solid-state route using melamine as carbon source.
► The experimental results show that the structure and morphology of Fe@C are different from those of Co@C and Ni@C.
► It is shown that the graphitization degree of carbon decreases in the order Fe@C > Co@C > Ni@C.
► The variations of magnetic properties of Co@C and Ni@C with the increase of synthesis temperature are discussed respectively.