The core-shell structure Fe3O4@C magnetic nanoparticles were synthesized with superparamagnetic Fe3O4 nanosphere as a
magnetic core, glucose, phenolic and soluble starch resin as carbon source via a solvothermal method. The structure of Fe3O4@C
magnetic nanoparticles was characterizes using TEM, XRD and VSM. The effects of preparation conditions in the structure of
the Fe3O4@C magnetic nanoparticles were taken out. The results indicate: Fe3O4@Cg magnetic nano particle with glucose as
carbon source has 250 nm diameter and 8-10 nm thickness of carbon shell; Fe3O4@Cp has 160 nm diameter and 6-8 nm carbon
shell with phenolic as carbon source; when the carbon source changes to soluble starch, the magnetic nano particle prepared with
150 nm diameter and 15-20 nm carbon shell. Through XRD, the magnetic nano particles Fe3O4@C synthesized with three kinds
of carbon sources have amorphous carbon diffraction peak except for all the characteristic peaks of Fe3O4. The magnetism of
Fe3O4@Cg, Fe3O4@Cp and Fe3O4@Cs are 74.1 emu/g, 48.7 emu/g and 41.3 emu/g, respectively.