Synthesis and magnetic properties of gamma-Fe2O3/SiO2 core-shell nanoparticles under hydrothermal conditions

摘要

gamma-Fe2O3/SiO2 core-shell nanoparticles with an average diameter by about 30 nm were synthesized by hydrothermal reaction of Tetraethoxysilane and Fe(NO3)(3)(center dot)9H(2)O as precursors. The phase component, structure and magnetic properties of the nanoparticles were characterized by X-ray diffraction, transmission electron microscopy and magnetic measurements. The results show that the uniform gamma-Fe2O3 nanoparticles were capped with an amorphous SiO2 thin shell by about 5 nm in the thickness. The effect of hydrothermal temperature and growth mechanism were discussed towards the end of this paper. The magnetic property of nanoparticles was also discussed.