NiO/SiO2 nanostructure and the magnetic moment of NiO nanoparticles

Abstract We report on the synthesis, morphology and magnetic properties of a novel NiO/SiO 2 nanostructure. The NiO/SiO 2 nanostructure was synthesized by a method based on the contribution of sol–gel and combustion processes. X-ray powder diffraction (XRPD) showed the formation of the nanocrystalline NiO phase. Transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) revealed perfectly spherical NiO nanoparticles with diameter of about 5 nm. Amorphous silica shell around the NiO nanoparticles was also observed by HRTEM showing NiO/SiO 2 core–shell nanostructure. Magnetic measurements show hysteretic behavior at 2 K with coercivity H C = 700 Oe, remanent magnetization M r = 3.9 emu/g, saturation magnetization M S = 28.2 emu/g and huge magnetic moment m p ≈ 1300 μ B of the nanoparticles.