NiO/SiO2 nanostructure and the magnetic moment of NiO nanoparticles

Abstract

We report on the synthesis, morphology and magnetic properties of a novel NiO/SiO2 nanostructure. The NiO/SiO2 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/SiO2 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) approximate to 1300 mu(B) of the nanoparticles. (C) 2010 Elsevier B.V. All rights reserved.