Structural, Optical and Magnetic Properties of Nickel–Silica Nanocomposite Prepared by a Sol–Gel Route

Abstract

Nickel-silica nanocomposites have been synthesized by a sol–gel method using dextrose (C6H12O6) as the reducing agent. The dried gel is heat treated at 850 and 900 °C for 30 min in an inert atmosphere by N2 purging to obtain the composite material. The samples have been characterized by powder X-ray diffraction, field emission scanning electron microscopy, atomic force microscopy, transmission electron microscopy and selected area electron diffraction. Pure polycrystalline nickel granular particle has been found to form with face-centered cubic structure and is entrapped in amorphous silica matrix with particle sizes in between 10 and 30 nm and is almost spherical in shape. The strong ferromagnetic nature of Ni–SiO2 composite became evident from the M-H curve which is quite different from the bulk nickel. The band gap of the synthesized Ni–SiO2 nanocomposite is found to be 2.35 eV. The reported sol–gel technique is a convenient and effective method to prepare high purity nanopowders with uniform size distribution.