magnetite (fe 3 o 4  and nio) nanoparticles with a size range of 40–60 nm were prepared by sol-gel technique in nano and micro reverse micelles (water- in-oil). the surface properties, size, morphology and crystallographic structure of fe 3 o 4 and nio particles are characterized by means of x-ray diffraction, transmission electron microscope and scanning electron microscope which will give muc...