Abstract
CoxFe(1−x)Fe2O4 (x = 0, 0.25, 0.50, 0.75 and 1 mol) nanoparticles and magnetic fluids less than 50 nm in diameter were prepared by the chemical co-precipitation method. X-ray diffraction and transmission electron microscopy were used to determine the average particle size and morphology of the prepared samples. The laser speckle interferometry technique was used to investigate the effect of the concentrations of CoxFe(1−x)Fe2O4 (x = 0, 0.25, 0.50, 0.75 and 1 mol) magnetic fluids. This was displayed through the variation of the number of moiré fringes obtained due to superposition of identical speckle patterns.