Nanoparticles of undoped and copper doped with Fe3
O4 of three concentrations (0.5, 1.0 and 1.5) are synthesized by
sonochemical method. Structural, optical and morphological properties of these compounds were studied. Fe2+/Fe3+
ratio is found to be 2.36. Crystalline structure, lattice parameters, surface morphologies, direct and indirect band gap
energies of the synthesized compounds were estimated and the results are discussed in detail. The XDR analysis indicates
the Cu doped Fe3
O4
nanoparticles have higher crystallinity than undoped samples. Average crystallite size is found
to increase as Cu concentration increased. The FTIR results are proven by the presence of mixed magnetite-hematite
nanostructures and it is complement to the XRD results. The presence of spherical, polygonal and agglomeration forms
of the particles are visually seen in the SEM images. Direct and indirect band gap energy is found to be decreased as the
copper concentration was increased.