Abstract
This paper examines the effect of copper substitution on the structural and magnetic properties in nanocrystalline ferrite series of nominal composition; Ni0.7-xCuxZnO3Fe2O4 (where x=0.1-0.6) synthesized by a simple method using metal nitrates and freshly extracted egg-white. X-ray diffraction measurements (XRD) confirmed the formation of single-phase cubic spinel structure. The average crystallite size was calculated using XRD pattern and confirmed by transmission electron microscope (TEM). The nearly constant lattice parameters obtained with Cu substitution was attributed to the small difference in the ionic radius between Ni2+ and Cu2+ ions. FT-IR spectra showed two absorption bands assigned to the tetrahedral and octahedral complexes. The effect of Cu concentration on the magnetic properties was investigated using vibrating sample magnetometer (VSM) and molar magnetic susceptibility measurements. The decrease in the saturation magnetization and the Curie temperature values with increasing Cu content was explained in terms of the magnetic moments and magnetic exchange interaction existing between the antiparallel uncompensated electron spin of A and B sublattices. The magnetic measurements also proved that the entire preparation method has a great effect on enhancing the magnetic properties of the system. (C) 2009 Elsevier B.V. All rights reserved.