Structural and electrical properties of nanometric Ni-Cu ferrites synthesized by citrate precursor method

Nanometric nickel copper ferrites Ni(1-x)Cu(x)Fe(2)O(4), 0 <= x <= 0.45 were prepared by the citrate precursor method. X-ray diffraction measurements confirm the formation of single phase cubic spinel structure. The lattice parameter (a) is increased with increasing Cu(2+) ion substitution. The crystallite size was calculated from XRD data and compared with that obtained from TEM micrographs. A significant increase in the density is observed with increasing Cu content. The IR absorption spectra were used for the detection and confirmation of the chemical bonds in spinel ferrites. The dielectric constant epsilon' and dielectric loss showed a decrease with increasing frequency for all samples. The decrease in the ac conductivity was ascribed to the increase in hopping length. (C) 2011 Elsevier B.V. All rights reserved.