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

Nanometric nickel copper ferrites Ni1-xCuxFe2O4, 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 Cu2+ 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 ε' 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. - Highlights: → Ni-Cu ferrite was successfully prepared using citrate auto combustion method. → The lattice parameter and the density increased with increasing Cu2+ content. → We suggest the use of Ni ferrite with large Cu2+ content in electrical devices.