Copper substitution effect on the structural properties of nickel ferrites

Nickel–copper ferrites with the general formula Ni1−x Cux Fe2 O4 (0≤x≤1) were studied using X-ray diffraction and infrared absorption spectroscopy. XRD diffraction patterns show that all samples have a pure single-phase cubic spinel structure over the whole composition range. From these patterns, the lattice parameters, crystallite size and porosity of these samples have been calculated and compared with those predicted theoretically. Most of the values were found to increase with increasing Cu content. Far infrared absorption spectra show high and low absorption bands corresponding to tetrahedral and octahedral sites confirming the single phase spinnel structure. The calculated force constants, Kt and Ko for the two sites are found to increase with increasing Cu content and their relative values are consistent with bond length magnitudes at tetrahedral and octahedral sites.