Structural and magnetic studies of Cu-substituted nanocrystalline Ni–Zn ferrites obtained via hexamine–nitrate combustion route

Abstract

Ni sub(0.6-x)Cu sub(x)Zn sub(0.4)Fe sub(2)O sub(4) ferrite compositions with x = 0.1, 0.2, 0.3, 0.5, and 0.6 were synthesized by a hexamine-nitrate combustion route. The phase purity and nanocrystalline nature was confirmed from XRD studies. The structural parameters such as lattice constant, X-ray density, bulk density, and porosity were calculated and compared for the effect of Cu inclusion in Ni–Zn ferrites. The lattice constant, X-ray density, and bulk density increase while the porosity exhibits a decreasing trend with increasing copper content. The FTIR spectra display two characteristic bands in the region 574-54 sup(8) and 421-395 cm sup(-1) assigned to M-O stretching vibrations in tetrahedral and octahedral sites, respectively. The AC susceptibility studies indicate the presence of superparamagnetic as well as single-domain particles and the decrease in Curie temperature with Cu substitution. The saturation magnetization, remanence, and coercivity were found to decrease with increasing Cu concentration and attributed to the lower magnetic moment of Cu ions than Ni ions.