Three series of nanocrystalline Ni0.7-xZn0.3MxFe2O4 ferrites (M = Mn2+, Co2+, and Cu2+; x = 0.0, 0.1, 0.3, 0.5, and 0.7) have been synthesized using the citrate method. Several techniques have been used to investigate the influence of the different dopant ions and their doping levels on the structural and magnetic properties of the Ni–Zn ferrites. X-ray diffraction (XRD) analysis confirmed the creation of a single-phase spinel structure. The lattice parameter was found to increase with increasing Mn2+ and Co2+ ion concentrations, but was not altered by adding Cu2+. The density decreased with increasing concentrations of Mn2+ or Co2+, but increased with increasing Cu2+ content. The average particle size estimated from transmission electron microscopy (TEM) images was found to be in the range 21–41 nm, which revealed the manufacture of nanocrystalline ferrites. Two prominent fundamental absorption bands detected in IR spectra between 370 and 570 cm 1 can be ascribed to the intrinsic stretching vibrations of tetrahedral and octahedral complexes.