Nanoparticles nickel ferrite of size 6 -8 nm, synthesized by the coprecipitation method with x varying from 0 to 1.0. The powder samples were characterized by XRD, VSM and FTIR. The average crystallite sizes of the particles were determined from X-ray diffraction. X-ray analysis showed that the samples were cubic spinel. The lattice constant (a o ) increased with the increase in zinc substitution. The specific saturation magnetization (M S ) of the particles was measured at room temperature. The magnetic parameter of M S , was found to decrease with the increase in zinc substitution. Fourier transform infrared spectroscopy (FTIR) spectra of the Ni 1-x Zn x Fe 2 O 4 with x = 0, 0.5, 1 in the range 400 -4000 cm -1 were reported. The spinel structure and the crystalline water adsorption of Ni 1-x Zn x Fe 2 O 4 nanoparticles were studied by using FTIR.

Ni 1-x Zn x Fe 2 O 4 (x = 0 to 1) nanoparticles of size less than 9 nm were prepared by a chemical coprecipitation method which could be used for ferrofluid preparation. XRD, VSM and DTA-TG (STA) were used to study the effect of variation in Zn substitution and its influence on particle size, magnetic properties such as M S , H C and Curie temperature, as well as on the water content. ICP was used to estimate Ni, Zn and Fe concentrations. The average crystallite size (D aveXR ) of the particles was found to decrease from 8.95 to 6.92 nm with increasing zinc substitution. The lattice constant (a o ) increased with increasing zinc substitution. The specific saturation magnetization (M S ) of the particles was measured at room temperature. Magnetic parameters such as M S , H c, and M r were found to decrease with increasing zinc substitution. Estimation of the water content, which varies the Zn concentration, plays a vital role for the correct determination of cation contents. The Curie temperature was found to decrease with increasing zinc substitution.