Thermogravimetric and Magnetic Properties of Ni 1-X Zn x Fe 2 O 4 Nanoparticles Synthesized by Coprecipitation

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. have reported the de- pendence on cation distribution of crystallite size, lattice parameter and magnetic properties in nanosized Mn-Zn ferrite for different degrees of Zn substitution prepared by hydrothermal precipitation method. The use of Mn-Zn ferrite for the preparation of temperature sensitive magnetic fluids by the coprecipitation method has already been studied 4-6 . Ni 0.2 Zn 0.8 Fe 2 O 4 fine particles have been prepared by