Electrical and magnetic characterization of nanocrystalline Ni–Zn ferrite synthesis by co-precipitation route

Abstract

Nickel zinc ferrite nanoparticles Ni 1− x Zn x Fe 2O 4 ( x=0.25, 0.5, 0.75, 1) have been prepared by the chemical co-precipitation route. The samples were characterized by X-ray diffraction (XRD), DC electrical resistivity, dielectric constant and low field AC magnetic susceptibility. The powder XRD patterns confirm the single phase spinel structure for the synthesized materials. The crystallite size was calculated from the most intense peak (3 1 1) using the Scherrer formula. The crystallite size was found within the range 7–15 nm. The crystallite size decreases with increasing zinc concentration. DC electrical resistivity decreases as the temperature increases indicating that the samples have semiconductor like behavior. DC electrical resistivity of the samples at room temperature was found to vary from 1.67×10 9 to 4×10 9 Ω cm with zinc concentration. The activation energy and drift mobility were calculated from DC electrical resistivity measurements. The dielectric constant for all the compositions has been studied as a function of frequency in the range from 500 Hz to 1 MHz at room temperature. The dielectric constant follows the Maxwell–Wagner interfacial polarization. AC magnetic susceptibility measurements were carried out as a function of temperature to measure the transition temperature, which was found to decrease with zinc concentration. The decrease of transition temperature has been explained by the distribution of cations on A and B sites.