Abstract
Nanoparticles of Zn1-xNixFe2O4 (x = 0.0-1.0 in step of 0.2) ferrites are synthesized by microwave combustion method using glycine as a fuel. The structure, site occupancy and ferrimagnetic behavior have been characterized by X-ray diffraction (XRD), Mossbauer Spectroscopy (MS) and Vibrating Sample Magnetometer (VSM). Special emphasis is given to the information provided by each of these techniques concerning the impact of the site occupancy on the magnetic properties. The results reveal the formation of single phase cubic spinel with crystallite sizes in the range of 30-42 nm. The lattice constants and the lattice strains decrease gradually with increasing Ni-content. Two well-defined Mossbauer sextets in the spectra at 78 K belong to octahedral [B] and tetrahedral (A) sites, respectively, confirming the formation of Zn1-xNixFe2O4 spinel. The isomer shift (delta(Fe)) values were assigned to Fe3+ ions distributed in both A and B sites. The quadrupole splitting (Delta) values showed also that the orientation of the magnetic hyperfine field (H-int) with respect to the principle axes of the electric field gradient (EFG) is random. The nanosize samples In the presence of an externally applied magnetic field prepared exhibit the hysteresis loops of the ferrimagnetic nature. The value of saturation magnetization increases with introducing Ni up to x = 0.8 and then it decreases. The magnetic data parameters of this structure are discussed as a function of the content of Ni ions.