Dielectric and magnetic properties of high porous Gd+3 substituted nickel zinc ferrite nanoparticles

We report on the synthesis and characterization of Gd+3 substituted Ni-Zn nano ferrites (Ni0.6Zn0.4 GdyFe2-yO4; y = 0, 0.1, 0.15, and 0.2) via low-temperature citrate gel auto-combustion method. The structural studies carried out by PXRD revealed a decrease in the lattice constant and crystallite sizes upon Gd+3 substitution with low concentration but increases with further increase in the concentration. We found the porosity of the samples decreases linearly as a function of Gd+3 concentrations. Well defined spherical grains with a higher porosity of the samples are confirmed by FESEM analysis. With an increase in the Gd+3 concentrations, the dielectric constant increased up to five folds in the magnitude. The contribution of grain boundary and other factors on the electrical properties was revealed by impedance spectroscopy. The reduced remanence ratios showed in the magnetic hysteresis imply the charge in change in the magnetic properties upon the substitution of Gd+3 in the prepared ferrite.