Impedance spectroscopic studies on NiFe2O4 with different morphologies: Microstructure vs. dielectric properties

NiFe2O4 powders were prepared by combustion synthesis, polyol-mediated and sol-gel methods. Morphological characterization of sintered disks was carried out using scanning electron microscopy (SEM). Dielectric properties of NiFe2O4 synthesized by different routes were investigated over the frequency range of 100 Hz-5 MHz at room temperature. A difference in dielectric constant (εr) and dissipation factor (tan δ) of NiFe2O4 samples obtained by different synthesis methods has been observed. The observed dissimilarity in the behavior originates from the variation in the microstructure of the samples that is evident in the Cole-Cole plot results.