Dielectric behavior of Zr4+doped MgFe2O4 spinel ferrite synthesized by solid-state reaction method

A series of Zr4+ doped MgFe2O4 samples (Mg1-xFe2O4: xZr (x = 0, 0.25, 0.5, 0.75, 1, 1.25 and 1.5 mol %) were synthesized using the solid-state reaction method. The XRD analysis confirms that the prepared sample has single phase cubic spinel structure with Fd-3m space group. The average crystallite size of the sample has been found to be 28.2 nm. The SEM image shows irregular cubical grains with agglomerated morphology, while the EDX spectrum confirms the presence of all essential elements. The dielectric constant and dielectric loss decrease at higher frequencies due to decreased polarization. The Complex impedance spectroscopy confirmed the existence of electrical relaxation phenomenon, and the Cole-Cole plot indicates the grain boundary contribution. The AC conductivity value remains constant at a low frequency range but shifts towards the higher value in the higher frequency region. The calculated activation energy values range from 0.27 to 0.55 eV.