Structural and complex impedance properties of Zn²⁺ substituted nickel ferrite prepared via low-temperature citrate gel auto-combustion method

We report the productive synthesis of nanocrystalline zinc substituted mixed ferrite (Ni_1−xZn_xFe₂O₄ (0 ≤ x ≤ 1)) particles via low-temperature citrate gel auto-combustion method. The structure and microstructure of the particles, elemental analysis, and complex impedance properties are carried out by PXRD, FESEM, EDS and impedance spectroscopy respectively. The increased lattice parameters with Zn²⁺ concentrations suggest the substitution of Zn²⁺ ions to Ni²⁺. Dielectric constant, dielectric loss and AC conductivity were studied as a function of frequency infer a significant alteration in the dielectric constant, dielectric loss and A.C. conductivity and also showed that zinc substituted ferrites possess low tangent loss (≈ 10⁻²) at high frequencies. Further, the impedance spectroscopic studies reveal that Zn²⁺ substituted (x = 0.2, 0.8 and 1) samples attain non-Debye type dielectric relaxation.