Influence of temperature on the electric, dielectric and AC conductivity properties of nano-crystalline zinc substituted cobalt ferrite synthesized by solution combustion technique

Cobalt–zinc nanoferrites with formulae Co\(_1-x\) Zn\(_x\)Fe\(₂\)O\(₄\), where x = 0.0, 0.1, 0.2 and 0.3, have been synthesized by solution combustion technique. The variation of DC resistivity with temperature shows the semiconducting behavior of all nanoferrites. The dielectric properties such as dielectric constant (\(\varepsilon \)’) and dielectric loss tangent (tan \(\delta )\) are investigated as a function of temperature and frequency. Dielectric constant and loss tangent are found to be increasing with an increase in temperature while with an increase in frequency both, \(\varepsilon \)’ and tan \(\delta \), are found to be decreasing. The dielectric properties have been explained on the basis of space charge polarization according to Maxwell–Wagner’s two-layer model and the hopping of charge between Fe\(²⁺\) and Fe\(³⁺\). Further, a very high value of dielectric constant and a low value of tan \(\delta \) are the prime achievements of the present work. The AC electrical conductivity (\(\sigma _\mathrm{AC})\) is studied as a function of temperature as well as frequency and \(\sigma _\mathrm{AC}\) is observed to be increasing with the increase in temperature and frequency.