Compositional,temperature and frequency dependence of dielectric behaviour of zinc substituted copper- ferri-chromates

The comprehensive study on compositional, temperature and frequency dependent dielectric properties of Zn_xCu_1−xFeCrO₄ (x = 0.0, 0.2, 0.4 and 0.6 ) was carried out by means of a. c. resistivity (ρ_ac), dielectric constant (ε′) and loss tangent (tanδ) measurements in the frequency range from 100 Hz to 1 MHz at different temperatures ranging from 40 °C to 500 °C. An abnormal behaviour of ε′ as a function of temperature is explained on the basis of contribution of two types of charge carriers in the polarization process. It is found that magnetic ordering does not have marked influence on the dielectric properties. The probable conduction mechanism in the present system is due to electron transition such as Fe²⁺ Fe³⁺ and Cu²⁺ Cu¹⁺ rather than ionization or polaron hopping mechanism.