Effect of Zn doping on temperature and frequency dependence of dielectric permittivity and dielectric relaxation for synthesized tetragonal copper–gallium ferrite

Abstract

CuFe 2O 4 and Cu 1− x Zn x Ga 0.3Fe 1.7O 4 with (0.0 ≤ x ≤ 0.5) are synthesized. Crystallographic phase transformation from tetragonal-to-cubic is occurred at x = 0.1. Dielectric permittivities ( ɛ′ and ɛ′′) and dielectric loss tangent (tan δ) are studied for the prepared samples from room temperature up to 700 K in the frequency range (10 2–10 5 Hz). The relation of tan δ with frequency at different temperatures shows relaxation spectra where the relaxation time and the maximum frequency of the hopping process are determined. Dielectric anomaly at the transition temperature T c is pronounced in the relation of dielectric permittivity with temperature. The determined T c is found to decrease linearly with increasing Zn concentration. The variation of ( ɛ′, ɛ′′ and tan δ) with frequency and temperature displayed a strong dependence on both of gallium and zinc concentrations. Obtained results are explained based on the cation–anion–cation and cation–cation interactions over the octahedral site in the spinel structure.