Relaxation dynamics of the conductive processes forPbNb2O6 ferroelectric ceramics in the frequency and time domain

Abstract

The relaxation dynamics of the conductive process present inPbNb2O6 piezoelectric ceramics was investigated. A relaxation function in the time domain,Φ(t), was found from the frequency dependence of the dielectric modulus (imaginary component,M′′) by using a relaxation function in the frequency domain,F*(ω). The bestrelaxation function, F*(ω), was found to be a Cole–Cole distribution function, in which relaxation characteristic parameters, suchas α and τCC, are involved. On the other hand, the relaxation function,Φ(t), obtained by the time domain method, was found to be a Kohlrausch–Williams–Watts (KWW)function type. The thermal evolution of the characteristics parameters of the KWW function(β and τ*) was analysed. The values of the activation energy(Ea), obtained in the whole investigated temperature interval, suggest the existence of arelaxation mechanism (a conductive process), which may be interpreted by an ion hoppingbetween neighbouring sites within the crystalline lattice. The results are corroborated withthe formalism of the AC conductivity.