Dielectric response of relaxor ferroelectrics in the time-domain

Abstract

Dielectric response of relaxor ferroelectrics was analyzed in the time-domain by evaluating the relaxation-time (tau) distribution of Pb(Mg1/3Nb2/3)O-3-10 mol % PbTiO3 using the method of Tikhonov regularization. The distribution function g(tau) became exponentially broad and flat as temperature approached a certain critical point (similar to230 K), indicating the advent of the frozen polar domains with infinitely long tau in a matrix of the thermally activated dynamic polar domains. The dielectric response of the high-temperature relaxation part was then separately estimated with the help of the two-states-polarization model. The estimated g(tau) of the relaxation part showed logarithmic Gaussian behavior, which manifested an ergodicity in the thermally activated flips of dynamic polarizations at high temperatures. In contrast to this, a resonance kernel was postulated to describe the dielectric response of the frozen polar domains at lower temperatures. (C) 2003 American Institute of Physics.