Relaxation and freezing of dielectric response in relaxor Pb(Mg1/3Nb2/3)O3 crystal

TL;DR

This study investigates the dielectric behavior of the relaxor ferroelectric Pb(Mg1/3Nb2/3)O3 crystal across a wide frequency range, revealing two relaxation processes that freeze at low temperatures, indicating glassy dipole dynamics.

Contribution

It provides a detailed analysis of the relaxation mechanisms in Pb(Mg1/3Nb2/3)O3, including their temperature dependence and freezing behavior, which was not previously characterized in such detail.

Findings

Two overlapping relaxation processes obeying Kohlrausch-Williams-Watts and Curievon Schweidler laws.

Relaxation parameters tend to zero at 211 K following Vogel-Fulcher law.

Evidence of glassy freezing of dipole dynamics in the relaxor crystal.

Abstract

Dielectric investigations of the relaxor ferroelectric Pb(Mg1/3Nb2/3)O3 crystal were performed in the frequency domain at 10^(-4) 10^5 Hz. In the ergodic relaxor phase two overlapping relaxation processes obeying the Kohlrausch-Williams-Watts law, exp[-(t/tau)^beta], and the Curievon Schweidler law, t^(-n), respectively, were found and parameterized. The values of beta, n and 1/tau tend to zero at 211 K following the Vogel-Fulcher law, pointing to the glassy freezing of the dipole dynamics related to both relaxation processes.