Pb(Mg1/3Nb2/3)O3 (PMN) Relaxor: Dipole Glass or Nano-Domain Ferroelectric ?

TL;DR

This study demonstrates that the prototypical relaxor PMN is essentially ferroelectric below 225 K, with its complex dielectric behavior arising from domain reorientation and multiscale inhomogeneities, including nano- and micro-domains.

Contribution

It provides a comprehensive analysis combining polarization, Raman, TEM, and literature data to clarify the ferroelectric nature of PMN and the role of domain structures in relaxor behavior.

Findings

PMN is essentially ferroelectric below 225 K.

Dielectric anomalies are due to domain reorientation.

Multiscale domain inhomogeneities influence relaxor phenomena.

Abstract

Combining our comprehensive investigations of polarization evolution, soft-mode by Raman scattering and microstructure by TEM, and the results reported in the literatures, we show that prototypical relaxor Pb(Mg1/3Nb2/3)O3 (PMN) is essentially ferroelectric for T<Tc~225 K. Its anomalous dielectric behavior over a broad temperature range results from the reorientation of domains in the crystal. A physic picture of the structure evolution in relaxor is also revealed. It is found that nanometric ferroelectric domains (gennerally called as polar nano-region (PNR)) interact cooperatively to form micrometric domain. Such multiscale inhomogeneities of domain structure in addition to the well-known inhomogeneities of chemical composition and local symmetry are considered to play a crucial role in producing the enigmatic phenomena in relaxor system.