Stability of Glassy and Ferroelectric States in the Relaxors PbMg1/3Nb2/3O3 and PbMg1/3Nb2/3O3-12% PbTiO3

TL;DR

This study investigates the stability of glassy and ferroelectric states in relaxor materials PMN and PMN-PT, revealing that PMN-PT tends toward ferroelectric order while PMN remains glassy, based on aging and thermal depolarization experiments.

Contribution

It provides new insights into the thermodynamic stability of glassy versus ferroelectric phases in relaxor materials through aging and polarization measurements.

Findings

PMN-PT spontaneously develops long-range ferroelectric order.

PMN remains in a glassy, non-ferroelectric state.

Thermal depolarization shows multiple broad peaks indicating complex phase behavior.

Abstract

The stability of the disordered glassy phase in the relaxors PbMg1/3Nb2/3O3 and (PbMg1/3Nb2/3O3)0.88(PbTiO3)0.12, called PMN and PMN-PT, was investigated by preparing partially polarized samples and allowing them to age at zero field in the temperature range for which the phase is history-dependent. The PMN-PT polarization would spontaneously increase until long-range order formed, first appearing as giant polarization noise. Thus the thermodynamically stable phase in PMN-PT appears to be ferroelectric. In contrast, a PMN sample lacking the sharp first-order field-driven transition found in some other samples spontaneously depolarized, consistent with its glassy state being thermodynamically stable. Detailed thermal depolarization results in PMN show two distinct broad peaks as well as a small fraction of material with a distribution of abrupt melting transitions.