Low-temperature phase transformations of PZT in the morphotropic phase-boundary region

TL;DR

This study investigates low-temperature phase transitions in PZT near the morphotropic phase boundary using spectroscopy, revealing first-order tetragonal-to-monoclinic transformations and octahedral rotations, with implications for material properties.

Contribution

It provides new experimental insights into phase transitions in PZT near the morphotropic boundary, confirming theoretical predictions and detailing the nature of low-temperature transformations.

Findings

First-order tetragonal-to-monoclinic transition causes significant elastic softening.

Octahedral rotations occur below 200 K within the tetragonal phase.

Transitions are observable in dielectric and anelastic measurements.

Abstract

We present anelastic and dielectric spectroscopy measurements of PbZr(1-x)Ti(x)O(3) with 0.455 < x < 0.53, which provide new information on the low temperature phase transitions. The tetragonal-to-monoclinic transformation is first-order for x < 0.48 and causes a softening of the polycrystal Young's modulus whose amplitude may exceed the one at the cubic-to-tetragonal transformation; this is explainable in terms of linear coupling between shear strain components and tilting angle of polarization in the monoclinic phase. The transition involving rotations of the octahedra below 200 K is visible both in the dielectric and anelastic losses, and it extends within the tetragonal phase, as predicted by recent first-principle calculations.