Origin of high piezoelectric response of Pb(Zr_xTi_1-x)O_3 at the morphotropic phase boundary: Role of elastic instability

TL;DR

This study investigates the structural and elastic properties of PZT near the morphotropic phase boundary, revealing that elastic softening in the tetragonal phase enhances its piezoelectric response, which is higher than in the monoclinic phase.

Contribution

It provides new insights into the role of elastic instability in the high piezoelectric response of PZT at the morphotropic phase boundary.

Findings

Intrinsic piezoelectric response is higher in the tetragonal phase than in the monoclinic phase.

High piezoelectric response correlates with elastic modulus softening near the phase boundary.

Elastic instability plays a key role in enhancing piezoelectric properties of PZT.

Abstract

Temperature dependent structural changes in a nearly pure monoclinic phase composition (x=0.525) of Pb(Zr_xTi_1-x)O_3 (PZT) have been investigated using Rietveld analysis of high-resolution synchrotron powder x-ray diffraction data and correlated with changes in the dielectric constant and planar electromechanical coupling coefficient. Our results show that the intrinsic piezoelectric response of the tetragonal phase of PZT is higher than that of the monoclinic phase. It is also shown that the high piezoelectric response of PZT may be linked with an anomalous softening of the elastic modulus (1/S_11) of the tetragonal compositions closest to the morphotropic phase boundary.