Role of Zinc and Niobium in the Giant Piezoelectric Response of PbZn1/3Nb2/3O3

TL;DR

This study investigates how zinc and niobium ions influence the giant piezoelectric response in PbZn1/3Nb2/3O3, revealing reversible polar shifts and dipole alignments that enhance ferroelectric switching and piezoelectric effects.

Contribution

It provides new insights into the atomic-level mechanisms involving Zn and Nb in PZN's giant piezoelectric response through in situ EXAFS analysis.

Findings

NbO6 dipoles align with electric field directions

Reversible Zn-O polar shifts occur under electric field

Zn shifts contribute to ferroelectric switching and piezoelectricity

Abstract

Relaxor ferroelectric perovskites are highly polarizable and can exhibit giant coupling between elastic strain and an applied electric field. Here, we report an in situ extended X-ray absorption fine structure (EXAFS) study of a PbZn1/3Nb2/3O3 (PZN) single crystal as a function of the electric field. We show that the strong dipoles in the NbO6 octahedra bonds are aligned along the four \textless{} 011 \textgreater{} directions close to the orientation of the electric field, while a small reversible polar shift occurs for Zn in the direction of the electric field, i.e., positive or negative. This reversible Zn-O polar shift is proposed to play an important role in both the "easy" switching of the ferroelectric polarization and the giant piezoelectric effect in PZN.