Dual structures in PZN-xPT ferroelectric relaxors

TL;DR

This study reveals the presence of distinct outer-layer structures with greater rhombohedral distortions in PZN-xPT ferroelectric relaxor crystals, with structural differences varying with composition and depth.

Contribution

It demonstrates the existence of dual structures in PZN-xPT crystals, showing that outer-layers differ structurally from the interior and that distortions increase with PT content.

Findings

Outer-layers are 10-50 μm thick with greater rhombohedral distortions.

Structural differences between outer-layers and interior depend on incident photon energy.

Rhombohedral distortions increase with higher PbTiO3 content.

Abstract

We performed x-ray diffraction studies on a series of (1-$x$)Pb(Zn$_{1/3}$Nb$_{2/3}$)O$_3$-$x$PbTiO$_3$ (PZN-$x$PT) single crystals with different incident photon energies, and therefore different penetration depths. Our results show that outer-layers of $\sim 10$ to 50 $\mu$m thick are present in all samples. The structure of those outer-layers is different from that of the inside of the crystals, by having much greater (rhombohedral) distortions. With increasing $x$, rhombohedral-type lattice distortions develop, both in the outer-layer and the inside.