Structural heterogeneity and diffuse scattering in morphotropic lead zirconate-titanate single crystals

TL;DR

This study uses synchrotron X-ray scattering to reveal that lead zirconate-titanate crystals near the morphotropic phase boundary are structurally inhomogeneous, with diffuse scattering indicating phase inclusions and lattice deformations.

Contribution

It provides direct experimental evidence of structural heterogeneity in PZT near the morphotropic phase boundary using diffuse and inelastic X-ray scattering.

Findings

Diffuse scattering appears between 293 K and 400 K and disappears above 400 K.

Diffuse scattering is explained by inhomogeneous lattice deformations due to phase inclusions.

PZT near the morphotropic phase boundary is structurally inhomogeneous.

Abstract

Complementary diffuse and inelastic synchrotron X-ray scattering measurements of lead zirconate-titanate single crystals with composition near the morphotropic phase boundary (x=0.475) are reported. In the temperature range 293 K < T < 400 K a highly anisotropic quasielastic diffuse scattering is observed. Above 400 K this scattering disappears. Its main features can be reproduced by model of inhomogeneous lattice deformations caused by inclusions of a tetragonal phase into a rhombohedral or monoclinic phase. This observation supports the idea that PZT at its morphotropic phase boundary is essentially structurally inhomogeneous.