Neutron Scattering Study of Relaxor Ferroelectric (1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3

TL;DR

This study uses neutron scattering to analyze how adding PbTiO3 to PZN affects the size, orientation, and correlations of polar nanoregions, revealing changes in diffuse scattering and phonon behavior.

Contribution

It provides new insights into the effects of PbTiO3 addition on the diffuse scattering and polar nanoregion dynamics in PZN-xPT relaxor ferroelectrics.

Findings

Diffuse scattering broadens along the diagonal with PT addition.

Polar nanoregions condense at higher temperatures with PT.

Broadening of TA phonon mode indicates polar nanoregion formation.

Abstract

Neutron elastic diffuse scattering experiments performed on Pb(Zn1/3Nb2/3)O3 (PZN) and on its solid solution with PbTiO3(PT), known as PZN-xPT, with x=4.5% and 9% around many reflections show that diffuse scattering is observed around reflections with mixed indices in the transverse and diagonal directions only. From the width of the diffuse scattering peak a correlation length is extracted. In PZN, we have reported that the diffuse scattering is more extended in the transverse than in the diagonal directions. In the present work, the results show that the addition of PT leads to a broadening of the diffuse scattering along the diagonal, relative to the transverse directions, indicating a change in the orientation of the polar regions. Also, with the addition of PT, the polar nanoregions condense at a higher temperature above the transition than in pure PZN (> 40 K), due to stronger correlations between the polar regions. Neutron inelastic scattering measurements have also been performed on PZN-xPT. The results show the broadening of the transverse acoustic (TA) phonon mode at a small momentum transfer q upon cooling. We attribute this broadening to the appearance of the polar nanoregions.