A monoclinic ferroelectric phase in the Pb(Zr1-xTix)O3 solid solution

TL;DR

This study discovers a new monoclinic ferroelectric phase in Pb(Zr0.52Ti0.48)O3 at low temperatures using high-resolution synchrotron x-ray diffraction, revealing a phase transition from tetragonal symmetry.

Contribution

The paper reports the identification of a previously unreported monoclinic ferroelectric phase in Pb(Zr,Ti)O3, expanding understanding of its phase diagram and symmetry properties.

Findings

Monoclinic phase appears below ~250 K.

Polar axis lies in the monoclinic ac plane near [111].

Phase transition from tetragonal to monoclinic symmetry observed.

Abstract

A previously unreported ferroelectric phase has been revealed on a highly homogeneous sample of Pb(Zr0.52Ti0.48)O3 by high-resolution synchrotron x-ray powder diffraction measurements. At ambient temperature the sample has tetragonal symmetry (at= 4.037 A, ct= 4.138 A), and transforms below ~250 K into a phase which, unexpectedly, has monoclinic symmetry (am= 5.717 A, bm= 5.703 A, cm= 4.143 A, beta= 90.53 deg., at 20K). The intensity data strongly indicate that the polar axis lies in the monoclinic ac plane close to the pseudo-cubic [111] direction, which would be an example of the species m3m(12)A2Fm predicted on symmetry grounds by Shuvalov.