X-ray diffuse scattering and polar nanoregion of a relaxor ferroelectric under electric field

Abstract

We have measured X-ray diffuse scattering (XDS) of a relaxor ferroelectric 0.7Pb(Mg1/3Nb2/3)O3 – 0.3PbTiO3 single crystal under an electric field along [111] to investigate the electric field response of polar nanoregions (PNRs). Our ellipsoidal PNR model with a polarization along [110] and principal axes along [-110], [111], and [11-2] well reproduced observed three-dimensional XDS intensities around each Bragg reflection under the electric field at 300 K. The dimension of the ellipsoidal PNR is estimated to be 0.6×1.8×1.2 nm3 along the principal axes. The electric field dependence of XDS strongly couples with the piezoelectric lattice strain and ferroelectric polarization switching. Irreversible changes in XDS intensities observed under the electric field are explained by an antiferroelectric dipolar stabilization of reoriented PNRs.