Diffuse X-ray scattering from 180° ferroelectric stripe domains: polarization-induced strain, period disorder and wall roughness

Abstract

A key element in ferroic materials is the presence of walls separating domains with different orientations of the order parameter. It is demonstrated that 180 stripe domains in ferroelectric films give rise to very distinct features in their diffuse X-ray scattering (DXS) intensity distributions. A model is developed that allows the determination of not only the domain period but also the period disorder, the thickness and roughness of the domain walls, and the strain induced by the rotation of the polarization. As an example, the model is applied to ferroelectric/paraelectric superlattices. Temperature-dependent DXS measurements reveal that the polarization-induced strain decreases dramatically with increasing temperature and vanishes at the Curie temperature. The motion of ferroelectric domain walls appears to be a collective process that does not create any disorder in the domain period, whereas pinning by structural defects increases the wall roughness. This work will facilitate in situ quantitative studies of ferroic domains and domain wall dynamics under the application of external stimuli, including electric fields and temperature. We have grown tricolour PbTiO 3 /SrTiO 3 /PbZr 0.2 Ti 0.8 O 3 (PT/ STO/PZT) SLs on TiO 2 -terminated (001)-oriented STO substrates using pulsed laser deposition following a procedure research papers 846 A. Boulle et al. Diffuse X-ray scattering from ferroelectric stripe domains J. Appl. Cryst. (2016). 49, 845-855 APPENDIX B Lognormal, Lévy-stable and pseudo-Voigt distributions A lognormal distribution is used to model the p.d.f. of the stripe period: research papers J. Appl. Cryst. (2016). 49, 845-855 A. Boulle et al. Diffuse X-ray scattering from ferroelectric stripe domains 853

Domain Wall Orientations in Ferroelectric Superlattices Probed with Synchrotron X-Ray Diffraction

“…We note that these observations differ from those of Fong et al 27 , who found that in ultrathin PbTiO 3 films, the diffuse scattering due to the periodic domain structure instead evolves from a uniform ring (F β phase) at lower temperatures to a structure with {100} DWs (F α phase) upon heating, accompanied by an abrupt decrease in the domain period. We also observe a gradual decrease in the domain period with temperature, but no abrupt changes, consistent with previous reports 28,29 . Our observations are also different from the abrupt change in the alignment of ferroelastic DWs observed on heating in BaTiO 3 thin films 30 .…”

Local negative permittivity and topological phase transition in polar skyrmions

“…5) showed the systematic disappearance of the skyrmion satellite peaks with increasing electric field, indicating field-induced structural changes related to the skyrmions ( ). The external electric field in the out-of-plane direction breaks the symmetry and tends to align the dipoles along the direction of the external field to minimize the energy 32,33 . The electric field-driven change in the size of the skyrmion directly impacts the effective dielectric permittivity as well as the negative component of permittivity (Supplementary Note 3, Extended Data Fig.…”

Domain alignment within ferroelectric/dielectric PbTiO3/SrTiO3 superlattice nanostructures

“…This possibility can be evaluated using the domain diffuse scattering intensities derived as a function of domainwall width. 33 Assuming that the domain wall width is zero in the SL nanostructure, the observed intensity enhancement occurs only when the domain wall width reaches 16 nm in the unpatterned region, which is an unphysically large value. [34][35] A final artifact would arise if the areas occupied by up and down polarizations within the nanodomain period were different in the SL nanostructure than in the unpatterned region.…”