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

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 degrees 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.