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° 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 facilitatein situquantitative studies of ferroic domains and domain wall dynamics under the application of external stimuli, including electric fields and temperature.

Thermal-Driven Evolution of Magnetic Domain Structures in Ultrathin Films

The thermal-driven evolution of stripe domain structures in ultrathin magnetic films is analyzed with regard to temperature dependencies of the film magnetic parameters. In the vicinity of the Curie temperature or points of the spin reorientation the equilibrium stripe domain period was found to exponentially decrease with increasing temperature. It is shown that the temperature dependence of the characteristic length is the key parameter controlling the domain period changes. Irreversible and reversible changes of the domain period as well as the so-called inverse domain melting are discussed.