Domain patterns in epitaxial rhombohedral ferroelectric films. I. Geometry and experiments

Abstract

Possible domain patterns are developed for (001) oriented (pseudocubic indexing) epitaxial rhombohedral perovskite ferroelectric (FR) films. We assume that the films are grown above their Curie temperature (TC) in a cubic paraelectric (PC) state. The rhombohedral distortion consists of a “stretch” along one of the four 〈111〉 crystallographic directions of the cubic perovskite unit cell. Domain pattern formation is concurrent with the PC→FR transformation on cooling from the growth temperature. The domain patterns form to minimize elastic energy in the film, at the energetic expense of both forming domain boundaries and developing local stresses in the substrate. Eight possible domains may form, half of which are related by inversion, thus leading to four mechanically distinct variants. The possible domain walls are determined by mechanical and charge compatibility and follow closely from the analysis of Fousek and Janovec [J. Appl. Phys. 40, 135 (1969)]. Domain patterns may develop with either {100} or {101} boundaries. In both cases, the individual domains in the patterns are energetically degenerate and thus equal width lamellar patterns are predicted. When polarization is included in the analysis, the {100} boundary patterns have no normal component of the net polarization, whereas the {101} boundary patterns correspond to the fully poled state. We report on experimental observation of {100} domain patterns in epitaxial PbZr0.80Ti0.20O3 and PbZr0.65Ti0.35O3 films.

Magnetotransport at Domain Walls inBiFeO3

“…• domain walls are ∼1-2 nm (3-5 unit cells) wide and, indeed, form on the 100-type planes as expected from literature [17].…”

Polarization Switching Ability Dependent on Multidomain Topology in a Uniaxial Organic Ferroelectric

“…Ferroelastic domain walls must be mechanically compatible; therefore, their possible orientations are limited. 17,18 This fact implies that the mobility of ferroelectric-ferroelastic domain walls may be affected not only by the presence or absence of compensation charges but also by the orientationdependent elastic energy. Therefore, to verify the mobility difference between charged and neutral ferroelectric domain walls, uniaxial ferroelectrics, in which only ferroelectric but nonferroelastic domain walls are allowed, present an ideal system; however, this system remains to be explored.…”

Local conductivity and the role of vacancies around twin walls of (001)−BiFeO3 thin films

“…BiFeO 3 thin films are monoclinic [15] but, in fact, they are quasirhombohedrally distorted and, thus, the ferroelastic domain walls that they present are very similar to those expected in a rhombohedral perovskite, that is 71 o and 109 o domain walls [16]. Initially, conducting behavior was observed only in artificially-written 109 o domain walls [14].…”