Ferroelectric Domain Continuity Over Grain Boundaries for Tetragonal, Orthorhombic, and Rhombohedral Crystal Symmetries.

ABSTRACT

Domain mobility is understood to have a significant impact on ferroelectric material properties. Grain boundaries are known to inhibit ferroelectric domain wall mobility, thereby limiting the properties of polycrystalline ferroelectrics. Continuous domains across grain boundaries can change the grain boundary impact on domain wall mobility. Such microstructures have been observed since the 1950s, but their impact on properties is not well understood. This paper predicts the likelihood of domain wall continuity over grain boundaries for typical perovskite oxide ferroelectric symmetries of tetragonal, orthorhombic, and rhombohedral. Five two-grain systems are studied for domain continuity over all possible grain boundary space. Results show that rhombohedral and orthorhombic symmetries have a higher probability for domain continuity over grain boundaries as compared with tetragonal symmetry. This observation is due to the greater number of domain wall planes and polarization vectors in these symmetries. Grain boundaries probable for domain continuity can be identified in each misorientation for each symmetry. This knowledge, combined with developments in microstructural measurements and ceramic processing techniques, may be used to control domain continuity at grain boundaries, and hence, influence the final properties of the material.