Domain wall contribution to lattice dynamics and permittivity of BiFeO₃

Ferroelectric materials are known for their exceptionally high dielectric permittivity.
It turns out, that important part of it originates their complicated microstructure and in particular in interfaces between ferroelectric domains.

In this study we investigate different types of interfaces in a multiferroic BiFeO₃, model and asses their capability to contribute to permittivity, and convey understanding which can be used in design of new materials [ J. Hlinka, M. Pasciak, S. Körbel, and P. Márton, Phys. Rev. Lett. 119, 057604 (2017)].

Figure: Change of the phonon spectrum due to presence of dense domain-interface structure (right panel) in comparison with the single-domain case (left panel).