Dielectric relaxation and charged domain walls in (K,Na)NbO3-based ferroelectric ceramics

The influence of domain walls on the macroscopic properties of ferroelectric materials is a well known phenomenon. Commonly, such extrinsic contributions to dielectric permittivity are discussed in terms of domain wall displacements under external electric field. In this work, we report on a possible contribution of charged domain walls to low frequency (10-10(6) Hz) dielectric permittivity in K1-xNaxNbO3 ferroelectric ceramics. It is shown that the effective dielectric response increases with increasing domain wall density. The effect has been attributed to the Maxwell-Wagner-Sillars relaxation. The obtained results may open up possibilities for domain wall engineering in various ferroelectric materials.