Tailoring non-linear dielectric properties by local field engineering in anisotropic porous ferroelectric structures

A method to control the nonlinear dielectric properties in porous anisotropic ceramics is proposed. The local field distributions in anisotropic porous ceramic structures were determined and the field-induced permittivity was estimated in parallel and perpendicular configurations (with respect to the pore orientation vs. the applied field direction). The predicted tunability behavior agrees well with the measured values obtained for Pb(Zr0.52Ti0.48)Nb0.024O3 ceramics with different anisotropic porosity levels. The paper demonstrates the concept of engineered local fields in porous microstructures for tailoring the permittivity and tunability values and the possibility to increase tunability with reducing permittivity for small porosity levels.