Effective Dielectric Function in High-Permittivity Ceramics and Films

Abstract Effective dielectric function in granular materials (ceramics and polycrystalline films) is discussed in terms of the recently developed generalized brick-wall model for arbitrary particle shape and size. The model is applied to the discussion of the dead grain-boundary layers in SrTiO 3 which are supposed to be formed by frozen dipoles at polar grain boundaries with the polarization penetrating inside the grain.