Dielectric relaxation and electrical conductivity in ferroelectric ceramic/polymer composite based on modified lead titanate

The dielectric relaxation and electrical conductivity behavior are studied in the ferroelectric ceramic/polymer composite (Pb0.88Sm0.08)(Ti0.99Mn0.01)O-3/polyetherketoneketone 50/50 % vol considering the semiempirical complex Cole-Cole equation and the universal relaxation law. The contribution of conductive processes to the dielectric relaxation for the low frequency range is discussed considering the space charges. For higher frequency range, the dielectric relaxation is analyzed considering the oxygen concentration in the ceramic phase due to the Mn4+ to Mn2+ conversion, which takes places during the sintering process of the ceramic material. The activation energy values suggest the involvement of charge carriers' motion in the dielectric relaxation process. The relaxation process is associated to the decay of the polarization in the oxygen defect-related dipoles due to their hopping conduction. (c) 2007 American Institute of Physics.