Dielectric relaxation and electrical conductivity in ferroelectric ceramic/polymer composites around the glass transition

摘要

The electrical conductivity behavior of the [(Pb_(0.88)Sm_(0.08))(Ti_(0.99)Mn_(0.01))O_3]/polyetherketoneketone ceramic/polymer composite is studied in a wide temperature and frequency ranges around the glass transition of the polymer phase (T_g). The universal relaxation law is applied to model the experimental response. The dc conductivity (σ_(dc)) and the hopping frequency (ω_H) follow an Arrhenius dependence. The activation energy values for σ_(dc) are associated to oxygen migration. The contribution of the conductive processes to the dielectric relaxation is analyzed, considering the oxygen vacancies concentration in the ceramic phase. It is also considered the structural change around T_g and its influence on the dielectric relaxation.