Large Dielectric Constant and Maxwell-Wagner Effects in BaTiO3/Cu Composites

Dense ceramic composites with ferroelectric BaTiO3 and metal Cu were prepared via the solid-state reaction route at 1280 degrees C in nitrogen atmosphere. The frequency and temperature dependence of impedance, resistance, and dielectric permittivity of BaTiO3/xCu in the range of 10-1106 Hz have been investigated, respectively. It was found that the electrical conduction and dielectric behavior of the materials vary with the ratio of the two phases. The maximum permittivity of 1.0 x 105 at 1 kHz was obtained for the composites of BaTiO3/20 wt% Cu. Moreover, the BaTiO3/Cu composites exhibited high values of permittivity at low frequencies than at high frequencies due to MaxwellWagner polarization. The application of the MaxwellWagner polarization model in this system was briefly discussed.