A percolative ferroelectric-metal composite with hybrid dielectric dependence

The hybrid dielectric dependence of a percolative ferroelectric-metal composite is investigated by analyzing BaTiO₃-Ni composite prepared by a conventional ceramic method. It is depicted by a novel theoretical expression that exhibits the relationships between the real permittivity, metal concentration and applied frequency of the system. Both the dipolar response and the space charge polarization contribute to the dielectric constant, especially near the percolation threshold. With decreasing conductivity of the BaTiO₃ matrix, the dependence of the dielectric constant on frequency decreases, especially at low frequency and near the percolation threshold.