High capacitance-temperature sensitivity and "giant" dielectric constant in SrTiO3

A dielectric relaxation with a "giant" dielectric constant (epsilon similar to 10(4)) at low frequencies and a remaining high epsilon(similar to 5x10(3)) background at high frequencies (>1 MHz) are observed in Bi doped SrTiO3 ceramics annealed in a reduced atmosphere. The material possesses a very high capacitance-temperature sensitivity at similar to 2 K, which is much higher than the values reported in the current literature. The giant dielectric constant at low frequencies is attributed to the "Maxwell-Wagner" interfacial polarization based on the study of the complex-impedance spectrum. The remaining high dielectric constant at high frequencies is tentatively attributed to the "electron-relaxation mode" coupling polarization. (C) 2007 American Institute of Physics.