High capacitance-temperature sensitivity and "giant" dielectric constant in SrTi O3

Abstract

A dielectric relaxation with a "giant" dielectric constant (ε∼ 104) at low frequencies and a remaining high ε (∼5× 103) background at high frequencies (>1 MHz) are observed in Bi doped SrTi O3 ceramics annealed in a reduced atmosphere. The material possesses a very high capacitance-temperature sensitivity at ∼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. © 2007 American Institute of Physics.