Dielectric relaxation in paraelectric phase of Ba(Ti,Sn)O₃ ceramics

Study on dielectric relaxation of various ferroelectric perovskites in their paraelectric phase had been reported recently. A common accepted idea is oxygen vacancy should be responsible for the observed nonferroelectric dielectric relaxation. The present authors had observed low-frequency dielectric relaxations in the paraelectric phase of Ba(Ti,Sn)O₃ ceramics. In the temperature range of 100 to 450 °C, peaks of loss tangent shift to higher temperature for higher frequency. The results of redox treatment excluded the possibility of defect polarization of oxygen vacancy. It is argued that hopping of localized hole contribute to the dielectric relaxation and to the electronic conducting characteristics.