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ST-xZS ceramics were prepared by solid-state sintering and have high temperature dielectric relaxation behavior at the temperature ranges of 300 °C–500 °C. We explore the origin of high temperature dielectric relaxation behavior of samples by activation energy calculation, XPS energy spectrum analysis and oxygen treatment experiment. We get a conclusion that the dielectric relaxation of pure ST ceramics comes from the migration of Vo. However, with the increase of ZS content, the dielectric relaxation related to Vo migration is gradually transformed into the influence of Ti4+ ion polarization, and the possible causes of relaxation behavior dependence are analyzed in detail. [ABSTRACT FROM AUTHOR]

Sr 1 − 3 x / 2 La x TiO 3 (SLTO) ceramics (x = 0.05, 0.10, 0.15) were prepared with giant dielectric constant by the traditional solid-state method at 1350 ∘ C. The temperature dependence of the dielectric constant was obtained at the temperature ranging from 29 ∘ C to 500 ∘ C and the frequency ranging from 2 kHz to 2 MHz. Two sets of relaxation peaks appear in the low temperature (region I) and the high temperature (region II), respectively. For region I, we conclude that the relaxation behavior is related to the oxygen vacancy migration. For region II, the two relaxation processes are caused by grain boundary for high frequency and Sr or Ti defects at grain interior for low frequency. With the doping amount reaching 0.15, the relaxation peaks disappear and become a common phase transition because of the aggravation of lattice distortion. These possible physical mechanisms of two sets of relaxation peaks are briefly discussed. [ABSTRACT FROM AUTHOR]

We present here the structural and dielectric properties of Tb0.5Y0.5MnO3 ceramics synthesized by solid state reaction. The X-ray diffraction pattern shows that the sample has an orthorhombic structure with space group Pbnm. Dielectric characteristics of Tb0.5Y0.5MnO3 ceramics are investigated over a broad temperature and a frequency range. Two dielectric relaxations are observed at 40-90 and 100-220 K. The results indicate that the low temperature dielectric relaxation (LTDR) may be exhibited variable ranger hopping behavior due to the oxygen vacancies (=start_CONVERSION_=VO+=start_CONVERSION_=), while the high temperature dielectric relaxation (HTDR) may come from the dipolar effects associated with the charge carrier hopping between Mn2+ and Mn3+. [ABSTRACT FROM AUTHOR]