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Dielectric relaxations and phase-transition-like behavior in SmAlO3 ceramics at high temperatures
- Lei, Changmei, Wang, Chunchang, Li, Teng, Wang, Guojing, Sun, Xiaohong, Liu, Lina, Wang, Jing
- Journal of materials science 2013 v.48 no.20 pp. 7294-7299
- ceramics, dielectric properties, electrodes, oxygen, temperature
- SmAlO₃ceramics samples were prepared via the solid-state reaction route. The low-frequency (20–10⁷ Hz) dielectric properties were investigated in the temperature range from 100 to 800 °C. It was found that SmAlO₃shows a flat dielectric plateau with the value about 20 independent frequency below 220 °C. In the temperature range higher than 220 °C, two oxygen-vacancy related Debye-like relaxations (PA, PB) and a non-relaxation hump (PH) were observed. Our results indicate that: (1) the low-temperature relaxation (PA) is associated with the bulk effect due to hopping motions of oxygen vacancies; (2) the high-temperature relaxation (PB) results from the sample/electrode contact effect; and (3) PHis suggested to be a phase-transition-like behavior as a result of the oxygen-vacancy ordering process.