Phase transition and PTCR effect in erbium doped BT ceramics

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• 作者：Y. Leyet^a ; ^b ; R. Peñ ; a^a ; Y. Zulueta^a ; F. Guerrero^a ; ^c ; J. Anglada-Rivera^c ; Y. Romaguera^d ; J. Pé ; rez de la Cruz^d ; ^{jcruz@inescporto.pt}
• 关键词：Er doped barium titanate ; PTCR ; Conductivity process ; Phase transition
• 刊名：Materials Science and Engineering ; B
• 出版年：2012
• 期刊代码：76_09215107
• 类别：ch
• 出版时间：25 June, 2012
• 卷：177
• 期：11
• 页码：832-837
• 文件大小：874 K

摘要

In this work the dielectric behaviour and main features of the phase transition of BaTiO₃ and Ba_0.99Er_0.01TiO₃ ceramics were carefully investigated. The temperature and frequency dependences of the dielectric properties of erbium doped BaTiO₃ ceramics were measured in the 25-225 掳C and 100 Hz to 10 MHz ranges, respectively. From this study, a dielectric anomaly in the ferroelectric-paraelectric phase transition of the Ba_0.99Er_0.01TiO₃ ceramic was observed. The features of the samples phase transition were analysed by using Curie-Weiss, Santos-Eiras鈥?and order parameter local phenomenological models. In the BaTiO₃ system, all models showed a normal phase transition, while was not possible to establish the character of the phase transition in the Ba_0.99Er_0.01TiO₃ system. The relaxation parameters of conductive processes for the study ferroelectric materials, analysed in the time domain, did not show any influence on the ferroelectric-paraelectric phase transition. Finally, it was demonstrated that the anomaly observed on the phase transition of the erbium doped BaTiO₃ ceramics is associated with the processes that results in the PTCR effect.