Grain Growth Anomaly and Dielectric Response in Ti-rich Strontium Titanate Ceramics

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• 作者：Lu铆s Amaral ; Manuela Fernandes ; Ian M. Reaney ; Martin P. Harmer ; Ana M. R. Senos ; Paula M. Vilarinho
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：November 27, 2013
• 年：2013
• 卷：117
• 期：47
• 页码：24787-24795
• 全文大小：491K
• 年卷期：v.117,no.47(November 27, 2013)
• ISSN：1932-7455

文摘

A grain growth anomaly in Ti-rich strontium titanate ceramics is reported. Here we show that three discontinuities on the temperature dependence of grain growth take place with drops in the grain size at temperatures around 1500, 1550, and 1605 掳C. We also show that similar discontinuities can be observed in the dependence of the grain boundary activation energy for conductivity and in the grain boundary thickness, assessed by impedance spectroscopy (IS). These notable coincidences are reported for the first time and strongly support the formation of different grain boundary complexions in polycrystalline oxides with transitions in between the observed grain growth regimens, which may be correlated to different grain boundary mobility and dielectric properties. These results call into question the discussion on the role of nonstoichiometry of SrTiO₃ and complexions on the microstructure development and open opportunities to design properties of functional materials.