Structural Factors that Influence Strain Behaviour in Bismuth Sodium Titanate -Barium Titanate Ceramics
讲座名称：
Structural Factors that Influence Strain Behaviour in Bismuth Sodium Titanate -Barium Titanate Ceramics
讲座时间：
2011-07-02
讲座人：
刘芸
形式：
校区：
兴庆校区
实践学分：
讲座内容：
应电子陶瓷与器件教育部重点实验室和西安交通大学国际电介质研究中心邀请，澳大利亚国立大学(Australian National University)刘芸博士(Dr. Liu Yun)将于7月2日上午在教二南楼304会议室举办题为“Structural Factors that Influence Strain Behaviour in Bismuth Sodium Titanate -Barium Titanate Ceramics”的学术讲座，欢迎广大师生参加。
讲座摘要：The dielectric, ferroelectric and strain response of bismuth sodium titanate-barium titanate (BNT-BT) ceramics have been systematically investigated as a function of temperature. It is found that ferroelectric and anti-ferroelectric (AFE)-like behavior can coexist at temperatures significantly lower than the depolarization temperature Td (even down to as low as ambient temperature) and that this leads to reversible giant strains of up to 0.48%. Electron microscopy suggests that such behavior results from the electric field-dependence of fine scale octahedral tilt twinning disorder and associated disorder in the local displacements of the Na/Bi/Ba and Ti ions. These local structural variations correlate with each other and become considerable under an applied external electrical field, leading to the anti-ferroelectric to ferroelectric phase transition observed by a combination of electrical property characterisation and diffraction studies. By changing chemical composition, it is also found that the stability of the induced ferroelectric phase strongly depends on the mole ratio of Na+ to Bi3+. This work thus provides new insight into ways to further optimize lead-free BNT-BT piezoelectric ceramics for practical uses.
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