Polarization properties and oxygen-vacancy distribution of SrBi2Ta2O9 ceramics modified by Ce and Pr
Polarization properties and oxygen-vacancy distribution of SrBi2Ta2O9 ceramics modified by Ce and Pr
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DOI：
10.1016/j.jeurceramsoc.2005.03.207
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发表时间：
2005
影响因子：
5.7
通讯作者：
M. Miyayama;Y. Noguchi
中科院分区：
文献类型：
--
作者：
M. Miyayama;Y. Noguchi
研究了铈和镨改性对层状铁电材料SrBi2Ta2O9（SBT）铁电畸变、缺陷结构和极化性能的影响。中子粉末衍射和x射线光电子分析表明，这些稀土离子（RE）在Sr位上被取代为RE3+，并产生Sr空位来补偿Sr2+和RE3+之间的电荷差。在pre - sbt中，钙钛矿层中存在氧空位，而在Ce-SBT中，钙钛矿层和bi2o2层都存在氧空位。致密陶瓷极化测量结果表明，Pr改性后的SBT的极化性能明显改善，而ce改性后的SBT由于畴钉钉和极化滞后位移导致的剩余极化较低。在SBT体系中，bi2o_2层中的氧空位是引起畴钉钉和迟滞位移等劣化的主要原因。
Effects of cerium and praseodymium modifications on the ferroelectric distortion, defect structure, and polarization properties were investigated for layered ferroelectric SrBi2Ta2O9(SBT). Neutron powder diffraction and X-ray photoelectron analyses showed that these rare-earth ions (RE) are substituted at the Sr site as RE3+and that Sr vacancies are created for compensating the charge difference between Sr2+and RE3+. Oxygen vacancies were present in perovskite layers for Pr–SBT, but in both perovskite and Bi2O2layers for Ce–SBT. Polarization measurements using dense ceramics indicated that Pr modification led to an marked improvement of polarization properties while Ce-modified SBT exhibited a lower remanent polarization caused by domain pinning and polarization-hysteresis shift. The oxygen vacancies in the Bi2O2layers are suggested to induce the deterioration such as the domain pinning and hysteresis shift in the SBT system.