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用传统固相烧结法制备了Sr2Bi4-xDyxTi5 O18(SBDT-x, x=0—0.20)陶瓷样品. x射线衍射分析表明, 微量的Dy掺杂没有影 响Sr2Bi4Ti5O18(SBTi) 原有的层状钙钛 矿结构. 通过研究样品的介电特性, 发现Dy掺杂减小了材料的损耗因子, 降低了样品铁电- 顺电相转变的居里温度. 铁电性能测量结果表明, 随Dy含量的增加, SBDT-x系列样品的剩余 极化先增大, 后减小. 当Dy掺杂量为0.01时, 剩余极化达到最大值, 约为20.1 μC·cm-2. 掺杂引起剩余极化的变化, 与材料中缺陷浓度、内应力以及晶格畸变程度等因 素有关, 是多种作用机理相互竞争的结果. (Bi2O2)2+ 层通常被看作是绝缘层和空间电荷库, 对材料的铁电性能起关键作用. 掺杂离子进入(Bi2O2)2+层会导致铁电性能变差.
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关键词:
- Sr2Bi4Ti5O18陶瓷 /
- Dy掺 杂 /
- 铁电性能 /
- 居里温度
Ferroelectric Sr2Bi4-xDyxTi5O18 (SBDT-x, x= 0—0.20) ceramic samples were prepared using the conventional solid-state reaction method. x-ray diffraction patterns (XRD) of SBDT-x ceramics show that doping with a small amount of Dy does not change the crystal structur e of Sr2Bi4Ti5O18 (SBTi). Their Curi e temperature (Tc) and dielectric loss (tanδ) decrease with Dy dopin g amount. The remnant polarization (2Pr) of SBDT-x increases at first , then decreases with increasing of Dy content. When Dy content is 0.01, the 2Pr reaches a maximum value of 20.1 μC·cm-2. The variation of 2Pr for SBDT-x relates to space charge density, internal strain an d structure distortion. (Bi2O2)2+ layer acting as an insulating layer and space charge storage plays an important role in their ferroelectric properties in BLSFs. The incorporation of doping ions into (Bi2O2)2+ layer may destroy its original function and deteriorate the ferroelectric property.-
Keywords:
- Sr2Bi4Ti5O18 ceramic s /
- Dy doping /
- ferroelectric properties /
- Curie temperature
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