Dielectric properties of the surface layer in ultra-thin films of a VDF/TrFE copolymer
Dielectric properties of the surface layer in ultra-thin films of a VDF/TrFE copolymer
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DOI：
10.1109/tdei.2004.1285891
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发表时间：
2004-06
影响因子：
3.1
通讯作者：
Y. Takahashi;A. Kitahama;T. Furukawa
中科院分区：
文献类型：
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作者：
Y. Takahashi;A. Kitahama;T. Furukawa
我们测量了使用蒸发铝电极旋涂在玻璃基板上的偏二氟乙烯和三氟乙烯 (VDF/TrFE) 薄膜的介电常数的温度和频率离散度。假设存在两个介电性能与块体材料不同的表面层，则推导出每个表面层的厚度为 2 nm。获得了表面层介电常数的频率分散的温度依赖性。每个表面层具有与块体的非晶区域的分段模式本质上相同的介电弛豫。它显示厚样品的顺电-铁电相变温度没有异常。表面层看起来是无定形的。
We measured the temperature and frequency dispersion of the permittivity of vinylidene fluoride and trifluoroethylene (VDF/TrFE) thin films spin-coated on glass substrates with evaporated aluminium electrodes. Assuming the existence of two surface layers with different dielectric properties from the bulk material, a thickness of 2 nm was deduced for each surface layer. The temperature dependence of the frequency dispersion of the permittivity of the surface layers was obtained. Each surface layer has a dielectric relaxation which is essentially the same as the segment mode of the amorphous region of the bulk. It shows no anomaly at the temperature of the paraelectric-ferroelectric phase transition for thick samples. The surface layers appear to be amorphous.