Domain structure and dielectric properties of metal-ferroelectric superlattices with asymmetric interfaces
Domain structure and dielectric properties of metal-ferroelectric superlattices with asymmetric interfaces
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DOI：
10.1103/physrevmaterials.4.094415
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发表时间：
2020-09
影响因子：
3.4
通讯作者：
M. Hadjimichael;Yaqi Li;L. Yedra;B. Dkhil;P. Zubko
中科院分区：
文献类型：
--
作者：
M. Hadjimichael;Yaqi Li;L. Yedra;B. Dkhil;P. Zubko
$\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}/\mathrm{Sr}\mathrm{Ru}{\mathrm{O}}_{3}$ 沉积在 $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_{3}$ 基板上的超晶格通过结合 X 射线衍射、压敏响应力显微镜、扫描透射电子进行研究显微镜、传输测量和阻抗谱。由于 $\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}$ 和 $\mathrm{Sr}\mathrm{Ru}{\mathrm{O}}_{3}$ 生长模式的差异，发现超晶格具有两个不等价的界面。 X射线衍射测量表明，尽管铁电层夹在金属$\mathrm{Sr}\mathrm{Ru}{\mathrm{O}}_{3}$层之间，但铁电层具有致密的纳米级域。观察到的磁畴尺寸与铁电-介电系统中发现的磁畴尺寸相当，它们归因于 $\mathrm{Sr}\mathrm{Ru}{\mathrm{O}}_{3}\ensuremath{-}\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}$ 界面的有限屏蔽长度引起的去极化场。测量了超薄 $\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}$ 层的宏观电容，发现其温度依赖性与畴壁运动导致的介电常数增强一致。
$\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}/\mathrm{Sr}\mathrm{Ru}{\mathrm{O}}_{3}$ superlattices deposited on $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_{3}$ substrates are studied using a combination of x-ray diffraction, piezoresponse force microscopy, scanning transmission electron microscopy, transport measurements, and impedance spectroscopy. The superlattices are found to have two inequivalent interfaces resulting from differences in the growth modes for $\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}$ and $\mathrm{Sr}\mathrm{Ru}{\mathrm{O}}_{3}$. X-ray diffraction measurements show that, despite being sandwiched between metallic $\mathrm{Sr}\mathrm{Ru}{\mathrm{O}}_{3}$ layers, the ferroelectric layers possess dense nanoscale domains. The observed domain sizes are comparable to those found in ferroelectric-dielectric systems, and they are attributed to the depolarizing field caused by the finite screening length of the $\mathrm{Sr}\mathrm{Ru}{\mathrm{O}}_{3}\ensuremath{-}\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}$ interface. The macroscopic capacitance of the ultrathin $\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}$ layers was measured, and its temperature dependence was found to be consistent with permittivity enhancement due to domain wall motion.