论文标题
铁电的阻抗光谱：域壁固定元件
Impedance spectroscopy of ferroelectrics: The domain wall pinning element
论文作者
论文摘要
我们根据随机系统中的接口钉理论引入了等效电路元件，以分析强制场下方的域壁运动对铁电的阻抗的贡献，这是振幅$ e_0 $的函数和施加的交流电场的频率$ f $。我们研究了电容器堆栈，其中包含铁电的0.5（ba $ _ {0.7} $ ca $ _ {0.3} $）tio $ _ {3} $ -0.5BA（zr $ _ {0.2} $ _ {0.2} $ ti $ _ {0.8} $ _ {0.8} $ $ $ _ $ _ {3} $ {3} $ {Bras epit，las las las las las las las las las las las las las las las las las las las las las las las las las las las las las las las las las。在NB掺杂的Srtio $ _3 $单晶基板上沉积，并用AU电极覆盖。从$ f = 10 $ \，hz到1 \，以不同的$ e_0 $收集的阻抗光谱。光谱的反卷积是通过将测量的阻抗与电容器堆栈的等效电路模型拟合而实现的，并且我们从获得的拟合参数中提取了BCZT膜的域壁运动诱导的振幅和频率依赖性介质响应。从扩展的瑞利分析中，我们量化了BCZT膜中介电非线性和介电分散之间的耦合强度，并识别不同的域壁运动状态。最后，我们构建了不同域壁摩托模式的示意图，并讨论相应的域壁动力学。
We introduce an equivalent-circuit element based on the theory of interface pinning in random systems, to analyze the contribution of domain wall motion below the coercive field to the impedance of a ferroelectric, as a function of amplitude $E_0$ and frequency $f$ of an applied ac electric field. We investigate capacitor stacks, containing ferroelectric 0.5(Ba$_{0.7}$Ca$_{0.3}$)TiO$_{3}$--0.5Ba(Zr$_{0.2}$Ti$_{0.8}$)O$_{3}$ (BCZT) thin films, epitaxially grown by pulsed laser deposition on Nb-doped SrTiO$_3$ single crystal substrates and covered with Au electrodes. Impedance spectra from $f=10$\,Hz to 1\,MHz were collected at different $E_0$. Deconvolution of the spectra is achieved by fitting the measured impedance with an equivalent-circuit model of the capacitor stacks, and we extract the domain-wall-motion induced amplitude- and frequency-dependent dielectric response of the BCZT films from the obtained fit parameters. From an extended Rayleigh analysis, we quantify the coupling strength between dielectric nonlinearity and dielectric dispersion in the BCZT films and identify different domain-wall-motion regimes. Finally, we construct a schematic diagram of the different domain-wall-motion regimes and discuss the corresponding domain-wall dynamics.
