A strategy for analysis and modelling of impedance spectroscopy data of electroceramics: Doped lanthanum gallate
A strategy for analysis and modelling of impedance spectroscopy data of electroceramics: Doped lanthanum gallate
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DOI：
10.1023/b:jecr.0000011215.56084.87
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发表时间：
2003-07-01
影响因子：
1.7
通讯作者：
West, AR
中科院分区：
文献类型：
--
作者：
Abram, EJ;Sinclair, DC;West, AR
电陶瓷阻抗谱（IS）数据的建模关键取决于等效电路的正确选择，以便提取的参数具有物理意义。提出的选择正确电路的策略涉及对四种复杂形式中的几种 IS 数据进行分析：阻抗、电模量、导纳和介电常数，同时考虑数据的频率和温度依赖性以及提取的电阻和电容值的幅度和温度依赖性。使用氧化物离子传导 La0.80Sr0.20Ga0.83Mg0.17O2.82 陶瓷在 182 至 280 摄氏度范围内的 IS 数据证明了这一点。首先拟合低温数据，以全面表征整体响应；然后可以固定一些体参数，以能够拟合较高温度数据，这些数据越来越多地表现出较低频率现象，例如晶界阻抗。在这种情况下，最合适的电路由用于体响应的电阻器、电容器和恒定相位元件 (CPE) 的并联组合以及用于压缩电阻的并联电阻器和电容器组成。抗收缩性的起源可能与晶粒内板状 LaSrGaO4 第二相的存在和/或晶界处孔隙的存在有关。论证了为要拟合和细化的各种电路参数选择（a）正确的等效电路和（b）近似正确的输入值的重要性。
Modelling of impedance spectroscopy (IS) data of electroceramics depends critically on the correct choice of equivalent electrical circuit so that the extracted parameters have physical significance. The strategy proposed to choose the correct circuit involves analysis of IS data in several of the four complex formalisms: impedance, electric modulus, admittance and permittivity together with consideration of the frequency and temperature dependence of data and the magnitude and temperature dependence of extracted resistance and capacitance values. This is demonstrated using IS data from oxide-ion conducting La0.80Sr0.20Ga0.83Mg0.17O2.82 ceramics over the range 182 to 280degreesC. Low temperature data are fitted first, to allow a full characterisation of the bulk response; some of the bulk parameters may then be fixed to enable fitting of the higher temperature data which increasingly feature lower frequency phenomena such as grain boundary impedances. The most appropriate circuit in this case is found to consist of a parallel combination of a resistor, capacitor and constant phase element (CPE) for the bulk response in series with a resistor and capacitor in parallel for a constriction resistance. The origin of the constriction resistance may be associated with the presence of plate-like LaSrGaO4 secondary phase within the grains and/or with the presence of pores at the grain boundaries. The importance of choosing (a) the correct equivalent circuit and (b) approximately correct input values for the various circuit parameters to be fitted and refined are demonstrated.