Impedance and Dielectric Spectroscopy of Functional Materials: A Critical Evaluation of the Two Techniques

Author:

Ramírez-González JuliaORCID,Sinclair Derek C.ORCID,West Anthony R.ORCID

Abstract

Impedance and dielectric spectroscopies are closely related techniques for measuring the electrical properties of materials. The techniques differ in two ways. First, impedance measurements are usually made over several decades of frequency (i.e. broadband) whereas most dielectric measurements are made at fixed frequency. Second, time constants that control semicircles in impedance complex plane plots and peaks in permittivity or tan δ spectroscopic plots are not the same. Differences between the techniques are confined to data analysis procedures and interpretation since they use similar instrumentation for measurements and data collection. In impedance data, time constants represent conducting components and parallel resistance-capacitance (RC) combinations; in permittivity data, they represent dielectric processes and series RC combinations. Using broadband data, it is possible to (i) determine the best equivalent circuit to fit experimental data, (ii) unambiguously evaluate and assign resistance, capacitance, and time constant parameters to regions of the material being measured and (iii) quantify departures from ideality using constant phase elements, CPEs. Using fixed frequency, variable temperature data in either impedance or dielectric methodologies, it is possible to detect the presence of different electrical components that contribute to a data set. However, it is not possible to separate the effects of frequency and temperature in terms of equivalent circuits, nor to deconvolute, parametrise, quantify, and assign the results to different regions of the sample. The advantages of using broadband measurements are highlighted with two examples: calcium copper titanate, CCTO which is often, erroneously, described as a giant or colossal dielectric; lead magnesium niobate, PMN, the classic relaxor ferroelectric whose characteristic properties are controlled entirely by the presence of non-ideality, represented by a CPE, in its equivalent circuit.

Publisher

The Electrochemical Society

Subject

Materials Chemistry,Electrochemistry,Surfaces, Coatings and Films,Condensed Matter Physics,Renewable Energy, Sustainability and the Environment,Electronic, Optical and Magnetic Materials

Reference68 articles.

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3