Study of Small Polaronic, Variable Hopping Conduction and Its Exploration By Impedance Analysis in I- Substituted CaCu3Ti4O12 at O- Ion Site By Fine-Tuning The Electrical Properties, Grains and Grain Boundaries

作     者：Yadav, Bhoomika Kumar, Rajesh Kar, Kamal K. Ghorai, Manas K. 

作者机构：Advanced Nanoengineering Materials Laboratory Materials Science Programme Indian Institute of Technology Kanpur Kanpur208016 India Chhatrapati Shahu Ji Maharaj University Kanpur208026 India Advanced Nanoengineering Materials Laboratory Department of Mechanical Engineering Indian Institute of Technology Kanpur Kanpur208016 India Department of Chemistry Indian Institute of Technology Kanpur Kanpur208016 India 

出 版 物：《Research Square》 (Research Square)

年 卷 期：2021年

核心收录：

主　　题：Dielectric properties 

摘      要：In this study, dielectric and impedance related investigation are carried out in solid-state synthesized iodine doped CaCu3Ti4O12-xIx (x= 0, 0.005, 0.05 and 0.2) at anion site in the varying temperature (300-500 K) and frequency (20 Hz - 1 MHz). The detailed analysis of dielectric and scaled plot (Z″, M″) confirm the Maxwell-Wagner relaxations unlike Debye type. Broad relaxation peaks in spectroscopic plots and nearly straight lines in admittance (Y″ vs. Y′) and Ε″ vs. Ε′ reveals the occurrence of various relaxation processes with a narrow distribution of time constants. Mismatch in peak frequencies of Z″/ Z″max and M″/ M″max suggest that relaxation mechanism is dominated by short-range (localized) movement of charge carriers. The twinning values of Ea,τ,M″ (≈ 0.067 eV) and Ea,τ,Z (≈0.081 eV) indicate the involvement of same type of charge carriers in conduction and relaxation processes. Correlating Jonscher’s power law and overlapping peaks in the combined plot of M″, Z″ vs. log f indicates high loss, due to DC conduction through localized hopping of small polarons via some defect states through Mott’s VRH mechanism, among the highly concentrated density of states, N (Ef), confined in the very low-temperature zone and nearest-neighbor hopping (NNH) of polarons due to Arrhenius in high-temperature zone both reserved in low-frequency region (≤1 kHz) only. © 2021, CC BY.