Giant dielectric response in microwave processed CaCu3Ti4O12 ceramics: A correlation among microstructure, dielectric and impedance properties
Polycrystalline CaCu3Ti4O12 (CCTO) ceramics was synthesized by microwave assisted solid-state reaction. Effect of sintering at different temperatures on the crystal structure, dielectric and impedance properties was investigated in detail. Rietveld analysis of X-ray diffraction data identified that...
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University of Novi Sad
2019-12-01
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doaj-92611b7fa9894caa8c6ce434626b659f2020-11-25T01:23:32ZengUniversity of Novi SadProcessing and Application of Ceramics1820-61312406-10342019-12-0113438740010.2298/PAC1904387SGiant dielectric response in microwave processed CaCu3Ti4O12 ceramics: A correlation among microstructure, dielectric and impedance propertiesBuddhadev SamantaDipika NandaPawan KumarRashmirekha SahuSujata SwainApurba MahapatraPolycrystalline CaCu3Ti4O12 (CCTO) ceramics was synthesized by microwave assisted solid-state reaction. Effect of sintering at different temperatures on the crystal structure, dielectric and impedance properties was investigated in detail. Rietveld analysis of X-ray diffraction data identified that crystal structure was a mixture of cubic CCTO and monoclinic CuO phases. Lattice parameters and amount of CuO secondary phase were also estimated as a function of sintering temperature. Microstructural investigation confirmed the existance and successive increase of the melted phase near the grain boundary region with increasing temperature of sintering. Cu-rich nature of the melted phase was further confirmed by selective area EDX spectra. Dielectric and impedance properties were studied as a function of frequency (100 Hz to 1 MHz) and temperature (room temperature to 300 °C). Improvement in dielectric properties as a function of sintering temperature (1000 to 1050 °C) was explained in terms of reduction in grain boundary dimension due to the successive increase in Cu-rich melted phase. However, dielectric constant started falling when sintered at 1075 °C, which may be accounted in terms of segregation of large amount of CuO phase after a certain temperature and hence a non-stoichiometry of Cu in CCTO lattice. Impedance data were modelled by equivalent electrical circuits to investigate different contributions of electrically heterogeneous systems. In addition, probable relaxation mechanism has been discussed on the basis of impedance and modulus data. Activation energies were calculated from different characterizations and a non-Debye-type relaxation phenomena were observed. In this work, an attempt is made to build up a correlation among synthesis procedure, sintering temperature, dielectric, impedance and microstructural properties.http://www.tf.uns.ac.rs/publikacije/PAC/pdf/PAC%2046%2008.pdfmicrowave processingstructuredielectric propertiescacu3ti4o12 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Buddhadev Samanta Dipika Nanda Pawan Kumar Rashmirekha Sahu Sujata Swain Apurba Mahapatra |
spellingShingle |
Buddhadev Samanta Dipika Nanda Pawan Kumar Rashmirekha Sahu Sujata Swain Apurba Mahapatra Giant dielectric response in microwave processed CaCu3Ti4O12 ceramics: A correlation among microstructure, dielectric and impedance properties Processing and Application of Ceramics microwave processing structure dielectric properties cacu3ti4o12 |
author_facet |
Buddhadev Samanta Dipika Nanda Pawan Kumar Rashmirekha Sahu Sujata Swain Apurba Mahapatra |
author_sort |
Buddhadev Samanta |
title |
Giant dielectric response in microwave processed CaCu3Ti4O12 ceramics: A correlation among microstructure, dielectric and impedance properties |
title_short |
Giant dielectric response in microwave processed CaCu3Ti4O12 ceramics: A correlation among microstructure, dielectric and impedance properties |
title_full |
Giant dielectric response in microwave processed CaCu3Ti4O12 ceramics: A correlation among microstructure, dielectric and impedance properties |
title_fullStr |
Giant dielectric response in microwave processed CaCu3Ti4O12 ceramics: A correlation among microstructure, dielectric and impedance properties |
title_full_unstemmed |
Giant dielectric response in microwave processed CaCu3Ti4O12 ceramics: A correlation among microstructure, dielectric and impedance properties |
title_sort |
giant dielectric response in microwave processed cacu3ti4o12 ceramics: a correlation among microstructure, dielectric and impedance properties |
publisher |
University of Novi Sad |
series |
Processing and Application of Ceramics |
issn |
1820-6131 2406-1034 |
publishDate |
2019-12-01 |
description |
Polycrystalline CaCu3Ti4O12 (CCTO) ceramics was synthesized by microwave assisted solid-state reaction. Effect of sintering at different temperatures on the crystal structure, dielectric and impedance properties was investigated in detail. Rietveld analysis of X-ray diffraction data identified that crystal structure was a mixture of cubic CCTO and monoclinic CuO phases. Lattice parameters and amount of CuO secondary phase were also estimated as a function of sintering temperature. Microstructural investigation confirmed the existance and successive increase of the melted phase near the grain boundary region with increasing temperature of sintering. Cu-rich nature of the melted phase was further confirmed by selective area EDX spectra. Dielectric and impedance properties were studied as a function of frequency (100 Hz to 1 MHz) and temperature (room temperature to 300 °C). Improvement in dielectric properties as a function of sintering temperature (1000 to 1050 °C) was explained in terms of reduction in grain boundary dimension due to the successive increase in Cu-rich melted phase. However, dielectric constant started falling when sintered at 1075 °C, which may be accounted in terms of segregation of large amount of CuO phase after a certain temperature and hence a non-stoichiometry of Cu in CCTO lattice. Impedance data were modelled by equivalent electrical circuits to investigate different contributions of electrically heterogeneous systems. In addition, probable relaxation mechanism has been discussed on the basis of impedance and modulus data. Activation energies were calculated from different characterizations and a non-Debye-type relaxation phenomena were observed. In this work, an attempt is made to build up a correlation among synthesis procedure, sintering temperature, dielectric, impedance and microstructural properties. |
topic |
microwave processing structure dielectric properties cacu3ti4o12 |
url |
http://www.tf.uns.ac.rs/publikacije/PAC/pdf/PAC%2046%2008.pdf |
work_keys_str_mv |
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1725121709659389952 |