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The effect of La3+, Mn2+ and Ni2+ doped calcium copper titanate, CaCu3Ti4O12 (CCTO), at higher concentrations (CR1 and CR2 with 5 mol% and 10 mol%, respectively), has been examined by semi-wet route at relatively lower temperature. This semi-wet route employs citrate–nitrate gel chemical method using TiO2 solid powders. X-ray diffraction (XRD) analysis confirms the formation of single phase in the doped samples sintered at 900 ℃ for 8 h. Scanning electron micrographs (SEM) show that the average grain size for CR2 is larger than that of CR1 composition. The energy dispersive X-ray spectroscopy (EDX) is used to study the percentage compositions of different ions present in both ceramics. Dielectric constant (εr) and dielectric loss (tanδ) values of CR1 are comparatively higher than those of CR2 ceramic at all measured frequencies and temperatures. The nature of temperature-dependent relaxation behavior of the ceramics is also studied by impedance, modulus spectroscopic analysis and confirms Maxwell–Wagner relaxation.


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Dielectric behavior of CaCu3Ti4O12 electro-ceramic doped with La, Mn and Ni synthesized by modified citrate-gel route

Show Author's information Laxman SINGHaU. S. RAIaAlok Kumar RAIbK. D. MANDALc,*( )
Department of Chemistry, Centre of Advanced Study, Faculty of Science, Banaras Hindu University, Varanasi 221005, U.P., India
Department of Materials Science and Engineering, Chonnam National University, 300 Yongbong-dong, Bukgu, Gwangju 500-757, Republic of Korea
Department of Applied Chemistry, Indian Institute of Technology, Banaras Hindu University, Varanasi 221005, U.P., India

Abstract

The effect of La3+, Mn2+ and Ni2+ doped calcium copper titanate, CaCu3Ti4O12 (CCTO), at higher concentrations (CR1 and CR2 with 5 mol% and 10 mol%, respectively), has been examined by semi-wet route at relatively lower temperature. This semi-wet route employs citrate–nitrate gel chemical method using TiO2 solid powders. X-ray diffraction (XRD) analysis confirms the formation of single phase in the doped samples sintered at 900 ℃ for 8 h. Scanning electron micrographs (SEM) show that the average grain size for CR2 is larger than that of CR1 composition. The energy dispersive X-ray spectroscopy (EDX) is used to study the percentage compositions of different ions present in both ceramics. Dielectric constant (εr) and dielectric loss (tanδ) values of CR1 are comparatively higher than those of CR2 ceramic at all measured frequencies and temperatures. The nature of temperature-dependent relaxation behavior of the ceramics is also studied by impedance, modulus spectroscopic analysis and confirms Maxwell–Wagner relaxation.

Keywords:

oxide materials, chemical synthesis, dielectric properties, grain boundaries, X-ray diffraction (XRD)
Received: 12 December 2012 Revised: 29 January 2013 Accepted: 20 February 2013 Published: 04 June 2013 Issue date: June 2013
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Publication history

Received: 12 December 2012
Revised: 29 January 2013
Accepted: 20 February 2013
Published: 04 June 2013
Issue date: June 2013

Copyright

© The author(s) 2013

Acknowledgements

One of the authors would like to thank Prof. Om Parkash, the head of Department of Ceramic Engineering, Indian Institute of Technology, B.H.U., for extending XRD facility.

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