The influence of the segregation of Cu-rich phase on the microstructural and impedance characteristics of $CaCu_3Ti_4O_{12}$ ceramics

Shri Prakash, B and Varma, KBR (2007) The influence of the segregation of Cu-rich phase on the microstructural and impedance characteristics of $CaCu_3Ti_4O_{12}$ ceramics. In: Journal of Materials Science, 42 (17). pp. 7467-7477.

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Abstract

The influence of sintering conditions on the microstructural features and impedance characteristics of the giant dielectric constant material $CaCu_3Ti_4O_{12}$ (CCTO) was investigated. The microstructure and impedance characteristics were found to be strongly dependent on the sintering conditions. Sintering of the CCTO ceramics at elevated temperatures $(>1100^ oC)$ for prolonged durations resulted in the segregation of Cu-rich phase, mostly confined to the surface, which was in concomitance with the appearance of the additional semicircle at the low frequency end in Impedance $(Z^\ast)$ plots. The absence of this additional semicircle in the Cu-deficient CCTO ceramics and the appearance of the same in Cu-rich CCTO ceramics that were deliberately fabricated corroborated the above observations. Also, $La_{2/3}Cu_3Ti_4O_{12}$ (LCTO), a low dielectric constant member of CCTO family, which consisted of small grains without the segregation of Cu-rich phase at the grain boundary, did not reveal the presence of additional semicircle in the $Z^\ast$ plots.

Item Type:	Journal Article
Publication:	Journal of Materials Science
Publisher:	Springer
Additional Information:	Copyright of this article belongs to Springer.
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	27 Sep 2007
Last Modified:	19 Sep 2010 04:39
URI:	http://eprints.iisc.ac.in/id/eprint/11943

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