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Giant dielectric constant, dielectric relaxations, and tunable properties of Sm 2/3 Cu 3 Ti 4 O 12 ceramics
Author(s) -
Thomas A. K.,
George Merin,
Abraham Kevin,
Sajan D.
Publication year - 2020
Publication title -
international journal of applied ceramic technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 57
eISSN - 1744-7402
pISSN - 1546-542X
DOI - 10.1111/ijac.13663
Subject(s) - materials science , dielectric , ceramic , grain boundary , permittivity , crystallinity , rietveld refinement , composite material , mineralogy , analytical chemistry (journal) , microstructure , crystal structure , crystallography , optoelectronics , chromatography , chemistry
Abstract The polycrystalline Sm 2/3 Cu 3 Ti 4 O 12 (SCTO) ceramics have been prepared by solid‐state reaction. The crystallinity of the compound has been investigated by Rietveld refinement which has revealed a cubic structure with space group Im3 . It is observed that at low frequencies, SCTO ceramic exhibits tremendously high values of dielectric permittivity ε ′, larger than 32,000, at room temperature. Two distinct, thermally triggered, dielectric relaxations have been noted. This mechanism has been confirmed through impedance analysis of the ceramics. The complex impedance plane shows three semicircles, which confirm the existence of two dielectric relaxations in SCTO ceramics. In general, the electrical as well as dielectric behavior of SCTO ceramics are seen to be reasonably analogous to those of CaCu 3 Ti 4 O 12 (CCTO) ceramics. The emergence of the enormous dielectric constant in SCTO ceramic is accredited to the combined effect of polarization both at the sample‐electrode interface as well as at the insulating grain boundary interface. The SCTO ceramics are identical to the CCTO ceramics in their structure and composition and hence, as the above results indicate, the IBLC effect mechanism, originally put forward for CCTO ceramics, is furthermore plausible to account for the mammoth values of dielectric constant in SCTO ceramics.