Incipient ferroelectric to a possible ferroelectric transition in Te4+ doped calcium copper titanate (CaCu3Ti4O12) ceramics at low temperature as evidenced by Raman and dielectric spectroscopy

Barman, Nabadyuti and Singh, Priyank and Narayana, Chandrabhas and Varma, K B R (2017) Incipient ferroelectric to a possible ferroelectric transition in Te4+ doped calcium copper titanate (CaCu3Ti4O12) ceramics at low temperature as evidenced by Raman and dielectric spectroscopy. In: AIP ADVANCES, 7 (3).

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Abstract

Partial replacement of Ti4+ by Te4+ ions in calcium copper titanate lattice improved its dielectric behaviour mostly due to cubic-to-tetragonal structural transformation and associated distortion in TiO6 octahedra. The relative permittivity values (23-30 x 10(3)) of Te4+ doped ceramics is more than thrice that of un-doped ceramics (8 x 10(3)) at 1 kHz. A decreasing trend in relative permittivity with increasing temperature (50-300 K) is observed for all the samples. Barrett's formula, as a signature of incipient ferroelectricity, is invoked to rationalize the relative permittivity variation as a function of temperature. A systematic investigation supported by temperature dependent Raman studies reveal a possible ferroelectric transition in Te4+ doped ceramic samples below 120 K. The possible ferroelectric transition is attributed to the interactions between quasi-local vibrations associated with the micro-clusters comprising TiO6 and TeO6 structural units and indirect dipole-dipole interactions of off-center B-cations (Ti4+ and Te4+) in double perovskite lattice. (C) 2017 Author(s).

Item Type:	Journal Article
Publication:	AIP ADVANCES
Additional Information:	Copy right for this article belongs to the AMER INST PHYSICS, 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	19 May 2017 10:24
Last Modified:	19 May 2017 10:24
URI:	http://eprints.iisc.ac.in/id/eprint/56669

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