Dielectric, Ferroelectric and Relaxor Behavior of BaLaxBi4-xTi4O15 Ceramics

Kumar, Sunil and Varma, KBR (2010) Dielectric, Ferroelectric and Relaxor Behavior of BaLaxBi4-xTi4O15 Ceramics. In: Advanced Science Letters, 3 (1). pp. 20-27.

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Abstract

Monophasic BaLaxBi4-xTi4O15 (x = 0, 0.2, 0.4, 0.6 and 0.8) ceramics, fabricated from the powders synthesized via the solid-state reaction route exhibited relaxor behavior. Dielectric properties of the well sintered ceramics were measured in a wide frequency range (1 kHz-1 MHz) at different temperatures (300-750 K). The temperature of dielectri maximum (T-m) was found to decrease significantly from 696 K for an undoped sample (x = 0) to 395 K for the sample corresponding to the composition x = 0.8 accompanied by a decrease in the magnitude ofdielectric maximum (epsilon(m)). The temperature variation of the dielectric constant on the high temperature slope of the peak (T > T-m) was analyzed by using the Lorentz-ype quadratic law and the diffuseness of the peak was found to increase with increasing x. Vogel-Fulcher modelling of dielectric relaxation showed a decrease in freezing temperature (T-VF) (from 678 to 340 K) and an increase in the activation energy (5 to 24 meV) for the frequency dispersion with increase in x (La-3 divided by content). Strength of frequency dispersion of the phase transition increased with lanthanum content. Polarization (P)-electric field (E) hysteresis loops recorded at 373 showed a transition from a nearly squarish to slim loop hysteresis behavior with increasing lanthanum content.

Item Type:	Journal Article
Publication:	Advanced Science Letters
Publisher:	American Scientific Publishers
Additional Information:	Copyright of this article belongs to American Scientific Publishers.
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	10 Jun 2010 08:10
Last Modified:	19 Sep 2010 05:59
URI:	http://eprints.iisc.ac.in/id/eprint/27014

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