Anomalous influence of grain size on the global structure, ferroelectric and piezoelectric response of Na0.5Bi0.5TiO3

Khatua, Dipak Kumar and Mehrotra, Tarang and Mishra, Anupam and Majumdar, Bhaskar and Senyshyn, Anatoliy and Ranjan, Rajeev (2017) Anomalous influence of grain size on the global structure, ferroelectric and piezoelectric response of Na0.5Bi0.5TiO3. In: ACTA MATERIALIA, 134 . pp. 177-187.

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Abstract

Na0.5Bi0.5TiO3 (NBT) based lead-free piezoelectrics have received significant attention in the last few years for their anomalous high-field electrostrain response. The positional disorder on the nano/meso scale in these systems have a profound effect on their perceived global structure and dielectric properties. Here we have carried out a systematic analysis of the grain size dependent structural, ferroelectric, piezoelectric and high temperature electrical conduction behaviour of NBT. We show that the global monoclinic lattice distortion collapses even while the grains are unusually large (similar to 2.5 mu m). We also found that the polarization switching ability and piezoelectric response of bulk NBT ceramics reduce drastically when grains are submicron in size. We use a powder poling technique to prove that the significant reduction of piezoelectricity in the submicron grain ceramic is not due to suppression of ferroelectricity within the grains itself, but rather due to inability of the grains to transform collectively to a long range rhombohedral ferroelectric state, either because of the clamping effect and/or enhanced incoherence of the grain boundaries. We also noted a qualitative change in the electrical conduction behaviour as a function of grain size and comment on a possible correlation between the grain size, global structure, piezoelectric response and oxygen ion conductivity of this lead-free compound. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Publication:	ACTA MATERIALIA
Additional Information:	Copy right for this article belongs to the PERGAMON-ELSEVIER SCIENCE LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	01 Sep 2017 09:25
Last Modified:	01 Sep 2017 09:25
URI:	http://eprints.iisc.ac.in/id/eprint/57715

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