Microscopic origin of giant piezoelectricity in ferroelectric xBi(Ni0.5Hf0.5) O3-(1-x)PbTiO3 beyond the morphotropic phase boundary

Datta, K and Kumar, N and Upadhyay, A and Mihailova, B and Ranjan, R (2021) Microscopic origin of giant piezoelectricity in ferroelectric xBi(Ni0.5Hf0.5) O3-(1-x)PbTiO3 beyond the morphotropic phase boundary. In: Physical Review B, 104 (14).

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Abstract

Local structural correlations in a novel ferroelectric solid solution xBi(Ni0.5Hf0.5)O3-(1-x)PbTiO3 at x=0.39 have been drawn out through atomistic modeling against neutron pair distribution functions and complementary Raman scattering measurements. By examining polar displacements of different cations from the refined structural models, we reveal the distributions of cation-specific dipolar fluctuations at the key composition where the maximum piezoelectric response was recorded. It becomes clear that the unusual structural modifications observed after the poling are simply a manifestation driven by the varying extent of the dipolar fluctuations and not a structural transformation caused by adaptive cationic displacements. Moreover, in addition to strong dipolar flexibility under an electric field, both poled and unpoled ceramics exhibit orientation-independent polarized Raman scattering, which is more typical of a dipolar glass with a responsive and polarizable matrix than a polycrystalline material composed of ferroelectric domains. Therefore, compared to other analogous xBi(Me)O3-(1-x)PbTiO3 systems, the current material is a unique case where chemical substitution has led to a highly polarizable ionic-covalent matrix that seems to be the key ingredient to generate giant piezoelectricity at a composition beyond the morphotropic phase boundary. © 2021 American Physical Society.

Item Type:	Journal Article
Publication:	Physical Review B
Publisher:	American Physical Society
Additional Information:	The copyright for this article belongs to American Physical Society
Keywords:	Crystallography; Distribution functions; Ferroelectric materials; Ferroelectricity; Lead titanate; Piezoelectricity; Positive ions; Raman scattering; Solid solutions, Atomistic modelling; Distribution of cations; Ferroelectric solid solutions; matrix; Morphotropic phase boundaries; Pair distribution functions; Piezoelectric response; Raman Scattering measurements; Structural correlation; Structural modeling, Polycrystalline materials
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	22 Nov 2021 10:16
Last Modified:	22 Nov 2021 10:16
URI:	http://eprints.iisc.ac.in/id/eprint/70556

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