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Adaptive dipolar correlation in ferroelectric x(Ba0.7Ca0.3)TiO3-(1-x)Ba(Zr0.2Ti0.8) O3

Datta, K and Brajesh, K and Ranjan, R and Mihailova, B (2020) Adaptive dipolar correlation in ferroelectric x(Ba0.7Ca0.3)TiO3-(1-x)Ba(Zr0.2Ti0.8) O3. In: Physical Review B, 102 (6).

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Official URL: https://dx.doi.org/10.1103/PhysRevB.102.060102


Deriving structure-property relationships for multicomponent ferroelectric materials has always been a challenging problem because the properties are mostly driven by subtle nanoscale correlations which are hard to detect. Here we have studied the famous Pb-free material x(Ba0.7Ca0.3)TiO3-(1-x)Ba(Zr0.2Ti0.8)O3 (xBCT-BZT) which has been at the center of attention for approximately the last 10 years because of its unprecedented piezoelectric properties. However, the structure-property relationship for xBCT-BZT remains elusive as neither the common concepts nor the experimental results lead to satisfactory models which can fully explain its unusual piezoelectric properties as a function of composition as well as recognize its uniqueness compared to other similar systems. Hence we have applied total neutron-scattering and Raman-scattering methods to examine the local structural correlations of xBCT-BZT in the range 0.40�x�0.60 at ambient conditions. By refining large-box atomistic models against the neutron pair distribution functions, we have observed an emerging coherence in the polar displacements of the cations at x=0.50, leading to an increased structural ergodicity at the key orthorhombic-tetragonal phase boundary. Given the very similar level of local structural disorder and spontaneous polarization found in the system with x, we propose that the abrupt amplification of piezoelectric properties in this material at a region of phase instability is a consequence of enhanced collaboration amongst the all cations in a strain-reduced local environment. It also indicates that the popular structure-property concept entailing a low-symmetry crystal structure cannot be a generic concept or a precondition. © 2020 American Physical Society.

Item Type: Journal Article
Publication: Physical Review B
Publisher: American Physical Society
Additional Information: The copyright of this article belongs to American Physical Society
Keywords: Crystal symmetry; Distribution functions; Ferroelectric materials; Ferroelectricity; Neutron scattering; Piezoelectricity; Positive ions; Titanium oxides, Low symmetry crystals; Pair distribution functions; Piezoelectric property; Spontaneous polarizations; Structural correlation; Structural disorders; Structure property relationships; Total neutron scattering, Structural properties
Department/Centre: Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited: 24 Sep 2020 07:34
Last Modified: 24 Sep 2020 07:34
URI: http://eprints.iisc.ac.in/id/eprint/66529

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