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The Effect of Electric Poling on the Performance of Lead‐Free (1− x ) Ba ( Zr 0.2 Ti 0.8 ) O 3 – x ( Ba 0.7 Ca 0.3 ) TiO 3 Piezoceramics
Author(s) -
Ehmke Matthias C.,
Glaum Julia,
Hoffman Mark,
Blendell John E.,
Bowman Keith J.
Publication year - 2013
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.12586
Subject(s) - poling , coercivity , piezoelectricity , phase boundary , materials science , electric field , ferroelectricity , condensed matter physics , tetragonal crystal system , polarization (electrochemistry) , dielectric , piezoelectric coefficient , permittivity , electromechanical coupling coefficient , phase (matter) , crystallography , crystal structure , composite material , optoelectronics , chemistry , physics , organic chemistry , quantum mechanics
The effect of increasing poling fields on the properties of (1− x ) BZT – x BCT compositions across the morphotropic phase boundary ( MPB ) is studied using large signal polarization and strain, small signal permittivity and piezoelectric coefficient, and XRD measurements. Successive poling causes charge carrier migration inducing an internal bias field, which becomes large with respect to the coercive field resulting in biased ferroelectric and ferroelastic switching. Improvements in piezoelectric coefficient of 9% are significantly smaller in the tetragonal 60 BCT composition compared with the improvement of approximately 50% in the rhombohedral 40 BCT and MPB 50 BCT compositions. While the properties continue to change with increased poling fields, the remnant ferroelastic domain texture parallel to the field direction, as observed from XRD , stays approximately constant. The improvement in overall domain alignment leading to largely enhanced intrinsic piezoelectricity originates from the alignment of 180° domains and possibly non‐180° domains in grains with orientations inclined to the electric field. As a result, poling is most effective in BZT – BCT materials that have low coercive fields, show low distortions and possess more polarization orientations, such as compositions in the rhombohedral phase field or near the MPB .