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Electric field‐induced irreversible relaxor to ferroelectric phase transformations in Na 0.5 Bi 0.5 TiO 3 ‐NaNbO 3 ceramics
Author(s) -
Wang Ge,
Lu Zhilun,
Zhang Zhenbo,
Feteira Antonio.,
Tang Chiu C.,
Hall David A.
Publication year - 2019
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.16676
Subject(s) - materials science , tetragonal crystal system , ferroelectricity , electric field , piezoelectricity , condensed matter physics , synchrotron , phase (matter) , trigonal crystal system , ceramic , phase transition , crystallography , crystal structure , dielectric , optics , composite material , optoelectronics , chemistry , physics , organic chemistry , quantum mechanics
(1‐x)Na 0.5 Bi 0.5 TiO 3 ‐xNaNbO 3 (x = 0.02, 0.04, 0.06, and 0.08) ceramics were fabricated by solid‐state reaction. High‐resolution synchrotron x‐ray powder diffraction (SXPD) data, coupled with macroscopic electromechanical measurements, reveal the occurrence of an electric field‐induced irreversible crystallographic transformation for x = 0.02 and 0.04, from a pseudo‐cubic non‐ergodic relaxor to a rhombohedral or coexisting rhombohedral‐tetragonal long range‐ordered ferroelectric phase, respectively. The highest unipolar electrostrain, corresponding to an effective longitudinal piezoelectric strain coefficient of approximately 340 pm V −1 , was obtained for x = 0.04; this effect is attributed to enhanced domain switching as a result of the co‐existing rhombohedral and tetragonal phases for this composition, which is critical for piezoelectric actuator applications.