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Effect of Ferroelectric Long‐Range Order on the Unipolar and Bipolar Electric Fatigue in Bi 1/2 Na 1/2 TiO 3 ‐Based Lead‐Free Piezoceramics
Author(s) -
Luo Zhenhua,
Granzow Torsten,
Glaum Julia,
Jo Wook,
Rödel Jürgen,
Hoffman Mark
Publication year - 2011
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/j.1551-2916.2011.04605.x
Subject(s) - ferroelectricity , materials science , piezoelectricity , electric field , domain wall (magnetism) , condensed matter physics , composite material , dielectric , optoelectronics , magnetic field , physics , magnetization , quantum mechanics
The fatigue behavior of the lead‐free piezoelectric Bi 1/2 Na 1/2 TiO 3 –BaTiO 3 −K 0.5 Na 0.5 NbO 3 ( BNT ‐ BT ‐ KNN ) under bipolar and unipolar electrical loading is investigated. Special attention is paid to the effect of a decreasing ferroelectric order which was affected by an increase in KNN ‐content. It is found that, in mainly ferroelectric systems with low KNN ‐content, bipolar cycling leads to domain wall pinning and formation of microcracks, while in mainly non‐ferroelectric systems with high KNN ‐content fatigue can be rationalized by the repeated field‐induced phase transition occurring during each field cycle. Under unipolar load, fatigue in low‐ KNN systems is dominated by domain wall pinning and the formation of a space charge field. Only the latter effect is present in non‐ferroelectric high‐ KNN systems, which fatigue to a smaller degree.