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Giant electromechanical strain response in lead‐free SrTiO 3 ‐doped (Bi 0.5 Na 0.5 TiO 3 –BaTiO 3 )–LiNbO 3 piezoelectric ceramics
Author(s) -
Wu Lei,
Shen Bo,
Hu Querui,
Chen Jing,
Wang Yiping,
Xia Yidong,
Yin Jiang,
Liu Zhiguo
Publication year - 2017
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.15009
Subject(s) - materials science , ferroelectricity , coercivity , piezoelectricity , piezoelectric coefficient , analytical chemistry (journal) , condensed matter physics , solid solution , doping , mineralogy , composite material , dielectric , chemistry , optoelectronics , physics , metallurgy , chromatography
Lead‐free 0.985[(0.94− x )Bi 0.5 Na 0.5 TiO 3 –0.06BaTiO 3 – x SrTiO 3 ]–0.015LiNbO 3 [( BNT – BT – x ST )– LN , x =0‐0.05] piezoelectric ceramics were prepared using a conventional solid‐state reaction method. It was found that the long‐range ferroelectric order in the unmodified ( BNT – BT )– LN ceramic was disrupted and transformed into the ergodic relaxor phase with the ST substitution, which was well demonstrated by the dramatic decrease in remnant polarization ( P r ), coercive field ( E c ), negative strain ( S neg ) and piezoelectric coefficient ( d 33 ). However, the degradation of the ferroelectric and piezoelectric properties was accompanied by a significant increase in the usable strain response. The critical composition ( BNT – BT –0.03 ST )– LN exhibited a maximum unipolar strain of ~0.44% and corresponding normalized strain, S max / E max of ~880 pm/V under a moderate field of 50 kV /cm at room temperature. This giant strain was associated with the coexistence of the ferroelectric and ergodic relaxor phases, which should be mainly attributed to the reversible electric‐field‐induced transition between the ergodic relaxor and ferroelectric phases. Furthermore, the large field‐induced strain showed relatively good temperature stability; the S max / E max was as high as ~490 pm/V even at 120°C. These findings indicated that the ( BNT – BT – x ST )– LN system would be a suitable environmental‐friendly candidate for actuator applications.