Microstructure and electrical properties of La-modified K0.5Na0.5NbO3lead-free piezoelectric ceramics

Daojiang Gao; Kin Wing Kwok; Dunmin Lin; H. L.W. Chan

doi:10.1088/0022-3727/42/3/035411

Microstructure and electrical properties of La-modified K_0.5Na_0.5NbO₃lead-free piezoelectric ceramics

Daojiang Gao, Kin Wing Kwok, Dunmin Lin, H. L.W. Chan

Research output: Journal article publication › Journal article › Academic research › peer-review

82 Citations (Scopus)

Abstract

Lead-free ceramics (K0.5Na0.5)1-3xLaxNbO3(0 ≤ x ≤ 0.0175) have been fabricated by a conventional sintering technique. The results of XRD show that the ceramics possess a perovskite structure with orthorhombic symmetry. Moreover, doping inhibits the grain growth, decreases the ferroelectric-paraelectric phase transition temperature and induces a diffuse phase transition. At low doping levels (x ≤ 0.0075), the observed remanent polarization (Pr) and coercive field (Ec) remain almost unchanged. As x increases from 0.0075 to 0.0175, Prstarts to decrease while Ecincreases. Nevertheless, due to the increase in relative permittivity, the ceramic with x = 0.0125 exhibits the optimum piezoelectric properties, giving a large piezoelectric coefficient (d33= 135 pC N-1) and a high planar electromechanical coupling coefficient (kP= 0.40).

Original language	English
Article number	035411
Journal	Journal of Physics D: Applied Physics
Volume	42
Issue number	3
DOIs	https://doi.org/10.1088/0022-3727/42/3/035411
Publication status	Published - 9 Apr 2009

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Condensed Matter Physics
Acoustics and Ultrasonics
Surfaces, Coatings and Films

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10.1088/0022-3727/42/3/035411

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title = "Microstructure and electrical properties of La-modified K0.5Na0.5NbO3lead-free piezoelectric ceramics",

abstract = "Lead-free ceramics (K0.5Na0.5)1-3xLaxNbO3(0 ≤ x ≤ 0.0175) have been fabricated by a conventional sintering technique. The results of XRD show that the ceramics possess a perovskite structure with orthorhombic symmetry. Moreover, doping inhibits the grain growth, decreases the ferroelectric-paraelectric phase transition temperature and induces a diffuse phase transition. At low doping levels (x ≤ 0.0075), the observed remanent polarization (Pr) and coercive field (Ec) remain almost unchanged. As x increases from 0.0075 to 0.0175, Prstarts to decrease while Ecincreases. Nevertheless, due to the increase in relative permittivity, the ceramic with x = 0.0125 exhibits the optimum piezoelectric properties, giving a large piezoelectric coefficient (d33= 135 pC N-1) and a high planar electromechanical coupling coefficient (kP= 0.40).",

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AU - Gao, Daojiang

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AU - Lin, Dunmin

AU - Chan, H. L.W.

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N2 - Lead-free ceramics (K0.5Na0.5)1-3xLaxNbO3(0 ≤ x ≤ 0.0175) have been fabricated by a conventional sintering technique. The results of XRD show that the ceramics possess a perovskite structure with orthorhombic symmetry. Moreover, doping inhibits the grain growth, decreases the ferroelectric-paraelectric phase transition temperature and induces a diffuse phase transition. At low doping levels (x ≤ 0.0075), the observed remanent polarization (Pr) and coercive field (Ec) remain almost unchanged. As x increases from 0.0075 to 0.0175, Prstarts to decrease while Ecincreases. Nevertheless, due to the increase in relative permittivity, the ceramic with x = 0.0125 exhibits the optimum piezoelectric properties, giving a large piezoelectric coefficient (d33= 135 pC N-1) and a high planar electromechanical coupling coefficient (kP= 0.40).

AB - Lead-free ceramics (K0.5Na0.5)1-3xLaxNbO3(0 ≤ x ≤ 0.0175) have been fabricated by a conventional sintering technique. The results of XRD show that the ceramics possess a perovskite structure with orthorhombic symmetry. Moreover, doping inhibits the grain growth, decreases the ferroelectric-paraelectric phase transition temperature and induces a diffuse phase transition. At low doping levels (x ≤ 0.0075), the observed remanent polarization (Pr) and coercive field (Ec) remain almost unchanged. As x increases from 0.0075 to 0.0175, Prstarts to decrease while Ecincreases. Nevertheless, due to the increase in relative permittivity, the ceramic with x = 0.0125 exhibits the optimum piezoelectric properties, giving a large piezoelectric coefficient (d33= 135 pC N-1) and a high planar electromechanical coupling coefficient (kP= 0.40).

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Microstructure and electrical properties of La-modified K_0.5Na_0.5NbO₃lead-free piezoelectric ceramics

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