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

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

Research output: Journal article publicationJournal articleAcademic researchpeer-review

73 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 languageEnglish
Article number035411
JournalJournal of Physics D: Applied Physics
Volume42
Issue number3
DOIs
Publication statusPublished - 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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