Piezoelectric anomalies at the ferroelastic phase transitions of lead-free tungsten bronze ferroelectrics

Takayuki Watanabe, Jumpei Hayashi, Takanori Matsuda, Toshihiro Ifuku, Bong Yeon Lee, Takashi Iijima, Hiroshi Funakubo, Houzhona Yu, Nobuhiro Kumada

研究成果: ジャーナルへの寄稿記事

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This paper reports on the piezoelectric anomalies at the temperature or composition-induced ferroelastic phase transitions of tungsten bronze ferroelectrics. First, the temperature-dependent piezoelectric properties of Sr1.9Ca0.1NaNb5O15 (SCNN) ceramics were characterized using a resonance/anti-resonance method. SCNN has a ferroelastic phase transition manifested by a broad dielectric peak in the temperature range of -60°C to 20°C. The electromechanical coupling factor and elastic compliance showed the maximum at -40°C, increasing the transverse piezoelectric constant (d31) by 38% compared with the room temperature value. Tungsten bronze ferroelectrics follow a trade-off relationship between the longitudinal piezoelectric constant (d33) and the Curie temperature, while SCNN deviates significantly from the trend curve. This deviation is attributed to the ferroelastic phase transition close to room temperature. Second, the ferroelastic phase transition was investigated for epitaxial films of (1-x)(Sr3Ba2)Nb10O 30-xBa4Bi2/3Nb10O30 as a function of the composition. A careful structural analysis by X-ray diffraction revealed that there is a ferroelastic phase boundary between tetragonal and orthorhombic crystals at x = 0.06-0.3. The electric field-induced strain and the relative dielectric constants characterized at 80K for the epitaxial films increased in the vicinity of the phase boundary composition. These results suggest that engineering the ferroelastic phase transition is an approach to improving the piezoelectric properties of lead-free tungsten bronze ferroelectrics.

元の言語英語
ページ(範囲)717-721
ページ数5
ジャーナルJournal of the Ceramic Society of Japan
118
発行部数1380
DOI
出版物ステータス出版済み - 1 1 2010
外部発表Yes

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All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry

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