Control of thermophysical properties of langasite-type La3Ta0.5Ga5.5O14 crystals for pressure sensors

Haruki Usui, Makoto Tokuda, Kazumasa Sugiyama, Takuya Hoshina, Takaaki Tsurumi, Kheirreddine Lebbou, Ikuo Yanase, Hiroaki Takeda

Research output: Contribution to journalArticlepeer-review

Abstract

We present a possible method to reduce the anisotropy of the thermal stress generated on langasite-type La3Ta0.5Ga5.5O14 (LTG) piezoelectric crystals arising from the mismatch of the thermal expansion coefficients and Young’s moduli of the crystals and metals at high temperatures. To formulate this method, the thermal stresses of order-type langasite crystals, in which each cation site is occupied by one element only, were calculated and compared to each other. Our results suggest that the largest cation site affects the thermal stress. We attempted to replace La3+ in LTG by a larger ion and considered Sr2+. Single crystals of strontium-substituted LTG (Sr-LTG) were grown using the Czochralski method. The thermal stress along the crystallographic c-axis decreased but that perpendicular to the c-axis increased by strontium substitution into the LTG crystal. The anisotropic thermal stress was reduced effectively. The Sr-LTG single crystal is a superior candidate material for pressure sensors usable at high temperatures.

Original languageEnglish
Article number936
Pages (from-to)1-9
Number of pages9
JournalCrystals
Volume10
Issue number10
DOIs
Publication statusPublished - 2020 Oct

Keywords

  • Anisotropy
  • Langasite
  • Pressure sensor
  • Substitution
  • Thermal stress

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Inorganic Chemistry

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