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Development and Characterization of Langasite-type crystals for surface acoustic wave device

Research Project

Project/Area Number 13650346
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Electronic materials/Electric materials
Research InstitutionNARA INSTITUTE OF SCIENCE AND TECHNOLOGY

Principal Investigator

SHINOSAKI Tadashi  Nara Institute of Science and Technology, Graduate School of Materials Science, Professor, 物質創成科学研究科, 教授 (80026153)

Co-Investigator(Kenkyū-buntansha) TAKEDA Hiroaki  Nara Institute of Science and Technology, Graduate School of Materials Science, Assistant Professor, 物質創成科学研究科, 助手 (00324971)
NISHIDA Takashi  Nara Institute of Science and Technology, Graduate School of Materials Science, Assistant Professor, 物質創成科学研究科, 助手 (80314540)
OKAMURA Soichiro  Nara Institute of Science and Technology, Graduate School of Materials Science, Associate Professor, 物質創成科学研究科, 助教授 (60224060)
Project Period (FY) 2001 – 2002
Project Status Completed (Fiscal Year 2002)
Budget Amount *help
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 2002: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2001: ¥1,700,000 (Direct Cost: ¥1,700,000)
KeywordsPiezoelectric material / Crystal growth / Czochralski technique / Surface acoustic wave device / Crystal structure
Research Abstract

In this study, we paid attention to Langasite (La_3Ga_5Sio_<14>: LGS) -type crystals. The LGS crystal is a leading material suitable for piezoelectric applications, because the crystal has intermediate properties between those properties of quartz and lithium tantalate (LiTaO_3) in electricity. However, a large amount of expensive gallium oxide as the raw material is necessary for mass-production. The aims of this study are to develop new LGS-type crystals consisting of lower gallium oxides.
In the first year, we have developed Al substituted LGS crystals (La_3Ga_<5-x>Al_xSiO_<14> (0<x<1): LGAS) crystals. The single crystals, with a 20-25 mm diameter and a 100-150 mm length, were grown by a conventional Czochralski technique. The chemical composition data disclosed that the effective segregation coefficient k_<eff> of Al in LGS was 1.03 to 1.07 and that the Al solubility limit was x<1.0. A single-crystal x-ray structure analysis reveals that Al atoms are distributed in all cation sites … More except for the decahedral one occupied by La, by rather favoring the smallest tetrahedral one. The piezoelectric modulus l d_<11> l increased; 1.3% and d_<14> decreased; 7.7% with the increasing Al content, x, up to 1.0. The Al-content obtaining the maximum electromechanical coupling factors (k_<12>, k_<25>, and k_<26>) was x=0.6.
In the second year, new piezoelectric Ba_3TaGa_3Si_2O_<14> (BTGS) crystal was synthesized by the Czochralski technique using raw materials with stoichiometric compositions. An analysis of growing process showed that the BTGS crystal congruently melts. The crystal structure of BTGS has been refined using single-crystal X-ray diffraction data. The distribution pf each cation was found to be ordered in each site. The maximum electromechanical factors k^2 in Y-cut BTGS wafer was about 0.43% at X-axis propagation. This value was larger than those of LGS.
For both LGAS and BTGS crystals enables the use of a lower amount of expensive gallium oxide as the raw material. Therefore, we can say that these two crystals are the preferable piezoelectric materials with the Langasite-type structure for both bulk- and surface-acoustic wave devices. Less

Report

(3 results)
  • 2002 Annual Research Report   Final Research Report Summary
  • 2001 Annual Research Report
  • Research Products

    (15 results)

All Other

All Publications (15 results)

  • [Publications] H.Takeda, M.Kumatoriya, T.Shiosaki: "Structure and Piezoelectric properties of Al-substituted Langasite (La_3Ga_<5-x>Al_xSiO_<14>) crystals"Electroceramics in Japan. V. 43-46 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] H.Takeda, M.Kumatoriya, T.Shiosaki: "Effect of alminium substitution in La_3Ga_5SiO_<14> crystals on their structure and piezoelectric properties"Appl.Phys.Lett. 79. 4201-4203 (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] H.Takeda, S.Okamura, T.Shiosaki: "Chemical etching study on lanthanum gallium silicate La_3Ga_5SiO_<14> single crystals"J.Mater.Sci.Lett.. 21. 1117-1119 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] H.Takeda, R.Aoyagi, S.Okamura, T.Shiosaki: "Cation distribution and melting behavior of La_3Ga_5Me^<4+>O_<14>(Me=Si, Ge, Sn, Ti, Zr and Hf) crystal"Ferroelectrics. (印刷中).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] H.Takeda, T.Nishida, S.Okamura, T.Shiosaki: "Synthesis and characterization of Ba_3MeGa_3Si_2O_<14>(Me=Nb^<5+>,Ta^<5+>) crystal"Trans.Mater.Res.Soc.Jpn.. (印刷中).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] H. Takeda, M. Kumatoriya, T. Shiosaki: "Structure and Piezoelectric properties of Al-substituted (La_3Ga_<5-x>Al_xSiO_<14>) crystals"Electroceramics in Japan. V. 43-46 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] H. Takeda, M. Kumatoriya, T. Shiosaki: "Effect of aluminum substitution in La_3Ga_5SiO_<14> crystals on their structure and piezoelectric properties"Appl. Phys. Lett.. 79. 4201-4203 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] H. Takeda, S. Okamura, T. Shiosaki: "Chemical etching study on lanthanum gallium silicate La_3Ga_5SiO_<14> single crystals"J. Mater. Sci. Lett.. 21. 1117-1119 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] H. Takeda, R. Aoyagi, S. Okamura and T. Shiosaki: "Cation distribution and melting behavior of La_3Ga_5Me^<4+>O_<14> (Me=Si, Ge, Sn, Ti, Zr and Hf) crystal"Ferroelectrics, in press.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] H. Takeda, T. Nishida, S. Okumura and T. Shiosaki: "Synthesis and characterization of Ba_3MeGa_3Si_2O_<14> (Me=Nb^<5+>, Ta^<5+>) crystal"Trans. Mater. Res. Soc. Jpn., in press.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] H.Takeda, S.Okamura, T.Shiosaki: "Chemical etching study on lanthanum gallium silicate La_3Ga_5SiO_<14> single crystals"J. Mater. Sci. Lett.. 21. 1117-1119 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] H.Takeda, R.Aoyagi, S.Okamura, T.Shiosaki: "Cation distribution and melting behavior of La_3Ga_5Me^<4+>O_<14>(Me=Si,Ge,Sn,Ti,Zr and Hf) crystal"Ferroelectrics. (印刷中).

    • Related Report
      2002 Annual Research Report
  • [Publications] H.Takeda, T.Nishida, S.Okamura, T.Shiosaki: "Synthesis and characterization of Ba_3MeGa_3Si_2O_<14>(Me=Nb^<5+>,Ta^<5+>) crystal"Trans. Mater. Res. Soc. Jpn.. (印刷中).

    • Related Report
      2002 Annual Research Report
  • [Publications] H.Takeda, M.Kumatoriya, T.Shiosaki: "Structure and Piezoelectric properties of Al-substituted Langasite(La_3Ga_<5-x>Al_xSiO_<14>)crystals"Electroceramics in Japan. V. 43-46 (2002)

    • Related Report
      2001 Annual Research Report
  • [Publications] H.Takeda, M.Kumatoriya, T.Shiosaki: "Effect of alminium substitution in La_3Ga_5SiO_<14> crystals on their structure and piezoelectric properties"Appl.Phys.Lett. 79. 4201-4203 (2001)

    • Related Report
      2001 Annual Research Report

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Published: 2001-04-01   Modified: 2016-04-21  

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