Crystal Growth of Ca₃Nb(Ga1- xAl x)₃Si₂O14 Piezoelectric Single Crystals with Various Al Concentrations

Yuui Yokota; Tetsuo Kudo; Yuji Ohashi; Andrey Medvedev; Shunsuke Kurosawa; Kei Kamada; Akira Yoshikawa

doi:10.3390/ma8095264

Crystal Growth of Ca₃Nb(Ga_{1- x}Al _x)₃Si₂O₁₄ Piezoelectric Single Crystals with Various Al Concentrations

Materials (Basel). 2015 Aug 26;8(9):5597-5605. doi: 10.3390/ma8095264.

Authors

Yuui Yokota¹, Tetsuo Kudo², Yuji Ohashi³, Andrey Medvedev⁴, Shunsuke Kurosawa^{5

6}, Kei Kamada^{5

7}, Akira Yoshikawa^{8

9

10}

Affiliations

¹ New Industry Creation Hatchery Center (NICHe), Tohoku University, 6-6-10, Aoba, Aramaki, Aoba-ku, Miyagi, Sendai 980-8579, Japan. yokota@imr.tohoku.ac.jp.
² Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Miyagi, Sendai 980-8577, Japan. t_kudo@imr.tohoku.ac.jp.
³ Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Miyagi, Sendai 980-8577, Japan. ohashi@imr.tohoku.ac.jp.
⁴ Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Miyagi, Sendai 980-8577, Japan. medvedev@imr.tohoku.ac.jp.
⁵ New Industry Creation Hatchery Center (NICHe), Tohoku University, 6-6-10, Aoba, Aramaki, Aoba-ku, Miyagi, Sendai 980-8579, Japan. kurosawa@imr.tohoku.ac.jp.
⁶ Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Miyagi, Sendai 980-8577, Japan. kurosawa@imr.tohoku.ac.jp.
⁷ Corporation 6-6-40, Aoba, Aramaki, Aoba-ku, Miyagi, Sendai 980-8579, Japan. kurosawa@imr.tohoku.ac.jp.
⁸ New Industry Creation Hatchery Center (NICHe), Tohoku University, 6-6-10, Aoba, Aramaki, Aoba-ku, Miyagi, Sendai 980-8579, Japan. yoshikawa@imr.tohoku.ac.jp.
⁹ Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Miyagi, Sendai 980-8577, Japan. yoshikawa@imr.tohoku.ac.jp.
¹⁰ Corporation 6-6-40, Aoba, Aramaki, Aoba-ku, Miyagi, Sendai 980-8579, Japan. yoshikawa@imr.tohoku.ac.jp.

Abstract

Ca₃Nb(Ga_1-xAl_x)₃Si₂O₁₄ (CNGAS) single crystals with various Al concentrations were grown by a micro-pulling-down (µ-PD) method and their crystal structures, chemical compositions, crystallinities were investigated. CNGAS crystals with x = 0.2, 0.4 and 0.6 indicated a single phase of langasite-type structure without any secondary phases. In contrast, the crystals with x = 0.8 and 1 included some secondary phases in addition to the langasite-type phase. Lattice parameters, a- and c-axes lengths, of the langasite-type phase systematically decreased with an increase of Al concentration. The results of chemical composition analysis revealed that the actual Al concentrations in as-grown crystals were almost consistent with the nominal compositions. In addition, there was no large segregation of each cation along the growth direction.

Keywords: langasite; micro-pulling-down method; piezoelectric crystal; single crystal.