title: Shaped crystal growth of langasite-type piezoelectric single crystals and their physical properties.
abstract: We have grown shape-controlled langasite-type crystals by the micro-pulling-down (μ-PD) method. Columnar shaped La(3)Ta(0.5)Ga(5.5)O(14) (LTG), Ca(3)NbGa(3)Si(2)O(14) (CNGS), Ca(3)TaGa(3)Si(2)O(14) (CTGS), Sr(3)NbGa(3)Si(2)O(14) (SNGS), and Sr(3)Ta- Ga(3)Si(2)O(14) (STGS) crystals were grown using a Pt-Rh crucible with a 3-mm-diameter columnar die at the bottom. All grown crystals showed high transparency except for the peripheral area and diameter of approximately 3 mm. The chemical phases at the central parts of the grown crystals were identified as a single phase of langasite-type structure and their lattice parameters were almost the same as those of crystals grown by the Czochralski (Cz) method; however, some impurity phases were observed in the peripheral area. In X-ray rocking curve measurements, the grown crystals indicated equivalent crystallinity to the crystal grown by the Cz method. The piezoelectric constant d(11) of the CNGS crystal was 3.98 pC/N; this value is well correlated with those of previous reports.
authors.affiliation: Tohoku University, Sendai, Japan. yokota@imr.tohoku.ac.jp
authors.forename: Yuui
authors.initials: Y
authors.lastname: Yokota
authors.forename: Akira
authors.initials: A
authors.lastname: Yoshikawa
authors.forename: Yoshisuke
authors.initials: Y
authors.lastname: Futami
authors.forename: Masato
authors.initials: M
authors.lastname: Sato
authors.forename: Kazushige
authors.initials: K
authors.lastname: Tota
authors.forename: Ko
authors.initials: K
authors.lastname: Onodera
authors.forename: Takayuki
authors.initials: T
authors.lastname: Yanagida