[14p-2K-1~17] 15.1 Bulk crystal growth

▼ [14p-2K-8] Piezoelectric Ca₃TaAl₃Si₂O₁₄ (CTAS) Single Crystals for High Temperature Sensors

〇(D)Xiuwei Fu^1,2, Encarnacion G. Villora¹, Isao Sakaguchi¹, Yuuki Kitanaka³, Yuji Noguchi³, Masaru Miyayama³, Kiyoshi Shimamura^1,2, Naoki Ohashi^1,4 (1.NIMS, 2.Waseda Univ., 3.The Univ. Tokyo, 4.Tokyo Inst. Tech.)

Keywords:Piezoelectric,Langasite,High temperature sensors

The piezoelectric langasite family is attracting much attention for high temperature sensor applications. These crystals do not present any phase transition up to their melting point (1300-1500^oC), exhibit good piezoelectric properties, are not pyroelectric, and can be grown by the Czochralski technique. Among them, the ordered Ca₃TaAl₃Si₂O₁₄ (CTAS) crystal is of particular interest, since it is Ga-free and exhibits high resistivity and thermal stability of dielectric and electromechanical properties. In this work, high quality CTAS single crystals have been grown successfully by the Cz method. The effect of growth conditions on their piezoelectric, electric and optical properties has been examined for the first time in detail. A notable influence is observed, especially in resistivity, which could be increased beyond the reported values for the same CTAS single crystals.