Growth and dielectric characterization of large single crystals of GaAsO 4, a novel piezoelectric material

Abstract

Gallium arsenate (GaAsO 4) is a new α-quartz-type piezoelectric material. Large single crystals (8 mm along the c-direction) were grown for the first time by hydrothermal methods. The different crystal faces were indexed by X-ray diffraction. The crystal quality was characterized by infrared measurements. X- and Z-cut crystals were prepared in order to perform dielectric measurements. The dielectric constants of GaAsO 4 ( ε′ 11=8.5, ε′ 33=8.6) are the highest found among α-quartz type materials. A linear relationship has been established between a structural property, the tetrahedral tilt angle δ, and the dielectric constants for the well-known α-quartz homeotypes. These results indicate that gallium arsenate should have the highest piezoelectric coupling coefficient of any material of this family.