Growth and dielectric characterization of large single crystals of GaAsO4, a novel piezoelectric material

Gallium arsenate (GaAsO4) is a new alpha-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 GaAsO4 (epsilon(11)' = 8.5, epsilon(33)' = 8.6) are the highest found among alpha-quartz type materials. A linear relationship has been established between a structural property, the tetrahedral tilt angle delta, and the dielectric constants for the well-known alpha-quartz homeotypes. These results indicate that gallium arsenate should have the highest piezoelectric coupling coefficient of any material of this family. (C) 2003 Editions scientifiques et medicales Elsevier SAS. All fights reserved.