Growth and Piezoelectric Properties of Melilite ABC3O7 Crystals

Abstract

Single ABC3O7 crystals with the melilite structure, including SrLaGa3O7, SrGdGa3O7, and BaLaGa3O7, have been successfully grown by the Czochralski method. A complete set of room temperature elastic, dielectric, and piezoelectric constants was determined using resonance techniques and impedance analysis. Our results indicate that the crystals exhibit superior piezoelectric and elastic properties. The electrical resistivity was found to be on the order of 6 × 1013 ohm·cm at room temperature. The dielectric permittivity e11, piezoelectric constant d14, and electromechanical coupling coefficient k′12 were found to be on the order of 15–17, 12–15 pC/N, and 16–19%, respectively. For an ABC3O7 group member such as SrLaGa3O7, the melting temperature was measured to be 1588 °C, below which the crystal maintains good thermal stability. Consequently, the piezoelectric properties were studied as a function of temperature over the range of −50 to 120 °C. The frequency vs temperature coefficient was determined to be −1...