Growth and characterization of Ca 2− x Ae x Al 2 SiO 7 ( Ae = Sr, Ba) piezoelectric single crystals

We report the effects of Sr or Ba substitution on the crystal growth and electrical and mechanical properties of Ca2Al2SiO7(CAS) piezoelectric single crystals, which are suitable for use in high-temperature pressure sensors. Ba was scarcely incorporated in the crystal lattice of CAS. Strontium-substituted CAS single crystal with a nominal chemical composition Ca0.75Sr1.25Al2SiO7 (CSAS125) was grown by the Czochralski method. Although the piezoelectric modulus d'(31) of CSAS125 is a bit lower than that of the CAS crystal, the rupture strength of the (XYt)45 degrees rotation cut substrate of CSAS125 crystal was 170 MPa, which was 1.2 times higher than that of CAS crystal. By considering the rupture strength and the apparent piezoelectric d*(31) coefficient calculated for the crystal rotation cut of CAS crystal, the CSAS125 crystal substrate with a rotation cut of (XYt)25 degrees was found to indicate a rupture strength of 220 MPa and a piezoelectric d'(31) coefficient of approximately 2 pC/N. (C) 2018 The Ceramic Society of Japan. All rights reserved.