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

Abstract : 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° 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° was found to indicate a rupture strength of 220 MPa and a piezoelectric d′31 coefficient of approximately 2 pC/N.