Crystal growth and ferroelectric related properties of (1-x)Pb(A 1/3Nb2/3)O3-xPbTiO3 (A=Zn 2+, Mg2+)

Crystals of (1-x)Pb(A_1/3Nb_2/3)O₃-xPbTiO₃ (A=Zn²⁺, Mg²⁺) were grown by the flux technique. The dielectric and piezoelectric properties as a function of composition and crystal orientation have been evaluated. Both MPB and non-MPB crystals were found to possess high piezoelectric properties. Values of longitudinal electromechanical coupling coefficients (k₃₃)>90%, dielectric constants ranging from 3000 to 5000 with low dielectric loss <1% were observed for rhombohedral crystals. Tetragonal crystals with increased PbTiO₃ content exhibited large thickness coupling coefficients (k_T)>63% with relatively low dielectric constant (~1000). Ultrahigh values of piezoelectric coefficients (d₃₃)>2000 pC/N were also measured for non-MPB crystals and confirmed by direct E-field strain measurements. These properties are briefly discussed in relation to device performance