Electromechanical characterization of Pb (In_0.5Nb_0.5) O₃ -Pb (Mg_1/3Nb_2/3) O₃ - PbTiO ₃ crystals as a function of crystallographic orientation and temperature

Relaxor based Pb (In_0.5Nb_0.5) O₃ -Pb (Mg_1/3 Nb_2/3) O₃ - PbTiO₃ ternary single crystals (PIN-PMN-PT) were reported to have broader temperature usage range (TR-T) and comparable piezoelectric properties to Pb (Mg _1/3Nb_2/3) O₃ - PbTiO₃ (PMNT) crystals. In this work, the orientation dependent dielectric, piezoelectric and electromechanical properties for PIN-PMN-PT crystals were investigated along 〈 001 〉 and 〈 110 〉 directions. The electromechanical couplings k₃₃ and k₃₂ for 〈 110 〉 poled crystals were found to be 0.91 and 0.91, respectively, with piezoelectric coefficients d₃₃ and d₃₂ on the order of 925 and -1420 pC/N. Of particular significance was the mechanical quality factor Q₃₃ for 〈 110 〉 oriented crystals, which was found to be 500, much higher than the Q values of 〈 001 〉 oriented relaxor-PT crystals (Q∼70-200). The temperature dependence of the piezoelectric properties exhibited good temperature stability up to their ferroelectric phase transition T_R-T ∼125 °C, indicating 〈 001 〉 and 〈 110 〉 oriented PIN-PMN-PT are promising materials for transducer applications, with the latter for high power resonant devices where low loss (high Q) was required.