Optimized orientation of 0.71Pb(Mg_1/3Nb_2/3)O₃–0.29PbTiO₃ single crystal for applications in medical ultrasonic arrays

In order to extend the potential applications of medical ultrasonic array transducers, two optimized directions with the maximal electromechanical coefficient k₃₃^′ and minimal k₃₁ are determined for [001] and [110] poled 0.71Pb(Mg_1/3Nb_2/3)O₃-0.29PbTiO₃ single crystals using the experimental method. The maximum values of k₃₃^′ can reach 92.8% and 93.3%, respectively, corresponding to [001]_W/[110]_L and [110]_W/[1–11]_L cuts. Furthermore, we simulate the performances of three 3.5 MHz linear array transducers based on the determined directions by PIEZOCAD. Results indicate that under the [001]_W/[110]_L direction, 25% broader bandwidth, 40% shorter pulse length, and 3 dB higher sensitivity can be obtained compared to the traditional Pb(Zr_1-xTi_x)O₃ transducers.