Superior dielectric and piezoelectric properties of Pb(Mg_1/3Nb_2/3)O₃–PbTiO₃ single crystals with optimized low electric field AC poling condition

Abstract

This study reports on the dielectric, piezoelectric, and microstructural properties of Pb(Mg_1/3Nb_2/3)O₃–0.305PbTiO₃ (PMN-PT) single crystals (SCs) prepared by the one-charge Bridgman method, focusing on the effects of varying AC cycles, 1 to 1600, of alternating current poling (ACP) on the piezoelectric properties. Optimal properties were obtained at a low electric field of 3 kVrms/cm with 80 ACP cycles of a 1.0 Hz bipolar sine wave, resulting in a dielectric constant (ε^T₃₃/ε₀) of 14700, a piezoelectric constant d₃₃ of 4200 pC/N and a low dielectric loss of 0.24 %. These superior properties are among the best reported to date for piezoelectric SCs whose phase change temperatures exceed 75 °C. Scanning electron microscopy analysis revealed significant microstructural changes, including the formation of finely striped 1 to 4 µm 109° domain wall patterns (with an average width of 1.5 µm), which developed with increasing ACP cycles. A significant decrease in piezoelectric properties—low ε^T₃₃/ε₀ of 9500 and d₃₃ of 2500 pC/N—were observed after 800 cycles, correlating with the microstructural change. The study demonstrates that precise control of ACP conditions is essential to achieve the desired piezoelectric properties in PMN-PT SC materials. These findings provide critical insights for optimizing the properties of PMN-PT SCs and their potential for high-performance piezoelectric applications.