Recent progress on AC poling of relaxor-PbTiO ₃ ferroelectric single crystals: a review

Compared to conventional DC poling (DCP) treatment, in 2014 a novel technology, AC poling (ACP) treatment, was found to be a low-cost, time-saving and smart-process method to significantly enhance the properties of relaxor-PbTiO 3 (PT) ferroelectric single crystal (SC) transducers. In total, over 35 papers have been reported since 2018 in which researchers achieved a piezoelectric coefficient of ( d 33 ) > 4000 pC/N and electromechanical coupling factors of ( k 33 ) > 96% for the ACP SCs. In this review, we introduce the history of ACP study on relaxor-PT SCs, and our research group’s ACP study during the past three years. In particular, we focus on ACP conditions and their mechanisms of binary (1- x )Pb(Mg 1/3 Nb 2/3 )O 3 - x PbTiO 3 (PMN-PT) and ternary (1- x - y )Pb(In 1/2 Nb 1/2 )O 3 - y Pb(Mg 1/3 Nb 2/3 )O 3 - x PbTiO 3 (PIN-PMN-PT) SCs near the morphotropic phase boundary (MPB). Furthermore, we provide insight for further studies on optimal ACP conditions and the reduction of spurious-mode vibrations (SMVs). This work offers promising prospects and practical value for high-end ultrasonic imaging probe transducers.