Abstract Relaxor‐based ferroelectric single crystals, such as Pb(Mg 1/3 Nb 2/3 )O 3 –PbTiO 3 (PMN–PT), are critical for advanced ultrasonic transducers due to their exceptional piezoelectric and electromechanical properties. To further enhance performance, domain engineering has emerged as a cost‐effective and versatile strategy for tailoring material functionality. In this work, an ultrahigh‐temperature field cooling poling (UFCP) method is applied to 001‐oriented PMN–PT single crystals. The approach combines DC–AC poling above the Curie temperature with a subsequent field cooling process, enabling controlled domain configuration and enhanced thickness‐mode vibration performance. Compared with conventional direct current poling (DCP), UFCP crystals exhibit a 51% increase in piezoelectric coefficient and a 23% improvement in the mechanical quality factor . Thickness‐mode ultrasonic transducers fabricated from these crystals further demonstrate a 7.2% enhancement in −6 dB bandwidth and a 2.3 dB reduction in insertion loss. These results establish UFCP as an effective domain engineering strategy that optimizes phase coexistence to achieve simultaneous improvements in material properties and device performance.
Zhu et al. (Thu,) studied this question.