Ultrahigh‐temperature field cooling poling of PMN–PT single crystals for enhanced material and transducer performance

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.