In the past decade, domain engineered relaxor-PT ferroelectric single crystals, including (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT), (1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 (PZN-PT) and (1-x-y)Pb(In1/2Nb1/2)O3-yPb(Mg1/3Nb2/3)O3-xPbTiO3 (PIN-PMN-PT), with compositions near the morphotropic phase boundary (MPB) have triggered a revolution in electromechanical devices owing to their giant piezoelectric properties and ultra-high electromechanical coupling factors. Compared to traditional PbZr1-x Ti x O3 (PZT) ceramics, the piezoelectric coefficient d33 is increased by a factor of 5 and the electromechanical coupling factor k33 is increased from < 70% to > 90%. Many emerging rich physical phenomena, such as charged domain walls, multi-phase coexistence, domain pattern symmetries, etc., have posed challenging fundamental questions for scientists. The superior electromechanical properties of these domain engineered single crystals have prompted the design of a new generation electromechanical devices, including sensors, transducers, actuators and other electromechanical devices, with greatly improved performance. It took less than 7 years from the discovery of larger size PMN-PT single crystals to the commercial production of the high-end ultrasonic imaging probe "PureWave". The speed of development is unprecedented, and the research collaboration between academia and industrial engineers on this topic is truly intriguing. It is also exciting to see that these relaxor-PT single crystals are being used to replace traditional PZT piezoceramics in many new fields outside of medical imaging. The new ternary PIN-PMN-PT single crystals, particularly the ones with Mn-doping, have laid a solid foundation for innovations in high power acoustic projectors and ultrasonic motors, hinting another revolution in underwater SONARs and miniature actuation devices. This article intends to provide a comprehensive review on the development of relaxor-PT single crystals, spanning material discovery, crystal growth techniques, domain engineering concept, and full-matrix property characterization all the way to device innovations. It outlines a truly encouraging story in materials science in the modern era. All key references are provided and 30 complete sets of material parameters for different types of relaxor-PT single crystals are listed in the Appendix. It is the intension of this review article to serve as a resource for those who are interested in basic research and practical applications of these relaxor-PT single crystals. In addition, possible mechanisms of giant piezoelectric properties in these domain-engineered relaxor-PT systems will be discussed based on contributions from polarization rotation and charged domain walls.

中文翻译：

---

基于驰豫基的铁电单晶：生长、域工程、表征和应用

近十年来，域工程弛豫-PT铁电单晶，包括(1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT)、(1-x)Pb(Zn1/3Nb2/3) O3-xPbTiO3 (PZN-PT) 和 (1-xy)Pb(In1/2Nb1/2)O3-yPb(Mg1/3Nb2/3)O3-xPbTiO3 (PIN-PMN-PT)，其成分接近同形相界（MPB）由于其巨大的压电特性和超高的机电耦合系数引发了机电设备的革命。与传统的PbZr1-x Ti x O3 (PZT)陶瓷相比，压电系数d33提高了5倍，机电耦合系数k33从<70%提高到>90%。许多新兴的丰富物理现象，例如带电畴壁、多相共存、畴图案对称性等，给科学家提出了具有挑战性的基本问题。这些域工程单晶的卓越机电性能促进了新一代机电器件的设计，包括传感器、换能器、执行器和其他机电器件，其性能大大提高。从更大尺寸PMN-PT单晶的发现到高端超声成像探头“PureWave”的商业化生产，仅用了不到7年的时间。发展速度是前所未有的，学术界和工业工程师在这个主题上的研究合作确实很有趣。同样令人兴奋的是，这些弛豫-PT 单晶正在用于替代传统 PZT 压电陶瓷，应用于医学成像以外的许多新领域。新型三元PIN-PMN-PT单晶，特别是Mn掺杂单晶，为高功率声波投影仪和超声波电机的创新奠定了坚实的基础，预示着水下声纳和微型驱动装置的另一场革命。本文旨在对弛豫-PT 单晶的发展、跨越材料发现、晶体生长技术、域工程概念、全基体特性表征直至器件创新进行全面回顾。它概述了现代材料科学领域一个真正令人鼓舞的故事。附录中提供了所有关键参考资料，并列出了不同类型弛豫-PT单晶的30套完整材料参数。这篇综述文章的目的是为那些对这些弛豫剂-PT 单晶的基础研究和实际应用感兴趣的人提供资源。此外，还将根据极化旋转和带电畴壁的贡献，讨论这些域工程弛豫-PT系统中巨压电特性的可能机制。