A Review of Lead Perovskite Piezoelectric Single Crystals and Their Medical Transducers Application
Yohachi Yamashita, Tomoaki Karaki, Ho-Yong Lee, Haotian Wan, Hwang-Pill Kim, Xiaoning Jiang
Abstract
Piezoelectric materials have been developed since early 1900s and many research had been conducted on the composition and process to obtain higher piezoelectric constants ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${d}_{33}$ </tex-math></inline-formula> ). Within composition research, lead perovskite relaxor piezoelectric single crystals (SCs) of Pb(Mg1/3Nb2/3)O3–lead titanate PbTiO3 type have been actively studied since 1990s because of their outstanding <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${d}_{33} >1500$ </tex-math></inline-formula> pC/N compared with those of the conventional Pb(Zr,Ti)O3 ceramics. A major driving force of these SC research has been promoted by mass production of ultrasound transducers and array probes for medical diagnostic systems since early 2000s. However, higher <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${d}_{33}$ </tex-math></inline-formula> material and process research for these ultrasound devices are almost saturated. In this review article, we present a brief overview of the history, current situation, and future perspective of piezoelectric SCs. The authors believe that the main research in the next century is high <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${d}_{33}$ </tex-math></inline-formula> SCs with a high composition uniformity and low-energy SC growth methods, such as solid-state SC growth, low-loss SC transducer manufacturing technique, and improved poling process. This is a big technical challenge for all the scientists; however, the relatively large market of medical ultrasound has been expanded year by year, and we hope that the community is motivated to solve such technical problems in the near future.