Zhang Shujun, Randall Clive A, Shrout Thomas R
Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA.
IEEE Trans Ultrason Ferroelectr Freq Control. 2005 Apr;52(4):564-9. doi: 10.1109/tuffc.2005.1428037.
The temperature behavior of various relaxor-PT piezoelectric single crystals was investigated. Owing to a strongly curved morphotropic phase boundary, the usage temperature of these perovskite single crystals is limited by TR-T--the rhombohedral to tetragonal phase transformation temperature--which occurs a significantly lower temperatures than the Curie temperature Tc. Attempts to modify the temperature usage range of Pb(Zn1/3Nb2/3)O3--PbTiO3 (PZNT) and Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMNT) rhombohedral crystals (Tx to approximately 150-170 degrees C, TR-T to approximately 60-120 degrees C) using minor dopant modifications were limited, with little success. Of significant potential are crystals near the mor photropic phase boundary in the Pb(Yb1/2Nb1/2)O3-PbTiO3 (PYNT) system, with a Tc > 330 degrees C, even thoug TR-T was found to be only half that value at approximately 160 degrees C. Single crystals in the novel BiScO3-PbTiO3 system offer significantly higher Tcs > 400 degrees C, while exhibiting electromechanical coupling coefficients k33 > 90% being nearly constant till the TR-T temperature around 350 degrees C, which greatly increases the temperature range for transducer applications.
研究了各种弛豫铁电-钛酸铅（PT）压电单晶的温度行为。由于存在强烈弯曲的准同型相界，这些钙钛矿单晶的使用温度受到TR-T（菱方相到四方相的转变温度）的限制，该转变温度出现在比居里温度Tc低得多的温度下。试图通过少量掺杂剂改性来改变Pb(Zn1/3Nb2/3)O3–PbTiO3（PZNT）和Pb(Mg1/3Nb2/3)O3–PbTiO3（PMNT）菱方晶体的温度使用范围（Tx至约150 - 170℃，TR-T至约60 - 120℃），但效果有限，几乎没有成功。在Pb(Yb1/2Nb1/2)O3–PbTiO3（PYNT）体系中，靠近准同型相界的晶体具有显著潜力，其Tc > 330℃，尽管发现TR-T仅约为160℃，即该值的一半。新型BiScO3–PbTiO3体系中的单晶具有显著更高的Tc > 400℃，同时展现出机电耦合系数k33 > 90%，并且在TR-T温度约350℃之前几乎保持恒定，这极大地增加了换能器应用的温度范围。
