THE GROWTH, PROPERTIES AND APPLICATIONS OF PMNT, A NEW PIEZOCRYSTAL
THE GROWTH, PROPERTIES AND APPLICATIONS OF PMNT, A NEW PIEZOCRYSTAL
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作者：
L. Hao
通过对PMN-PT二元系高温相结构、相稳定性和相图的研究，建立了用改进的Bridgman法生长高质量大尺寸PMNT单晶的可行方法。生长出的单晶体尺寸为40× 70 mm，板尺寸为20×20× 1 mm 3。介电常数e ~5000，损耗tan δ 0.9%，压电常数d 33 ~ 1500 pC/N，耦合系数k 33 ~ 94%。在MPB附近的组成下，晶体具有很大的压电活性和不稳定的性质，其中晶体结构非常复杂，因此生长应远离MPB进行。该单晶已成功地应用于扫描电子声显微镜换能器中，明显提高了电子声图像的分辨率。这些结果表明，PMNT单晶在医学超声成像、声纳换能器和高应变致动器等方面具有良好的应用前景。
A feasible method to grow high-quality large PMNT single crystals by the modified Bridgman technique has been set up on the basis of studies of the phase structure, phase stability and phase diagram of the PMN-PT binary system at high temperature. Single crystals have been grown with a boule size of 40×70mm and plate size of 20×20×1mm 3. The dielectric constant e is ～5000, loss tan δ0.9%, piezoelectric constant d 33 1500pC/N,and coupling k 33 ～94%. The crystals have great piezoelectric activity and unstable properties at a composition near the MPB where the crystal structure is very complex, so growth should take place far from the MPB. The single crystals have been successfully used in transducers for scanning electron acoustic microscopes, with clear improvement in the resolution of the electron acoustic images. These results indicate that PMNT single crystals are promising for applications in medical ultrasonic imaging, sonar transducers and high strain actuators.