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Improved performances of relaxor-based single crystals for sensor applications
|Haosu Luo , Xiangyong Zhao , Xiaobing Li|
Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050, China
Large size and high quality of relaxor-based single crystals have grown by the modified Bridgman technique in SICCAS. These crystals exhibit not only extra high piezoelectric performances but also high opto-electric and pyroelectric performances. They could be widely used in various fields such as ultrasound transducers, actuators, and infrared detectors etc. However, for a few piezoelectric device applications, PMNT single crystals, the first generation of generation of relaxor-based single crystals, needs to increase their Tc, Trt, and Ec further. Thus PIMNT single crystals, as the second generation of relaxor-based single crystals, have been grown in the same technique, and they exhibit higher Tc, Trt, and Ec, but more serious issue of compositional segregation. For some sensor applications, PMNT and PIMNT doped transition elements, as the third generation of relaxor-based single crystals, have been grown to improve their ferroelectric and dielectric performances.
After investigated the dielectric, piezoelectric and pyroelectric performances, Mn-doped PMNT and PIMNT could reduce their dielectric loss tandsignificantly, and increase their coercive field Ec. For example, the dielectric loss could be significantly reduced from 0.3% undoepd PMNT to 0.05%. Dipole defect MnTi’’-VO ××is suggested upon on the XAFS and EPR results, where Mn2+ is in B-site of perovskite ABO3 structure. These dipole defect MnTi’’-VO ××produce an inner electric field, and pin the movement of domain wall, in the result of lower dielectric loss and higher the coercive field Ec.
By using the third generation of relaxor-based single crystals, high performances of infrared detectors and magnetic sensors have been fabricated to reduce their intrinsic dielectric noise and increase the ratio of signal and noise.
Presentation: Invited oral at 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17, Topical Session 6, by Haosu Luo
See On-line Journal of 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17
Submitted: 2012-11-20 00:12 Revised: 2012-11-20 00:17