MAE Department - PG Seminar - Design and fabrication of Relaxor-PT single crystals-based devices

After enhanced the piezoelectric performances of PMNT and PIMNT single crystals by AC poling technique, two kinds of relaxor-PT based 3MHz phased array transducers have been designed by FEM simulation with PizeoFlex, then they have been fabricated with well performances, one has got the bandwidth 91.41%@-6dB and insertion loss -45.5dB by using three matching layers, anther has got the bandwidth 88.12%@-6dB and -32.46 by using de-matching layers, much higher performances compared with conventional PZT transducers. These single crystal transfers have higher resolution, deeper penetration depth for medical ultrasound imaging. 

By doing Mn2+, the comprehensive pyroelectric and dielectric performances of PMNT and PIMNT single crystals have been enhanced for 12×10-4Cm-2K-1 pyroelectric coefficient, 0.05%@1kHz dielectric loss, and 40.2×10-5Pa-1/2 FOM for detectivity (Fd), much higher pyroelectric performances than conventional LiTaO3 single crystal. Novel single element detector, and dual compensated pyroelectric detectors have been fabricated with detectivity D*～2×109 cmHz1/2/W@5Hz, 6 times higher than conventional LiTaO3 pyroelectric detector. Based on the novel pyroelectric detectors, NDIR gas detectors have been designed and fabricated to measure the concentration of various gases, such as CO2 CO and CH4.

 ME composite PMNT/Metglas has been fabricated with ME charge coupling αQ~6200pC/Oe，capacity Cp~399pF，dielectric loss D~0.5%. Based on ME composite，ME magnetic sensors were designed and fabricated with the performances of sensitivity 0.8 pT/Hz1/2@1Hz, 0.2pT/Hz1/2@100Hz, 9fT/Hz1/2@EMR, power 20mW, and bandwidth 0.1Hz~15kHz, which are much better than conventional flux gate. Such novel magnetic sensors could be used in many area for sensing magnetic field.