Study On Properties Of Relaxor Ferroelectric Single Crystal PZN-PT

In recent years,Perovskite relaxor ferroelectric single crystal is the highest piezoelectric performance crystal,is also an important stage of piezoelectric material development,further enhance piezoelectric performance to meet the growing demand of piezoelectric devices is now everyone is keen on research field.Therefore,the study of high performance relaxor ferroelectric single crystal is also the pursuit of the majority of researchers,and PZN-PT crystal is widely studied because of these excellent properties.In this paper,PZN-7PT,Sm-PZN-7PT and PZN-6PT crystals were grown by high-temperature solution method,and their phase structure,electrical,optical properties were studied.The phase transition of crystal was confirmed by XRD and Raman.The XRD test results showed that the crystals are typical cubic perovskite structure,and the Sm-PZN-PT diffraction peak moves like large angles,indicating that Sm³⁺doped into PZN-7PT crystals can also correspond to the TEM results.The electrical test results show that the PZN-7PT and PZN-6PT crystals perform very well,the PZN-7PT crystal(001)piezoelectric constant d₃₃can reach 2400 PC/N,but the low coercivity field Ec limits the use of high-power equipment,through the doped Sm-PZN-7PT crystal coercivity field improves three times over the undoped crystal,and has photoluminescence characteristics,broadening the application field.The relaxation of the crystals at different frequencies is also fitted,indicating that the growing crystals are better relaxation ferroelectric single crystals.Optical tests showed that PZN-7PT,Sm-PZN-7PT,and PZN-6PT crystals had six distinct Raman peaks,respectively located at 59 cm^-1,136 cm^-1,264 cm^-1,400 cm^-1,600cm^-1,777 cm^-1.The results of the variable temperature Raman test found that the Raman peak has a blue shift and the half peak width is due to the increased temperature,and the intense thermal movement inside the crystal gradually enhances the atomic bond energy,while the disorder of the thermal movement reduces the order of the crystal structure.Fluorescence testing of the Sm-PZN-7PT crystals showed that the doped Sm-PZN-7PT crystals had four wide-peak emission peaks,respectively located at 563 nm(green),596 nm(orange),643 nm(red),and 710 nm(red).These peaks correspond to the ~4G_5/2-~6H_Jof Sm³⁺(J=5/2,7/2,9/2,and 11/2).The strength of these emission peaks decreases with increasing temperature in the temperature range of-190-310?.The average fluorescence lifetime was up to 0.076 ms.The results provide many new ideas for the design of multifunctional devices.