The Ferroelectric Domain Inversion Behaviors Of The Lead Niobate Magnesium – Lead Titanate Relaxor Ferroelectric Single Crystal

Lead magnesium niobate-lead titanate(PMN-PT)relaxation ferroelectric single crystal has been paid much attention in scientific research and industrial fields due to its excellent properties such as ultra-high piezoelectric constant and electromechanical coupling coefficient,and it has been playing an important role in various ultrasonic transducers and photoelectric devices.At present,the technology of growing PMN-PT relaxation ferroelectric single crystal is relatively mature,and the research on its domain structure had started very early,and now we have some authoritative research.As we all know,PMN-PT single crystal is solid solution,the research results of the local characteristics of ferroelectric domain cannot be directly applied to the macroscopic study,the reference significance of the microscopic research results in practical application is limited because of that.So the study of the macroscopic characteristics of the domain inversion of PMN-PT single crystal is still a little bit vacant.It is indispensable to study the macroscopic ferroelectric properties of these monocrystalline materials in order to make them used in electromechanical devices widely.The study about loop dynamics can provide a lot of domain flip information of PMN-PT.By studying the domain flip and loop dynamics of PMN-PT single crystal,we can find out the working state of PMN-PT single crystal under different working conditions,and then provide data reference for the practical application design which use this kind of single crystal.In this paper,we measured the macroscopic ferroelectric parameters and electromechanical parameters of PMN-0.27PT?PMN-0.29PT?PMN-0.31PT?PMN-0.34PT?PMN-0.37PT and PMN-0.38PT ferroelectric single crystal polarized in direction[001]_c at ambient temperatures,and we found the piezoelectric properties of the components near the MPB were the best.By fitting the dielectric temperature spectra of single crystal using Curie-Weiss law and modified Curie-Weiss law,the dispersion phase transition characteristics of PMN-PT single crystal were studied.At the ambient temperatures,we measured the hysteresis loop of 6 different components PMN-PT single crystal under different applied electric fields,and the effect of the intensity of external electric field on the ferroelectric properties of PMN-PT single crystal was analyzed.We measured the electric hysteresis loop of PMN-PT in different frequency under high electric field and low electric field respectively.We studied how the coercive field,the residual polarization and the loop area change because of the change of the electric field intensity and the frequency of the applied electric field.And for all the samples,the loop dynamic scale was analyzed,We've found how the electric field and frequency affect the domain switching.The effects of PT components in PMN-PT single crystal on coercive field,residual polarization intensity and macroscopic domain inversion were also discussed.Choose the PMN-PT single crystal in different phase and measured the electric hysteresis loop under different temperature,study how coercive field,residual polarization and loop area change with the change of temperature.Find how temperature influence the macroscopic PMN-PT single crystal's domain switching.By fitting curve,study how temperature influenced the different phase of PMN-PT single crystal's electric hysteresis loop in different situations.Complete the research about the macroscopic domain switching of PMN-PT single crystal under different working conditions.