Phase Transition Current Characterization Dependent On External Field And Test Method For Antiferroelectric Materials

New functional materials have increasingly become research focus of development andapplication of functional devices due to the perception and response function and easy tointelligence, integration and miniaturization. Antiferroelectric/ferroelectric functionalmaterials have wonderful phase transition characterization induced by external field （electricfield, temperature and stress） owing to their special crystal structure. They can happen phasetransition between antiferroelectric-ferroelectric and ferroelectric-antiferroelectric remarkablechanges in dielectric constant, polarization and current. Therefore, the sensitive and efficientperception and response capabilities of these functional materials can be used to design newintelligent sensor system, which have the potential usage in pyroelectric thermal sensors、high-strain transducers、fuze insurance agencies and other fields.In this paper, phase transition current characterization betweenantiferroelectric-ferroelectric and ferroelectric–antiferroelectric and test method of phasetransition current were studied in detail for the application in practice. （Pb,La） （Zr,Ti） O₃antiferroelectric thick films of different thickness and anneal near byantiferroelectric/ferroelectric morphotropic phase boundary which had high （100） orientationwere successfully prepared on Pt（111）/Ti/SiO₂/Si substrate by sol-gel technology.Theelectrical properties of antiferroelectric-ferroelectric phase transition under varioustemperature and dc electric fields were studied. The experimental results show that PLZTantiferroelectric thick film happened mutual phase transformation of antiferroelectric,ferroelectric and paraelectric depending on temperature and electric field. With the increase ofapplied electric field, phase transition temperature of antiferroelectric–ferroelectric anddielectric constant gradually decreases. The phase transition current gradually appears. Thephase transition electric field、saturation polarization and phase transition current are gradually decreased with the increase of temperature. The electric properties of the thick filmsare improved by increased thickness and multistep annealing treatment. The max tested phasetransition current density is up to the order of 10^-5A/cm².（Pb,La） （Sn,Zr,Ti）O₃ferroelectric ceramics of different Sn/Ti components near byantiferroelectric/ferroelectric morphotropic phase boundary which have high （110） orientationwere successfully prepared by conventional ceramic preparation process. The electricalproperties of ferroelectric - antiferroelectric phase transition under various temperature and dcelectric fields were studied. The experimental results show that PLZST ceramics have morestable ferroelectricity with the decrease of Sn/Ti content. PLZST ferroelectric ceramics whichshow strong ferroelectricity by the electrode treatment go through ferroelectric phase -antiferroelectric - paraelectric phase transition with the increase of temperature. PLZSTceramics present high phase transition the current and low leakage current under thetemperature field. The phase transition temperature of ferroelectric-antiferroelectric to thehigher temperature is forced by the increased electric field. The relevant phase transitioncurrent is also decreased. The external resistor and capacitor of the ceramics could mostlyrelease 272μJ energy.The simple and effective testing circuit of phase transition current of the ceramic wasprimarily designed. AD549 electrometer operational amplifier was selected to change andenlarge current signal. The real-time collection、display and storage of phase transition currentdata were achieved by the computer under the control of AT89C51 single chipmicrocomputer.