Phase Diagram of Sub-GHz Electric-Field-Induced Polarization Oscillation

Polarization oscillation under GHz electric field stimuli is a key issue for the future development of ultrafast sensor devices. An ultrafast phase-field model is developed to study the phase diagram of polarization oscillation under sub-GHz electric field for Pb(Zr,Ti)O₃. At the morphotropic phase boundary region, the polarization and strain oscillation show maximum amplitude (electric field stimuli frequency <0.1 GHz). The phase difference of π/2 between the input of electric field and the polarization response, which can be tuned by the frequency of ac electric field stimuli, can lead to a maximum of polarization oscillation amplitude (electric field stimuli frequency >0.1 GHz). Moreover, under this phase difference, the polarization oscillation amplitude can be increased furthermore with the increasing ac electric field strength. With the absence of a phase transition, it is found that the polarization component along the z-direction has a maximum oscillation amplitude of 0.2, and the strain has a maximum oscillation amplitude of 0.35%. The results provide useful guidance to explore and manipulate dynamic functionalities of ferroelectric sensing materials.