POLARIZATION FATIGUE BEHAVIORS IN Bi3.5Nd0.5Ti3O12 FERROELECTRIC THIN FILMS

Abstract

The evolution of the fatigue behaviors in Bi3.5Nd0.5Ti3O12 (BNT) ferroelectric thin films deposited on Pt(111)/Ti/SiO2/Si(100) substrates by chemical solution deposition (CSD) method effected by amplitude, frequency and profile of the driving electric field were reported. It is found that the switching with lower frequency and higher amplitude of the external voltages resulted in higher fatigue rates and only bipolar waveform type voltage can result in fatigue, whereas a unipolar voltage cannot. An empirical function with N/f is proposed in the frequency-dependence of polarization fatigue, where N is the number of switching cycles and f is the frequency of driving. It is indicated that injected charges from electrodes into films, the trapped charges, and suppression of the seeds of opposite domain nucleation are the main mechanism of fatigue in ferroelectric BNT thin films.