Direct observation of pulse poling effect on reversible 90° domain wall motion in tetragonal Pb(Zr,Ti)O₃ thin films

Abstract

We investigated the effects of the pulse poling process on macroscopic ferroelastic domain structures in (100)/(001)-oriented Pb(Zr_0.44Ti_0.56)O₃ films. The poling process consisted of an applied electric field square waveform for poling cycles (10⁰–10⁷ cycles) combined with triangular waveforms for polarization–electric field and strain–electric field measurements. The remanent polarization (P_r) and the inverse piezoelectric coefficient (d_33,f) were enhanced at 10³ poling cycles but decreased with further increases in poling cycles. After 10³ poling cycles, the 90° domain switching behavior was directly observed via in situ X-ray diffraction (XRD). The results showed a 4 % change in the volume fraction of the c-domain (V_C) during the application of an electric field of +150 kV/cm. The 90° domain structure was altered by the poling process, contributing to increased electric field-induced strain. However, in situ XRD results after 10⁷ poling cycles indicated only slight changes in V_C under an applied electric field, with degraded P_r and d_33,f. The degradation of d_33,f values by pulse poling is partly due to the reduced contribution of ferroelastic 90° domain switching.