Evaluation of ferroelectric Domain Structures on Bulk and Surface in Lead Zirconate Titanate Ceramics

(1)Statical evaluation of ferroelectric domain structures(1)The minimum planar coupling factors(Kp)were obtained at the coercive fields(Ec)in case of hard and soft lead zirconate titanate(PZT)，lead titanate(PT)and barium titanate(BT)ceramics.The 180°domain clamping occurred at the Ec.(2)The minimum dielectric constant(εr)and maximum frequency constant(Fcp)were mainly observed at Ec in case of hard tetragonal PZT，soft PZT，PT and BT ceramics.On the other hand，these were not observed in case of hard rhombohedarl PZT ceramics.(3)The poling field dependence ofεr could be explained by the domain switching and rotation.(2)Dynamical evaluation of ferroelectric domain structures(1)From the pulse cycle dependence of the remanent polarization(Pr)，the Pr decreased with the increase of the pulse cycle。Further increasing the cycle，the Pr increased with the increase of the cycle.We call the decrease in Pr transient phenomena due to the electrical domain clamping.(2)The bipolar pulse poling was confirmed by the asymmetry P-E hysteresis loops.The shifted direction of P-E loops was determined by the combination of the bipolar pulses.(3)It was found that a space charge field was generated while applying pulse and the direction of the field was fixed independent of the pulse cycle.From both the evaluations，it could be clarified the poling field and pulse response dependence of domain structures in ferroelectric ceramics such as，PZT PT and BT ceramics.We believe the data obtained were useful to develop ferroelectric random access memory(FRAM)，domain-controlled ferroelectric ceramic devices and piezoelectric ceramic devices applied to high power use.

(1) Statical evaluation of ferroelectric domain structures(1) The minimum planar coupling factors (kp) were obtained at the coercive fields (Ec) in case of hard and soft lead zirconate titanate (PZT), lead titanate (PT) and barium titanate (BT) ceramics. The 180゜ domain clamping occurred at the Ec.(2) The minimum dielectric constant (εr) and maximum frequency constant (fcp) were mainly observed at Ec in case of hard tetragonal PZT, soft PZT, PT and BT ceramics. On the other hand, these were not observed in case of hard rhombohedarl PZT ceramics.(3) The poling field dependence of εr could be explained by the domain switching and rotation.(2) Dynamical evaluation of ferroelectric domain structures(1) From the pulse cycle dependence of the remanent polarization (Pr), the Pr decreased with the increase of the pulse cycle. Further increasing the cycle, the Pr increased with the increase of the cycle. We call the decrease in Pr transient phenomena due to the electrical domain clamping.(2) The bipolar pulse poling was confirmed by the asymmetry P-E hysteresis loops. The shifted direction of P-E loops was determined by the combination of the bipolar pulses.(3) It was found that a space charge field was generated while applying pulse and the direction of the field was fixed independent of the pulse cycle.From both the evaluations, it could be clarified the poling field and pulse response dependence of domain structures in ferroelectric ceramics such as PZT, PT and BT ceramics. We believe the data obtained were useful to develop ferroelectric random access memory (FRAM), domain-controlled ferroelectric ceramic devices and piezoelectric ceramic devices applied to high power use.