Bipolar pulse poling and space charge field in lead zirconate titanate ceramics

We studied the effect of repeated bipolar pulses applied to soft and hard lead zirconate titanate (PZT) ceramics on ferroelectric properties. Almost symmetrical P-E hysteresis loops were observed in the case of soft PZT ceramics. On the other hand, the loops in the case of hard PZT ceramics were asymmetrical and shifted to the positive electric field. It was found that a space charge field was generated while applying pulse and the direction of the field was fixed independently of the pulse cycles. The possibility of bipolar pulse poling was investigated. Furthermore, we discuss the effect of pulses on planar coupling factor when the pulses were applied to poled soft and hard PZT ceramics.