Driving force behind voltage shifts in ferroelectric materials

By systematically poling Pb(Zr,Ti)O-3 capacitors to different extents, we observe a linear relationship between the remanent polarization and the magnitude of voltage offsets in the hysteresis curve. This result directly shows that the polarization is the impetus behind voltage shifts and, thus, imprint in ferroelectric capacitors. It is proposed that the increased polarization lowers the electrostatic potential well for the trapping of electrons thereby leading to greater voltage shifts. We also find that the remanent polarization and defect occupancy are temperature dependent which collectively impact the observed voltage offsets measured at elevated temperature. (C) 1996 American Institute of Physics.