Reduction of depolarization field effect on ferroelectric switching process in semiconductor–relaxor ferroelectric composite

Abstract

Temperature-dependent dynamic ferroelectric hysteresis of semiconductor–relaxor ferroelectric (0–3) type composite {0.30(ZnO)–0.70[(Bi0.5Na0.5)0.94Ba0.06TiO3 (BNBTO)]} has been investigated using polarization–electric field (P–E) loops, current density–electric field (J–E) curves, and temperature-dependent dielectric permittivity. It is well known that the polarization reversal mechanism can be explained by the concept of ferroelectric domain switching kinetics, which depends strongly on the temperature. The present work ascribes the role of polar nanoregion induced thermal depolarization field on the temperature-dependent ferroelectric hysteresis loop along with polarization reversal mechanism. The present composite exhibits unique ferroelectric switching behavior above the thermal depolarization temperature (∼100 °C), which is observed in P–E and J–E loops. The depolarization field-induced pinched P–E loops of a BNBTO solid solution above Td (∼100 °C) have been significantly overcome by the incorporation of semiconductor (ZnO) particles, which extensively described the underlying mechanism in the present context. In addition, the temperature-dependent polarization reversal mechanism displays unique two-stage processes [low-T (<100 °C) and high-T (>100 °C)] for the minor loops (∼30 and 40 kV) and saturated loops (∼45 kV) as described by the electric field–temperature phase diagram. The present results may provide a distinct way to Bi0.5Na0.5TiO3-based solid solutions for high-temperature piezoelectric applications.