Double hysteresis loops at room temperature in NaNbO3-based lead-free antiferroelectric ceramics

Polarization-field double hysteresis loops have hardly ever been observed at room temperature in polycrystalline NaNbO3, one of a few lead-free antiferroelectric compounds. In this Letter, it is shown that the exposure of a modified NaNbO3 ceramic to bipolar electric fields of +/- 160kV/cm at 100 degrees C can preserve the double hysteresis loops at room temperature. These double hysteresis loops can still be observed after 125 days room temperature aging with some decay in maximum polarization. Frequency dependence analysis suggests that the double hysteresis loops originate from the antiferroelectric <-> ferroelectric phase transition, not the charged defects. [GRAPHICS] IMPACT STATEMENT A novel electrical treatment of a NalMbO(3)-based polycrystalline ceramic to achieve double hysteresis loops at room temperature is reported for the first time.