Realizing room temperature double hysteresis loops in antiferroelectric NaNbO3 based ceramics

Lead-free antiferroelectric (AFE) materials have seen a surge of research activity in environmentally friendly energy storage technologies. Recently, considerable work has been done to improve the stability of AFE in NaNbO3 (NN) ceramics, but it remains a grand challenge to obtain typical AFE characteristic double P-E loops in NN ceramics at ambient conditions. In a preliminary estimate of tolerance factor versus average electronegativity difference, we reported the stable AFE phase in 0.95NaNbO3-0.05BiMg2/3Ta1/3O3 sample. The orthorhombic Q to P phase transition was verified by XRD and TEM. Then, the remarkable double P-E loops were obtained in 0.95NaNbO3-0.05BiMg2/3Ta1/3O3 ceramics. Furthermore, a phenomenological model was proposed to explain the P-E relationships and our results. Compared with other reported compounds, the TP-R decreased more obviously from 350 °C to 200 °C. Superior temperature stability (variations of maximum current, current density, and power density within 15% over 30–140 °C) and field induced phase transition were also confirmed by the pulse charge testing. Our work develops a new road for achieving room-temperature double P-E loops in NN ceramics by BiM1M2O3 (M1 might be Mg, Zn, etc; M2 might be Nb, Ta, etc) additives.