Enhanced antiferroelectricity and double hysteresis loop observed in lead-free (1−x)NaNbO3-xCaSnO3 ceramics

Well-defined polarization-electric field double hysteresis loops are rarely observed in pure NaNbO3 (NN) ceramics due to the metastability of the field-induced ferroelectric phase. In order to stabilize the antiferroelectric phase, various ABO3-type binary oxides were incorporated into a NaNbO3 ceramic, where the B-site is occupied with transition elements. In this work, CaSnO3 was chosen to construct the NaNbO3-based solid solution by reducing the Goldschmidt tolerance factor and ionic polarizability. X-ray diffraction patterns, transmission electron microscopy images, and Raman spectra indicate enhanced antiferroelectricity. Typical double hysteresis loops were also observed from polarization-electric field measurements in ambient conditions with slightly weakened maximum polarization as the content of CaSnO3 increased. Our results reveal the generality of this strategy and pave the way for various applications involving high-power energy for NaNbO3-based ceramics.