High dense structure boosts stability of antiferroelectric phase of NaNbO3 polycrystalline ceramics

For NaNbO3, its intrinsic phase transition sequence is still controversial in literature. In this paper, high-densified NaNbO3 ceramics derived from mechanochemical nanostructures presented a stabilized antiferroelectric characteristic. In addition to the T-c of 360 degrees C, another diffuse dielectric anomaly appeared around 100 degrees C, which did not vanish after O-2 annealing treatment. The fine structure analysis indicated that this dielectric anomaly belongs to first order phase transition from P phase to Q phase. Moreover, even exerting the strong electric field close to breakdown value, the normal ferroelectric loops cannot be induced, proving the large free energy difference between these two phases. Published by AIP Publishing.