Structure-Driven, Ferroelectric Wake-Up Effect for Electrical Fatigue Relief

In this work, we report the first observation of a structure-driven ferroelectric (FE) wake-up effect in polycrystalline AgNbO3-based antiferroelectric (AFE) materials, by which polarization gradually goes up with an increasing cycle number of the electric field. Unlike the defect-driven FE wake-up effect broadly observed in HfO2-based thin films, this wake-up effect is associated with a phase transition from AFE to FE under low-field cycling. Doping LiTaO3 into AgNbO3 disrupts the initial long-range ordered octahedral tilting around the «0 0 1»p direction, resulting in some local regions with a lower energy barrier between the AFE and FE phases. Therefore, under the cyclic field, the nucleation and growth of the FE phase lead to the increasing polarization. Such an intrinsic FE wake-up effect is more controllable and thus useful. We have experimentally demonstrated that such a wake-up effect enables compensation of the electrical fatigue, the fatal drawback that has significantly limited the application of FE materials in smart devices, such as non-volatile memory. We therefore believe that this work not only provides new insight into the polarization-electric field relationship of AFE materials, an important supplement to the existing antiferroelectric theory, but also potentially introduces a new strategy to solve the electrical fatigue problem for achieving fatigue-free FE devices.