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

Abstract

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.

Silver niobate perovskites: structure, properties and multifunctional applications

“…27g). 110 Moreover, the structure renements also reveal that the off-center cation displacements of the Ag + and Nb 5+ ions gradually increase, indicating enhanced ferroelectricity of the FE R3c lattice (see Fig. 27h).…”

“…8d, in which a sequence of two in-phase and two antiphase octahedral rotations about the c-axis yields a 4a c periodicity with two crystallographically distinct Ag sites. The chain-like correlation for the local off-centering Nb displacements within two adjacent octahedral columns directed along [111] c and c can give rise to the average Nb displacements along the [110] c direction (i.e., the b-axis of the orthorhombic Pbcm structure) as shown in Fig. 8e.…”

“…42 Using PLD technology, 43 thin lms grown on SrTiO 3 (STO) single crystal substrates with different orientation can exhibit ultrahigh E b values ($400 kV cm À1 ). Furthermore, it is interesting to note that AgNbO 3 lms grown on (001) STO exhibited "double" polarization hysteresis, while AgNbO 3 lms deposited on (110) and (111) STO substrates showed a "ferroelectric-like" polarization hysteresis under strong-eld cycling. However, the authors did not perform a structure investigation to clarify the reasons for this difference.…”

“…At high temperature, the Nb 5+ cations are randomly displaced among eight sites along the h111i c directions, which give the ideal positions on average in the O phase. Upon cooling, the off-centered ordered arrays of Nb 5+ cations displacement along the [111] c and c directions in two adjacent octahedral layers gives an average displacement component along the [110] c direction (i.e., along the b-axis of the orthorhombic Pbcm structure). In the two next adjacent layers, these average displacement components point in opposite directions, leading to AFE structural order.…”

Time‐Dependent Imprint in Hf0.5Zr0.5O2 Ferroelectric Thin Films

“…[ 5–11 ] However, there are still reliability issues for practical use, including insufficient switching endurance [ 12,13 ] and fatigue properties. [ 14–16 ] In the case of HfO 2 ‐based ferroelectric thin films, their large time‐dependent imprint [ 17–22 ] and wake‐up effect [ 16,17,23–27 ] —which distinguish them from conventional ferroelectric materials—play important roles in understanding these critical issues.…”