Field-induced antiferroelectric to ferroelectric transitions in (Pb1–xLax)(Zr0.90Ti0.10)1–x/4O3 investigated by in situ X-ray diffraction

Phase transitions and field-induced preferred orientation in (Pb_1-xLa_x)(Zr_0.90Ti_0.10)_1–x/4O₃ (PLZT x/90/10) ceramics upon electric field cycling using in situ X-ray diffraction were studied. The evolution of the {200}_pc and {111}_pc diffraction line profiles indicate that PLZT 4/90/10 and PLZT 3/90/10 compositions undergo an antiferroelectric (AFE)–ferroelectric (FE) phase switching. Both PLZT 4/90/10 and PLZT 3/90/10 exhibit irreversible preferred orientation after experiencing the field-induced AFE-to-FE phase switching. An electric field-induced structure develops in both compositions which has a reversible character during the field decreasing in PLZT 4/90/10 and an irreversible character in PLZT 3/90/10. In addition, structural analysis of pre-poled PLZT 3/90/10 ceramics show that it is possible to induce consecutive FE-to-AFE and AFE-to-FE transitions when fields of reversed polarity are applied in sequence. The field range required to induce the AFE phase is broad, and the phase transition is kinetically slow. This kind of transition has rarely been reported before.     

High-performance antiferroelectric ceramics via multistage phase transition

Lead-based antiferroelectric (AFE) ceramics have attracted increasing interest in pulse power systems owing to their high-energy storage and power densities. However, the single AFE–ferroelectric (FE) phase transition in conventional AFE materials usually leads to premature polarization saturation and low breakdown strength, which are disadvantageous to energy storage performance. In this study, high energy storage performance was achieved in Pb_0.94−xLa_0.04Ca_x[Nb_0.02(Zr_0.99Ti_0.01)_0.975]O₃ (PLCNZT) AFE ceramics by constructing electric-field-induced multiple phase transitions. A maximum recoverable energy storage density of 12.15 J/cm³ and a high energy efficiency of 85.4% were obtained for the PLCNZT ceramic with x = 0.03 at 420 kV/cm. These excellent properties are attributed to the AFE–FE Ⅰ-FE Ⅱ multiple phase transitions induced by Ca²⁺ doping, which effectively enhances the breakdown strength. This result indicates that field-induced multiple phase transitions significantly improve the energy storage of AFE materials.     

Induced slim ferroelectric hysteresis loops and enhanced energy-storage properties of Mn-doped (Pb0·93La0.07)(Zr0·82Ti0.18)O3 anti-ferroelectric thick films by aerosol deposition

In this study, the high ferroelectric hysteresis loss of (Pb_0·93La_0.07)(Zr_0·82Ti_0.18)O₃ (PLZT 7/82/18) antiferroelectric (AFE) ceramics was reduced by employing a combinatorial approach of Mn acceptor doping followed by thick film fabrication via an aerosol deposition (AD) process. The grains of the as-deposited PLZT 7/82/18 AFE AD thick films were grown by thermal annealing at 550 °C to enhance their electrical properties. Investigation of the electrical properties revealed that Mn-doping results in improved dielectric and ferroelectric properties, increased dielectric breakdown strength (DBS), and energy-storage properties. The Mn-doped PLZT AFE AD films possess a frequency-independent high dielectric constant (ε_r ≈ 660) with low dielectric loss (tan δ ≈ 0.0146), making them suitable candidates for storage capacitor applications. The bipolar and unipolar polarization vs. electric field (P-E) hysteresis loops of PLZT 7/82/18 AFE AD thick films were found to be slimmer than those of their bulk form (double hysteresis) with significantly reduced ferroelectric hysteresis loss, which is attributed to the AD-induced mixed grain structure. The Mn-doped PLZT 7/82/18 AFE AD thick films exhibited a low remnant polarization (P_r ≈ 9.22 μC/cm²) at a high applied electric field (~2750 kV/cm). The energy-storage density and energy efficiency of the Mn-doped PLZT AFE AD thick films were calculated from unipolar P-E hysteresis loops and found to be ~38.33 J/cm³ and ~74%, respectively.     

Fabrication,structural and dielectric property of lead-free perovskite silver niobate ceramics

Dielectric capacitors with high recoverable energy density are in high demand for their application in electrical and electronic systems. Among lead-free dielectric materials, silver niobate (AgNbO₃) has attracted growing interest due to its superior energy storage density at room temperature. The field-induced phase transition from antiferroelectric (AFE) phase to ferroelectric (FE) phase contributes to its large energy density. In this work, pure perovskite silver niobate ceramics were fabricated in an oxygen atmosphere by the solid-state reaction technique. The Pbcm orthorhombic phase of AgNbO₃ was closely observed using the Rietveld refinement method to provide explanation for the origin of high spontaneous polarization within a unit cell. Local structural analysis via piezoelectric force microscopy revealed the existence of ferroelectric nano domains, which may contribute to the high energy storage efficiency (η = 99.9926%) in AgNbO₃ at low electric fields. The phase transitions of AgNbO₃ were also investigated via the dependence of the dielectric permittivity (ε′ and ε″) and loss angle tangent (tanδ) on temperatures, providing insights into the further modification of AgNbO₃.     

Antiferroelectric‐ferroelectric phase transition in lead‐free AgNbO3 ceramics for energy storage applications

The high‐energy storage density reported in lead‐free AgNbO₃ ceramics makes it a fascinating material for energy storage applications. The phase transition process of AgNbO₃ ceramics plays an important role in its properties and dominates the temperature and electric field dependent behavior. In this work, the phase transition behavior of AgNbO₃ ceramics was investigated by polarization hysteresis and dielectric tunability measurements. It is revealed that the ferrielectric (FIE) phase at room temperature possesses both ferroelectric (FE)‐like and antiferroelectric (AFE)‐like dielectric responses prior to the critical AFE‐FE transition point. A recoverable energy storage density of 2 J/cm³ was achieved at 150 kV/cm due to the AFE‐FE transition. Based on a modified Laudau phenomenological theory, the stabilities among the AFE, FE and FIE phases are discussed, laying a foundation for further optimization of the dielectric properties of AgNbO₃.     

Large enhancement of energy storage density in (Pb0.92La0.08)(Zr0.65Ti0.35)O3/PbZrO3 multilayer thin film

(Pb_0.92La_0.08)(Zr_0.65Ti_0.35)O₃ (PLZT), PbZrO₃ (PZO) films, and type A and type B PLZT/PZO multilayer thin films were deposited on Pt(111)/TiO_x/SiO₂/Si substrates by sol-gel method, where type A and type B films stand for PLZT/PZO/PLZT/PZO/PLZT/PZO and PLZT/PZO/PLZT/PLZT/PZO/PLZT multilayer thin film, respectively. Compared to the PLZT and PZO film, enhanced breakdown field strength and improved energy storage density were obtained in type A and B multilayer thin films. A superior energy storage density of 29.7 J/cm³ with the energy storage efficiency of 50.8% was achieved in type B multilayer thin film, corresponding to 81% enhancement compared with the energy storage density of PLZT films (16.4 J/cm³). Additionally, the type B multilayer thin film exhibits a good thermal stability up to 160 °C and excellent fatigue endurance after 10⁷ charging-discharging cycles. The enhanced energy storage performance of type B multilayer thin film shows promise and may stimulate further researches on energy storage applications of multilayer dielectric thin films.     

Artificially induced ferroelectric-like behavior in an antiferroelectric sandwich structure by interface engineering

Interface engineering is essential for achieving fascinating interfacial functionalities in a single all-oxide-interface-based device. In the present work, a sandwich structure (Pb_0.94La_0.06(Zr_0.95Ti_0.05)O₃ (PLZT)/HfO₂/ Pb_0.94La_0.06(Zr_0.95Ti_0.05)O₃) was fabricated via a chemical solution approach. A distinct “ferroelectricity-like” behavior with high P_max (～ 80 μC/cm²) and P_r (～ 36 μC/cm²) is demonstrated. The dielectric HfO₂ thin layer presents a tetragonal symmetry structure, which stabilizes a slight distorted structure of the upper PLZT layer (PLZT(T)) with a= 4.19(9) Å, b= 4.10(6) Å, β ～ 91.04?. In PLZT(T), the ferroelectric (FE) phase is identified as the matrix embedded with a small amount of AFE nanodomains, while the bottom PLZT layer (PLZT(B)) exhibits typical AFE incommensurately modulated structures. The near-interface structures in both PLZT layers are characterized by ferroelectric polarizations with head-to-tail configuration across the heterointerface. Such discontinuous, downward polarizations support the accumulation of oxygen vacancies at the heterointerface that facilitate the local polarization enhancement. It is the combination effect of stable ferroelectric polarization in the PLZT(T) layer, interfacial oxygen vacancies and large surface to volume ratio that leads to the superior polarization performance of the antiferroelectric sandwich structure. It indicates that interface engineering is a feasible approach to manipulate the ferroic behavior.     

Energy storage and thermodynamics of PNZST thick films with coexisting antiferroelectric and ferroelectric phases

Pb_0.99Nb_0.02(Zr_0.85Sn_0.13Ti_0.02)O₃ (PNZST) antiferroelectric (AFE) thick films are successfully deposited on silicon-based Pt and LaNiO₃ electrodes by a sol-gel method. The coexistence of ferroelectric (FE) and AFE phases are revealed in PNZST films by XRD, electric-induced hysteresis loops, dielectric, and leakage current properties. Comparing with PNZST/Pt film, larger recoverable energy density and efficiency are obtained in PNZST/LaNiO₃ film due to the lower FE phase proportion. It is analyzed and demonstrated by a thermodynamic model of AFE and FE coexistence system. In addition, the fatigue behaviors of both AFE films are also affected by the proportion of the coexisting FE phase. PNZST/LaNiO₃ film exhibits good fatigue resistance on energy storage even after 10¹⁰ switching cycles, which is attractive to pulsed power applications.     

Bistable Optical Information Storage Using Antiferroelectric-Phase Lead Lanthanum Zirconate Titanate Ceramics

A recently discovered photostorage effect in antiferroelectric-phase (AFE-phase) lead lanthanum zirconate titanate (PLZT) compositions appears to be particularly applicable to binary optical information storage. The basis for bistable optical information storage is that exposure to near-UV or visible light shifts the electric field threshold of the phase transition between the field-induced ferroelectric (FE) phase and the stable AFE phase in the direction of the initial AFE → FE phase transition. Properties of this photoactivated shift of the FE → AFE phase transition, including preliminary photosensitivity measurements and photostorage mechanisms, are presented. Photosensitivity enhancement by ion implantation is also discussed.     

Impact of fatigue behavior on energy storage performance in dielectric thin-film capacitors

The polarization hysteresis loops and the dynamics of domain switching in ferroelectric Pb(Zr_0.52Ti_0.48)O₃ (PZT), antiferroelectric PbZrO₃ (PZ) and relaxor-ferroelectric Pb_0.9La_0.1(Zr_0.52Ti_0.48)O₃ (PLZT) thin films deposited on Pt/Ti/SiO₂/Si substrates were investigated under various bipolar electric fields during repetitive switching cycles. Fatigue behavior was observed in PZT thin films and was accelerated at higher bipolar electric fields. Degradation of energy storage performance observed in PZ thin films corresponds to the appearance of a ferroelectric state just under a high bipolar electric field, which could be related to the nonuniform strain buildup in some regions within bulk PZ. Meanwhile, PLZT thin films demonstrated fatigue-free in both polarization and energy storage performance and independent bipolar electric fields, which are probably related to the highly dynamic polar nanodomains. More importantly, PLZT thin films also exhibited excellent recoverable energy-storage density and energy efficiency, extracted from the polarization hysteresis loops, making them promising dielectric capacitors for energy-storage applications.     

Achieving high energy storage performance of Pb(Lu1/2Nb1/2)O3 antiferroelectric ceramics via equivalent A-site engineering

Manipulating the critical switching field between antiferroelectric (AFE) state and ferroelectric (FE) is an important concept for tuning the energy storage performance of AFEs. As one of the lead-based AFE systems, Pb(Lu_1/2Nb_1/2)O₃ promises high potential in the miniaturization of pulsed power capacitors, but the extremely high critical switching field and low induced saturated polarization demonstrate severe drawbacks with respect to temperature stability and flexibility. Here, A-site Ba²⁺ doping engineering is used to effectively reduce the critical switching field and improve the saturated polarization in Ba_xPb_1-x(Lu_1/2Nb_1/2)O₃ (0.01 ≤ x ≤ 0.08, abbreviated as xBa-PLN) ceramics. We found the AFE-FE phase transition can be occurred at 80ºC with a high energy storage density of 4.03 J/cm³ for Ba_0.06Pb_0.94(Lu_1/2Nb_1/2)O₃ ceramic. Our results show that Ba²⁺ additions destroy the antiparallel structure of AFE phase, and finally reduce the critical switching field, demonstrating a potential alternative to modulate the energy storage performance of AFEs.     

锆钛酸铅镧压电陶瓷纤维的制备与性能

以锆钛酸铅镧[(Pb1-xLax)(Zr1-yTiy)O3,lead lanthanum zirconate titanate,PLZT]压电陶瓷为原料,用塑性聚合物法制备不同截面的PLZT陶瓷纤维。用X射线衍射、扫描电镜、密度测试仪、微力试验机和铁电分析仪分别测试PLZT陶瓷纤维的相结构、显微形貌、密度、力学性能和铁电性能。结果表明:PLZT陶瓷纤维为三方相钙钛矿结构,圆柱形纤维的直径和方柱形纤维的边长分别约250μm和300μm。圆柱形和方柱形纤维的最终抗拉伸强度和弹性模量分别为24.88MPa、6.90×103MPa和23.97MPa、5.71×103MPa。PLZT陶瓷纤维均具有良好的铁电性能,圆柱形纤维的饱和场强、剩余极化强度(Pr)和矫顽场(Ec)分别为10kV/mm、41.40μC/cm2和1.10kV/mm;方柱形的饱和场强、Pr及Ec分别为10kV/mm、41.68μC/cm2和1.03kV/mm。     

Excellent energy-storage property and thermal stability of PLZT-based antiferroelectric ceramics

(Pb, La)(Zr, Ti)O₃ antiferroelectric (AFE) materials are promising materials due to their energy-storage density higher than 10 J cm⁻³, but their low energy-storage efficiency and poor temperature stability limit their application. In this paper, the (1 − x)(Pb_0.9175La_0.055)(Zr_0.975Ti_0.025)O₃–xPb(Yb_1/2Nb_1/2)O₃ (PLZTYN100x) AFE ceramics were prepared via two-step sintering method and investigated thoroughly. With the doping of Yb³⁺ and Nb⁵⁺, the phase structure transforms from the orthorhombic phase (AFE_O) to the coexistence of the orthorhombic-and-tetragonal phases. This structure reduces the free energy difference between the AFE and ferroelectric phases and reduces the fluctuation of energy with temperature, improving the energy storage efficiency and temperature stability. When the x = 0.05 (PLZTYN5), the AFE ceramic exhibits excellent temperature stability and ultrahigh energy storage performance, whose recoverable energy density (W_rec) is 6.8–8.2 J cm⁻³ at 30 kV mm⁻¹ in the temperature range from −55 to 75°C, and efficiency (ƞ) is 78%–86.7%. In addition, the change of W_rec is less than 15%, exceeding the performance of most AFE ceramics. The results demonstrate that the PLZTYN5 ceramic has great potential in pulse power capacitors.     

Significantly improved energy storage properties and cycling stability in La-doped PbZrO3 antiferroelectric thin films by chemical pressure tailoring

In this work, Pb_1−3x/2La_xZrO₃ (x = 0–0.12) (PLZ-x) antiferroelectric thin films were fabricated on Pt(111)/TiO₂/SiO₂/Si substrates using chemical solution method. Smaller cations (La³⁺) and vacancies were introduced into A-sites of perovskite structure to construct chemical pressure. According to phenomenological theory, chemical pressure can increase the energy barrier between antiferroelectric (AFE) and ferroelectric (FE) phase, and enhance antiferroelectricity of the system. As a result, a large energy storage density (W_re) of 23.1 J cm⁻³ and high efficiency (η) of 73% were obtained in PLZ-0.10 films, while PLZ-0 films displayed lower W_re (15.1 J cm⁻³) and η (56%). More importantly, PLZ-0.10 films exhibited an excellent cycling stability with a variation of ˜2% after 1 × 10⁸ cycles. The results demonstrate that heavily La-doped PbZrO₃ films with high energy storage density, high efficiency and excellent cycling stability can be considered as potential candidates for energy storage applications.     

Softening of antiferroelectric order in a novel PbZrO3-based solid solution for energy storage

PbZrO₃-based antiferroelectric (AFE) materials have received growing attention for their attractive energy storage performance. However, a major drawback of PZ is its high critical electric field (E_cr) which makes it difficult to switch the antiparallel dipoles therein so as to be useful. Therefore, softening of AFE order in PbZrO₃ is thought to be a promising approach for its practical applications. In this work, a new binary AFE solid solution of (1-x)PbZrO₃-xPb(Mg_1/2Mo_1/2)O₃ (PZ-PMM), with x = 0.00–0.10, was successfully synthesized in form of ceramics via the solid-state reaction method. The effect of chemical modification by introducing Pb(Mg_1/2Mo_1/2)O₃ on the crystal structure, phase transition behavior and electrical properties of the PbZrO₃ ceramics are investigated systemically. It is found that a perovskite phase with orthorhombic Pbam symmetry is preserved at room temperature for all the compositions studied, and a broadened ferroelectric intermediate phase exists between the paraelectric (PE) and the antiferroelectric phases of the PZ-PMM solid solution. At 160 °C, typical double hysteresis loop can be displayed for all the compositions. Most importantly, the maximum electric field-induced polarization is significantly increased, whereas the critical field is decreased with increasing PMM content, suggesting a remarkable softening effect of the antiferroelectric order in PZ due to some degree of dipole frustration. This work could bring about the development of a new series of PZ-based solid solutions for energy storage applications in the future.     

Significantly enhanced energy storage performance in Sm-doped 0.88NaNbO3-0.12Sr0·7Bi0·2TiO3 lead-free ceramics

Lead-free antiferroelectric (AFE) ceramic materials have attached increasing attention in application of high-power capacitors for the past few years, due to their high energy storage density and environmental protection. However, the related applications are seriously restricted because of the limited number of environment friendly AFE candidate materials, high cost and low energy storage efficiency. In this work, the A-site ion Sm³⁺ doped 0.88NaNbO₃-0.12Sr_0·7Bi_0·2TiO₃ lead-free AFE P phase ceramics (0.88Na_1-3xSm_xNbO₃-0.12Sr_0·7Bi_0·2TiO₃, abbreviated as NN-SBT-100xSm) were prepared and characterized. With the increase of Sm doping amount, a relaxor-like behavior was found in the dielectric-temperature curves of NN-SBT-100xSm, indicating the AFE orthorhombic P phase is gradually replaced by an AFE orthorhombic R phase. As a result, double-like and slim P-E curve with near-zero residual polarization and suppressed hysteresis loss was obtained at x > 0.01. More encouragingly, a good discharge energy storage density (W_rec = 3.58 J/cm³) and a high efficiency (η = 82%) at a low electric field (E = 200 kV/cm) has been recorded simultaneously for NN-SBT-2Sm relaxor AFE ceramic, which are better than the other lead-free energy storage ceramics under the same E. In addition, the energy storage properties of NN-SBT-2Sm ceramics exhibit outstanding temperature and frequency stability. These results indicate that NN-SBT-2Sm relaxor AFE ceramic has a great practical value in pulse power capacitors.     

Antiferroelectrics: History,fundamentals, crystal chemistry,crystal structures,size effects,and applications

Antiferroelectric (AFE) materials are of great interest owing to their scientific richness and their utility in high-energy density capacitors. Here, the history of AFEs is reviewed, and the characteristics of antiferroelectricity and the phase transition of an AFE material are described. AFEs are energetically close to ferroelectric (FE) phases, and thus both the electric field strength and applied stress (pressure) influence the nature of the transition. With the comparable energetics between the AFE and FE phases, there can be a competition and frustration of these phases, and either incommensurate and/or a glassy (relaxor) structures may be observed. The phase transition in AFEs can also be influenced by the crystal/grain size, particularly at nanometric dimensions, and may be tuned through the formation of solid solutions. There have been extensive studies on the perovskite family of AFE materials, but many other crystal structures host AFE behavior, such as CuBiP₂Se₆. AFE applications include DC-link capacitors for power electronics, defibrillator capacitors, pulse power devices, and electromechanical actuators. The paper concludes with a perspective on the future needs and opportunities with respect to discovery, science, and applications of AFE.     

Stress Effects on Stabilizing Antiferroelectric Phase in Multilayer Ceramics

Controllable phase transformation between antiferroelectric (AFE) and ferroelectric (FE) states suggests multifunctional properties valuable for many device applications. Compared to AFE bulk ceramics with large voltage required for driving electric field‐induced phase transition, implementation of structures comprising multiple thin AFE ceramic layers can realize applications by reducing the switching operation voltage in the feasible range. Here, it is found that a compressive residual stress is developed in multilayer (Pb_0.97,La_0.02)(Zr_0.66,Sn_x,Ti_0.34?x)O₃ (PLZST) ceramic co‐fired with multiple Pd/Ag electrode layers, and the compressive residual stress can stabilize AFE phase. AFE phase forms in the PLZST multilayer ceramic with composition corresponding to FE in the bulk materials. Thermodynamic analysis based on free energy of FE and AFE phases well explains the FE to AFE phase transformation observed in the multilayer ceramic under the compressive stress. The findings exhibit a new strategy to tune structure and functional properties of multilayer ceramics through stress engineering for achieving device applications.     

Unusual Polarization Ordering in Lanthanum Modified Lead Zirconate Titanate (Pb0.97La0.03)(Zr0.90Ti0.10)0.9925O3

Lanthanum incorporation in lead zirconate titanate (PLZT) increases the stability range of the antiferroelectric phase in the Zr‐rich side of the phase diagram. The paper presents the analysis, which has been carried out on (Pb_0.97La_0.03)(Zr_0.90Ti_0.10)_0.9925O₃ ceramic system since it exhibits interesting results with ferroelectric (FE) and antiferroelectric (AFE) phases, and coexistence of both properties in some temperature range. Transmission electron microscopy evidences a complex domain structure, where nanodomains appear within larger ones. The data are consistent with the possibility to have in this material a ferroelastic phase of novel type in which the coexistence mechanism between FE and AFE properties is associated with the oscillation in space of the polarization. The possibility for a determining role of a rigid unit mode in structural instabilities, dependence on composition and doping, and pretransitional effects in the perovskite family is underlined by the obtained results for the studied system.     

Composition-dependent xBa(Zr0.2Ti0.8)O3-(1-x)(Ba0.7Ca0.3)TiO3 bulk ceramics for high energy storage applications

This work reports the composition dependent microstructure, dielectric, ferroelectric and energy storage properties, and the phase transitions sequence of lead free xBa(Zr_0.2Ti_0.8)O₃-(1-x)(Ba_0.7Ca_0.3)TiO₃ [xBZT-(1-x)BCT] ceramics, with x?=?0.4, 0.5 and 0.6, prepared by solid state reaction method. The XRD and Raman scattering results confirm the coexistence of rhombohedral and tetragonal phases at room temperature (RT). The temperature dependence of Raman scattering spectra, dielectric permittivity and polarization points a first phase transition from ferroelectric rhombohedral phase to ferroelectric tetragonal phase at a temperature (T_R-T) of 40?°C and a second phase transition from ferroelectric tetragonal phase - paraelectric pseudocubic phase at a temperature (T_T-C) of 110?°C. The dielectric analysis suggests that the phase transition at T_T-C is of diffusive type and the BZT-BCT ceramics are a relaxor type ferroelectric materials. The composition induced variation in the temperature dependence of dielectric losses was correlated with full width half maxima (FWHM) of A₁, E(LO) Raman mode. The saturation polarization (P_s) ≈8.3?μC/cm² and coercive fields ≈2.9?kV/cm were found to be optimum at composition x?=?0.6 and is attributed to grain size effect. It is also shown that BZT-BCT ceramics exhibit a fatigue free response up to 10⁵ cycles. The effect of a.c. electric field amplitude and temperature on energy storage density and storage efficiency is also discussed. The presence of high T_T-C (110?°C), a high dielectric constant (ε_r ≈?12,285) with low dielectric loss (0.03), good polarization (P_s ≈?8.3?μC/cm²) and large recoverable energy density (W?=?121?mJ/cm³) with an energy storage efficiency (η) of 70% at an electric field of 25?kV/cm in 0.6BZT-0.4BCT ceramics make them suitable candidates for energy storage capacitor applications.