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The temperature scaling of the ferroelectric hysteresis was first investigated in (K,Na)NbO3 films grown on SrRuO3/SrTiO3 over a temperature range from 100 K to 340 K. The power-law temperature scaling relations were obtained for , Pr, and Ec in the two distinguished temperature regions, separated by T ∼ 245 K. It was observed that and Pr had a similar temperature dependence, compared with Ec. With increasing T, and Pr decreased in the first region, and increased in the second region. While Ec decreased in the whole temperature range, but with different decrease rate in the two temperature regions. [ABSTRACT FROM AUTHOR]

In this work, we report a giant strain (0.42%) in lead-free ceramics of (1– x) (0.79Bi 0.5 Na 0.5 TiO 3 –0.20 Bi 0.5 K 0.5 TiO 3 –0.01NaNbO 3)– x SrTiO 3 with x =0.03. Most importantly, ultra-high temperature stability was simultaneously achieved under this giant strain with the variation less than 10% in the range of 20 °C and 140 °C. Systematic temperature dependent Raman spectra measurements and Ginzburg–Landau–Devonshire thermodynamic theory analysis revealed that the intrinsic lattice strain and electric field induced relaxor-ferroelectric phase transition provide reverse strain response with the increase of temperature, jointly conducive to the ultra-high temperature stability of strain property. These materials are extremely competitive in practical application of actuators. Image, graphical abstract [ABSTRACT FROM AUTHOR]

The electric field dependence on the dielectric properties of the porous ceramics was studied theoretically. The dielectric constant of the porous ceramics under certain direct current (dc) bias field and the real strength electric field in the porous ceramics were given quantitatively. As the pore can share the electric field, the tunability of the porous ceramics will be decreased when the porosity increases. The dielectric constant evolution of Ba0.6Sr0.4TiO3-based porous ceramics with the dc bias electric field can be successfully explained by our theoretical results. Taking Ba0.6Sr0.4TiO3-based porous ceramic samples, for example, there is good correspondence between the theoretical and the experimental results. [ABSTRACT FROM AUTHOR]

Using spectroscopic ellipsometry, the optical properties of the Bi[sub 3.25]La[sub 0.75]Ti[sub 3]O[sub 12] (BLT) thin films with different film thicknesses on platinized silicon substrates prepared by chemical solution methods have been investigated in the 400-1700 nm wavelength range. By fitting the measured ellipsometric parameter (ψ and Δ) data with a multilayer model system and the classical dispersion relation for the BLT thin films, the optical constants and thicknesses of the thin films have been obtained. Meanwhile, some degree of inhomogeneity (in the form of low density layers or surface roughness) has been found in the BLT thin films except for the thinnest film, which was homogeneous throughout its thickness. The multilayer model system became very complicated with increasing thickness. It indicated that the microstructure of the BLT thin films varied with increasing thickness. The refractive index n of the BLT thin films increases with increasing thickness, and on the contrary, the extinction coefficient k decreases with increasing thickness. The dispersion of the refractive index can be well explained by a single-term Sellmeier relation. [ABSTRACT FROM AUTHOR]

Dielectric ceramics have raised particular interest since they enable pulsed-power systems to achieve high voltage gradient and compact miniaturization. In this work, x wt%Ni 2 O 3 doped Al 2 O 3 -SiO 2 -TiO 2 based dielectric ceramics were prepared using conventional solid-state reaction and the effects of Ni 2 O 3 on the crystal structure, dielectric properties and dielectric breakdown strength were investigated. It was found that with the doping of Ni 2 O 3 , the Al 2 O 3 -SiO 2 -TiO 2 based dielectric ceramics became denser and the distribution of each phase was more uniform. For the composition of x = 2.0, the dielectric breakdown strength was increased into 82.1 kV/mm, more than twice compared with that of the undoped one. In addition, the relationship between the dielectric breakdown strength and the resistance of Al 2 O 3 -SiO 2 -TiO 2 based dielectric ceramics was discussed. The results show that the doping of Ni 2 O 3 is a very feasible way to improve the dielectric breakdown strength and optimize the dielectric properties for the Al 2 O 3 -SiO 2 -TiO 2 based dielectric ceramics. [ABSTRACT FROM AUTHOR]

In this paper, the converse magnetoelectric (CME) effect by electric field tuning of magnetization in an original heterostructure composed of a polycrystalline yttrium iron garnet (YIG) film and a lead magnesium niobate-lead zirconate titanate (PMN-PZT) ceramic is presented. The magnetic performances of the YIG films with different thicknesses under a DC electric field applied to the PMN-PZT ceramics and a bias magnetic field are investigated. All the magnetization-electric field curves are found to be in good agreement with the butterfly like strain curve of the PMN-PZT ceramic. Both the sharp deformation of about 2.5‰ of PMN-PZT and the easy magnetization switching of YIG are proposed to be the reasons for the strongest CME interaction in the composite at the small electric coercive field of PMN-PZT (4.1 kV/cm) and the small magnetic coercive field of YIG (20 Oe) where the magnetic susceptibility reaches its maximum value. A remarkable CME coefficient of 3.1 × 10−7 s/m is obtained in the system with a 600 nm-thick YIG film. This heterostructure combining multiferroics and partially magnetized ferrite concepts is able to operate under a small or even in the absence of an external bias magnetic field and is more compact and power efficient than the traditional magnetoelectric devices. [ABSTRACT FROM AUTHOR]

Microstructure, phase transition and electric properties of Pb 0.99 (Zr 0.95 Ti 0.05 ) 0.98 Nb 0.02 O 3 (PZTN 95/5) ferroelectric ceramics modified with x wt% ZnO additive (where x  = 0, 0.1, 0.2, 0.3 and 0.4) were systematically investigated. It was found that ZnO modification brought out an improvement of densification and an increase in grain size of PZTN 95/5 ceramics. Results of dielectric and pyroelectric measurements demonstrated that, the low temperature rhombohedral-high temperature rhombohedral ferroelectric phase transition temperature ( T LH ) gradually decreased with increasing x to 0.2, while the Curie temperature ( T c) gradually increased. With further increasing ZnO content, however, T LH and T C almost showed no change. Additionally, the excellent ferroelectric, pyroelectric and piezoelectric properties were all achieved by less than 0.2 wt% ZnO modification. It is suggested that, due to superior room–temperature pyroelectric properties, the 0.2 wt% ZnO-modified PZTN 95/5 ceramics may be a promising material for applications in uncooled pyroelectric infrared detectors. [ABSTRACT FROM AUTHOR]

Antiferroelectric thin films have attracted blooming interest due to their potential application in energy storage areas. Pb(1−3x/2)LaxHfO3 (PLHO-x, x = 0–0.05) thin films were fabricated on Pt(111)/TiO2/SiO2/Si substrates via the chemical solution deposition method. The x-ray diffraction and high-resolution transmission electron microscopy results show that the doping of La3+, which has a smaller ion radius, leads to a slight decrease in the lattice constant and unit cell volume, which can induce the lattice distortion. In addition, the dielectric and polarization properties indicate that with an increase in the temperature or La3+ content, the antiferroelectric (AFE) I phase can transform into an AFE II phase, exhibiting a slimmer P–E loop with enhanced switching field and more pronounced polarization dispersion. Notably, PLHO-0.04 showcases excellent energy storage performance (55 J/cm3, at 2.8 MV/cm). This material also exhibits good thermal, frequency, and fatigue stability. These results suggest that the energy storage performance of PbHfO3-based films can be enhanced through the phase structure design, presenting a valuable approach to fulfill the growing demand for advanced energy storage devices. [ABSTRACT FROM AUTHOR]

The Al 2 O 3 -modified Pb 0.99 (Zr 0.95 Ti 0.05 ) 0.98 Nb 0.02 O 3 (PZT 95/5) ferroelectric ceramics with enhanced breakdown strength were prepared from PZT 95/5 powders coated with a thin Al 2 O 3 shell layer, which were fabricated by a Citrate-Chelation method followed by a conventional sintering process. The microstructure and electrical properties of the as-prepared ceramics as a function of Al 2 O 3 content were systematically investigated. The results reveal that Al 2 O 3 nanoparticles are successfully coated on PZT 95/5 powders to form the core–shell structure and well dispersed at the grain boundaries of the PZT 95/5 ceramic matrix after sintering, which strengthened the grain boundaries. In particular, compared with pure PZT 95/5 ferroelectric ceramics, PZT 95/5 ceramics with less than 1.0 wt% Al 2 O 3 inclusion possess the enhanced breakdown strength and energy density, of which the largest increment being 25.9% and 13.5%, respectively. It is indicated that the as-prepared PZT 95/5 ferroelectric ceramics may be a promising candidate for explosively driven power supply. [ABSTRACT FROM AUTHOR]

The phase transition behaviors of Pb 0.99 (Zr 0.95 Ti 0.05 ) 0.98 Nb 0.02 O 3 ferroelectric ceramics doped with different MgO concentrations (0–0.2 wt%) were systematically investigated by Raman and dielectric measurements. Raman results showed that the phase transitions were strongly dependent on MgO concentration. It was found that the low temperature rhombohedral (F R(LT) )–high temperature rhombohedral (F R(HT) ) ferroelectric phase transition shifted toward a lower temperature with increasing MgO concentration up to 0.1 wt%, while the F R(HT) –cubic paraelectric (P C ) phase transition changed to a higher temperature. The Raman results were in good agreement with phase transition determined by dielectric measurements. Moreover, it was indicated that the changes of Raman active modes were related to distortion of BO 6 octahedra during the phase transitions. Then, the distortion of BO 6 octahedron caused by B-site replacement of Mg 2+ ions was proposed to explain the observed behaviors. In addition, the effects of MgO doping on the dielectric, ferroelectric and pyroelectric properties were also discussed. [ABSTRACT FROM AUTHOR]

Abstract: Highly (001) oriented (K,Na)NbO3 lead-free piezoelectric films were fabricated on SrRuO3 buffered SrTiO3(001) single crystal substrates by RF magnetron sputtering. The films showed a stable frequency dependence of dielectric permittivity and loss tangent in the range of 1kHz–1MHz. A fairly high tunability of 69.7% (@400kV/cm) was obtained in the films. Well saturated P–E hysteresis loops were obtained at E=250kV/cm, the remnant polarization P r was 8μC/cm2, and coercive field E c was only 40kV/cm. These films showed a fatigue-free behavior up to 1010 switching cycles. The decreased coercive field, improved dielectric and fatigue properties may be related to SRO bottom electrodes, which can efficiently suppress the “dead layer” near the ferroelectric-electrode interface. The leakage current density of the films was only 3.48×10−6 A/cm2 at the electric field of 250kV/cm, which is even lower than that of Mn-doped KNN films. In addition, the piezoelectric constant d 33 was estimated to be 36pm/V. [Copyright &y& Elsevier]

Highlights: [•] The FR(LT)–FR(HT) phase transition was reduced from 41°C to 24°C with MgO addition. [•] Superior pyroelectric properties were obtained in 0.10wt% MgO-modified sample. [•] The largest p of 65×10−8 Ccm−2 K−1 was achieved at room temperature. [•] Fd of 20×10−5 Pa−1/2 and Fv of 0.91m2C−1 were also attained at room temperature. [ABSTRACT FROM AUTHOR]

Antiferroelectric and ferroelectric materials are prominent non-linear dielectric materials with significant applications across various fields. To fully understand their electrical properties, it is crucial to accurately discriminate the two phases, especially in compositions with the coexistence of antiferroelectric and ferroelectric phases. In this study, we propose an easy method for differentiating domain structures from phase coexistence based on split outskirt reflections. The proposed method addresses existing limitations in the spatial phase distribution and lays the groundwork for understanding their structure–property relationships. [ABSTRACT FROM AUTHOR]

With the developments of the electronic industry, efforts to achieve high DC insulating reliability are underway to improve the mean time to failure (MTTF) of multilayer ceramic capacitors (MLCCs). However, there are few studies on appropriate measuring methods to evaluate their different reliability characteristics quantificationally. This study measured different reliability characteristics of BaTiO 3 -based multilayer ceramic capacitors sintered at three different temperatures with highly accelerated life tests (HALTs). Kaplan–Meier survival analysis, two-parameter Weibull fitting, and a new method using a stud genetic algorithm were used to calculate their MTTF in HALT conditions, and the comparison among them was carried out to select a proper fitting way. With the appropriate method, their MTTF at the rated condition was predicted and compared. Their conduction modes were also differentiated to explain their aging sensitivities to temperature and voltage. As a result, a proper way to evaluate the sample's reliability characteristics with a bathtub curve was established, and the best sintering temperature for capacitance that is also the best for reliability at the rated condition was confirmed. Meanwhile, different conducting models of MLCCs were also proved to be related to their insulation stability. [ABSTRACT FROM AUTHOR]

The low-temperature sintering and electric properties of Pb0.99( Zr0.95 Ti0.05)0.98 Nb0.02 O3 ( PZTN 95/5) ferroelectric ceramics with CuO addition was investigated. The CuO addition significantly promoted the densification and reduced the sintering temperature of PZTN 95/5 ceramics by more than 200°C. The 0.2 wt% CuO-added sample sintered at 1150°C exhibited the optimum relative density of 96.7% and excellent electric properties with values of Pr = 37.80 μC/cm2, TC = 223°C, εr = 329, and tan δ = 0.016, which were superior to that of PZTN 95/5 ceramics sintered at 1350°C. [ABSTRACT FROM AUTHOR]

Highly (001) oriented ( K, Na) NbO3 ( KNN) lead-free piezoelectric thin films were grown on LaNiO3 ( LNO)-coated silicon by RF magnetron sputtering. The effects of the top electrodes on the electrical properties of KNN thin films were investigated. The dielectric and piezoelectric properties were remarkably improved in LNO/ KNN/ LNO (εr = 899 at 1 kHz, d33 = 58 pm/V), compared with that in Pt/ KNN/ LNO (εr = 584 at 1 kHz, d33 = 26 pm/V). An enhanced ferroelectricity was also obtained in LNO/ KNN/ LNO, with a remnant polarization of 12 μC/cm2 and a maximum polarization of 23 μC/cm2 at the applied field of 200 kV/cm. Besides, the temperature dependence of piezoelectricity of the films was characterized in this study. [ABSTRACT FROM AUTHOR]

Abstract: Sr x Ba1−x Nb2O6 (with x=0.50, 0.45, 0.40 and 0.30) ceramics were synthesized by conventional solid-state method and sintered at 1350°C for 3h. The phase structure, microstructure, dielectric, ferroelectric and pyroelectric properties of obtained ceramics were systematically investigated. Pure tungsten bronze phase could be obtained in all ceramics. The dielectric characteristics showed that SBN ceramic was a relaxor with strong diffuse phase transition and weak frequency dispersion. As Sr molar fraction x increases from 0.30 to 0.50, the transition temperature T C decreased linearly while the diffusivity parameter γ declined from 1.88 to 1.68. The saturated polarization, remnant polarization and pyroelectric coefficient were also found to be enhanced in SBN ceramics with increasing Sr content. The pyroelectric coefficient of about 2×10−8 C/cm2K can be obtained for polarized SBN50 ceramics at room temperature. [Copyright &y& Elsevier]

Abstract: (K,Na)NbO3 ferroelectric films were grown on LaNiO3 coated silicon substrates by RF magnetron sputtering. The conductive LaNiO3 films acted as seed layers and induced the highly (001) oriented perovskite (K,Na)NbO3 films. Such films exhibit saturated hysteresis loops and have a remnant polarization (2P r) of 23μC/cm2, and coercive field (2E c) of 139kV/cm. The films showed a fatigue-free behavior up to 109 switching cycles. A high tunability of 65.7% (@300kV/cm) was obtained in the films. The leakage current density of the films is about 6.0×10−8 A/cm2 at an electric field of 50kV/cm. [Copyright &y& Elsevier]

Abstract: BiScO3–PbTiO3 piezoelectric ceramics were fabricated by the conventional solid state reaction method. The effects of sintering atmosphere on microstructure and electrical properties of BiScO3–PbTiO3 were studied. Different weight changes were found in samples sintered in different atmospheres. X-ray diffraction analysis reveals that all the samples have perovskite structure and a second phase is observed in the samples sintered in sacrificial powders. EDS analysis suggests the second phase could be the compound containing Bi and Pb. Samples sintered in air show lower dielectric constant than those sintered in sacrificial powders, but a higher piezoelectric coefficient. The resisitivity of samples sintered in air is about one order of magnitude higher than that of those sintered in sacrificial powders. These results suggest a promising method to gain BiScO3–PbTiO3 high-temperature piezoceramics with excellent electromechanical properties. [Copyright &y& Elsevier]

Hysteresis loops measured at various temperatures were used to study the intrinsic, induced and total pyroelectric responses in Pb(Sc1/2Ta1/2)O3 (PST) ceramics. The intrinsic pyroelectric response was directly measured from the change rate of the remnant polarization with temperature. The induced one was calculated using the data of the dielectric permittivity derived from hysteresis loops. By analyzing the pyroelectric effect of PST ceramics under 30 kV/cm, the results showed that the induced pyroelectric response played a dominant role in the total pyroelectric coefficient near Curie temperature. [ABSTRACT FROM AUTHOR]

Abstract: Highly (110)- and (100)-oriented LaNiO3 (LNO) thin films were successfully grown on Si (100) substrate using radio frequency (RF) magnetron sputtering at room temperature (RT). Effects of oxygen partial pressures on the orientation, film composition, surface morphology, and electrical properties of the films were investigated. The nearly complete (100) orientation was first achieved with oxygen partial pressure beyond 15% in the sputtering gas. The preferred (100) orientation of growing films is determined by uniform distribution of Ni3+ and La/Ni ratio in the films caused by oxygen during sputtering, as well as the lowest surface energy of the films in the crystalline process. LNO films with controlled orientation have low resistivity of 7.0×10−6 Ωm which is a good basis for integrating ferroelectric capacitors. [Copyright &y& Elsevier]

Abstract: Pure perovskite phase Ba0.70Sr0.30TiO3 (BST) powders were successfully synthesized by molten-salt method in NaCl–KCl flux at a low temperature of 850°C for 2h, which is 300°C lower than that of the conventional solid-state reaction. This simple process involved mixing of the raw materials and salts in a certain proportion. Subsequent calcining of the mixtures led to BST powders at 800–900°C. XRD and SEM techniques are used to characterize the phase and morphology of the fabricated BST powders, respectively. [Copyright &y& Elsevier]

Abstract: The F R(LT)–F R(HT) phase transition and pyroelectric properties of porous Zr-rich lead zirconate ceramics were investigated. There was a relatively slight change of dielectric constant and a maximum peak of pyroelectric coefficient during F R(LT)–F R(HT) phase transition. The F R(LT)–F R(HT) and F R(HT)–P C phase transition temperature changed slightly with an increase in porosity The dielectric constant and pyroelectric coefficient at F R(LT)–F R(HT) phase transition temperature decreased with increasing porosity. However, the pyroelectric figure of merit (F v) increased with an increase in porosity due to a further decrease in dielectric constant with increasing porosity. When porosity exceeded 18.7%, the figure of merit of porous PZT ceramics was higher than that of dense PZT ceramics, which demonstrated figure of merit of PZT ceramics can be enhanced by inducing porosity. [Copyright &y& Elsevier]

This work demonstrates a mechanism of heterogeneous nucleation for the synthesis of BaTiO 3 nanowires utilizing K 2 Ti 4 O 9 as template by manipulating alkalinity, temperature and reaction time. Results suggest that the synthesis of BaTiO 3 does not occur through a hydrothermal ion-exchange, instead, the predominant mechanism observed is the heterogeneous of dissolution-crystallization. The consistency of crystallographic orientation for BaTiO 3 nanowires is affected by the hydrothermal conditions. BaTiO 3 nanowires synthesized at 190 °C/0.2 M exhibit a uniform (100)/(001) crystallographic orientation, albeit not consistently along the length of the nanowires, while BaTiO 3 crystal grains no longer have the same crystallographic orientation at 190 °C/0.8 M. By investigating the reaction mechanism of BaTiO 3 , this work may have great significance for the synthesis of perovskite-type MTiO 3 (M = Ba,Ca, Sr, Pb) utilizing layered titanates. [ABSTRACT FROM AUTHOR]

Energy storage capacitors for advanced pulse power systems and high-power electric devices is a kind of important electronic components, the demand continues to grow, specifications are constantly being upgraded, and performance boundaries are continuously being pushed. Multilayer ceramic capacitors (MLCCs) for energy storage applications have received increasing attention due to the advantages of ultralow equivalent series inductance, equivalent series resistance, good frequency characteristics, strong voltage overload ability, and stable operability at high temperatures. However, the relatively low energy storage density significantly limits its broader applications. Here, 0.4Ba 0.55 Sr 0.45 TiO 3 -0.4Bi 0.5 Na 0.5 TiO 3 -0.2SrZrO 3 (0.4BST-0.4BNT-0.2SZ) relaxor ferroelectric MLCCs are prepared at different heating rates. Excellent recoverable energy storage density of 10.3 J cm−3 and high energy efficiency of 93 % are achieved in fast-fired MLCCs under the electric field of 106.3 V μm−1. The impedance spectroscopy and thermally stimulated depolarization current technologies are employed to investigate the conductance mechanism of MLCCs, and the results can explain the effect of heating rate on the performance of MLCCs. In addition, the charge-discharge performances of fast-fired MLCCs are also thoroughly investigated, exhibiting great thermal and fatigue stability. [ABSTRACT FROM AUTHOR]

In recent years, the development of environmentally friendly, lead-free ferroelectric films with prominent electrostrictive effects have been a key area of focus due to their potential applications in micro-actuators, sensors, and transducers for advanced microelectromechanical systems (MEMS). This work investigated the enhanced electrostrictive effect in lead-free sodium bismuth titanate-based relaxor ferroelectric films. The films, composed of (Bi0.5Na0.5)0.8−xBaxSr0.2TiO3 (BNBST, x = 0.02, 0.06, and 0.11), with thickness around 1 μm, were prepared using a sol-gel method on Pt/TiO2/SiO2/Si substrates. By varying the Ba2+ content, the crystal structure, morphology, and electrical properties, including dielectric, ferroelectric, strain, and electromechanical performance, were investigated. The films exhibited a single pseudocubic structure without preferred orientation. A remarkable strain response (S > 0.24%) was obtained in the films (x = 0.02, 0.06) with the coexistence of nonergodic and ergodic relaxor phases. Further, in the x = 0.11 thick films with an ergodic relaxor state, an ultrahigh electrostrictive coefficient Q of 0.32 m4/C2 was achieved. These findings highlight the potential of BNBST films as high-performance, environmentally friendly electrostrictive films for advanced microelectromechanical systems (MEMS) and electronic devices. [ABSTRACT FROM AUTHOR]

Mn‐doped (1‐x)Bi0.5(Na0.8K0.2)0.5TiO3‐xBiAlO3 (Mn:BNKT‐xBA) thin films were synthesized on lanthanum nickelate‐coated silicon substrates by sol‐gel method. The second phase issue of the film can be effectively addressed by optimizing the substrate, and the maximum polarization and breakdown strength can be increased by introducing the proper amount of Al3+, which is advantageous for the film for energy storage. The results have shown that the Mn:BNKT‐0.03BA film exhibits superior ferroelectric properties (with remanent polarization (Pr) of 23.72 µC/cm2, maximum polarization (Pmax) of 75.37 µC/cm2), which could be an excellent candidate for ferroelectric thin film capacitors. [ABSTRACT FROM AUTHOR]

Pyroelectric materials have been widely studied because of their important role in infrared detectors, sensors, thermal imaging, and other applications, among which, lead-based ceramics are extensively adopted. However, the environmental problems caused by lead-based compounds in production and processing are becoming increasingly serious. Meanwhile, the surface mounting technology is extensively employed in the electronics industry for device miniaturization and integration. However, due to its high processing temperature (∼260 °C), it makes most pyroelectric ceramic materials unsuitable for this process. Therefore, it is of great significance to develop novel high-performance lead-free pyroelectric ceramics with high depolarization temperature (>260 °C). In this work, we report the Na0.995Ag0.005NbO3-0.1%Mn (NANM) pyroelectric ceramics. The antiferroelectric–ferroelectric phase transition field and coercive field of NaNbO3 ceramics were reduced by the introduction of AgNbO3 and Mn, making it easier to induce the ferroelectric phase and realize poling in NANM ceramics. The NANM ceramics exhibited an excellent pyroelectric coefficient of 2.55 × 10−4 C m−2 K−1 and figures of merit as Fi = 0.93 × 10−10 m/V, Fv = 6.46 × 10−2 m2/C, and Fd = 2.92 × 10−5 Pa−1/2 at room temperature. More importantly, a high depolarization temperature of 280 °C was achieved, ensuring the ability to withstand high temperature during production and operation. The NANM ceramics with excellent pyroelectric properties and high depolarization temperature are expected to be a promising lead-free candidate for uncooled infrared detector applications. [ABSTRACT FROM AUTHOR]

The ferroelectric domain plays an important role in determining the piezoelectric performance of ferroelectric ceramics. Herein, LiNbO 3 (LN) is used as an additive to tune the ferroelectric domain of 0.49Pb(Ni 1/3 Nb 2/3)O 3 -0.2Pb(In 1/2 Nb 1/2)O 3 -0.31PbTiO 3 (PNN-PIN-PT) ceramics. PNN-PIN-PT-0LN ceramic exhibits the ordered tetragonal phase (90 °) domain wall and rhombohedral phase (71 ° and 109 °) domain wall. Incorporating LN into the system leads to the transformation of the majority of structured macro-domains into random micro-domains with smaller sizes, which disrupt their long-range ordered ferroelectric domains, resulting in significant piezoelectric enhancement. Compared to PNN-PIN-PT-0LN ceramics, PNN-PIN-PT-1.8LN ceramics exhibit giant piezoelectric responses with d 33 = 1112 pC/N, d 31 =521 pC/N, d 33 * =1220 pm/V (@ E = 5 kV/cm), ε r = 12092. These findings shed light on a specific aspect of domain engineering in piezoelectric materials, thus contributing to a more comprehensive understanding of the underlying factors that give rise to the phenomenon of giant piezoelectricity. [ABSTRACT FROM AUTHOR]

(Pb,La)(Zr,Ti)O3 antiferroelectric (AFE) ceramics have attracted considerable interest due to their high‐energy storage density and numerous field‐induced phase transitions. However, the positional equilibrium of the A‐site and B‐site is typically maintained without considering that heterovalent doping of La3+ can induce defects within the material, leading to high‐temperature leakage conduction. In this work, we introduced the acceptor ion Na+ at the A‐site simultaneously and designed Pb0.9175–0.5xLa0.055NaxZr0.975Ti0.025O3 (x = 0.01, 0.03, 0.055, 0.07, 0.10) AFE ceramics. The dielectric properties of these ceramics exhibited a consistent pattern of improvement followed by deterioration as the content of Na+ increased. Notably, when x = 0.055 (Na5.5), the AFE ceramic demonstrated superior high‐temperature frequency stability with negligible leakage conduction. Impedance spectroscopy analysis suggested that Na5.5 displays the greatest resistance and highest Edc. Concurrently, the thermally stimulated depolarization current indicates that Na5.5 possesses the lowest defect concentration and the largest Ea. This can be attributed to the internal generation of defect dipole clusters (VPb′′−VO••−NaPb′−LaPb•$V_{{\mathrm{Pb}}}^{{\prime\prime}} - V_{\mathrm{O}}^{ \bullet \bullet } - {\mathrm{Na}}_{{\mathrm{Pb}}}^{\prime} - {\mathrm{La}}_{{\mathrm{Pb}}}^ \bullet $), which effectively restrict the movement of charged defects. These findings suggest that Na5.5 holds significant potential for application and offer insights into the understanding of internal defects in lead‐based AFE materials. [ABSTRACT FROM AUTHOR]

Pb0.7Sr0.3TiO3/La0.7Sr0.3MnO3 (PST/LSMO) thin film has been deposited on Si substrate by chemical solution deposition. Obvious changes in dielectric constant and loss as functions of frequency and magnetic field were observed in PST/LSMO thin film. By applying both dc bias electric and magnetic fields, apparent dielectric anomalies were observed in the 'butterfly-hysteresis' curves. These effects may be useful for practical application. The mechanism for the magnetocapacitance effects in PST/LSMO is rationalized by combining the Maxwell-Wagner capacitor model and the magnetoresistivity and magnetostriction of the LSMO. [ABSTRACT FROM AUTHOR]

The discharge performance of antiferroelectric (AFE) capacitors is complicated and difficult to simulate due to the nonlinear polarization behavior of AFE. In this work, a nonlinear model for pulsed discharge AFEs was proposed based on a combination of the Preisach model and Kirchhoff's law. The model was driven by the data from first-order reversal curves and direct-current-bias (DC-bias) dielectric test measurements. Thus, the discharge behavior of the AFE can be studied without actual discharge experiments. Specifically, AFE discharge waveforms were calculated and evaluated for different size parameters and external circuit parameters that were conducive to compare the properties of different AFE materials. Moreover, the size effect of the capacitor on the discharge performance was discussed, which should draw the attention of researchers to prevent exaggerated conclusions. As a consequence, this method would fill the gap of AFE discharge simulation. [ABSTRACT FROM AUTHOR]

The pressure‐driven force‐electric conversion materials with extremely rapid response time have been widely used in mining, defense, and energy areas. The discharge process by the force‐electric conversion effect in ferroelectrics is dominated by polar‐nonpolar phase transformation. In this work, (Pb0.985La0.01)(ZrxTi1‐x)O3 (PLZT, x = 0.85–0.94) ceramics is designed by tunning Zr4+/Ti4+ ratio and aliovalent La doping to achieve high remnant polarization (Pr) and excellent temperature stability. We focus on the pressure‐driven depolarization in PLZT ceramics, and their corresponding phase structure, ferroelectric properties, dielectric properties, and thermal depolarization. In PLZT (x = 0.93) ceramics, the original polarization P0 increases to 43.42 μC/cm2. The pressure‐driven depolarization releases 37.66 μC/cm2 with the depolarization proportion of 86.73%, which is attributed to irreversible ferroelectric‐antiferroelectric phase transition. It also exhibits excellent temperature stability up to 120°C (> 36 μC/cm2). This work provides a high‐performance alternative to Pb(Zr0.95Ti0.05)O3 and guidance for the development of pulse power energy conversion devices. [ABSTRACT FROM AUTHOR]

We present a study on the hydrothermal synthesis of BaTiO 3 utilizing NaTi 3 O 6 (OH)- (H 2 O) 2 nanowires, which was conducted by controlling temperature, alkalinity and time. Initially, increased temperature has promoted the synthesis of BaTiO 3 and induce a change in the morphology. When the temperature increases within the range of 90 °C–210 °C, the morphology of the product transitions from nanoparticle to spindle-shaped to nanowires. Then, a time-dependent experiment was conducted to investigate the mechanisms involved in the transformation of the morphology. The formation of nanoparticle occurs through the process of dissolution-crystallization, while the formation of BaTiO 3 nanowires is attributed to hydrothermal ion exchange. Also, the hydrothermal process is characterized by grain aggregation and grain growth. By investigating the synthesis and morphology evolution of BaTiO 3 , this work holds significant potential for the synthesis of BaTiO 3 nanowires or other perovskite-type MTiO 3 employing titanate as a precursor. [ABSTRACT FROM AUTHOR]

With the gradual promotion of new energy technologies, there is a growing demand for capacitors with high energy storage density, high operating temperature, high operating voltage, and good temperature stability. In recent years, researchers have been devoted to improving the energy storage properties of lead‐based, titanium‐based, and iron‐based multilayer ceramic capacitors (MLCCs). However, limited research has been conducted into MLCC development using NaNbO3 (NN)‐based materials. In this paper, the successful achievement of excellent overall energy storage performance in a novel NaNbO3–(Bi0.5Na0.5)TiO3–Bi(Mg0.5Hf0.5)O3 lead‐free MLCCs is presented. The disordered tilting around the cp axis, disrupts Na and Bi ions' long‐range displacements and induces PNRs and strong relaxor behavior, which ensures a superior energy storage performance, together with the multilayer ceramic design strategy. As a result, the NN‐based MLCC device presents an ultra‐high Wrec = 12.65 J cm−3 and η = 88.5%, simultaneously showing superior temperature stability (Wrec varies <±1% and η varies <±6% from −50 to 125 °C) and fatigue resistance (Wrec and η vary <±1% over 107 cycles). This study highlights the advanced energy storage potential of NaNbO3‐based MLCCs for various applications, and ushers in a new era for designing high‐performance lead‐free capacitors that can operate in harsh environments. [ABSTRACT FROM AUTHOR]

The capacitors are in rising demand for cryogenic applications. As for now, it still remains an ongoing challenge for simultaneously achieving high energy storage density and cryogenic temperature stability. Herein, the strategy of stable backward phase transition was demonstrated in the antiferroelectric composition of (Pb0.9175La0.055)(Zr0.975Ti0.025)O3. As a result, we achieved high recoverable energy density about 10 J/cm3 with exceptional low-temperature stability from −160 to 25 °C. Multi-layer ceramic capacitors designed for pulse discharge applications also demonstrated high performance in cryogenic conditions, with the peak current fluctuations of less than 4%. Through in situ characterizations using x-ray diffraction, Raman spectra, and transmission electron microscopy, we discovered that the anisotropic structural evolution is responsible for a stable backward phase transition, providing the material with robust stability at cryogenic temperatures. These results offer a good paradigm for improving the temperature stability of antiferroelectric multi-layer capacitors to meet the rigorous demands of energy storage applications. [ABSTRACT FROM AUTHOR]

The ultrahigh piezoelectric coefficient (d 33 ≥ 1000 pC/N) exhibited by piezoelectric Pb(Zr,Ti)O 3 (PZT) ceramics not only captivates researchers but also holds considerable practical value across various applications. While significant progress has been made in enhancing piezoelectricity of PZT-based ceramics, novel mechanisms need to be proposed to explain the piezoelectric behavior of new systems with ultrahigh d 33. In this study, we initially employ LiNbO 3 as an additive to enhance the piezoelectric properties of the Pb(Ni 1 / 3 Nb 2 / 3)O 3 –PbZrO 3 –PbTiO 3 ceramics. and the optimal performance is achieved by incorporating 1.5 mol% of LiNbO 3 into the system, resulting in an ultrahigh d 33 ∼1178 pC/N (d 33 * ∼1560 p.m./V (@ E = 5 kV/cm)). The corresponding mechanism for this superior piezoelectric response involves the AB-site co-doping effect, especially the (Li Pb ′ − Nb Zr / Ti ∙) defect dipoles formed by the introduction of LiNbO 3. In particular, the addition of LiNbO 3 leads to a more uniform distribution of domain sizes, thereby further enhancing the ultrahigh piezoelectricity. These findings pave the way for a deeper under-standing of the origin of ultrahigh piezoelectric properties and make substantial contributions to the advancement of piezoelectric materials for practical applications in electromechanical devices. [ABSTRACT FROM AUTHOR]

Antiferroelectric ceramics can realize ultra-high energy storage, which benefits from transformation between an antiferroelectric phase and a ferroelectric phase. Understanding the mechanism of such phase transition is the key point for building the structure-property correlation. Here, we report the observation of electric-induced devil's staircase in the course of antiferroelectric–ferroelectric phase transition in PbZrO3-based antiferroelectric ceramics by in situ transmission electron microscopy. The dynamic evolution as-revealed in both reciprocal- and real-space involves stepwise rather than monotonic increase in modulation periods along with simultaneous proliferation of nanodomains. Desynchrony of phase transition is observed for incommensurate domains with different initial modulation periods within a single antiferroelectric domain. Then, the synergistic effect of the devil's staircase and as small as possible the initial modulation period is believed to contribute to the superior energy-storage performance. These findings will be helpful for the development of theories for antiferroelectric–ferroelectric phase transition and the design of high-power antiferroelectric materials. [ABSTRACT FROM AUTHOR]

Recently, Bi0.5Na0.5TiO3-based ceramics have drawn widespread attention due to their excellent energy storage properties. Here, a comprehensive analysis of the composition- and temperature-driven transition processes in (1 − x)Bi0.5Na0.5TiO3-xSm2Ti2O7 (BNST-x) polycrystals have been presented using Raman scattering and spectroscopic ellipsometry. With increasing Sm2Ti2O7 content, BNST-x ceramic gradually becomes disordered and belongs to the superparaelectric state at x = 0.12 near room temperature. Moreover, the thermal evolution of the lattice kinetic behaviors shows two crucial temperatures: the depolarization temperature Td and the temperature at the maximum dielectric permittivity Tm, which suggest the transitions from nonergodic relaxor ferroelectric—ergodic relaxor (ER) ferroelectric and ER ferroelectric—superparaelectric, respectively. It is noteworthy that the series of changes is closely related to the ordering degree of the B-site ion affected by the doping and the temperature. This work gives an insight into the connection among the phonon behavior, electronic transition, and lattice structure of BNST-x ceramics, which can further understand the phase transition mechanisms under the doping and thermal field. [ABSTRACT FROM AUTHOR]

Lead-free (Bi 0.5 Na 0.5)TiO 3 (BNT)-based piezoelectric materials, have a great potential for high-precision actuators' applications. In this work, the high-quality (0.94- x %)(Bi 0.5 Na 0.5)TiO 3 -0.06BaTiO 3 - x %NaNbO 3 (x = 2–10, BNT-6BT- x NN) thin films have been successfully deposited on Pt/TiO 2 /SiO 2 /Si substrates by sol-gel method. An ultra-high poling strain S pol value of 1.7% with a unipolar strain S uni value of 1.47% was reported in the BNT-6BT-6NN thin films. The coexistence of the ferroelectric phase and relaxor state was observed in the compositions of x = 2–8. Furthermore, the BNT-6BT-6NN thin films show more active domain switching compared to other compositions. It is demonstrated that the optimized strain responses in the BNT-6BT-6NN are attributed to a synergistic reaction of active domain switching and reversible electric-field-induced phase transition between the ferroelectric phase and relaxor state. Our systematic study demonstrates that the BNT-6BT- x NN thin films with an improved strain response are promising candidates for the applications of miniaturized actuators. [ABSTRACT FROM AUTHOR]

Due to the high demand for dielectric materials with high energy density, the energy storage performance of antiferroelectric ceramic capacitors has always gained much attention. Polarization intensity is a key factor that is closely related to the energy storage density. However, thus far, there has been a lack of research studies or successful methods to effectively modulate polarization intensity. The behavior of the polarization process is complex and contains domain nucleation, growth, and flip-flapping. Based on this finding, the introduction of Nb5+ at the B-site was designed to influence the three stages of antiferroelectric polarization by regulating the balance between the ferroelectric and antiferroelectric phases, and eventually realized regulation of the saturation polarization intensity in the (Pb 1-1.5x La x)(Zr 0.5 Sn 0.43 Ti 0.07)O 3 antiferroelectric ceramics. The saturation polarization intensity has increased from 25.56 to 42 μC/cm2 with Nb5+ content increases from 0 to 4 mol% and the hysteresis was kept low, Pb 0.94 La 0.04 (Zr 0.65 Sn 0.35) 0.975 Nb 0.02 O 3 is the optimal component with a high releasable energy density of 8.26 J/cm3 and an energy storage efficiency of 90.31%. This work provides an in-depth explanation of the microscopic mechanism of antiferroelectric ceramic polarization and presents a novel approach for the composition design of high-energy storage density antiferroelectric ceramics. [ABSTRACT FROM AUTHOR]

Bismuth layer structured ferroelectrics (BLSFs) have drawn much attention due to their great potential for high‐temperature applications. It is generally accepted that BLSFs with small orthorhombic distortion should have low TC. In this paper, we report an anomalous example Li0.5Bi2.5Nb2O9 (LBN), which has small orthorhombic distortion but very high TC. LBN shows the highest TC (834°C) among currently reported prototype alkali‐metal BLSFs, which is attributed to its small tolerance factor. However, the refinement result reveals that LBN is orthorhombic with the space group of A21am, and the orthorhombic distortion of LBN a/b is merely 1.0019. The measurement of piezoelectric coefficient (d33 ∼ 6 pC/N) and observation of striped domain structure confirm the ferroelectricity nature of LBN. This work deepens our understanding of BLSFs and may lead to the finding of more novel BLSFs with high performance. [ABSTRACT FROM AUTHOR]

High polarization of ferroelectric materials has profound research significance and is the decisive factor in the application of energy storage, pyroelectricity, and explosive energy conversion. Herein, in force-electric conversion field, an ultrahigh remanent polarization (51.43 μC/cm2) and record-breaking energy density (4.59 J/cm3) after poling were achieved with a lead-free (1 − x)Bi0.5Na0.5TiO3 − xAgNbO3 [(1 − x)BNT – xAN] relaxor ceramics. The enhancement effect of AgNbO3 on polarization is attributed to the increase in lattice distortion and orientation after poling. Additionally, a significant force-electric conversion effect under hydrostatic pressure (depolarization rate ∼44.8%, 400 MPa) and shock pressure (depolarization rate ∼54.4%, 6.3 GPa) in (1 − x)BNT – xAN was attributed to the pressure-driven ferroelectric/relaxor (FE/RE) phase transition. This work is expected to enlighten the further design of ferroelectric materials with high polarization for pulse power energy conversion application. [ABSTRACT FROM AUTHOR]

The pressure‐driven explosive energy‐conversion (EEC) effect of ferroelectric (FE) materials has been extensively studied in scientific research and high‐tech applications owing to its high pulse‐power output capability. The fundamental principle of this effect is pressure‐driven phase transition and depolarization in FE materials, accompanied by discharging behavior from the charge release upon pressure loading. Pb(Zr,Ti)O3 has been an excellent example of a materials exhibiting these properties. However, recent investigations have been focused on developing other lead‐based or lead‐free materials with a higher energy‐storage ability and better temperature stability. In this article, we review the recent progress achieved in the past decades on different types of lead‐based and lead‐free ceramics, single crystals, and multilayer films, based on their unique pressure‐driven phase transition and energy‐conversion properties. Their pulse power discharging performance under actual shock‐wave compression is also summarized, followed by a detailed discussion of the failure mechanism under shock‐wave compression. Finally, several issues and perspectives are proposed for future investigation in this area. All these not only assist in the design of new materials for high‐performance EEC but are also helpful for the practical application of these promising materials in pulse‐power technologies. [ABSTRACT FROM AUTHOR]

It has been reported that grain size has significant influence on the dielectric properties of barium strontium titanate (BST) thin films. In this paper we have proposed a multilayer structure in which BST layers are separated by thin MgO layers which are expected to function as barrier to atomic diffusion so that the grain size of BST could be confined. By simulation we have found that for a device with a coplanar/composite film/substrate configuration, the introduction of MgO can effectively change the dielectric constant of the composite while the tunability is not significantly affected, provided the amount of MgO is smaller than 25%. A prototype device was prepared to demonstrate the feasibility of this idea. By X-ray diffraction measurements it is revealed that BST and MgO coexist in the composite. The dielectric property of the composite film was determined and it was found that the film has a tunability of up to ~7% at 500 MHz and under an electric field of 13.3 kV/mm. [ABSTRACT FROM AUTHOR]

Compared to the bulky ceramic counterparts, antiferroelectric (AFE) thin films exhibit higher energy-storage performance. It has been demonstrated that the performance of the AFE thin films is strongly affected by the thickness. However, possible changes in the phase structures and microstructures accompanied by varying thicknesses have been less known, which makes it hard to fully understand the physical insight of the thickness effect. Herein, we fabricate a series of PbZrO3 (PZ) thin films by chemical solution deposition whose thickness is approximately proportional to the number of deposition layers, i.e., one to four layers with each layer of about 60 nm in thickness. The detailed structural characterization has been performed by using x-ray diffraction, a scanning electron microscope, and a transmission electron microscope. The films are composed of nanorods oriented normal to the films in which each nanorod maintains single crystalline though segmented by the horizontal interfaces between each of the two neighboring layers, suggesting nearly perfect epitaxy during multilayer growth. The multidomain state is found in three-/four-layer PZ thin films while the one-/two-layer PZ films always present a monodomain state. Meanwhile, incommensurate phases with different modulation periods have been observed in the four-layer PZ films. By comparing the as-observed structural features with the measured electrical properties of different films, it seems that microstructural evolution with the film thickness should not be negligible in evaluating the structure–property relation of PZ-based thin films. [ABSTRACT FROM AUTHOR]

The ferroelectric hysteresis loops of 63PbTiO3-37BiScO3 ceramics were measured under sinusoidal electric fields in the range of frequency from 0.1 to 100 Hz and field from 5 to 55 kV/cm. The fitting results showed two linear relations existed between the logarithm of hysteresis area and the logarithm of the amplitude of field E0 in the first and third field region. In the second region, no linear relation existed due to polarization reversal. These three-stage behaviors were distinct from the existing two-stage behaviors. The slopes in the third stage increase with the increasing of frequency, which can be attributed to dielectric loss under high frequency. [ABSTRACT FROM AUTHOR]

Abstract: The effect of lanthanum (La) content on the phase transformation of Pb1−3x/2Lax(Zr0.42Sn0.40Ti0.18)O3 (PLZST 100x/42/40/18, 0 ≤ x ≤ 0.06) ceramics was investigated by the dielectric and ferroelectric properties. The base composition PLZST 0/42/40/18 located in the ferroelectric (FE) rhombohedral phase region. As x increased, the compositions showed successively FE and antiferroelectric (AFE) state at room temperature, and their peak temperatures (Tmax) decreased gradually in line as Tmax = 162.21‐1507x. Evidence was presented that there were two dielectric anomalies in PLZST 2/42/40/18, which were corresponding to the FE‐AFE and AFE‐paraelectric (PE) phase transformations, respectively. With increasing the dc bias fields, the two phases merged into one. PLZST 3/42/40/18 showed AFE characteristics with the first loop outside of the second loop and there was only one dielectric inflection. The critical lanthanum content occurred at x = 0.03 from the dielectric temperature spectra and hysteresis loops. Furthermore increase in La above 0.03, these compositions showed typical antiferroelectric behaviors with double hysteresis loops. The stored energy properties of the three compositions (PLZST 4/42/40/18, 5/42/40/18 and 6/42/40/18) displayed different temperature dependencies from room temperature to 140°C (over their respective Tmax). Comparing the above results with previous investigations on PLZSTs, some questions were discussed. [ABSTRACT FROM AUTHOR]

The most promising candidates for energy storage capacitor application are relaxor ferroelectrics, among which, the perovskite structure ferroelectric ceramics have witnessed great development progress. However, less attention has been paid on tetragonal tungsten bronze structure (TTBS) ceramics because of their lower breakdown strength and polarization. Herein, a multiscale regulation strategy is proposed to tune the energy storage performances (ESP) of TTBS ceramics from grain, domain, and macroscopic scale. The enhanced relaxor behavior with dynamic polar nanodomains guarantees low remanent polarization, while the refined grains and enlarged bandgap ensure increased breakdown strength. Hence, excellent ESP is realized in unfilled TTBS Sr0.425La0.1□0.05Ba0.425Nb1.4Ta0.6O6 (SLBNT) ceramics with an ultrahigh recoverable energy density of 5.895 J cm−3 and a high efficiency of 85.37%. This achievement notably surpasses previous studies in TTBS ceramics and is comparable to that of perovskite components. Meanwhile, the energy density exhibits a wide temperature, frequency, and cycling fatigue stability. In addition, high power density (257.89 MW cm−3), especially the ultrafast discharge time (t0.9 = 16.4 ns) are achieved. The multiscale regulation strategy unlocks the energy storage potential of TTBS ceramics and thus highlights TTBS ceramics as promising candidates for energy storage, like perovskite structured ceramics. [ABSTRACT FROM AUTHOR]