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In this study, the influence of La3+ substitution on the phase structure, microstructure, electrical and energy storage properties of (Sr 0.3 Bi 0.35 Na 0.335 Li 0.015) 1-x La x TiO 3 (SBNLT-xLa) ceramics with x = 0–0.05, using the solid-state combustion technique, was investigated. X-ray diffraction (XRD) patterns indicated a pure perovskite structure formed, along with coexisting rhombohedral and tetragonal phases in all ceramics. The Rietveld refinement analysis showed the tetragonal phase increased while the rhombohedral phase decreased with increased La3+ content. The morphology of the SBNLT-xLa ceramics displayed polygonal grain shapes and anisotropic grain growth. Average grain sizes increased from 2.01 to 2.43 μm as x increased from 0 to 0.01 and afterwards decreased as x increased further. Both the measured density and maximum dielectric constant (ɛ m) decreased from 5.48 to 5.29 g/cm3 and from 4667 to 2313, respectively, when x increased from 0 to 0.05. A decrease in the dielectric properties caused by the phase ratio shifting away from a morphotropic phase boundary (MPB) condition, poor microstructure and low density was produced with La3+ replacement. The maximum polarization (P max), remnant polarization (P r) and coercive field (E c) decreased with increased La3+ content. A decline in P r and E c improved the energy storage efficiency (ƞ) and energy storage loss (W loss), resulting in enhanced energy storage properties. At x = 0.02, the ceramic showed good energy storage properties (W total of 0.781 J/cm3, W rec of 0.624 J/cm3, W loss of 0.157 J/cm3 and ƞ of 79.8%), measured at 60 kV/cm. [ABSTRACT FROM AUTHOR]

To design novel materials suitable for high-temperature electromechanical applications, a bismuth-based ternary solid solution system, (1- x - y)BiScO 3 - y Pb(Sc 1/2 Nb 1/2)O 3 - x PbTiO 3 , with compositions situated around the morphotropic phase boundary, were designed and synthesized in the form of ceramic. The crystal structure, microstructure, dielectric, ferroelectric and piezoelectric properties, and the local polar domain structure of the ceramics were investigated in detail. The examined ceramics exhibit large grain sizes ranging from 20 μm to 45 μm, along with noteworthy characteristics, including a relatively large strain of 0.21 %, a high large-signal piezoelectric coefficient (d 33 * = 368 pm/V), a low dielectric loss (tanδ = 1.7 %), and a high Curie temperature (T C ∼ 423 °C). These enhanced properties signify the suitability of the designed ternary ceramics for future high-temperature electromechanical applications. This work demonstrates an effective approach for designing ferro-/piezoelectric materials characterized by substantial strain and low dielectric loss. [ABSTRACT FROM AUTHOR]

Ceramic compounds BaTi 1-x Fe x O with x = 0–0.2 prepared by solid state reaction technique were studied using X-ray diffraction, Raman spectroscopy, and magnetometry methods focusing on the correlation between the structure and magnetic properties. Chemical doping with Fe ions leads to a concentration driven structural transformation from the single phase tetragonal (T-) structure to the hexagonal (H-) structure with a mixed structural state stable in the concentration range 0.06 < x ≤ 0.2. Increase in the Fe ions content causes a stabilization of weak ferromagnetic state driven by the exchange interactions Fe3+ – O – Fe3+ ions strongly dependent on the structural positions of the Fe ions. Increase of the dopant content above x = 0.08 leads to a decrease of the remnant magnetization which is mainly caused by a stabilization of Fe4+ ions as well as by the lattice defects associated with oxygen vacancies formed to keep electroneutrality of the compounds. The results of the structural and magnetization measurements allowed to itemize the type of exchange interactions between Fe ions residing different structural positions of the hexagonal lattice as well as to reveal structural instability of the T- and H- phases under ambient conditions and applied electric field which shows a possibility to control the structure and magnetic properties of the mixed compounds via external stimuli. [ABSTRACT FROM AUTHOR]

Antiferroelectric (AFE) materials have great potential for applications in large-strain actuators due to their unique field-induced phase transition properties. In particular, AFE ceramics that exhibit a high level of field-induced strain with reversible and "on/off" features at low electric fields are well suited for use in reliable actuators. In this study, we designed Pb 0.97 La 0.02 (Zr 0.72-x Sn 0.17+x Ti 0.11)O 3 (x = 0, 0.03, 0.06, 0.09, 0.12, 0.15) AFE ceramics with the components close to the morphotropic phase boundary (MPB). The polarized Pb 0.97 La 0.02 (Zr 0.60 Sn 0.29 Ti 0.11)O 3 AFE ceramics exhibit an excellent field-induced strain of 1.21 % at a low electric field (60 kV/cm). This phenomenon can be attributed to the more miniaturized and disordered domain structure, which provides an important contribution to its field-induced strain beyond the AFE-FE phase transition. This work not only provides an AFE ceramic candidate for actuators but also explains the origin of the excellent field-induced strain properties of AFE ceramics with components close to the MPB. [ABSTRACT FROM AUTHOR]

Bi 1-y Sm y Fe 1-x Ti x O 3 ceramics with compositions at the rhombohedral- orthorhombic morphotropic phase boundary (y = 0.1, 0.12, 0 ≤ x ≤ 0.1) were prepared by solid state reaction method. Analysis of the crystal structure of the compounds based on the results of laboratory and synchrotron X-ray diffraction measurements as well as Raman spectroscopy experiments revealed a coexistence of the rhombohedral phase (SG R 3 c) and the anti-polar orthorhombic phase (SG Pbam) in the compounds Bi 0.88 Sm 0.12 Fe 1-x Ti x O 3 with 0 ≤ x ≤ 0.1; the compounds Bi 0.9 Sm 0.10 Fe 1-x Ti x O 3 are characterized by the mixed structural state for the concentration range 0 ≤ x ≤ 0.06 and by the single phase rhombohedral state within 0.06 < x ≤ 0.1. Room temperature magnetization measurements demonstrate a gradual increase of remanent magnetization with Ti content in the compounds of both systems up to the maximal value of M R ∼0.28 emu/g for compounds with x = 0.06 which is followed by a decrease in magnetization with further titanium doping. Temperature decrease leads to a reduction of remanent magnetization which is mainly caused by a partial recovery of spatially modulated spin structure occurred in the compounds of both systems. Time aging of the compounds for about ∼1 year leads to a drastic increase of M R , which is caused by a change in the structural phase ratio, homogeneity of the structural state and a contribution of unbounded spins demonstrated by low field measurements. Subjecting of the annealed compounds to external electric field of E ∼40 kV/cm leads to a decrease of magnetization associated with backward structural transformations and redistribution of the local structural defects in the compounds. [ABSTRACT FROM AUTHOR]

Artificial neurons and synapses are crucial for efficiently implementing spiking neural networks (SNNs) in hardware. The distinct functional requirements of artificial neurons and synapses present significant challenges in the implementation of area‐ and energy‐efficient SNNs. This study reports an all‐ferroelectric SNN system through co‐optimization of material properties and device configurations using wafer‐scale atomic layer deposition. For the first time, a double‐gate (DG) morphotropic phase boundary‐based thin‐film transistor (MPBTFT) is utilized for a leaky integrate‐and‐fire (LIF) neuron. The DG MPBTFT‐based LIF neuron eliminates the need for capacitors and reset circuits, thereby enhancing area and energy efficiency. The DG configuration demonstrates various neuronal functions with high reliability. Co‐optimizing materials and devices significantly enhance the performance and functional versatility of artificial neurons and synapses. Meticulous material engineering facilitates the seamless co‐integration of DG MPBTFT‐based neurons, ferroelectric thin‐film transistor (TFT)–based synapses, and normal TFTs on a single wafer. All‐ferroelectric SNN systems achieved a high classification accuracy of 94.9%, thereby highlighting the potential of DG MPBTFT‐based LIF neurons for advanced neuromorphic computing. [ABSTRACT FROM AUTHOR]

Background: The unique non-uniform polar nanoregions and complex phase structure near morphotropic phase boundaries (MPBs) in relaxor ferroelectric materials lead to rich microstructure changes (domain transition, phase transition) under external field stimulation. This not only results in the material with extremely high electromechanical properties, but also greatly affects their mechanical properties and stability. Objective: This study investigated the fundamental mechanical properties of the rhombohedral phase (R-phase) and tetragonal phase (T-phase) structures of the relaxor ferroelectric single crystal PMN-PT material using the nanoindentation with different shapes of indenters. Methods: The basic mechanical properties of the material were measured by nanoindentation, and the fracture caused by indentation was analyzed by scanning electron microscopy. Results: The elastic modulus of R-phase relaxed ferroelectric materials showed a significant dependence on the indentation depth, and the hardness of different phases (R, T-phase) materials all show obvious indentation size effects (ISE). Under the loading of the spherical indenter, both R and T phase materials exhibited a pop-in phenomenon caused by the transition from elastic to inelastic. Under the loading of the Berkovich indenter, the R and T phase materials showed different fracture characteristics of crack propagation response with the increase of the indentation depth. Conclusions: The result demonstrate that the mechanical properties of relaxor ferroelectric materials are significantly related to their phase structure, providing guidance for the design of load bearing and material selection in the practical application of related ferroelectric devices. [ABSTRACT FROM AUTHOR]

Multiferroic BiFeO3 exhibits a morphotropic phase boundary at large compressive strain that merges metastable phases of tetragonal (T) and rhombohedral (R) character resulting in giant ferroelectric and electromechanical responses. To utilize this functionality in devices, it is essential to understand the response of these ferroelectric phases to the environment of a nanoscale heterostructure. Here, the emergence of ferroelectricity near the morphotropic phase boundary in BiFeO3 is explored directly during thin‐film growth, using optical second harmonic generation. It is found that the epitaxial films form at the growth temperature purely in the T phase with zero critical thickness for the spontaneous polarization. Signatures of monoclinic T‐like and R‐like phases only appear upon sample cooling. The robustness of a single‐domain configuration in the high‐temperature T phase is furthermore demonstrated during growth of capacitor‐like metal | ferroelectric | metal heterostructures. Here, a reduction in tetragonality, rather than multidomain formation, lowers the electrostatic energy in the few‐unit‐cell thickness regime. For this lower tetragonality, density‐functional calculations and scanning transmission electron microscopy point to the stabilization of a novel metastable monoclinic structure upon cooling toward room temperature. The synergistic combination of strain and electrostatic phase stabilization in BiFeO3 heterostructures hence provides a basis for designing new ferroelectric phases and ultrathin ferroelectric devices. [ABSTRACT FROM AUTHOR]

The contradiction between high piezoelectricity and uniquely poor temperature stability generated by polymorphic phase boundary is a huge obstacle to high-performance (K, Na)NbO3 -based ceramics entering the application market as Pb-based substitutes. We possess the phase boundary by mimicking Pb(Zr, Ti)O3's morphotropic phase boundary structure via the synergistic optimization of diffusion phase boundary and crystal orientation in 0.94(Na0.56K0.44)NbO3−0.03Bi0.5Na0.5ZrO3−0.03(Bi0.5K0.5)HfO3 textured ceramics. As a result, a prominent comprehensive performance is obtained, including giant d33 of 550 ± 30 pC/N and ultrahigh temperature stability (d33 change rate less than 1.2% within 25-150 °C), representing a significant breakthrough in lead-free piezoceramics, even surpassing the Pb-based piezoelectric ceramics. Within the same temperature range, the d33 change rate of the commercial Pb(Zr, Ti)O3−5 ceramics is only about 10%, and more importantly, its d33 (~ 350 pC/N) is much lower than that of the (K, Na)NbO3-based ceramics in this work. This study demonstrates a strategy for constructing the phase boundary with MPB feature, settling the problem of temperature instability in (K, Na)NbO3-based ceramics. The authors induce a phase boundary similar to Pb(Zr, Ti)O3's morphotropic phase boundary structure in (K, Na)NbO3-based ceramics, which exhibit high residual polarization as well as a significantly improved piezoelectric constant d33. [ABSTRACT FROM AUTHOR]

Studies on the piezoelectric materials capable of efficiently outputting high electrostrains at low electric fields are driven by the demand for precise actuation in a wide range of applications. Large electrostrains of piezoceramics in operation require high driving fields, which limits their practical application due to undesirable nonlinearities and high energy consumption. Herein, a strategy is developed to enhance the electrostrains of piezoceramics while maintaining low hysteresis by incorporating lead magnesium niobate relaxors into lead zirconate titanium at the morphotropic phase boundary. An ultrahigh inverse piezoelectric coefficient d 33 * of 1380 pm/V with a reduced hysteresis of 11.5% is achieved under a low electric field of 1 kV/mm, outperforming the major lead-based piezoelectric materials. In situ synchrotron X-ray diffraction and domain wall dynamics characterization with sub-microsecond temporal resolution reveal that the outstanding performances originate from facilitated domain wall movement, which in turn is due to reduced lattice distortion and miniaturized domain structures. These findings not only address the pending challenges of effective actuation under reduced driving conditions but also lay the foundation for a more systematic approach to exploring the origin of large electrostrains. The authors develop an application-oriented low-field actuating piezoceramic via relaxor substitution. Their in situ synchrotron XRD analysis along with domain wall dynamics characterization reveals the mechanisms of outstanding performance. [ABSTRACT FROM AUTHOR]

A novel synergistic strategy was used to improve the piezoelectric characteristics of high-temperature piezoelectric ceramics. This work combined three commonly used strategies, constructing the Morphotropic Phase Boundary to reduce energy barriers, changing domain structures impacting macroscopic piezoelectric properties, and adjusting BO 6 octahedral distortions reflecting microstructural changes, thus effectively regulating the piezoelectric behaviors of BiFeO 3 -based ceramics. As a result, the 0.67BiFeO 3 -0.32BaTiO 3 -0.01BiAlO 3 component, exhibiting the maximum distortion of the BO 6 octahedron and the coexistence of macrodomains and nanodomains, achieved the optimal piezoelectric characteristics (d 33 = 225 ± 10 pC N−1, T C = 450 °C). Additionally, the ceramic maintained its high piezoelectric properties even at temperatures as high as 280 °C (346 pC N−1). This study presents a novel collaborative design strategy that combines phase structure, domain structure, and BO 6 octahedral distortion, significantly enhancing the development potential of lead-free high-temperature piezoelectric materials in the future. [ABSTRACT FROM AUTHOR]

The inevitable feedback between the environmental and energy crisis within the next decades can probably trigger and/or promote a global imbalance in both financial and public health terms. To handle this difficult situation, in the last decades, many different classes of materials have been recruited to assist in the management, production, and storage of so-called clean energy. Probably, ferromagnets, superconductors and ferroelectric/piezoelectric materials stand at the frontline of applications that relate to clean energy. For instance, ferromagnets are usually employed in wind turbines, superconductors are commonly used in storage facilities and ferroelectric/piezoelectric materials are employed for the harvesting of stray energy from the ambient environment. In this work, we focus on the wide family of ferroelectric/piezoelectric materials, reviewing their physical properties in close connection to their application in the field of clean energy. Among other compounds, we focus on the archetypal compound Pb(Zr,Ti)O3 (or PZT), which is well studied and thus preferred for its reliable performance in applications. Also, we pay special attention to the advanced ferroelectric relaxor compound (1−x)Pb(Mg1/3Nb2/3)O3−xPbTiO3 (or PMN-xPT) due to its superior performance. The inhomogeneous composition that many kinds of such materials exhibit at the so-called morphotropic phase boundary is reviewed in connection to possible advantages that it may bring when applications are considered. [ABSTRACT FROM AUTHOR]

Lead-based piezoelectric materials cause many environmental problems, regardless of their exceptional performance. To overcome this issue, a lead-free piezoelectric composite material was developed by incorporating different percentages of carbon fiber (CF) into the ceramic matrix of Bismuth Sodium Titanate (BNT) by employing the microwave sintering technique. The aim of this study was also to evaluate the impact of microwave sintering on the microstructure and the electrical behavior of the carbon-fiber-reinforced Bi0.5Na0.5TiO3 composite (BNT-CF). A uniform distribution of the CF and increased densification of the BNT-CF was achieved, leading to improved piezoelectric properties. X-ray diffraction (XRD) showed the formation of a phase-pure crystalline perovskite structure consisting of CF and BNT. A Field Emission Scanning electron microscope (FESEM) revealed that utilizing microwave sintering at lower temperatures and shorter dwell times results in a superior densification of the BNT-CF. Raman Spectroscopy confirmed the perovskite structure of the BNT-CF and the presence of a Morphotropic Phase Boundary (MPB). An analysis of nanohardness indicated that the hardness of the BNT-CF increases with the increasing amount of CF. It is also revealed that the electrical conductivity of the BNT-CF at a low frequency is significantly influenced by the amount of CF and the temperature. Moreover, an increase in the carbon fiber concentration resulted in a decrease in dielectric properties. Finally, a lead-free piezoelectric BNT-CF showing dense and uniform microstructure was developed by the microwave sintering process. The promising properties of the BNT-CF make it attractive for many industrial applications. [ABSTRACT FROM AUTHOR]

Lattice defects such as oxygen vacancies, interstitials, and their complexes are present in crystalline oxide materials. In particular, anti‐Frenkel defects, which refer to charge‐neutral anion vacancy‐interstitial pairs, are strongly coupled with ferroelectric and dielectric properties as electric dipoles. However, in order to observe their macroscopic manifestation, delicate defect controls are required to the extent that electronic and ionic charges are almost completely suppressed. Here, the thermal cycle dependence of dielectric and piezoelectric properties is scrutinized in the strain‐driven morphotropic phase boundaries of multiferroic La‐substituted BiFeO3 thin films. Electrochemical impedance spectroscopy provides the Warburg feature that is considered evidence of the ionic origin. The observations are discussed based on anti‐Frenkel defects that are created or annihilated reversibly by thermal cycles through high‐temperature structural phase transition temperature or magnetic Néel temperature. The defect dipoles are spontaneously aligned by the flexoelectric effect in the phase boundaries inducing a metastable interfacial ferroelectric phase. The findings offer useful insight into defect dipoles. [ABSTRACT FROM AUTHOR]

Eco-friendly (0.73- x)Bi 1.05 FeO 3 - x LiNbO 3 -0.27BaTiO 3 ternary ceramics were designed and prepared via a solid-state sintering route. Based on the X-ray diffraction results and Rietveld refinement, it was found that the structure of the ceramics transformed from rhombohedral to tetragonal symmetry with the addition of LiNbO 3 , and at x = 0.003, there existed a morphotropic phase boundary separating the two phases. Near the phase boundary, the largest values were achieved for the piezoelectric constant d 33 and planar electromechanical coupling coefficient k p , being 180 pC/N and 0.27, respectively. Due to the addition of LiNbO 3 , the grain size tended to become smaller. Additionally, the ceramics were transitioned from normal to relaxor ferroelectrics with increasing x. Despite the fact that the LiNbO 3 addition would result in a gradual decrease of Curie temperature, a relatively high Curie temperature (535 °C) was still maintained at x = 0.003, the phase boundary composition, which also showed good temperature stability of piezoelectric properties. These experimental results can provide a reference for the practical applications of high-temperature lead-free ceramics. [ABSTRACT FROM AUTHOR]

The pressure-induced structural changes in the perovskite-type (ABO 3 ) ferroelectric solid solution (1-x)Na 0.5 Bi 0.5 TiO 3 -xBaTiO 3 (NBT-xBT) at the morphotropic phase boundary (MPB) ( x MPB = 0.048 ) have been analyzed up to 12.3 GPa by single-crystal x-ray diffraction with synchrotron radiation. A pressure-induced phase transition takes place between 4.4 and 5.0 GPa, where the pseudocubic low-pressure phase transforms into an orthorhombic high-pressure phase with space group Pnma. The high-pressure phase is comprised of mixed BO 6 tilts and anti-polar A-cation displacements, without exhibiting coherent off-centered shifts of the B-site Ti 4 + cations that can be detected by synchrotron x-ray diffraction. Our results reveal that at ambient pressure and room temperature the NBT- x MPB BT structure possesses anti-phase BO 6 tilts with a relatively large correlation length and the same type of polar distortions as those present in pure NBT, but with strongly violated correlation length due to Ba 2 + -induced local elastic-stress fields. For x MPB the effect of Ba on the mesoscopic-scale structure is compensated by a mild external pressure of only 0.7 GPa, resulting in structural features resembling those of pure NBT at ambient conditions. [ABSTRACT FROM AUTHOR]

This document is a corrigendum for an article titled "Recent progress in piezoelectric thin films as self-powered devices: material and application." The corrigendum addresses errors in the references and their citations in the published article. It provides the correct references for several studies related to AlN and PZT piezoelectric films. The corrigendum aims to rectify the inaccuracies in the original article and ensure the accuracy of the references cited. [Extracted from the article]

Yttrium (1 mol %) -doped 0.49BiFeO3-0.20Pb(Mg1/3Nb2/3)O3-0.31PbTiO3 ceramic at the morphotropic phase boundary was synthesized by a solid-state reaction via columbite precursor technique. X-ray diffraction (XRD) and FESEM analysis confirmed a perovskite phase in the P1m1 space group with a homogeneous microstructure sintered at 920 °C. Rietveld refinement yield lattice parameters a = 3.95984 Å, b = 3.93828 Å, c = 4.04466 Å, α = 90.000°, β = 89.970°, γ = 90.000°. Studies of dielectric permittivity and ferroelectric hysteresis at room temperature shows Y doping impact, exhibiting low dielectric loss and a saturated hysteresis loop. The synthesized sample remains fatigue-free over 104 cycles, with a high value of converse piezoelectric coefficient of d33* ̴ 723 pm/V. Weak ferromagnetism is observed in the magnetic hysteresis loop (M-H) at room temperature, suggesting potential applications in ferroelectric-based technologies. [ABSTRACT FROM AUTHOR]

Perovskite high-entropy ceramics (HECs) are favorable for energy storage performance due to the novel high-entropy effects. However, highly disordered states of HECs with equal molar ratio at the same site greatly reduce polarization intensity, yielding unsatisfactory energy storage properties. Herein, non-equiatomic [((Bi 0.5 Na 0.5) 0.94 Ba 0.06) 0.65 (Sr 0.5 Ca 0.5) 0.35 ](Ti 0.95 Me 0.05)O 3 (Me = Zr (Zr 0.5 Hf 0.5), (Zr 1/3 Hf 1/3 Sn 1/3), abbreviated as BNBSCT-Zr, BNBSCT-ZrHf, BNBSCT-ZrHfSn), HECs have been designed and prepared by a hydrothermal method. As-prepared HECs exhibit high maximum polarization, which are related to the morphotropic phase boundary (MPB) induced by the (Bi 0.5 Na 0.5) 0.94 Ba 0.06 TiO 3 composition. In addition, the A-site doping of Sr and Ca and B-site doping of Zr, (Zr 0.5 Hf 0.5), and (Zr 1/3 Hf 1/3 Sn 1/3) rooted in high configuration entropy improves the degree of dielectric relaxation, decreases the grain size, increases the resistivity, and enlarges the band gap, resulting in a higher breakdown electric field. As a result, BNBSCT-ZrHfSn ceramics exhibit the significant energy storage properties with a high W rec (6.44 J/cm3) and η (73.8 %) under a large E b (477 kV/cm), as well as good temperature, frequency, and fatigue stability. The results show that the "entropy engineering + MPB" strategy provided in this study can remarkablely develop the energy storage properties of dielectric ceramics. [ABSTRACT FROM AUTHOR]

In this research, the authors explore the structural, dielectric, electrical insulating, electromechanical, and piezoelectric characteristics of ceramics that have been modified using BaTiO 3 and (K 0.5 Bi 0.5)TiO 3.as key components. Specifically, they explore the composition (1-x-y)(Na 0.5 Bi 0.5)TiO 3 -xBaTiO 3 -y(K 0.5 Bi 0.5)TiO 3 , where x (mol.%) varies between 0, 6, and NBT, and y (mol.%) varies between 0, 18, and KBT. These ceramics were fabricated using a solid-state synthesis technique. The optimized calcination temperature for achieving a pure perovskite phase was determined to be 1000 °C for a duration of 4 h. The research involves a comprehensive analysis of the composition, microstructure, electrical insulating, and electromechanical characteristics of the ceramics. Rietveld analysis of X-ray diffraction (XRD) data was employed to accurately ascertain the morphotropic phase boundary (MPB) within this material. In this paper, we discuss the impact of crystallite size on the shifts in Raman band frequencies. Sintering at 1100 °C for 4 h was found to enhance densification, with scanning electron microscopy (SEM) images illustrating a nearly uniform distribution of compact grains. Electrical insulating assessments demonstrate that each of the ceramics displays a scattered phase transition around the temperature T m , with a diffusivity ranging from 1.4 to 1.8, and a shift of T m towards elevated temperatures. Exceptional piezoelectric properties were observed at the morphotropic phase boundary (MPB), including a d 33 value of 149 pC/N and electromechanical coupling factors kp of 0.297. These findings are attributed to the coexistence of rhombohedral and tetragonal phases, as well as precise grain size control. This research presents a novel approach to enhancing lead-free ferroelectric materials based on the composition 0.76(Na 0.5 Bi 0.5)TiO 3 -0.06BaTiO 3 -0.18(K 0.5 Bi 0.5)TiO 3. [ABSTRACT FROM AUTHOR]

The relationship between phase structure and piezoelectric characteristics is demonstrated by producing a sequence of (1 − x)BiFeO3–xBaTiO3 ceramics. A morphotropic phase boundary between the R and PC phases in BF–xBT ceramics is observed within the 0.285 ≤ x ≤ 0.315 range. High piezoelectric properties with a piezoelectric constant (d33) of 174 pC/N and a planar electromechanical coupling coefficient of 0.33 are achieved in BF–xBT ceramics at 0.285 ≤ x ≤ 0.315 due to the coexistence of the R and PC phases. In addition, a slight variation (±15%) in Δd33/d33 over the temperature range of 25–400 °C is noted in BF–xBT ceramics at 0.285 ≤ x ≤ 0.315, indicating that BF–xBT ceramics hold promising potential for use in high-temperature applications. [ABSTRACT FROM AUTHOR]

In this manuscript, for the first time, the exploration of the microstructural, ferroelectric, piezoelectric, and dielectric performances are measured for Sm-ion-influenced pseudo-cubic, morphotropic phase boundary (MPB) regional 0.62BiFeO3−0.38SrTiO3:xwt%Sm2O3 (BFST:xSm) ceramics with x = 0–0.25. All the compositions maintained their pseudo-cubic MPB structural stability. The composition of BFST:0.15Sm ceramics exhibited an excellent remnant polarization (Pr) of ~52.11 μC/cm2, an enhanced d33 of 101 pC/N, and the highest relative dielectric constant (ɛr) of ~1152, which are much improved as compared to that of pure BFST ceramics. BFST:0.15Sm ceramics demonstrated a Curie temperature (TC) of 378 °C. Moreover, the composition exhibited high thermal stability for d33 72 pC/N (only a 28% decrease), even at a high temperature of 300 °C. Such outstanding outcomes make BFST:0.15Sm ceramics an ideal applicant for high-temperature piezoelectric applications. [ABSTRACT FROM AUTHOR]

Ternary system piezoelectric ceramics 0.7PbZrxTi1−xO3-0.3Pb(Zn1/3Nb2/3)O3 (abbreviated as 0.7PZTx-0.3PZN) were prepared by a traditional solid-phase process. With the increase in Zr content, the electrical properties of the ceramics were significantly improved, and this result could be attributed to the change in the ceramic phase structure. The relationship between the change in Zr content and the ceramic phase structure and properties was investigated in detail by component modulation. X-ray diffraction (XRD) analyses showed that the phase structure of the ceramics undergoes a transition from the coexistence of tetragonal (T) and rhombohedral (R) phases to the predominance of rhombohedral (R) phases as the Zr content x increases. The phase structure of the ceramics at x = 0.49 is closer to the morphotropic phase boundary (MPB), with about 32% of the T-phase and 68% of the R-phase, and possesses good electrical properties: d33 = 483 pC/N, kp = 0.69, εr = 2171.7, tanδ = 0.016, Tc = 292.5°C, Pr = 35.9 μC/cm2, Ec = 7.7 kV/mm. Constructing the MPB of 0.7PZT-0.3PZN piezoelectric ceramics by varying the Zr content can be effective in improving the electrical properties and understanding more broadly how the change in Zr/Ti composition affects the piezoelectric behavior. [ABSTRACT FROM AUTHOR]

The versatile electrocaloric (EC) behaviors of the (1-x)Pb(Mg1/3Nb2/3)O3-xPT (PMN-100xPT) single crystal are closely related to the multiple phase transitions under the multiple fields of electric field and temperature. In this work, the EC effect of <001>-oriented PMN-30PT single crystals with chemical composition at morphotropic phase boundary has been studied during the phase transformation process from the ferroelectric rhombohedral (R) phase to the tetragonal (T) phase. Two consecutive negative EC peaks have been achieved for the first time. Based on the projection of the EC effect in the electric field-temperature phase diagram, the relationship between the EC behaviors and the phase transitions is further established. It was found that the monoclinic (M) phase actually existed during the transformation from the R phase to the T phase, and the related R-M phase transition and M-T phase transition could both induce negative EC peaks. Under the electric field of E = 10 kV/cm, the first negative EC peaks induced by the R-M phase transition is at 57 °C with ΔTmax = −0.11 K. And the M-T phase transition can produce a higher negative EC peak, and its value can reach −0.22 K at 68 °C. Based on thermodynamic calculations, the relationship between the entropy change in different phase transitions and the EC behaviors has been further elucidated. The negative EC effect originates from the structural entropy increase in the electric field-induced phase transition process. This work not only advances the research on the electrical properties of relaxor ferroelectric single crystals but also provides a new insight into high-performance ferroelectric materials design. [ABSTRACT FROM AUTHOR]

Piezoelectricity of organic polymers has attracted increasing interest because of several advantages they exhibit over traditional inorganic ceramics. While most organic piezoelectrics rely on the presence of intrinsic local dipoles, a highly nonlocal electronic polarisation can be foreseen in conjugated polymers, characterised by delocalised and highly responsive π-electrons. These 1D systems represent a physical realisation of a Thouless pump, a mechanism of adiabatic charge transport of a topological nature which results, as shown in this work, in anomalously large dynamical effective charges, inversely proportional to the bandgap energy. A structural (ferroelectric) phase transition further contributes to an enhancement of the piezoelectric response reminiscent of that observed in piezoelectric perovskites close to morphotropic phase boundaries. First-principles density functional theory (DFT) calculations performed in two representative conjugated polymers using hybrid functionals, show that state-of-the-art organic piezoelectric are outperformed by piezoelectric conjugated polymers, mostly thanks to strongly anomalous effective charges of carbon, larger than 5e—ordinary values being of the order of 1e—and reaching the giant value of 30e for band gaps of the order of 1 eV. [ABSTRACT FROM AUTHOR]

Electric field (E) control of magnetism is a persistent challenge in low-power consumption spintronic devices. A promising way to realize this control is to use the conversemagnetoelectric (ME) effect in insulating multiferroics.Here,we report considerable and repeatable E-modulated magnetization (M) at room temperature and even at 350 K via the significantly enhanced converseME effect near the morphotropic phase boundary (MPB) of the Cr-Mn co-doped (1-y)BiFe1-xCrxO3- yBaTi1-xMnxO3 (0.15 ≤ y ≤ 0.33, 0 ≤ x ≤ 0.03) solid solutions. In situ X-ray diffraction and Raman scattering experiments at different applied E for the sample near the MPB (i.e., y = 0.27, x = 0.03) show E-induced shift, broadening, and splitting in the {002}PC reflection, as well as a nearly monotonous variation in intensity of several phonon modes with E, reminiscent of the E-dependent M behavior. These results indicate that both E-induced lattice distortion and phase transformation dominate the converseME effects in these samples. Our demonstration of the E-regulation of magnetism via the E-sensitive crystal structures in designed insulating multiferroics near MPB may suggest a potential route to obtain efficient low-power spintronic devices. [ABSTRACT FROM AUTHOR]

Lead Zirconium Titanate (PZT) is a potential piezoelectric material for sensor and transducer applications due to its outstanding piezoelectric coupling near the morphotropic phase boundary (MPB). This is because PZT can switch between tetragonal and rhombohedral phases. PZT is still considered to be one of the piezoelectric materials that has received the greatest amount of attention from researchers and is used the most frequently. Modification with Lithium will improve the piezoelectric properties. In this study, the structural properties and morphological studies of Lead zirconium titanate and Lead zirconium titanate with Lithium modification have been evaluated. Various Scherrer's models and other models, such as the Williamson-Hall model and Size-strain plots model, were used to display the observed fluctuations in crystallite size. Morphological analysis was used to determine the particle size. Graphs showing the distribution of particle sizes were drawn. [ABSTRACT FROM AUTHOR]

In this paper, (1- x)(Bi 0.5 Na 0.5)TiO 3 - x BaTiO 3 (x = 0, 0.06, 0.08, and 0.10) ceramic coatings were prepared by supersonic plasma spraying. Phase structure, microstructure, dielectric, ferroelectric, and piezoelectric properties of the (Bi 0.5 Na 0.5)TiO 3 ceramic coatings doped with BaTiO 3 were all thoroughly examined. According to the findings, all of the (1- x)(Bi 0.5 Na 0.5)TiO 3 - x BaTiO 3 ceramic coatings have a typical perovskite structure and form a morphotropic phase boundary (MPB) with rhombohedral and tetragonal phases coexisting in the x = 0.06–0.10 range. The coating's overall surface is uniformly flat, with a surface roughness (Sa) of less than 10 μm and a line roughness (Ra) of less than 2 μm. The coating has a homogeneous cross section, a well-integrated interface, a few pores and cracks, and a porosity of less than 6 %. With no obvious valence changes of the other elements, the results of XPS indicate a certain degree of breakdown during the spraying process, when Ti4+ changes to generate oxygen vacancy defects of Ti3+. The best electrical conductivity of the 0.92BNT-0.08BT coating has been found at x = 0.08, where the dielectric constant is 255 (0.02), the remnant polarization (P r) is 22.21 μC/cm2, the coercive field (E c) is 29.17 kV/cm, and the piezoelectric coefficient (d 33) is 35.1 pC/N. The (1- x)(Bi 0.5 Na 0.5)TiO 3 - x BaTiO 3 ceramic coating application space and range at high temperature are expanded when the temperature (T m) close to the maximum dielectric constant increases significantly reaching 431.2 °C. [ABSTRACT FROM AUTHOR]

Ferroelectric materials possessing exceptional piezoelectric attributes have garnered widespread utilization in various applications. Solid solution systems improve piezoelectric properties through multiphase mixing, but the methodologies for effective design remain wanting. Based on the Landau–Devonshire theory, we propose a theoretical design method. Binary materials with morphotropic phase boundary (MPB) compositions are added with new elements to increase the free energy of the original stabilized phase and lower the energy barrier (EB). Flatter EBsand higher piezoelectric coefficients are found at the phase boundaries of the ternary system. By calculating the phase diagram, piezoelectric coefficient, dielectric constant, polarization, and EBs, we reveal the origin of the highest piezoelectric coefficient at the phase boundaries. This study underscores the importance of the EBs for polarization rotation in characterizing piezoelectric properties and proposes a theoretical design method for exploring materials with high piezoelectric coefficients. [ABSTRACT FROM AUTHOR]

The morphotropic phase boundary (MPB) Ba 0.85 Ca 0.15 Zr 0.10 Ti 0.90 O 3 composition is successfully transferred into <001>-textured ceramic having Lotgering factor f-74 % (abbreviated as BCZT-T74) using high aspect ratio BaTiO 3 -template particles via templated grain growth (TGG) method. The microstructural aspects reveal the distinctive grain growth formation for non-textured (BCZT-NT) and textured (BCZT-T74) ceramics; confirming the proper grain growth formation for textured ceramics. The polarization behavior was tested at 1 Hz, 5 Hz, and 10 Hz electric field frequencies by applying a voltage bias of 1000 V; the BCZT-NT ceramics show more variation in remnant polarization (P r) as well as maximum polarization (P max) peak position while BCZT-T74 ceramics exhibit nearly steady values. The frequency-dependent variation in P r (i.e. ΔP r) for non-textured and textured BCZT ceramics is ±11.08 % and ±3.25 % respectively in the frequency range 1Hz–10Hz at an applied voltage bias of 1000 V. The bipolar strain-electric field (S-E) butterfly loop evidences the typical piezoelectric nature; for both non-textured and textured BCZT ceramics having the effective piezoelectric strain coefficient d 33 * of 576 pm/V and 657 pm/V respectively. The BCZT-NT and BCZT-T74 ceramics revealed the average positive strain % values of 0.063 % and 0.1123 % and negative strain % values of 0.003985 % and 0.02281 % respectively at the applied voltage 1000 V functioning at 1Hz. The enhancement in negative strain% for BCZT-T74 ceramics is > 5.70 times higher than BCZT-NT ceramics. The variation in positive strain (i.e. ΔS + ve) and variation in negative strain (i.e. ΔS -ve) for non-textured ceramics is ±11.74 % and ±67.34 %, however, for textured ceramics is only ±3.33 % and ±5.00 % respectively. The BCZT-NT and BCZT-T74 ceramics exhibit the piezoelectric charge coefficient (d 33) of 370 pC/N and 520 pC/N (1.4 times that of BCZT-NT ceramics) respectively. The electrostrictive coefficient (Q 33) of BCZT-T74 ceramics is 0.039 m4/C2, which is > 2 times higher than BCZT-NT ceramics as well as commercially used toxic PZT-5H ceramics. Therefore, less variation in a strain, as well as polarization nature with varying frequencies and enhancement in piezo properties, suggests the present textured MPB BCZT-T74 ceramics is a promising candidate for piezoelectric devices functioning at the wide range of applied electric field frequencies. [ABSTRACT FROM AUTHOR]

A strategy is developed to enhance the energy storage properties of lead-free Bi 0.5 Na 0.5 TiO 3 -based solid solutions, which is implemented through coupling the lattice instability in 0.94(Bi 0.5 Na 0.5)TiO 3 -0.06BaTiO 3 (0.94BNT-0.06BT) ferroelectric with a composition at its morphotropic phase boundary with the chemical disorder in (Bi 0.2 Na 0.2 K 0.2 La 0.2 Sr 0.2)TiO 3 (BNKLST) high-entropy ceramic (HEC). The addition of BNKLST in 0.94BNT-0.06BT could suppress the relaxor behaviors in the resulting solid solutions (1-x)(0.94BNT-0.06BT)-xBNKLST. With increasing content x, BNKLST may triggers more polar nano-regions which are in ergodic states at elevated temperatures. As a result, the thermal stability for energy storage properties is increased. In particular, the solid solution with x = 0.3 not only possesses large dielectric constants but also has a low content of oxygen vacancies, beneficial to its dielectric properties; It exhibits an excellent recoverable energy storage density of 2.24 J/cm3 under an electric field of 140 kV/cm, and a good thermal stability at 50 kV/cm with energy storage efficiency η >80 % up to 200 °C. The results demonstrate that the synergy effect of lattice instability and chemical disorder in the solid solutions is effective in enhancing energy storage properties of HECs, facilitating the design and optimization of dielectric energy storage devices. [ABSTRACT FROM AUTHOR]

Multiferroic (BiFeO3)1−x-(PbTiO3)x (1−x)BF−xPT thin films exhibit very high electromechanical properties in the vicinity of the morphotropic phase boundary (MPB), making them important candidates for use in several modern device applications. However, preparing high-quality (1−x)BF−xPT thin films is challenging due to the high conductivity caused by oxygen vacancies produced during the synthesis process. This study aims to understand the effect of size and porosity density on the electrical properties of (1−x)BF−xPT thin films. A series of (1−x)BF−xPT solid solution thin films were fabricated using the spin-coating method on Pt/TiO2/SiO2/Si(100) substrates through chemical solution deposition. X-ray diffraction studies revealed a polycrystalline structure. Surface SEM images showed that the films have a uniform surface with average grain sizes ranging between 50 and 200 nm and an average film thickness of 1.5 μm. A decrease in average pore size and an increase in the number of pores were observed with the increase in PT concentration in the prepared films. Ferroelectric characterization revealed that the films exhibit room-temperature ferroelectric hysteresis loops. Sources of various contributions to polarization were extracted from hysteresis loops, including true ferroelectric switching and space charge contributions. Thin films with 0.30 < x < 0.45 show higher remanent and saturation polarization values, suggesting that these compositions exhibit the MPB. The highest remanent polarization value (PR = 16.68 μC/cm2) was observed for the thin film with x = 0.40. The correlation between the phase, composition, film morphology, and ferroelectric response is described and discussed. [ABSTRACT FROM AUTHOR]

The development of artificial tactile receptor systems is important in the fields of prosthetic devices, interfaces for the metaverse, and sensors. A pressure sensor and memory device may be used in this system to replicate the tactile detecting capabilities of human skin. The implementation of systems that take into account mass production and miniaturization is still difficult. Here, a flexible artificial tactile receptor built using conventional semiconductor processes that combine a vertically stacked piezoelectric sensor with neuromorphic memory is presented. As a fundamental component for both sensors and memory, hafnium zirconium oxide (HZO) formed by using semiconductor deposition technique is introduced. Due to its exceptional piezoelectric performance, the morphotropic phase boundary of HZO is studied. The entire materials and processes are highly compatible with conventional semiconductor processes, including microwave annealing‐based low‐temperature crystallization. Even after 10,000 times of bending stress, the sensor and memory constructed on a flexible substrate exhibit consistent pressure detection characteristics over a wide range of 2–25 kPa. The feasibility of the approach is further demonstrated by a deep neural network simulation, which reached 90.8% braille recognition accuracy. Wearable electronics and medical devices are two examples of industrial domains that can use these flexible, exceptionally durable devices. [ABSTRACT FROM AUTHOR]

Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) stands out among lead‐free ferroelectric oxides under consideration to replace state‐of‐the‐art high‐sensitivity piezoelectric Pb(Zr,Ti)O3, for a range of energy conversion ceramic technologies. However, the best performances have been reported for very coarse‐grained materials, and attempts to refine microstructure below 10 µm grain size consistently result in significant property degradation. Here a comprehensive study of the grain size effects on the properties of BCZT across the micron scale is reported, down to the verge of the submicron one. Results show a distinctive early evolution of properties for grain sizes between 1 and 5 µm. For the larger sizes in this range, an opposite effect is found for the piezoelectric charge coefficient and electric field‐induced strain with respect to the very coarse‐grained material, while very good overall performance is maintained. For the lower sizes, relaxor features appear, yet materials can still be poled indicating their ferroelectric nature. This strongly resembles size effects in the Pb(Mg1/3Nb2/3)O3‐PbTiO3 system, driven by the slowing down of the relaxor to ferroelectric transition with size reduction, though kinetics seem to slow down across much larger grain sizes for BCZT. Concomitant changes in the polymorphic phase coexistence are described and discussed by synchrotron X‐ray diffraction. [ABSTRACT FROM AUTHOR]

Temperature–field phase diagrams in the [001]c and [011]c directions in the cubic coordinate in 24%Pb(In1/2Nb1/2)O3–46%Pb(Mg1/3Nb2/3)O3–30%PbTiO3 (24PIN–46PMN–30PT) and 31PIN–43PMN–26PT near the morphotropic phase boundary have been clarified by measuring the temperature dependences of permittivity under an electric field. Field-induced intermediate orthorhombic and tetragonal phases have been newly found in 24PIN–46PMN–30PT and 31PIN–43PMN–26PT, respectively. The temperature dependences of the remanent polarization have also been determined by polarization–electric field (P–E) hysteresis loop evaluation. On the basis of our experimental results, the phase transition and dielectric anisotropy in PIN–PMN–PT have been discussed. [ABSTRACT FROM AUTHOR]

In this study, Piezoelectric energy harvesters (PEHs) are fabricated based on epitaxial Pb(Zr,Ti)O3 (PZT) thin films deposited by an RF magnetron sputtering with varied Zr/[Zr+Ti] ratio. For a compatibility with micro‐electromechanical systems, the epitaxial PZT thin films are deposited on Si substrates (PZT/Si). The morphotropic phase boundary (MPB) are formed in the compositional range of 0.44 ≤ Zr/[Zr+Ti] ≤ 0.51 of the epitaxial PZT/Si, which is far broader than that of the bulk PZT. Meanwhile, effective transverse piezoelectric coefficient (|e31,f|) values are evaluated by the direct and converse piezoelectric effects using the unimorph cantilever method. Among the compositions, the rhombohedral‐dominant MPB (MPB‐R) of Zr/[Zr+Ti] = 0.51 exhibits a direct |e31,f| of 10.1 C m−2 and a relative permittivity (εr) of 285, leading to the maximum figure of merit of 40 GPa in this study. On the other hand, the maximum converse |e31,f| of 14.0 C m−2 is measured from the tetragonal‐dominant MPB (MPB‐T) of Zr/[Zr+Ti] = 0.44. At a resonance frequency, the MPB‐T presents a high output power density of 301.5 µW−1/(cm2 g2) under an acceleration of 3 m−1 s−2, which is very promising for the high‐performance PEH applications. [ABSTRACT FROM AUTHOR]

Designing BiScO3‐PbTiO3 (BS–PT) ceramics that merge high Curie temperature (TC) and large piezoelectric coefficient (d33) has always been a significant challenge for high‐temperature applications. Doping is a commonly used and effective method for enhancing the electrical performances of piezoelectric ceramics. In this study, the Li+/W6+ acceptor–donor co‐doping method was used to enhance the piezoelectric properties of 0.36BiSc1‐xLixO3–0.64PbTi1‐yWyO3 (0.36x = 0.64y) ceramics. The optimal electrical performance was observed at x = 0.01 near morphotropic phase boundaries, with a large d33 (505 pC/N), high TC (407°C), huge remnant polarization (Pr ∼ 40.9 μC/cm2), and inverse piezoelectric coefficient (d33* = 601 pm/V). Rietveld refinement and piezoelectric force microscopy results revealed that incorporating Li+/W6+ into the BS–PT ceramics decreased the T phase proportion and domain size and increased the domain wall density. The enhancement in piezoelectricity can be attributed to the lowered energy barrier resulting from the reduced T‐phase proportion and complex domain structure, which promotes polarization rotation and facilitates domain wall motion. This work demonstrates that acceptor–donor co‐doping is a promising strategy for optimizing the electrical performance of the BS–PT ceramics. [ABSTRACT FROM AUTHOR]

BiFeO3–SrTiO3 (BF–ST) ceramics have been considered a novel class of lead‐free dielectric materials exhibiting notable dielectric constants and remarkable thermal stability. In this work, we fabricated a series of (1 − x)BF–xST (0.32 ≤ x ≤ 0.44) ceramics near the morphotropic phase boundary and comprehensively investigated their microstructure and electrical properties, which seeks to optimize the piezoelectric performance. As the ST content increases, a gradual reduction in the rhombohedral phase fraction is observed alongside a corresponding increase in the cubic phase fraction. Although x = 0.38, the maximum grain size of 5.66 μm is obtained, accompanied by a distinctive heterogeneous core–shell microstructure, which demonstrates a high remanent polarization of 51.2 μC/cm2 and a maximum d33 value of 72 pC/N. Furthermore, impedance spectroscopy analysis reveals the formation of a conductive core and a nonconductive shell within the sample. These findings highlight the potential of optimized BF–ST ceramics as promising alternatives to lead‐based piezoelectric materials, offering exceptional ferroelectric and piezoelectric properties. [ABSTRACT FROM AUTHOR]

Piezoelectric ceramics with excellent piezoelectric properties and a high Curie temperature are important for numerous electromechanical devices in a broad range of temperature environments. In this work, the relaxor ferroelectric Pb(Yb1/2Nb1/2)O3 end member was selected to be introduced into a BiScO3-PbTiO3 high-temperature piezoelectric ceramic to reduce the dielectric loss and improve the piezoelectric properties while slightly reducing the Curie temperature. The phase structure and dielectric, ferroelectric and piezoelectric properties of 0.025Pb(Yb1/2Nb1/2)O3-(0.975 − x)BiScO3-xPbTiO3 (0.60 ≤ x ≤ 0.63) ceramics were systematically analyzed, and the best electrical properties were observed in the morphotropic phase boundary region x = 0.61 with d33 = 370 pC/N, kp = 44%, Pr = 33.9 μC/cm2. Importantly, no significant depolarization was observed in the x = 0.61 ceramic from room temperature to 290 °C, demonstrating its good thermal stability and potential applications in a wide range of temperature environments. [ABSTRACT FROM AUTHOR]

Simultaneously achieving large piezoelectricity and excellent thermal stability in a piezoceramic is highly desired for constructing advanced high-temperature electromechanical coupling devices. Here, a large high-temperature piezoelectric coefficient (d 33 = 523 pC/N at 200 °C) with a small fluctuation rate (η ≤ ±10 %) over an ultra-broaden temperature range of 48–342 °C was achieved in novel z BiScO 3 - x BiInO 3 - y PbTiO 3 (z BS- x BI- y PT) ternary perovskite piezoceramics with a high Curie temperature of 440 °C. The morphotropic phase boundary (MPB) of multiphase coexistence can be driven and optimized in this system, which is mainly responsible for the enhanced piezoelectricity, and the optimal MPB composition is located at x / y / z = 0.010/0.625/0.365. The excellent temperature stability of the optimal MPB sample should be attributed to the increase in the number of thermally stable irreversible non-180° domains. z BS- x BI- y PT perovskite ceramics with excellent comprehensive high-temperature piezoelectric properties exceed many reported lead-based counterparts, and are more suitable for electromechanical coupling applications at harsh elevated temperatures. [ABSTRACT FROM AUTHOR]

This paper reports the effect of lanthanum addition on the structural and electrical properties of (Pb 1-x La x)(Zr 0.65 Ti 0.35)O 3 (PLZT x/65/35, x = 8%,10%,12%,15%) ceramics near the morphotropic phase boundary. Studies were conducted on the PLZT x/65/35 ceramics synthesized via a combinatorial approach of high-energy ball milling (mechanical activation method) followed by Cold Isostatic Pressing (CIP). Due to the application of CIP, PLZT ceramics exhibited improved density and a closely packed microstructure. The SEM analysis showed that PLZT x/65/35 ceramics exhibited an increase in grain size with higher concentrations of La3+ ions. Room temperature X-ray diffraction results revealed the formation of perovskite PLZT phase. The investigation on temperature-dependent dielectric, ferroelectric properties of PLZT x/65/35 ceramics provided experimental confirmation of structures cited in XRD analysis. Among all the compositions, PLZT 8/65/35 samples showed a well saturated, uniform P–E hysteresis loop with a high remanent polarization (P r). Poled PLZT 8/65/35 samples displayed electric field induced large strains with limited hysteresis. Piezoelectric charge coefficients (d 33), electromechanical coupling factors (k p , k 33 , k 31) were determined for poled PLZT x/65/35 ceramics and it was found that PLZT 8/65/35 ceramics reveal properties superior to other compositions. Furthermore, the unipolar strain, P r , d 33 , k p , k 33 , k 31 values of PLZT 8/65/35 composition exceeded the previously reported ones for the same composition prepared via sol-gel synthesis technique. [ABSTRACT FROM AUTHOR]

BaTiO 3 (BT)-templated (1-x) (Bi 0.97 Sm 0.03)ScO 3 -xPbTiO 3 [(1-x)BSS-xPT] (0.60≤x≤0.64) ceramics were evaluated as to their phase transition behavior and electrical properties for high temperature piezoelectric devices. The morphotropic phase boundary (MPB) of rhombohedral and tetragonal phases was obtained for template-free 0.36BSS-0.64PT ceramic. However, the addition of tetragonal BT to 0.36BSS-0.64PT resulted in a highly textured microstructure but degraded piezoelectric properties due to a shift of tetragonal-rich MPB. Compositional modification of 4 vol% BT-templated (1-x)BSS-xPT can restore good piezoelectric performance by enriching the BSS phase. Especially, the textured 0.38BSS-0.62PT ceramic with highly preferred (100) orientation exhibited excellent piezoelectric properties of d 33 (719 pC/N), k p (61.8%), Q m (14), and g 33 (45 × 10−3 Vm/N). In addition, the relaxor-like textured ceramic, having a high depolarization temperature of 373 °C, is highly promising for high temperature piezoelectric devices. [ABSTRACT FROM AUTHOR]

BiFeO3–BaTiO3 is a promising lead-free piezoelectric ceramic, exhibiting high Curie temperature and superior electrochemical characteristics. In this work, (1 − x) BiFeO3–xBaTiO3 (BF–xBT, x = 0. 2 6 , 0.28, 0.30, 0.32, 0.34, 0.36) ceramics were fabricated using the conventional solid-state reaction method through precise composition control. Multiple characterization techniques, including X-ray powder diffraction (XRD), scanning electron microscope (SEM), and electrical property testing systems, were applied to systematically examine the crystallographic structure, microstructure, as well as the dielectric, ferroelectric and piezoelectric properties of the BF–xBT ceramics. The XRD results confirm that all compositions exhibit a typical perovskite structure, transitioning from a single rhombohedral phase to a rhombohedral–cubic phase mixture as the BT content increases. SEM shows apparent core–shell microstructures in the ceramics. Notably, the results demonstrated that the BF–0.30BT ceramic exhibits the maximum piezoelectric constant ( d 3 3 ) ∼ 2 1 7 pC/N, while the BF–0.34BT ceramic displays the maximum converse piezoelectric constant (d 3 3 ∗) ∼ 3 2 3 pm/V, which highlights the suitability of BF–BT ceramics for high-performance piezoelectric applications. [ABSTRACT FROM AUTHOR]

The electrocaloric properties of commercially modified Pb(Zr,Ti)O 3 - (PZT)-based soft and hard ceramics were investigated by the indirect estimation via measurement of temperature–electric field P (T,E) hysteresis loops. The adiabatic temperature change ΔT due to electrocaloric effects was estimated from the polarization change of these samples. Both positive and negative electrocaloric temperature change was obtained for all ceramics. The existence of the negative electrocaloric effect was related to the FE-FE field-induced phase transition, between rhombohedral and monoclinic phases that occur in PZT ceramics synthesized near the morphotropic phase boundary. The resulting negative electrocaloric temperature change reveals higher values for the hard-type ceramics (∼-1.5 K for PIC 300) than for the soft-type. Insignificant positive effect values were achieved for all ceramics. The highest values of positive ECE were recorded for PIC 155 (soft) and PIC 181 (hard) and are of the order of ΔT = 0.67 K. In this case, no correlation was observed between the type of PZT ceramics soft or hard. [ABSTRACT FROM AUTHOR]

It is difficult to obtain high d 33 and d 33 * simultaneously in one piezoelectric ceramic system via a conventional method due to the conflicting structure–properties responding mechanism between the direct piezoelectric and converse piezoelectric effects. In this work, a synergistic approach of constructing morphotropic phase boundary and introducing the internal bias fields in (Bi 0.5 Na 0.5)TiO 3 ceramics is proposed through Sr2+ and Li+ doping for mitigating the conflict between d 33 and d 33 *. By this strategy, both high d 33 (197 pC/N) and d 33 * (1500 p.m./V) are realized in Sr x (Bi 1-x Na 0.97-x Li 0.03) 0.5 TiO 3 when x = 0.24. The large d 33 stems from rhombohedral and tetragonal (R3c and P4bm) phase coexistence. The internal bias field introduced by defect dipoles tends to counteract the effects of depolarization field, thus greatly aiding the external fields with higher actual excitation fields. The superposition of internal bias field, depolarization field and external fields yields strong asymmetry bipolar strain curves, thereby contributing to the large d 33 *. Thus, this work opens a new door for developing lead-free ceramics with excellent piezoelectric performance. [ABSTRACT FROM AUTHOR]

Atomic layer engineering is investigated to tailor the morphotropic phase boundary (MPB) between antiferroelectric, ferroelectric, and paraelectric phases. By increasing the HfO2 seeding layer with only 2 monolayers, the overlying ZrO2 layer experiences the dramatic phase transition across the MPB. Conspicuous ferroelectric properties including record‐high remanent polarization (2Pr ≈ 60 µC cm−2), wake‐up‐free operation, and high compatibility with advanced semiconductor technology nodes, are achieved in the sub‐6 nm thin film. The prominent antiferroelectric to ferroelectric phase transformation is ascribed to the in‐plane tensile stress introduced into ZrO2 by the HfO2 seeding layer. Based on the high‐resolution and high‐contrast images of surface grains extracted precisely by helium ion microscopy, the evolution of the MPB between tetragonal, orthorhombic, and monoclinic phases with grain size is demonstrated for the first time. The result indicates that a decrease in the average grain size drives the crystallization from the tetragonal to polar orthorhombic phases. [ABSTRACT FROM AUTHOR]

A near-morphotropic phase boundary (MPB) composition of ternary 0.49BiFeO3-0.20Pb(Mg1/3Nb2/3)O3-0.31PbTiO3 (BF-PMN-PT) ceramic was synthesized for various dielectric, ferroelectric and piezoelectric applications using the conventional solid-state reaction method via a two-step columbite precursor technique. Powder x-ray diffraction (XRD) confirms the perovskite phase of the synthesized ceramic with a monoclinic crystal structure belonging to the P1m1 space group. The dielectric properties and the relaxation mechanisms of this ternary ceramic were studied using dielectric spectroscopy measurements for the frequency range of 10 Hz to 1 MHz over a wide range of temperature from 50°C to 400°C. A good dielectric response was observed with a high dielectric constant value (~ 800) that decreases with increasing frequency. A phase transition temperature (Tc = 275°C) and a low dielectric loss were also observed. The dielectric exhibits a clear and distinct Debye-type relaxation in the ferroelectric phase. The measured dielectric data fit quite well with the modified Debye model. Various Debye fitting parameters were obtained which show a temperature-dependent nature. The value of Debye broadening parameter α exhibits a decreasing trend from 0.136 to 0.003 as temperature increases from 50°C to 200°C, after which it increases and attains a maximum value of 0.566 at 350°C. The Cole–Cole plot obtained from the measured data reveals the distributive nature of the sample's dielectric relaxation. [ABSTRACT FROM AUTHOR]

We report the structural, piezoelectric, multiferroic and magnetoelectric (ME) properties of the ternary 0.65BiFeO3–0.35[(1 − x)Bi0.5K0.5TiO3 − xBaTiO3] (0.0 ≤ x ≤ 1.0) (BF–BKT–BT) solid solutions. These samples show a rhombohedral to pseudo-cubic structure transition in the vicinity of x ~ 0.4, i.e., the morphotropic phase boundary (MPB), where the maximum piezoelectric coefficient d33 occurs. In addition, maximum electric-field (E) induced strain is also observed for x ~ 0.4 near the MPB. All the samples show good ferroelectricity and basically antiferromagnets at room temperature. The room-temperature E control of magnetization, i.e., converse ME effect, increases with increasing x, reaches a maximum near x = 0.6, and decreases again with x ≥ 0.8. In-situ X-ray diffraction studies at different applied E demonstrate an important role of E-induced variation in the phase fraction, Fe–O bond length and Fe–O–Fe bond angle in the converse ME effect. These results reveal a possible effective route to obtain multi-functional devices with both good piezoelectricity and ME effect in the BF–BKT–BT based systems. [ABSTRACT FROM AUTHOR]

As the energy demand is expected to double over the next 30 years, there has been a major initiative towards advancing the technology of both energy harvesting and storage for renewable energy. In this work, we explore a subset class of dielectrics for energy storage since ferroelectrics offer a unique combination of characteristics needed for energy storage devices. We investigate ferroelectric lead-free 0.5[Ba(Ti0.8Zr0.2)O3]-0.5(Ba0.7Ca0.3)TiO3 epitaxial thin films with different crystallographic orientations grown by pulsed laser deposition. We focus our attention on the influence of the crystallographic orientation on the microstructure, ferroelectric, and dielectric properties. Our results indicate an enhancement of the polarization and strong anisotropy in the dielectric response for the (001)-oriented film. The enhanced ferroelectric, energy storage, and dielectric properties of the (001)-oriented film is explained by the coexistence of orthorhombic-tetragonal phase, where the disordered local structure is in its free energy minimum. [ABSTRACT FROM AUTHOR]

As a promising lead-free high-temperature piezoelectric material, BiFeO 3 –BaTiO 3 (BF-BT) is still under debate on its crystal structure, especially for the compositions in the morphotropic phase boundary (MPB). Herein, the crystal structure of (1- x)BF- x BT ceramics near the MPB with x = 0.20–0.33 was analyzed by X-ray diffraction and Raman spectroscopy. With the addition of BT, the phase transition from distorted rhombohedral to pseudo-cubic structure was determined by Rietveld refinement. Raman analysis showed the weakening interactions between the A-site cations and BO 6 octahedron, as well as the degenerated distortions of BO 6 octahedron. Intriguingly, the results of X-ray photoelectron spectroscopy suggested the inhibition of Fe3+ reduction and decrease in oxygen vacancy concentration by the incorporation of BT. In terms of the electrical properties, the significant decline in Curie temperature, improvement in permittivity, and reduction in high-temperature dielectric loss can be observed with the increase of BT content. The increased remnant polarization, enhanced dielectric response and decreased coercive field were helpful for the piezoelectric performance. The maximum room-temperature piezoelectric coefficient of ∼160 pC/N and high-temperature piezoelectric coefficient of ∼324 pC/N were acquired in the x = 0.30 ceramics. This work provides a clear scope for further research on the structural transformation and high-temperature piezoelectric applications of BF-BT system. [ABSTRACT FROM AUTHOR]