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xPb(Zn1/3Nb2/3)O3–(1−x)Pb(Zr0.52Ti0.48)O3 (xPZN–PZT) ternary piezoelectric ceramics with different PZN content were prepared by the traditional solid-state reaction method. The effect of relaxor ferroelectric PZN content on the phase structure, dielectric, piezoelectric and ferroelectric properties of xPZN–PZT ceramics has been systematically investigated. The XRD and SEM analysis results showed a slight increase in grain size with the increase in PZN content. The 0.2PZN–PZT ceramic samples have good grain size and exhibit the optimum properties: Tc = 318 °C, d33 = 347 pC/N, kp = 0.617, εr = 1232, tanδ = 3.0%, Pr = 37.9 µC/cm2, Ec = 6.6 kV/mm, respectively. Furthermore, all these results suggest that 0.2PZN–PZT can maintain a balance between the Curie temperature and piezoelectric properties. That is, it still has optimum electrical properties at high Curie temperatures. Enhanced piezoelectric ceramics properties could be attributed to its dielectric relaxor behavior. [ABSTRACT FROM AUTHOR]

Ferroelectric materials have been explored for a long time for easy integration with state-of-the-art semiconductor technologies. Doped wurtzite nitrides have been reported as promising candidates due to their high stability, compatibility, and scalability. We investigate doping effects on ferroelectric properties of Sc-doped AlN (AlScN) and B-doped AlN (AlBN) by first-principles methods. The energy barrier against polarization switching is observed to decrease with increasing doping concentration at low concentration ranges, which is the origin of the emerging ferroelectricity in doped AlN. Further increasing the doping concentration to a critical value, the ferroelectric wurtzite phase transforms into paraelectric phases (a rock salt phase for AlScN and a zinc blende phase for AlBN), making it invalid to decrease the coercivity by increasing the doping concentration. Furthermore, it is revealed that different nonpolar structures (a hexagonal phase for AlScN and a β -BeO phase for AlBN) appear in the ferroelectric switching pathway, generating different switching features in doped AlN. Our results give a microscopic understanding of the ferroelectricity in doped wurtzite materials and broaden the route to improve their ferroelectric properties. [ABSTRACT FROM AUTHOR]

A group of ferroelectric polyvinylidene‐trifluoroethylene (P(VDF‐TrFE)) with 6, 9, 20, and 50 mol% trifluoroethylene (TrFE) is synthesized by an hydrogenation process using a new catalyst (SiMe3)3SiH from polyvinylidene‐chlorotrifluoroethylene. We find the crystalline region of hydrogenated P(VDF‐TrFE) 80/20 mol% is β crystal phase predominant, which is responsible to the favorable ferroelectric property. Moreover, polyvinylidene fluoride (PVDF) blending is used to fabricate the ferroelectric and relaxor ferroelectric properties of P(VDF‐TrFE) 80/20 mol%. Interestingly, with the increasing of PVDF content, PVDF/P(VDF‐TrFE) has three successional conversion stages of ferroelectricity, antiferroelectricity, and relaxor ferroelectricity, respectively, indicating that the β crystal domains in hydrogenated P(VDF‐TrFE) films gradually reduces with the introduction of PVDF. Otherwise, after an unidirectional stretching process, the ferroelectricity of relaxor PVDF/P(VDF‐TrFE) blend film is reformed. As such, the maximum polarization (Pm) and remnant polarization (Pr) of stretched PVDF/P(VDF‐TrFE) with 90 wt% PVDF reached to 13.8 and 7.5 μC/cm2 under 200 MV/m, respectively. Thus, the three methods proposed in this work including fabricating configuration by changing TrFE content, physical blending by introduction of PVDF, and simple stretching can modify the ferroelectric performances of this hydrogenated P(VDF‐TrFE), which also provides a reference of application of this polymer on ferroelectric areas. [ABSTRACT FROM AUTHOR]

Ferroelectricity is demonstrated for the first time in Si(100)/SiO2/TiN/HfO2-ZrO2/TiN stack using pulsed laser deposition (PLD) and the effects of temperatures, partial oxygen pressures, and thickness for the stabilization of the ferroelectric phase were mapped. Thin films deposited at a higher temperature and a higher oxygen partial pressure have a higher thickness, demonstrating a better ferroelectric response with ~12 µC/cm² remnant polarization, a leakage current of 10-7 A (at 8 V) and endurance >1011 cycles indicative of an orthorhombic crystal phase. In contrast, thin films deposited at lower temperatures and pressures does not exhibit ferroelectric behavior. These films can be attributed to having a dominant monoclinic phase, having lower grain size and increased leakage current. Finally, the effects of ZrO2 as top and bottom layer were also investigated which showed that ZrO2 as the top layer provided better mechanical confinement for stabilizing the orthorhombic phase instead of as the bottom layer. [ABSTRACT FROM AUTHOR]

Ferroelectric materials have shown great value in the modern semiconductor industry and are considered important function materials due to their high dielectric constant and tunable spontaneous polarization. A ferroelectric field effect transistor (FeFET) is a field effect transistor (FET) with ferroelectric polarization field introduced to regulate carriers in semiconductors. With the coupling of ferroelectric and semiconductor, FeFETs are attractive for advanced electronic and optoelectronic applications, including emerging memories, artificial neural networks, high-performance photodetectors, and smart sensors. In this review, representative research results of FeFETs are reviewed from the perspective of structures and applications. Here, the background and significance of ferroelectrics and FeFETs are given. Furthermore, methods of building FeFETs in different structures and physical models describing the characteristics of FeFET are introduced. Important applications of FeFETs in electronics and optoelectronics are presented, with a comparison of performance between FeFETs and FETs without ferroelectrics, including memories and memristive devices, photodetectors, negative capacitance FETs, sensors, and multifunctional devices. Finally, based on the above discussions, promising applications and challenges of FeFETs are summarized. [ABSTRACT FROM AUTHOR]

The flexoelectric effect, which exists in all dielectrics, is an electromechanical effect that arises due to the coupling of strain gradients (or electric field gradients) with electric polarization (or mechanical stress). Numerous experimental studies have demonstrated that ferroelectric materials possess a larger flexoelectric coefficient than other dielectric materials; thus, the flexoelectric response becomes significant. In this review, we will first summarize the measurement methods and magnitudes of the flexoelectric coefficients of ferroelectric materials. Theoretical studies of the flexoelectric coefficients of ferroelectric materials will be addressed in this review. The scaling effect, where the flexoelectric effect dramatically increases when reducing the material dimension, will also be discussed. Because of their large electromechanical response and scaling effect, ferroelectric materials offer vast potential for the application of the flexoelectric effect in various physical phenomena, including sensors, actuators, and transducers. Finally, this review will briefly discuss some perspectives on the flexoelectric effect and address some pressing questions that need to be considered to further develop this phenomenon. [ABSTRACT FROM AUTHOR]

Amphoteric rare‐earth ion dopants can improve ferroelectric ceramic electrical performance because of their amphoteric ion radius and valences. Herein, Ho3+‐doped Ba0.90Ca0.10(Ti0.95Zr0.05)2O5 ceramics are sintered at 1230 °C with as‐synthesized nanoparticles. The effects of various holmium contents (x) on the phase, structure, dielectric, and piezoelectric characteristics are investigated. For low x (<1.5 mol%), Ho3+ occupies the Ba2+ or/and Ca2+ sites, leading to high dielectric properties due to decreased oxygen vacancies, while the electrical properties weaken with further increase in x. The ferroelectricity and piezoelectricity also deteriorate when x > 1.5 mol% because of the re‐emerged oxygen vacancies and interrupted long‐range ordering with large compositional fluctuations. The defect chemistry mechanism at different x contents is deduced in accordance with the phase and electrical properties. The activation energy initially elevates to 1.56 eV and then decreases to 1.35 eV with increasing x. Results indicate that the ceramics are promising candidates for lead‐free ferroelectric ceramics. [ABSTRACT FROM AUTHOR]

Hafnium oxide-based ferroelectrics have been extensively studied because of their existing ferroelectricity, even in ultra-thin film form. However, studying the weak response from ultra-thin film requires improved measurement sensitivity. In general, resonance-enhanced piezoresponse force microscopy (PFM) has been used to characterize ferroelectricity by fitting a simple harmonic oscillation model with the resonance spectrum. However, an iterative approach, such as traditional least squares (LS) fitting, is sensitive to noise and can result in the misunderstanding of weak responses. In this study, we developed the deep neural network (DNN) hybrid with deep denoising autoencoder (DDA) and principal component analysis (PCA) to extract resonance information. The DDA/PCA-DNN improves the PFM sensitivity down to 0.3 pm, allowing measurement of weak piezoresponse with low excitation voltage in 10-nm-thick Hf0.5Zr0.5O2 thin films. Our hybrid approaches could provide more chances to explore the low piezoresponse of the ultra-thin ferroelectrics and could be applied to other microscopic techniques. [ABSTRACT FROM AUTHOR]

A full understanding of the impact of charge trapping on the memory window (MW) of HfO2-based ferroelectric field effect transistors (FeFETs) will permit the design of program and erase protocols, which will guide the application of these devices and maximize their useful life. The effects of charge trapping have been studied by changing the parameters of the applied program and erase pulses in a test sequence. With increasing the pulse amplitude and pulse width, the MW increases first and then decreases, a result attributed to the competition between charge trapping (CT) and ferroelectric switching (FS). This interaction between CT and FS is analyzed in detail using a single-pulse technique. In addition, the experimental data show that the conductance modulation characteristics are affected by the CT in the analog synaptic behavior of the FeFET. Finally, a theoretical investigation is performed in Sentaurus TCAD, providing a plausible explanation of the CT effect on the memory characteristics of the FeFET. This work is helpful to the study of the endurance fatigue process caused by the CT effect and to optimizing the analog synaptic behavior of the FeFET. [ABSTRACT FROM AUTHOR]

Polymer films doped by different porphyrins, obtained by crystallization from the acetone solutions, differ in absorption and fluorescence spectra, which we attribute to the differences in the structuring and composition of the rotational isomers in the polymer chains. According to the infrared spectroscopy data, the crystallization of the films doped with tetraphenylporphyrin (TPP) proceeds in a mixture of α- and γ-phases with TGTG− and T3GT3G− conformations, respectively. Three bonds in the planar zigzag conformation ensures the contact of such segments with the active groups of the porphyrin macrocycle, significantly changing its electronic state. Structuring of the films in the presence of TPP leads to an increase in the low-voltage AC-conductivity and the registration of an intense Maxwell-Wagner polarization. An increased conductivity by an order of magnitude in TPP-doped films was also observed at high-voltage polarization. The introduction of TPP during the film formation promotes the displacement of the chemical attachment defects of "head-to-head" type in the monomeric units into the surface. This process is accompanied by a significant increase in the film surface roughness, which was registered by piezo-force microscopy. The latter method also revealed the appearance of hysteresis phenomena during the local piezoelectric coefficient d33 measurements. [ABSTRACT FROM AUTHOR]

Infrared photodetectors have attracted much attention considering their wide civil and military applications. Two-dimensional (2D) materials offer new opportunities for the development of costless, high-level integration and high-performance infrared photodetectors. With the advent of a broad investigation of infrared photodetectors based on graphene and transition metal chalcogenides (TMDs) exhibiting unique properties in recent decades, research on the better performance of 2D-based infrared photodetectors has been extended to a larger scale, including explorations of new materials and artificial structure designs. In this review, after a brief background introduction, some major working mechanisms, including the photovoltaic effect, photoconductive effect, photogating effect, photothermoelectric effect and bolometric effect, are briefly offered. Then, the discussion mainly focuses on the recent progress of three categories of 2D materials beyond graphene and TMDs. Noble transition metal dichalcogenides, black phosphorus and arsenic black phosphorous and 2D ternary compounds are great examples of explorations of mid-wavelength or even long-wavelength 2D infrared photodetectors. Then, four types of rational structure designs, including type-II band alignments, photogating-enhanced designs, surface plasmon designs and ferroelectric-enhanced designs, are discussed to further enhance the performance via diverse mechanisms, which involve the narrower-bandgap-induced interlayer exciton transition, gate modulation by trapped carriers, surface plasmon polaritons and ferroelectric polarization in sequence. Furthermore, applications including imaging, flexible devices and on-chip integration for 2D-based infrared photodetectors are introduced. Finally, a summary of the state-of-the-art research status and personal discussion on the challenges are delivered. [ABSTRACT FROM AUTHOR]

This paper reports a semi-empirical, SPICE compatible and computationally efficient compact model for ferroelectric capacitors (Fe-CAP) description. This compact model is inspired by the Jiles–Atherton model of ferromagnets, which features significantly smaller computational effort than other state-of-the-art models. It successfully computes the evolution of the memory window and hysteresis of ferroelectric capacitors for any arbitrary signal. We have successfully calibrated this model with the experimentally characterized polarization switching dynamics of fabricated 10 nm silicon-doped hafnium oxide based Fe-CAP. • Transfer of the Jiles–Atherton model to ferroelectrics. • Semi-empirical compact model description of ferroelectric capacitors. • Analytical description of ferroelectric field effect transistor gate capacitors. [ABSTRACT FROM AUTHOR]

The material realization with significant coupling between magnetic and electric order named "magnetoelectric effect" would be a major turning point for the modern electronic industry and information technology. This paper emphasises progress on magnetoelectric coupling, focusing on the impact of charge and strain in composite heterostructures in bulk and thin-film forms. Furthermore, the direct and converse magnetoelectric effect on improving the "magnetoelectric coefficient-a measure of coupling" has been discussed. Eventually, a brief overview of multiferroic magnetoelectric materials-based devices and their future perspectives is presented. [ABSTRACT FROM AUTHOR]

Structural transition, tetragonality, and dielectric properties are investigated along with thermal and compositional expansion of lead strontium titanate in order to reveal composition dependence and structure-property relation of the ferroelectric structure. Based on the available structural and dielectric data, dielectric stiffness and temperature-dependent paraelectric cubic lattice parameters are analyzed. Non-zero sixth-order free energy coefficients are derived for strontium titanate. Spontaneous polarization, spontaneous strain, volumetric change, and dielectric permittivity are modeled as a function of composition, and the theoretical results are in agreement with experimental data reported in the literature and reveal solid solution effect. [ABSTRACT FROM AUTHOR]

Ferroelectric resistive switching (RS) devices with functional oxide electrodes allow controlled emergent phenomena at an interface. Here, we demonstrate RS polarity reversal due to ferroelectrically induced phase transition at a doped charge transfer insulator interface. For BiFeO3/Ca0.96Ce0.04MnO3 bilayers grown on a NdAlO3 substrate, by applying voltages to a Ca0.96Ce0.04MnO3 bottom electrode, the resistance changes from a high resistance state (HRS) to a low resistance state (LRS) during a positive voltage cycle (0 → 3 → 0 V), and from a LRS to a HRS during a negative voltage cycle (0 → −3 → 0 V). The RS polarity is completely opposite the expected RS behavior in ferroelectric heterostructures induced by polarization reversal. It is proposed that the unique resistance switching polarity is attributed to the band-filling controlled metal-insulator transition in a Ca0.96Ce0.04MnO3 film, triggered by ferroelectric based electrostatic doping. The results address the importance of ferroelectric field effect on the electronic properties of the interfacial system in ferroelectric/complex oxide-based resistive memory devices. [ABSTRACT FROM AUTHOR]

Recently, hafnia-based ferroelectrics are currently being investigated as next-generation memory devices due to their excellent CMOS process compatibility and functionality. However, some of the ferroelectric devices commonly exhibit an imprint effect due to charged defects around the interfacial layer, which has negative impacts on the ferroelectric memory devices. However, it can be applied to various applications as long as the imprint field is carefully adjusted. In this work, we introduced a strategy to control the imprint field in bilayer capacitors by utilizing tantalum oxide (TaO) interfacial layers and various Zr contents in Hf0.83Zr0.17O2 (HZO) films. The TaO layer (1 nm) was inserted into the bilayer capacitors to alter the imprint field's (positive or negative) direction. Whereas to control the imprint fields, we adjusted the Zr doping content (17%–83%) in the ferroelectric HZO films (8 nm). As the Zr content increased, reduced imprint fields were observed in those bilayer capacitors. In addition, it was found that a high imprint field (+2.43 MV/cm) was observed in Hf-rich films (Hf0.83Zr0.17O2) due to the higher amount of oxygen vacancies. In addition, we examined those oxygen vacancies through x-ray photoelectron spectroscopy depth profile analysis by considering sub-oxide fractions in the tantalum, which further confirms the root cause of the imprint field variations in the bilayer capacitors. Our study will contribute to a deeper understanding of imprinted hafnia-based ferroelectrics and will provide an insight into devices that utilize the imprint effect. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) van-der-Waals (vdW) layered ferroelectric semiconductors are highly desired for in-memory computing and ferroelectric photovoltaics or detectors. Beneficial from the weak interlayer vdW-force, controlling the structure by interlayer twist/translation or doping is an effective strategy to manipulate the fundamental properties of 2D-vdW semiconductors, which has contributed to the newly-emerging sliding ferroelectricity. Here, we report unconventional room-temperature ferroelectricity, both out-of-plane and in-plane, in vdW-layered γ-InSe semiconductor triggered by yttrium-doping (InSe:Y). We determine an effective piezoelectric constant of ∼7.5 pm/V for InSe:Y flakes with thickness of ∼50 nm, about one order of magnitude larger than earlier reports. We directly visualize the enhanced sliding switchable polarization originating from the fantastic microstructure modifications including the stacking-faults elimination and a subtle rhombohedral distortion due to the intralayer compression and continuous interlayer pre-sliding. Our investigations provide new freedom degrees of structure manipulation for intrinsic properties in 2D-vdW-layered semiconductors to expand ferroelectric candidates for next-generation nanoelectronics. Exploring two-dimensional layered ferroelectric semiconductors is highly desired for ferroelectric-based devices. Here, the authors realize the room-temperature ferroelectricity in layered Y-doped γ-InSe due to the microstructure modifications. [ABSTRACT FROM AUTHOR]

Herein, Bi4Ti3O12(BIT)/TiO2 composite films have been successfully prepared on indium tin oxide (ITO) via the sol–gel method. The microstructures, physical characteristics, and photoelectric response as well as the effects of polarization on the photoresponse of the films were investigated. The current–voltage and current–time characteristics showed that the BIT/TiO2 films have better photoelectric properties than those of pure BIT and TiO2 films. The energy band change of the heterojunction was used to explain the conduction mechanism of the composite film to enhance photovoltaic performance. Additionally, the effects of external bias and polarization operation on the photoelectric characteristics of the composite films are explored. The results show that the photoelectric response is increased by applying positive voltage and decreased by applying negative voltage. Moreover, the photoelectric performance is obviously improved by the negative polarization operation, while the positive polarization operation not only reduces the photocurrent, but also reverses the direction of the photocurrent. Such a tunable photovoltaic effect is attributed to the coupling effect between the ferroelectric depolarization field and the internal electric field of the heterojunction interface. This study provides an approach for enhancing the photovoltaic performance of the films, and enabling control of the ferroelectric photovoltaic, which can be applied to the new solar energy conversion technology. [ABSTRACT FROM AUTHOR]

For the first time, a composite from cellulose nanoparticles (CNP) and a classical ferroelectric of glycine silver nitrate (G-Ag-N) were synthesized for investigation of structural contributions to ferroelectricity using experimental methods (X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), dielectric spectroscopy) and theoretical analysis with hyperbolic law (HL). It was figured out that the presence of cellulose inhibited the formation of G-Ag-N crystals in the composite and dragged the Curie point toward higher temperatures. Besides, the increase in CNP content led to reducing the contributions of lattice and reversible domain-wall motion to dielectric permittivity; and enhanced the role of defects. [ABSTRACT FROM AUTHOR]

For the first time, to our knowledge, an eco-friendly nanocomposite based on a classical molecular ferroelectric of Tris-sarcosine calcium chloride (TSCC) with an addition of cellulose nanoparticles (CNPs) was synthesized. The samples containing different cellulose concentrations were compressed under various pressures from 0.1 to 0.7 GPa to investigate the effects of composition and compression pressure on the ferroelectricity of the composites. Experiments were conducted on samples in the fresh state and after 200 h under normal conditions. The results obtained demonstrated higher phase transition temperatures in the composites than those of pure TSCC. Besides, a deformation of the dielectric hysteresis loops with changing cellulose content was detected. Importantly, an increase in compression pressure applied on the samples led to the movement of the phase transition point toward higher temperatures. The results also revealed an instability of the ferroelectric properties in the composites with high content of cellulose. [ABSTRACT FROM AUTHOR]

Ferroelectric hafnium oxides are poised to impact a wide range of microelectronic applications owing to their superior thickness scaling of ferroelectric stability and compatibility with mainstream semiconductors and fabrication processes. For broad-scale impact, long-term performance and reliability of devices using hafnia will require knowledge of the phases present and how they vary with time and use. In this Perspective article, the importance of phases present on device performance is discussed, including the extent to which specific classes of devices can tolerate phase impurities. Following, the factors and mechanisms that are known to influence phase stability, including substituents, crystallite size, oxygen point defects, electrode chemistry, biaxial stress, and electrode capping layers, are highlighted. Discussions will focus on the importance of considering both neutral and charged oxygen vacancies as stabilizing agents, the limited biaxial strain imparted to a hafnia layer by adjacent electrodes, and the strong correlation of biaxial stress with resulting polarization response. Areas needing additional research, such as the necessity for a more quantitative means to distinguish the metastable tetragonal and orthorhombic phases, quantification of oxygen vacancies, and calculation of band structures, including defect energy levels for pure hafnia and stabilized with substituents, are emphasized. [ABSTRACT FROM AUTHOR]

Intensive research into functional oxides has been triggered by the quest for a solid-state universal memory with high-storage density, non-volatility, high read/write speed, and random access. The ferroelectric random-access memory (FeRAM), in which the information is stored in the spontaneous ferroelectric polarization of the material, offers great promise as nonvolatile and multistate memory, but its destructive electrical reading step requires a rewrite step after each reading, increasing energy consumption. As an alternative, optical nondestructive readout is based on the ferroelectric polarization dependence of the photovoltaic response in materials and has been reported in two-states ferroelectric memories and multistate devices with limited photocurrent switchability due to asymmetric interfacial effects. In this work, we report a nonvolatile oxide memory device based on a symmetric heterostructure with eight stable and well-controlled remanent polarization (Pr) states, written electrically by voltage pulse and read optically through polarization-dependent short-circuit photocurrent Isc or open circuit photovoltage Voc. This symmetric capacitor demonstrates a clear proportionality between Isc (Voc) and Pr, allowing to achieve a 100% switchability of the photovoltaic response. The memory devices based on 3-bit data storage show good performance in terms of data retention, fatigue behavior, and repeatability of writing and reading cycles. Thanks to the very high sensitivity of the optical reading method, the number of states could largely exceed eight, being limited only by the electrical writing step precision. These results are particularly exciting for the development of next-generation ferroelectric memory devices with increased memory storage density and lower power consumption. [ABSTRACT FROM AUTHOR]

Traditional von Neumann architecture is facing severe challenges due to separated physical structure of memory and processing units, which inspires the development of in‐memory computing electronics. Intriguingly, as a kind of complementary metal‐oxide‐semiconducor compatible ferroelectric material, HfO2 is widely studied based on first‐principles calculation in the semiconductor field, showing great potential in constructing emerging electronics. Different structures including ferroelectric diode, ferroelectric field effect transistor, and ferroelectric tunnel junctions based on HfO2 are proposed for in‐memory computing application. Here, this work reviews the progress of HfO2 from materials to devices, including crystal structure, fatigue mechanism, first‐principles calculation, and neuromorphic computing application of HfO2‐based device. This work can provide a reference for the HfO2 ferroelectric device development for next‐generation in‐memory computing applications. [ABSTRACT FROM AUTHOR]

The presence of the top electrode on hafnium oxide‐based thin films during processing has been shown to drive an increase in the amount of metastable ferroelectric orthorhombic phase and polarization performance. This "Clamping Effect," also referred to as the Capping or Confinement Effect, is attributed to the mechanical stress and confinement from the top electrode layer. However, other contributions to orthorhombic phase stabilization have been experimentally reported, which may also be affected by the presence of a top electrode. In this study, it is shown that the presence of the top electrode during thermal processing results in larger tensile biaxial stress magnitudes and concomitant increases in ferroelectric phase fraction and polarization response, whereas film chemistry, microstructure, and crystallization temperature are not affected. Through etching experiments and measurement of stress evolution for each processing step, it is shown that the top electrode locally inhibits out‐of‐plane expansion in the HZO during crystallization, which prevents equilibrium monoclinic phase formation and stabilizes the orthorhombic phase. This study provides a mechanistic understanding of the clamping effect and orthorhombic phase formation in ferroelectric hafnium oxide‐based thin films, which informs the future design of these materials to maximize ferroelectric phase purity and corresponding polarization behavior. [ABSTRACT FROM AUTHOR]

On the basis of comparative study of the morphology of silver nanoparticles deposited on a surface of single crystalline NH2(CH3)2Al(SO4)2 × 6H2O (DMAAlS) and glass as well as of the absorption spectra of these composites the impact of the ferroelectric phase transition of the "order–disorder" type on the surface plasmon resonance (SPR) was investigated.The observed anomalies of the SPR band parameters were explained in terms of the resonance type coupling between the dipole clusters arising in a narrow region in vicinity of the Curie point and the free electrons within the silver nanoparticles. It was shown that such a coupling is followed by decreasing of these particles' polarizability under the influence of a high frequency electric field of the propagating light photons. The mechanism of growth of the peculiar type of the silver nanoelements on the surface of DMAAlS single crystals—so-called nanowells—is proposed. [ABSTRACT FROM AUTHOR]

Electrocaloric effect is the adiabatic temperature change in a dielectric material when an electric field is applied or removed, and it can be considered as an alternative refrigeration method. Materials with ferroelectric order exhibit large temperature variations in the vicinity of a phase transition, while antiferroelectrics and relaxors may exhibit a negative electrocaloric effect. In this study, the temperature variation in polarization was investigated for epitaxial ferroelectric thin film structures based on PbZrTiO3 materials in simple or complex multilayered structures. We propose the intriguing possibility of a giant negative electrocaloric effect (ΔT = −3.7 K at room temperature and ΔT = −5.5 K at 370 K) in a simple epitaxial Pb(ZrTi)O3 capacitor. Furthermore, it was shown that abnormal temperature variation in polarization is dependent on the non-FE component introduced in a multilayered structure. No significant variation in polarization with temperature was obtained for PZT/STON multilayered structures around room temperature. However, for PZT/BST or PZT/Nb2O5 multilayers, an abnormal temperature variation in polarization was revealed, which was similar to a simple PZT layer. The giant and negative ∆T values were attributed to internal fields and defects formed due to the large depolarization fields when the high polarization of the FE component was not fully compensated either by the electrodes or by the interface with an insulator layer. The presented results make Pb(ZrTi)O3-based structures promising for cooling applications operating near room temperature. [ABSTRACT FROM AUTHOR]

The artificial synapses are basic units in the hardware implementation of neuromorphic computing, whose performances should be gradually modulated under external stimuli. The underlying mechanism of the increasing and decreasing device conductance is still unclear in the Hf0.5Zr0.5O2 based synapses. In this study, the Hf0.5Zr0.5O2 capacitors with different stack orders are fabricated in atomic layer deposition, whose ferroelectric properties are investigated by analyzing the capacitanceâ€"voltage and polarization-voltage curves. The enhanced ferroelectricity is found after the rapid thermal annealing treatment for all the TiN/Hf0.5Zr0.5O2/TiN, TiN/HfO2-ZrO2/TiN and TiN/ZrO2-HfO2/TiN devices. In the device with poor ferroelectricity, the conductance gradually decreases under both positive and negative identical pulse schemes, which corresponds to the gradual dissolution process of the conductive filaments established in the initial pulse. For the capacitors with strong ferroelectricity, dual-direction conductance modulation can be observed due to the partial domain switching process, which can emulate the potentiation and depression process of biological synapses. [ABSTRACT FROM AUTHOR]

A novel ferroelectric nanocomposite based on potassium dihydrogen phosphate (KDP) combined with the oxidised form of multiwalled carbon nanotubes (OMWCNT) was prepared and utilised for investigating the influence of OMWCNT on structure, phase transition, ferroelectric switching and electrical properties. The results pointed out the expansion of the ferroelectric phase and the increase in dielectric constant in comparison with pure KDP. Besides, a weaker ferroelectric switching accompanied by the deformation of hysteresis loops has been found with a higher OMWCNT content. Finally, the impedance and conductivity measurements demonstrated the electrode effects. The interaction of KDP with OMWCNT, and the high electrical conductivity of OMWCNT were supposed to be related to the described anomalies. [ABSTRACT FROM AUTHOR]

SmFeO3 has received the increasing scientific attention as a promising room‐temperature single‐phase multiferroic material with great application potential in the next‐generation spintronic devices. However, the ferroelectricity of SmFeO3 has remained as a controversial issue. In the present work, high resistivity incipient ferroelectric CaTiO3 was introduced as a charge blocking layer on an SmFeO3 thin film to suppress the leakage current. CaTiO3/SmFeO3/Nb–SrTiO3 (1 0 0) thin films were prepared by a PLD (pulsed laser deposition) process, and the epitaxial growth of thin films was confirmed by XRD (X‐ray diffraction) and HRTEM (high resolution transmission electron microscope) images. The interface strain resulted in the polar non‐centrosymmetry in space group P42/mc for SmFeO3, and subsequently the room‐temperature ferroelectricity was achieved with a robust remanent polarization of about 4.9 μC/cm2. The 180° switchable domain structure was confirmed by PFM (piezoelectric force microscope). Meanwhile, strong magnetoelectric coupling with magnetoelectric coefficient (αME) of about 2.5 V/(cm Oe) was observed. The present work has revealed the structural origin of ferroelectricity in an SmFeO3 thin film and provided the great reference for its room temperature multiferroic applications. [ABSTRACT FROM AUTHOR]

We investigate the origin of ferroelectricity in the BiFeO3–LaFeO3 system in rhombohedral R3c and tetragonal P4mm symmetries by ab initio density functional theory calculations and compare their electronic features with paraelectric orthorhombic Pnma symmetry. We show that a coherent accommodation of stereo-active lone pair electrons of Bi is the detrimental factor of ferroelectricity. A Bloch function arising from an indirect Bi_6p–Fe_3d hybridization mediated through O_2p is the primary origin of spontaneous polarization (Ps) in the rhombohedral system. In the orthorhombic system, a similar Bloch function was found, whereas a staggered accommodation of stereo-active lone pair electrons of Bi exclusively results in paraelectricity. A giant Ps reported in the tetragonal system originates from an orbital hybridization of Bi_6p and O_2p, where Fe-3d plays a minor role. The Ps in the rhombohedral system decreases with increasing La content, while that in the tetragonal system displays a discontinuous drop at a certain La content. We discuss the electronic factors affecting the Ps evolutions with La content. [ABSTRACT FROM AUTHOR]

The relationship between microstructure, ion diffusion and dielectric properties of (1-x) (Ba0.5Sr0.5)1.01TiO3-x ZnAl2O4 composite ceramics were systematically studied. With the increase of ZA content, the grain morphology of composite ceramics changed dramatically, of which the grain size of (BS)1.01T50 decreased first and then increased. The introduction of ZA diluted the ferroelectricity of (BS)1.01T50, which reduced the permittivity of (BS)1.01T50. When the content of ZA was 50 wt%, a high tunability of 34% was obtained. Ion diffusion and grain size affected the Curie temperature, which in turn affected the tunability. In addition, the significant changes in grain morphology weaken the connectivity between the (BS)1.01T50 grains, thereby reducing the tunability. The variation of Q value was mainly associated with the doping effect and the composite effect. [ABSTRACT FROM AUTHOR]

Harvesting solar energy to solve the energy crisis and environmental pollution is a research hotspot in the photovoltaic industry today. Conventional ferroelectric materials have a bandgap between 3.0 and 3.8 eV, and their low absorption coefficients and photocurrent densities limit the photovoltaic applications of ferroelectric materials. Inorganic ferroelectric thin film materials with narrow bandgap (1.1–2.0 eV) have high optical absorption coefficient and broad spectral response, wide bandgap tuning range (1.2–3.0 eV), as well as high photocurrent density and switchable ferroelectric photoelectric effect, which have great potential for photovoltaic and optoelectronic applications in solar cells, photodetection, photocatalysis. This review summarizes the recent developments of narrow bandgap inorganic ferroelectric thin‐film materials and aims to stimulate research interest and efforts in ferroelectric photovoltaic materials. [ABSTRACT FROM AUTHOR]

Metal halide perovskites (MHPs) have been shown to be key materials for next‐generation photovoltaic energy harvesting, electro‐optic detection, and all‐optical conversion. Room‐temperature tetragonal MAPbI3 has been reported to possess two space groups: polar I4cm and non‐polar I4/mcm. Although the space group of MAPbI3 is still under debate, significant effort has been expended to prove that I4cm MHPs are ferroelectric and I4/mcm MHPs are antiferroelectric. Both structures belong to the ferroelastic point group, and there has been debate regarding whether the domain structures observed on MHPs are ferroelectric or ferroelastic. The relationship between the ferroelectricity and ferroelasticity of MHPs has been discussed, whereas these two properties sometimes are regarded as mutually exclusive in MHPs. In this work, the ferroelectricity and ferroelasticity of MHPs originating from structural symmetry have been reviewed, and the interrelationship between the ferroelectricity and ferroelasticity of MHPs are discussed. [ABSTRACT FROM AUTHOR]

The present work reports anomalous ferroelectric properties of two nanocomposites containing oxidized multiwalled carbon nanotubes (ox-MWCNT) as an electrically conductive filler combined with each of hydrogen-bonded ferroelectrics of potassium dihydrogen phosphate (KDP) and triglycine sulfate (TGS). It was shown that the influence of ox-MWCNT led to the anomalous increase in a phase transition point, domain-wall freezing temperatures and coercive fields in ferroelectric parts of the composites. The OH radicals equipped on the carbon nanotube surface after oxidation were responsible for the observed anomalies. [ABSTRACT FROM AUTHOR]

Studies of preliminary structural and detailed frequency–temperature dependence of electrical (dielectric, impedance, polarization, and conductivity) properties of Bi/Na-modified barium titanate compound have been performed in this work. The proposed compound has been synthesized by a conventional solid-state sintering route with a composition of (Ba0.8Bi0.1Na0.1)TiO3. The prepared sample has been pre-heated (calcined) at 1050 °C. Preliminary structural analysis using X-ray diffraction method of the calcined powder confirms the phase purity of the prepared barium titanate compound with tetragonal symmetry. The pellet of this compound has been sintered at 1100 °C. Study of the surface morphology of the pellet by scanning electron microscope (SEM) reveals the homogeneous distribution of grains throughout the sample surface. The dielectric study in the temperature range of 25–500 °C at different frequencies (1 kHz to 1 MHz) shows a high dielectric constant and low tangent loss in a wide temperature range. The temperature response of AC conductivity with impedance spectrum confirms the semiconducting nature of the material at high temperatures. The Nyquist plots reflect the grain and grain boundary contributions to the conduction mechanism of this modified BaTiO3 compound. The existence of ferroelectricity at room temperature of the above sample is confirmed by polarization versus electric field (P–E hysteresis loop) measurements. The J versus E characteristic suggests the Ohmic conduction mechanism of the Bi/Na-modified barium titanate compound. All the studied properties conclude that this composition has potential for device application in the electronic industry. [ABSTRACT FROM AUTHOR]

A concise overview of ferroelectric ceramics and composites, which constitute the backbone of transducer applications such as actuators, sensors, energy harvesting, and storage are provided. For piezoelectric composites based on ferroelectric ceramics, underlying principles are developed using linear equations of state for piezoelectricity and the concepts of crystalline anisotropy, symmetry, composite connectivity, and form factor engineering as unifying themes. Emphasis is given to diphasic piezoelectric composites which have revolutionized transducer engineering in fields such as sonar and medical ultrasound imaging. It is shown that through judicious selection of a ferroelectric ceramic in conjunction with an inactive material such as a polymer or metal, effective material properties exceeding the performance of single-phase ceramics can be achieved. The application of traditional composite strategies and advances in fabrication technologies to rapidly growing fields such as dielectric energy storage and piezoelectric energy harvesting are also discussed. [ABSTRACT FROM AUTHOR]

Electrostrictive effects in complex-perovskite “relaxor” ferroelectrics (FEs) exhibit superior performance in comparison with the simple-perovskite normal FEs, such as giant electrostriction in its paraelectric phase and high electromechanical coupling in its FE phase. As one of the discoverers, the author will deliver the historical background of these epoch-making phenomena and the development strategy of how we considered performance improvement. Though both discoveries were actually originated from a sort of “serendipity” (lucky & accidental occurrence!), some of the key factors have been embedded in the research base: 1) interrelation between complex perovskite structure and ferroelectricity; 2) anharmonicity in relaxor FEs; and 3) microdomain contribution in relaxor FEs. In the last part of this article, the author introduces a bit different “mesoscopic” approach, “fractal analysis of microdomain configuration” in conjunction with the “domain engineering” concept, to distinguish the electromechanical coupling among the normal and relaxor FEs for remaining the future research seeds. [ABSTRACT FROM AUTHOR]

Low-power voltage transformers using magnetoelectric (ME) effect in ferromagnetic-piezoelectric heterostructures occupy an intermediate position between electromagnetic and piezoelectric transformers. They have low input and high output impedance, their transformation ratio is controlled by magnetic field. The paper describes design and manufacturing technology of monolithic ME transformers based on the nickel-zinc ferrite - lead zirconate-titanate structure. A prototype of the transformer is fabricated, in which a bulk electromagnetic coil in the input circuit is replaced with a planar electrode, deposited directly on the ferrite layer. This results in simplification of the design and reduction in the size of the transformer. At operating frequency of 70 kHz, the input impedance of the transformer is 0.1 Ω, the output impedance depends on the direction of the piezoelectric polarization and is 6–300 kΩ, the transformation ratio is tuned in the range 0–43 by magnetic field up to 60 Oe. The coil-free magnetoelectric transformers are promising to match circuits with very different impedances. [Display omitted] • Design and technology for manufacturing a monolithic voltage transformer. • Transformer uses magnetoelectric effect in a ferrite-piezoelectric heterostructure. • Magnetoelectric transformer posses low input and high output impedance. [ABSTRACT FROM AUTHOR]

In this paper we have discussed the impact of electric poling on structure, magnetism and ferroelectricity of 0.7PbFe 0·5 Nb 0·5 O 3 - 0.3BiFeO 3 (PBFN) multiferroic. Magnetization data exhibit the presence of strong converse magneto electric coupling in a material. The temperature dependent Raman measurements demonstrate considerable changes in Raman scattering intensity and spectrum structure around T C , indicating a structural change around T C. The octahedral stretching vibration modes revealed a remarkable frequency shift below T N and the anomalies are owing to the coupling interaction between the spin-phonons. Changes in Raman modes and magnetization data support the hypothesis of converse magnetoelectric coupling. By poling, the improvement in ferroelectric domain ordering occurs and it was confirmed by P-E loops. We present the implications of our investigation on electric poling of PBFN multiferroic in the current interest of spintronics. • Changes in Raman modes and magnetization data support the hypothesis of converse magnetoelectric coupling. • Unpoled PBFNO exhibit broad and overlapping 10 active modes at room temperature, ranging from 100 to 1300 cm−1, at 147, 212, 255, 431, 479, 561, 700, 795,835 and 1112 cm−1. These peaks demonstrate considerable changes in Raman scattering intensity and spectrum structure around T C , indicating a structural change around T C. The octahedral stretching vibration modes revealed a remarkable frequency shift below the Neel temperature T N and the anomalies are owing to the coupling interaction between the spin-phonons. • By poling the improvement in ferroelectric domain ordering occurs and it was confirmed by P-E loops. • We present the implications of our investigation on electric poling of PBFNO in the current interest of spintronics. [ABSTRACT FROM AUTHOR]

Combining the experimental characterization with the large-scale density functional theory calculations based on finite-element discretization (DFT-FE), we address the stabilization of polar orthorhombic phases (o-HfO2) in Al:HfO2 nanofilms by means of the atomic registry distortions and lattice deformation caused by Al substitutional defects (AlHf) and Schottky defects (2AlHf + VO) in tetragonal phases (t-HfO2) or monoclinic phases (m-HfO2). The phase transformation directly from the t-HfO2 into polar o-HfO2 are also elucidated within a heterogeneous distribution of Al dopants in both t-HfO2 bulk crystal structure and Al:HfO2 nanofilm. It is revealed using large-scale DFT calculations that the Al substitutional defects (AlHf) or the Schottky defect (2AlHf + VO) could induce the highly extended atomic registry distortions or lattice deformation in the t- and m-HfO2 phases, but such effects are greatly diminished in ferroelectric orthorhombic phase. By purposely engineering the multiple AlHf defects to form dopant-rich layers in paraelectric t-HfO2 nanofilm or bulk crystal, the induced extended lattice distortions surrounding the defect sites exhibit the shearing-like atomic displacement vector field. The large-scale DFT calculations further predicted that the shearing-like microscopic lattice distortions could directly induce the phase transformation from the t-HfO2 into polar orthorhombic phase in both Al:HfO2 bulk crystal and nanofilms, leading to the large remanent polarization observed in Al:HfO2 nanofilms with the presence of Al-rich layers. The current study demonstrates that the ferroelectricity of HfO2 bulk crystal or thin film can be optimized and tuned by delicately engineering both the distribution and concentration of Al dopants in atomic layer deposition without applying the top capping electrode, providing the extra flexibility for designing the HfO2 based electronic devices in the future. [ABSTRACT FROM AUTHOR]

The instability of TiN/HfZrO/TiN ferroelectric capacitors becomes a dominant obstacle in its practical application. To improve this problem, the effects of N-plasma treatment at both top and bottom TiN interfaces are investigated on the ferroelectricity behaviors and reliability characteristics of TiN/HfZrO/TiN ferroelectric capacitors. The results show that the high remanent polarization and large dielectric constant in the capacitors can be obtained by treating at the both top and bottom TiN interfaces. The wake-up and fatigue effects can be effectively suppressed and the lower leakage current can be acquired with extending the treatment time. The XPS analyses show that the oxygen vacancies in HfZrO film can be reduced efficiently by extending treatment time. The cycling test confirms that the better ferroelectricity characteristics can be measured by treating at two interfaces than that of single interface. The N-plasma treatment at both top and bottom TiN interfaces provides a new approach for the realization of highly reliable TiN/HfZrO/TiN ferroelectric capacitors. [ABSTRACT FROM AUTHOR]

At the interface of van der Waals heterostructures, the crystal symmetry and the electronic structure can be reconstructed, giving rise to physical properties superior to or absent in parent materials. Here by studying a Bernal bilayer graphene moiré superlattice encapsulated by 30°-twisted boron nitride flakes, we report an unprecedented ferroelectric polarization with the areal charge density up to 1013 cm−2, which is far beyond the capacity of a moiré band. The translated polarization ~5 pC m−1 is among the highest interfacial ferroelectrics engineered by artificially stacking van der Waals crystals. The gate-specific ferroelectricity and co-occurring anomalous screening are further visualized via Landau levels, and remain robust for Fermi surfaces outside moiré bands, confirming their independence on correlated electrons. We also find that the gate-specific resistance hysteresis loops could be turned off by the other gate, providing an additional control knob. Furthermore, the ferroelectric switching can be applied to intrinsic properties such as topological valley current. Overall, the gate-specific ferroelectricity with strongly enhanced charge polarization may encourage more explorations to optimize and enrich this novel class of ferroelectricity, and promote device applications for ferroelectric switching of various quantum phenomena. Interfacial ferroelectricity may emerge in moiré superlattices. Here, the authors find that the polarized charge is much larger than the capacity of the moiré miniband and the associated anomalous screening exists outside the band. [ABSTRACT FROM AUTHOR]

All-solid-state Li-metal batteries (ASSLBs) are highly desirable, due to their inherent safety and high energy density; however, the irregular and uncontrolled growth of Li filaments is detrimental to interfacial stability and safety. Herein, we report on the incorporation of piezo-/ferroelectric BaTiO3 (BTO) nanofibers into solid electrolytes and determination of electric-field distribution due to BTO inclusion that effectively regulates the nucleation and growth of Li dendrites. Theoretical simulations predict that the piezoelectric effect of BTO embedded in solid electrolyte reduces the driving force of dendrite growth at high curvatures, while its ferroelectricity reduces the overpotential, which helps to regularize Li deposition and Li+ flux. Polarization reversal of soft solid electrolytes was identified, confirming a regular deposition and morphology alteration of Li. As expected, the ASSLBs operating with LiFePO4/Li and poly(ethylene oxide) (PEO)/garnet solid electrolyte containing 10% BTO additive showed a steady and long cycle life with a reversible capacity of 103.2 mAh g-1 over 500 cycles at 1 C. Furthermore, the comparable cyclability and flexibility of the scalable pouch cells prepared and the successful validation in the sulfide electrolytes, demonstrating its universal and promising application for the integration of Li metal anodes in solid-state batteries. [ABSTRACT FROM AUTHOR]

2D hybrid halide double perovskites (HHDPs) have been demonstrated to be a promising alternative to conventional lead‐based halide perovskites as a new system of photoferroelectrics, due to their unique characteristics of environmental friendliness, favorable stability, and fascinating optoelectronic properties. Herein, for the first time, a 2D iodide double perovskite photoferroelectric is reported based on Ag/Sb ions, (4,4‐DFPD)4AgSbI8 (4,4‐DFPD = 4,4‐difluoropiperidinium), which possesses a high Curie temperature of 414 K (above BaTiO3), a large spontaneous polarization of 9.6 μC cm−2, ferroelectric photovoltaic effect, and photostrictive effect. Notably, to the best of the authors' knowledge, the discovery of photostriction in HHDP photoferroelectrics is unprecedented. Moreover, (4,4‐DFPD)4AgSbI8 exhibits an impressive X‐ray responsivity, with a sensitivity as high as 704.8 μC Gyair−1 cm−2 at 100 V bias and a detection limit as low as 0.36 μGyair s−1 at 10 V bias, both of which outperform the current all HHDP photoferroelectrics. This work enriches the photoferroelectric family, and proves that Ag/Sb‐based HHDP photoferroelectrics are a promising candidate for the next‐generation optoelectronic devices. [ABSTRACT FROM AUTHOR]

We propose a nonlinear thermoelectric framework adequate for capturing the phenomenon of electrical hysteresis in ferroelectric materials. We call this formulation rate-independent ferroelectricity, because the rate of polarisation is linear in the rate of the electric field, so that the process is independent of the time scale. This is inspired by the theory of rate-independent plasticity in the early form proposed by Green and Naghdi (Arch Ration Mech Anal 18:251–281, 1965) and Kratochvil and Dillon (J Appl Phys 40(8):3207–3218, 1969), whose works were in turn based on the formulation of thermodynamics with internal variables by Coleman and Gurtin (J Chem Phys 47:597–613, 1967). We impose thermodynamical restrictions on the proposed constitutive equations in order to guarantee positive dissipation under irreversible switching (domain switching). Finally, we illustrate the proposed framework with the numerical solution of a one-dimensional example, in which a cyclic electric field is applied, resulting in a ferroelectric polarisation-electric field hysteresis loop. The novelty of this work is in the use of an analogue of the evolution law proposed by Green and Naghdi (1965) to simulate the electrical hysteresis behaviour in ferroelectric materials, caused by domain wall motion under cyclic electric loadings. This hysteresis loop eventually results in a significant residual electric polarisation. [ABSTRACT FROM AUTHOR]

In this report, the effect of rare-earth (RE3+) ion substitution on structural, microstructural, and electrical properties in barium bismuth titanate (BaBi4Ti4O15) (BBTO) Aurivillius ceramics has been investigated. The Rietveld refinements on X-ray diffraction (XRD) patterns confirm that all the samples have an orthorhombic crystal system with A21am space group. Meanwhile, temperature dependent synchrotron XRD patterns reveal that the existence of dual phase in higher temperature region. The randomly oriented plate-like grains are experimentally strived to confirm the distinctive feature of bismuth layered Aurivillius ceramics. The broad band dielectric spectroscopic investigation signifies a shifting of ferroelectric phase transition (Tm) towards low temperature region with a decrease of the RE3+-ionic radii in BBTO ceramics. The origin of diffuse ferroelectric phase transitions followed by stabilization of the relaxor ferroelectric nature at high frequency region is explained using suitable standard models. The temperature dependent ac and dc conductivity results indicate the presence of double ionized oxygen vacancies in BBTO ceramics, whereas the dominance of single ionized oxygen vacancies is observed in RE-substituted BBTO ceramics. The room temperature polarization vs. electric field (P–E) hysteresis loops are shown to be well-shaped symmetric for BBTO ceramics, whereas slim asymmetric ferroelectric characteristics developed at RE-substituted BBTO ceramics. [ABSTRACT FROM AUTHOR]

A sodium bismuth titanate-based thin film is widely investigated lead-free piezoelectrics with potential applications for modern micro-devices such as PiezoMEMS. In this work, a 0.9Na1/2Bi1/2TiO3–0.1BaZr0.2Ti0.8O3 thin film was deposited on a Pt/Ti/SiO2/Si (001) substrate by the sol–gel spin coating method. The deposited piezoelectric film shows low dielectric loss and high remnant polarization. The measured ferroelectricity loop showed a coercive field of 110 kV/cm and a saturation polarization of 46.83 μC/cm2. The piezoelectric response of this thin film does not decrease from room temperature to around 100 °C. The fabricated piezoelectric device with bottom and top electrodes showed a large macro-scale strain value of ∼4% under the DC (30 V) and AC voltages (f = 800 kHz, Vpp = 10 V). [ABSTRACT FROM AUTHOR]