Search

Abstract: Recent progress in both low pretilt and high pretilt defect-free C1 surface stabilized ferroelectric liquid crystal (SSFLC) devices for e-paper application is reviewed. First, by using numerical calculation to investigate the balance between surface azimuthal anchoring energy and bulk elastic energy within the confined chevron layer geometry of C1 and C2, we found it is possible to achieve a zigzag-free C1 state by low azimuthal anchoring alignment with a low pretilt angle. The critical azimuthal anchoring coefficient for defect-free C1 state is calculated. Its relationship with elastic constants, chevron angle, and surface topography effect are also discussed. Second, by using 5° oblique SiO deposition alignment, a defect-free, large memory angle, high contrast ratio, and bistable C1 SSFLC display, which has potential for electronic paper applications has also been developed. The electro-optical properties and bistability of this device have been investigated. Various aspects of defect control are also discussed. [Copyright &y& Elsevier]

An important improvement was made in the derivation of the thermodynamical relations at characteristic points, presented in the previous paper, to prove that the derived relations are generally valid for different type thermodynamical (discontinuous and continuous) transitions (transformations). [ABSTRACT FROM PUBLISHER]

Based on his many years of experience, a JMEMS editor provides guidelines for authors that will, if followed, greatly reduce the risk of a devastatingly negative result from the review process. The premise is that there are certain things that rightfully anger reviewers, and, once angered, the reviewers become both negative and aggressive in their judgments—hence, the imagery of "the reviewer's axe" and how to avoid it. [ABSTRACT FROM AUTHOR]

Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers. [ABSTRACT FROM AUTHOR]

Describes the above-named upcoming special issue or section. May include topics to be covered or calls for papers. [ABSTRACT FROM AUTHOR]

Nitride ferroelectrics have recently emerged as promising alternatives to oxide ferroelectrics due to their compatibility with mainstream semiconductor processing. ScAlN, in particular, has exhibited remarkable piezoelectric coupling strength (K2) comparable to that of lithium niobate, making it a valuable choice for RF filters in wireless communications. Recently, ScAlN has sparked interest in its use for nanophotonic devices, chiefly due to its large bandgap facilitating operation in blue wavelengths coupled with promises of enhanced nonlinear optical properties such as a large second-order susceptibility (χ(2)). It is still an open question whether ScAlN can outperform oxide ferroelectrics concerning the Pockels effect—an electro-optic coupling extensively utilized in optical communications devices. In this paper, we present a comprehensive theoretical analysis and experimental demonstration of ScAlN's Pockels effect. Our findings reveal that the electro-optic coupling of ScAlN, despite being weak at low Sc concentration, may be significantly enhanced and exceed LiNbO3 at high levels of Sc doping, which points the direction of continued research efforts to unlock the full potential of ScAlN. The authors predict the Pockels effect of ScAlN with varying Sc concentration, realizing a ScAlN-on-insulator-on-silicon material platform, which allows the formation of low-loss, electrically-tunable microring resonators for accurate measurement of ScAlN's Pockels coefficients. [ABSTRACT FROM AUTHOR]

This paper investigates the excitation and propagation characteristics of a piezoelectric acoustic wave propagating in a rotated Y-cut X-propagating Pb(In0.5Nb0.5)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) relaxor-based ferroelectric single crystal substrate. Numerical simulations were performed to evaluate the acoustic wave properties by FEM software COMSOL. For comparison, two types of structures are taken into consideration: one is the traditional metal electrode/YX-PIN-PMN-PT and the other is silicon dioxide (SiO2) overlay/metal electrode/YX-PIN-PMN-PT substrate. It is shown that shear-horizontal (SH)-type piezoelectric boundary acoustic waves (PBAW) exist in the SiO2 overlay/metal electrode/YX-PIN-PMN-PT substrate and offer a fairly large electromechanical coupling factor K2 of 30%. Compared to a surface acoustic wave excited in the metal electrode/YX-PIN-PMN-PT substrate, enlarged phase velocity and significantly improved quality factor (∼3500) are simultaneously obtained for SH-type PBAW, which are promising for electromechanical transducer applications with high performance. [ABSTRACT FROM AUTHOR]

We argue that the “N-acetyl glycine phosphite” crystal grown and characterized in the title paper actually is glycine phosphite. [ABSTRACT FROM PUBLISHER]

THE ADMINISTRATI VE COMMITTEE of the IEEE Ultrasonics, Ferroelectrics, and Frequency Control Society takes great pleasure in announcing the selection of the Outstanding Paper published in its 2011 Transactions, Vol. 58. The award was presented during ceremonies at the 21st IEEE International Ultrasonics Symposium, October 7-10, 2012, in Dresden, Germany. The Awards Committee Members selected one paper from among a total of 251 full papers which appeared in Vol. 58 of the Transactions on Ultrasonics, Ferroelectrics, and Frequency Control. [ABSTRACT FROM AUTHOR]

Fast response time, high contrast ratio various FLC electrooptical modes, are achieved through the application of photoaligning layers in FLC cells. Fast FLCD with a high resolution can be used in the screens field sequential color (FSC) FLC microdisplays, which are now one of the most advanced technologies for pico-projectors. The switchable goggles and lenses based on new FLC prototypes can be efficiently applied in the new generation of switchable 2D/3D LCD TVs. [ABSTRACT FROM AUTHOR]

Recently the in-plane switching (IPS) has been heavily exploited in particular for high-resolution mobile displays. The IPS displays offer good optical quality, however, the complex fabrication and manufacturing cost offers several limitations for their application. On the other hand, electrically suppressed helix ferroelectric liquid crystals (ESHFLC's) because of their intrinsic in-plane switching offer better solutions with simpler and cheaper fabrication for high-resolution displays. In this article, the ESHFLC's with fast response time (˜10µs), high contrast ratio (˜ 10k: 1) with low driving voltage (2˜5V/µm) has been achieved through photo alignment technology with acceptable shock stability and without natural diffraction. The ESHFLC's provide good optical quality with simpler fabrication procedures and therefore could secure application for high-resolution displays. [ABSTRACT FROM AUTHOR]

Ultrasound techniques for flow investigation have been extensively developed for several years. Many methods have reached a level of maturity that allows widespread and still growing clinical use. Recently, new exciting developments have been introduced by the combination of Doppler techniques with advanced (e.g. plane wave) imaging methods. Therefore, a comprehensive review of the current state-of-the-art ultrasound methods applied to flow measurement and imaging becomes relevant. [ABSTRACT FROM AUTHOR]

The IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control (T-UFFC) accepts manuscript submissions of Papers, Review Papers, and Letters. To qualify for publication, the submissions must be unpublished, specifically prepared for the IEEE T-UFFC, and not be under consideration elsewhere (see Ethics). It is the responsibility of the corresponding author to obtain consent from all co-authors and sponsors before submission. By submission, authors agree to pay all charges and fees associated with publication of the manuscript (see Charges and Costs). [ABSTRACT FROM AUTHOR]

The IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control (T-UFFC) accepts manuscript submissions of Papers, Review Papers, and Letters. To qualify for publication, the submissions must be unpublished, specifically prepared for the IEEE T-UFFC, and not be under consideration elsewhere (see Ethics). It is the responsibility of the corresponding author to obtain consent from all co-authors and sponsors before submission. By submission, authors agree to pay all charges and fees associated with publication of the manuscript (see Charges and Costs). [ABSTRACT FROM PUBLISHER]

The IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control (T-UFFC) accepts manuscript submissions of Papers, Review Papers, and Letters. To qualify for publication, the submissions must be unpublished, specifically prepared for the IEEE T-UFFC, and not be under consideration elsewhere (see Ethics). It is the responsibility of the corresponding author to obtain consent from all co-authors and sponsors before submission. By submission, authors agree to pay all charges and fees associated with publication of the manuscript (see Charges and Costs). [ABSTRACT FROM PUBLISHER]

Monoclinic ferroelectric phases are prevalent in various functional materials, most notably mixed‐ion perovskite oxides. These phases can manifest as regularly ordered long‐range crystallographic structures or as macroscopic averages of the self‐assembled tetragonal/rhombohedral nanodomains. The structural and physical properties of monoclinic ferroelectric phases play a pivotal role when exploring the interplay between ferroelectricity, ferroelasticity, giant piezoelectricity and multiferroicity in crystals, ceramics and epitaxial thin films. However, the complex nature of this subject presents challenges, particularly in deciphering the microstructures of monoclinic domains. In Paper I [Biran & Gorfman (2024). Acta Cryst. A80, 112–128] the geometrical principles governing the connection of domain microstructures formed by pairing MAB type monoclinic domains were elucidated. Specifically, a catalog was established of 'permissible domain walls', where 'permissible', as originally introduced by Fousek & Janovec [J. Appl. Phys. (1969), 40, 135–142], denotes a mismatch‐free connection between two monoclinic domains along the corresponding domain wall. The present article continues the prior work by elaborating on the formalisms of permissible domain walls to describe domain microstructures formed by pairing the MC type monoclinic domains. Similarly to Paper I, 84 permissible domain walls are presented for MC type domains. Each permissible domain wall is characterized by Miller indices, the transformation matrix between the crystallographic basis vectors of the domains and, crucially, the expected separation of Bragg peaks diffracted from the matched pair of domains. All these parameters are provided in an analytical form for easy and intuitive interpretation of the results. Additionally, 2D illustrations are provided for selected instances of permissible domain walls. The findings can prove valuable for various domain‐related calculations, investigations involving X‐ray diffraction for domain analysis and the description of domain‐related physical properties. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) valleytronic materials are both fundamentally intriguing and practically appealing to explore novel physics and design next-generation devices. However, traditional control means such as optic pumping or magnetic field cannot meet the demands of modern electron devices for miniaturization, low-dissipation, and non-volatility. Thus, it is attractive to combine the ferroelectric property with valley property in a single compound. In this paper, the recent progress of ferroelectric-valley coupling is reviewed. First, we briefly recall the development of valleytronics in the past several years. Then, various structures demonstrating ferroelectric-valley coupling, including heterostructures and intrinsic materials, are introduced. Subsequently, we describe ferroelectric-valley coupling in sliding and adsorption system and the unconventional ferroelectricity in the moiré system. Finally, we discuss the research status and outlook. We hope that this perspective will be helpful to bridge the gap between valleytronics and ferroelectrics in 2D materials and inspire further exciting findings. [ABSTRACT FROM AUTHOR]

These instructions give guidelines for preparing papers for this publication. Presents information for authors publishing in this journal. [ABSTRACT FROM AUTHOR]

Alternating current poling (ACP) has been proven to significantly improve the performance of relaxor-based perovskite ferroelectrics. However, there is still a lack of methods to scientifically optimize ACP conditions which has remarkable influence on the polarization effects. In this paper, the orthogonal experimental design (OED) is proposed to accomplish the optimization of ACP conditions with minimum experiments. Using this method, the optimal ACP conditions of Sm-doped PMN-PT rhombohedral single crystal were obtained, and giant piezoelectric coefficient d 33 and relative dielectric permittivity ε r /ε 0 of 4520 pC/N and 13290 were achieved, which is 24.5% and 29.5% higher than that under DCP. Because of the orthogonality, high efficiency and being user-friendly for individuals unfamiliar with the material mechanism, the proposed OED is expected to provide experimental instruction for ACP for all kinds of piezoelectric single crystal and ceramics. [ABSTRACT FROM AUTHOR]

Pb-based perovskites play pivotal roles in ferroelectric research. In the search for new Pb-based ferroelectrics, we investigated the ferroelectric properties of Dion–Jacobson type CsPb2Nb3O10 and exfoliated 2D nanosheets. Ferroelectricity in CsPb2Nb3O10 was demonstrated for the first time. CsPb2Nb3O10 adopted a polar tetragonal structure with a modest TC = 260 °C and polarization PS = 7.93 μC cm−2; the polarization mainly arose from the out-of-plane displacements of Nb5+ ions and nearby oxygens. CsPb2Nb3O10 layered perovskite offers additional advantages for tailoring ferroelectric nanomaterials, as exfoliated 2D nanosheets provide novel platforms for investigating ferroelectric properties down to the 2D limit. Piezoresponse force microscopy confirmed stable ferroelectricity even in exfoliated 2D Pb2Nb3O10 nanosheets. [ABSTRACT FROM AUTHOR]

The refrigeration technology of electronic devices has faced severe challenges with the increasing demand for miniaturization and high frequency, and the research on the electrocaloric effect (ECE) of ferroelectric nanomaterials has made it possible to solve such problems. Due to the symmetry breaking on surfaces of a ferroelectric crystal, the polarizations on surfaces are different from those inside the crystal, which can significantly affect the electrocaloric properties of the materials. In addition, considering the electromechanical coupling between the spontaneous polarization and stress field, the applied stress has a drastic influence on the ECE of the material. In this paper, the extrapolation length is incorporated in the phase-field method based on the time-dependent Ginzburg–Landau equation to investigate the effects of different stress and surface polarization on the ECE of PbTiO3 (PTO) nanocylinders. The stress–adiabatic temperature change (ATC) curves with different extrapolation lengths are obtained through the simulations, which reveal the effect of extrapolation length and stress on the PTO nanocylinders. The results of this paper can provide theoretical guidance for the design of next-generation solid-state cooling devices. [ABSTRACT FROM AUTHOR]

Ferroelectric and negative-capacitance field-effect transistors (FeFETs and NCFETs) have recently garnered great attention as devices for applications in memory and low-power logic, respectively. As these technologies are pursued, it is critical to have a variety of measurement approaches, including methods familiar to the electron-device and microwave communities that can aid in fully understanding the behavior of ferroelectrics in FeFETs and NCFETs. In this paper, we propose and show the viability of using frequency-domain electrical measurement techniques employing the well-known microwave S-parameters, and their large-signal generalization and X-parameters. Our methods provide the means to trace the intrinsic polarization versus electric-field curve of the ferroelectric, i.e., with the parasitics de-embedded, thereby showing the innate ferroelectric response, which cannot be done using conventional techniques. These methods also enable extraction of all the parameters of the Landau–Khalatnikov equation, which is commonly used to model ferroelectric behavior in FeFETs and NCFETs. This paper hence takes a useful step toward methods familiar to the electron-device community that can help to better understand and optimize FeFET and NCFET technologies. [ABSTRACT FROM AUTHOR]

These instructions give guidelines for preparing papers for this publication. Presents information for authors publishing in this journal. [ABSTRACT FROM AUTHOR]

For over two decades Na0.5Bi0.5TiO3 (NBT) -based lead-free piezoelectrics have attracted attention due to its ability to exhibit large electric-field driven strain. Compared to the popular Pb(Zr, Ti)O3 (PZT)-based piezoelectrics, which exhibit electrostrain of about 0.3%, the derivatives of NBT-based lead-free piezoelectrics at the ergodic—non ergodic relaxor crossover exhibit larger electric-field driven strain ∼0.45%. In recent years, there has been a concerted effort to increase the maximum electrostrain in lead-free piezoceramics. Recent reports suggest that oxygen deficient NBT- based piezoceramics can exhibit electrostrain ∼1%. In this paper we explore this phenomenon and show that the ultra high electric field driven strain measured is primarily a consequence of reducing the thickness of the disc dimension below 500 microns and not an exclusive effect of the composition. [ABSTRACT FROM AUTHOR]

Relaxor ferroelectric single crystal Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIN–PMN–PT) has received extensive research and attention due to its excellent piezoelectric, electromechanical, and other properties. In particular, tetragonal relaxor ferroelectric single crystals have shown greater application potential in high‐temperature devices due to their higher Curie temperature and better stability. However, the low piezoelectric performance of tetragonal crystals also greatly limits its application, and research on its optical properties is not sufficient. In this paper, the tetragonal phase Sm–PIN–PMN–PT single crystal was obtained by the Bridgman method, and its piezoelectric and electro‐optical properties are studied. At the same time, we gave a complete set of piezoelectric, dielectric, and elastic coefficient matrices. The results show that the crystal has excellent piezoelectric and electromechanical properties. The piezoelectric coefficient can reach 905pC/N, the electromechanical coupling coefficient k33 is 85%, and the kt is 72%. The transmittance of the sample polarized along [001] direction can reach 66%. The effective electro‐optical coefficient γc is 60 pm/V at room temperature and can reach 86 pm/V at 70°C. It has a wide operating temperature range and stable performance with frequency variation, which has certain reference significance for application in new electro‐optical devices. [ABSTRACT FROM AUTHOR]

The polarization and strain response of ferroelectric materials at electric fields below the macroscopic coercive field is of paramount importance for the operation of many electronic devices. The response of real ferroelectric and related materials is, in general, complex and difficult to interpret. The reason for this is that many processes in a ferroelectric material contribute to its properties, often concurrently. Examples include the motion of ferroelectric and ferroelastic domains, the presence of domains within domains, the dynamics of different types of polar nano-entities, the interaction of polar nano-entities (e.g., polar nanoregions in relaxors) with the strain and polarization within domains, motion of defects, and rearrangement of defect clusters and their interaction with polarization and strain. One signature of these processes is nonlinearity of the strain and polarization. Most ferroelectrics exhibit nonlinear response at all practical field levels, meaning that the apparent material coefficients depend on the amplitude of the driving excitation. In this paper, we show that an investigation of nonlinear behavior is a sensitive way to study various mechanisms operating in dielectric and piezoelectric materials. We review the basic formalism of the nonlinear description of polarization and strain, give a physical interpretation of different terms, and illustrate this approach on numerous examples of relaxors, relaxor ferroelectrics, hard and soft ferroelectrics, and morphotropic phase boundary compositions. An experimental approach based on a lock-in technique that is well suited for such studies is also discussed. [ABSTRACT FROM AUTHOR]

Through numerical simulations corroborated by an analytical subthreshold model considering drain coupling, this paper systematically investigates the short-channel effects in negative-capacitance FETs with 2D MoS2 channel (2D-NCFET). Our study indicates that, due to the impact of drain coupling on the negative-capacitance effect, the 2D-NCFET exhibits distinct short-channel behaviors such as improved average subthreshold swing and threshold-voltage roll-up with decreasing gate length. In addition, the fringe field through the high-k interlayer dielectric can significantly alter the subthreshold characteristics of the short-channel 2D-NCFET, and hence needs to be carefully taken into account. Our study may provide insights for device design using negative-capacitance FETs. [ABSTRACT FROM AUTHOR]

In this paper, domain switching in ferroelectric ceramics near the morphotropic phase boundary (MPB), where tetragonal phase and rhombohedral phase coexist, is analyzed by a micromechanical model using an inverse-pole-figure (IPF) method. Charge screening effect in ferroelectric ceramics is taken into account, thus the depolarization field by polarization switching vanishes. The mechanical constraint caused by non-180° switching, however, cannot be neglected and is assumed to be proportional to the switching strain caused by non-180° domain switching with a factor β as the measure of the constrained level. Using the IPF method, the domain switching induced polarization and strain can be explicitly obtained via integrations over the unit spherical surface. Two limiting cases are studied in this paper, i.e., the energy barrier for the interphase non-180° domain switching is equal to or much larger than that for the in-phase non-180° switching. In the former case, it is found that domains always tend to switch to the rhombohedral phase especially when the constrained level is high, i.e., at a large value of β. If the mechanical constraint is neglected, i.e., β=0, the maximum achievable polarization and strain can be analytically obtained in this case. While in the latter case, interphase domain switching is suppressed, thus domain switching in MPB ceramics is only a superposition of independent in-phase domain switching in tetragonal ceramics and rhombohedral ceramics. [ABSTRACT FROM AUTHOR]

Detailed analysis of local polarization switching will promote the further development of a wide range of applications using ferroelectrics. Here, we propose a local C – V mapping technique using scanning nonlinear dielectric microscopy (SNDM) that enables visualization of dynamic ferroelectric switching behavior in real space. Using this method, C – V butterfly curves characteristic of ferroelectrics can be measured on a scanning probe microscopy platform with nanoscale resolution by virtue of the high capacitance-detection sensitivity of SNDM. This provides real-space mapping of the net switchable polarization, the switching voltage, and the local imprint with a short measurement time (e.g., 10 min or less for 256 × 256 pixels). Furthermore, the proposed method will be useful for study of the electric-field response of domain walls. In this paper, we present some examples of experiments with LiTaO 3 single crystals and HfO 2 -based ferroelectric thin films and give an overview of what kind of evaluation is possible with the local C – V mapping technique. [ABSTRACT FROM AUTHOR]

In this paper, a 1D nonlinear plasma photonic crystal (NPPC) structure composed of polarized ferroelectric crystals and nonlinear plasma periodic alternation is proposed. The transfer matrix method is employed to analyze the second harmonic generation (SHG) problem of this structure. In the designed NPPCs, the fundamental wave (FW) operates in the gigahertz (GHz) band and the nonlinear plasma is controlled by an external high‐intensity control wave (CW). Numerical simulations are performed to investigate the effects of different incident angles and external CW intensities on the total conversion efficiency (T‐con) of the second harmonic wave (SHW). Additionally, the internal electric field distribution and incident light intensity within the nonlinear structure are analyzed. The importance of the relationship between the FW frequency and photonic band gap (PBG) in enhancing SHG is summarized. The results demonstrate that the optimal structure can be obtained by changing the structural parameters, such that the FW and SHW are tuned to the edge of the PBG. At this point, the electromagnetic field density is large, the group velocity is small, the local field is enhanced, and the nonlinear optical interaction is increased, resulting in a significant increase in the T‐con of the SHW. [ABSTRACT FROM AUTHOR]

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

Nowadays, the demand for advanced functional materials in transducer technology is growing rapidly. Piezoelectric materials transform mechanical variables (displacement or force) into electrical signals (charge or voltage) and vice versa. They are interesting from both fundamental and application points of view. Ferrooelectrets (also called piezoelectrets) are a relatively young group of piezo-, pyro- and ferroelectric materials. They exhibit ferroic behavior phenomenologically undistinguishable from that of traditional ferroelectrics, although the materials per se are essentially non-polar space-charge electrets with artificial macroscopic dipoles (i.e., internally charged cavities). A lot of work has been done on ferroelectrets and their applications up to now. In this paper, we review and discuss mostly the work done at University of Potsdam on the research and development of ferroelectrets. We will, however, also mention important results from other teams, and prospect the challenges and future progress trend of the field of ferroelectret research. [ABSTRACT FROM AUTHOR]

This paper reports the retention behavior for Al0.93B0.07N thin films, a member of the novel family of wurtzite ferroelectrics. Our experiments suggest that bipolar cycling of metal (Pt/W)/Al0.93B0.07N/W/Al2O3 film stacks first induced wake-up and then a region of constant switchable polarization. The films showed excellent retention of the stored polarization state. As expected, data retention was slightly inferior in the opposite state (OS) measurements. However, it is noted that even after 3.6 × 106 s (1000 h) at 200 °C, the OS signal margin still exceeded 200 μC/cm2. The predicted OS retention is 82% after 10 yr baking at 200 °C. [ABSTRACT FROM AUTHOR]

The relaxor ferroelectric single crystal (1−x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT) has high piezoelectric constants, and thus has a good application prospect in the field of highly sensitive piezoelectric sensors. In this paper, for relaxor ferroelectric single crystal PMN-PT, the bulk acoustic wave characteristics on pure- and pseudo-lateral-field-excitation (pure- and pseudo-LFE) modes are investigated. LFE piezoelectric coupling coefficients and acoustic wave phase velocities for PMN-PT crystals in different cuts and electric field directions are calculated. On this basis, the optimal cuts of pure-LFE and pseudo-LFE modes of relaxor ferroelectric single crystal PMN-PT are obtained, namely, (zxt)45° and (zxtl)90°/90°, respectively. Finally, finite element simulations are carried out to verify the cuts of pure-LFE and pseudo-LFE modes. The simulation results show that the PMN-PT acoustic wave devices in pure-LFE mode have good energy-trapping effects. For PMN-PT acoustic wave devices in pseudo-LFE mode, when the device is in air, no obvious energy-trapping emerges; when the water (as a virtual electrode) is added to the surface of the crystal plate, an obvious resonance peak and the energy-trapping effect appears. Therefore, the PMN-PT pure-LFE device is suitable for gas-phase detections. While the PMN-PT pseudo-LFE device is suitable for liquid-phase detections. The above results verify the correctness of the cuts of the two modes. The research results provide an important basis for the development of highly sensitive LFE piezoelectric sensors based on relaxor ferroelectric single crystal PMN-PT. [ABSTRACT FROM AUTHOR]

In this paper, the effect of negative-capacitance (NC) on germanium FinFET (GeFinFET) with the presence of fixed trap charges (${N}_{\text {ftc}}$) has been studied. The analysis of various parameters of NCGeFinFET has shown that the positive trap charges improve the device characteristics whereas the negative trap charges (NTC) degrade the performance of devices. Therefore, we have optimized properties of ferroelectric (FE) to suppress the degradation caused by NTC. Furthermore, the impact of ${N}_{\text {ftc}}$ has been studied on the output characteristics of NCGeFinFET inverter, and it has been shown that the degradation due to NTC reduces by optimizing the FE properties. It has also been demonstrated that NCGeFinFET exhibits excellently improved characteristics as compared to GeFinFET. [ABSTRACT FROM AUTHOR]

In this paper, we reported a ferroelectric HfAlOx negative capacitor transistor with gate-stress (GS) engineering. Compared to control device, the HfAlOx transistor with GS engineering percentage of $\text{I}_{ \mathrm{\scriptscriptstyle ON}}$ enhancement and 27% $\text{V}_{T}$ reduction under the assistance of the negative capacitance (NC) effect. The orthorhombic phase transition played a crucial role in realizing the NC effect. From the results of the material analysis, the theoretical Landau simulation and electrical measurement, we demonstrated that the GS is favorable for inducing orthorhombic phase crystallization of HfAlOx and stabilizing the NC effect, which shows the potential for the application of advanced technology node. [ABSTRACT FROM AUTHOR]

Proton-transfer type molecular ferroelectrics hold significant promise for practical application due to their large spontaneous polarizations, high Curie temperatures, and small switching fields. However, it remains puzzling that preparation of quasi-2D films exhibiting macroscopic ferroelectric behaviors has been reported in only few molecular ferroelectrics. To address this puzzle, we studied the impact of microstructures on the macroscopic ferroelectric properties of 5,6-dichloro-2-methylbenzimidazole (DC-MBI) films grown using the low-temperature deposition followed by the restrained crystallization (LDRC) method. Our findings revealed a competition between dense spherulites and porous microstructures containing randomly oriented nanograins in the as-grown films. Post-growth annealing at moderate temperature promotes the formation of spherulites, leading to macroscopic ferroelectric polarization switching. These results underscore the critical role of microstructure density in determining macroscopic ferroelectric properties, potentially resolving the puzzle for the absence of such behavior in many molecular ferroelectric films. We anticipate that the approach proposed in this study to enhance microstructure density will significantly advance the fabrication of quasi-2D molecular ferroelectric films and unlock their potential in device applications. [ABSTRACT FROM AUTHOR]

In the era of information, emerging hardware security primitives, i.e., hardware random number generators and physically unclonable functions, hold profound promise for the establishment of exceptionally secure network information systems. Nonetheless, these potential solutions are constrained by inherent drawbacks, including the need for additional error correction circuits or algorithms, heightened susceptibility to environmental interference, and limited data density. This paper demonstrates the extremely high‐density, physical‐unclonable cryptographic keys by harnessing stochastically ferroelectric domain polarizations in Aurivillius ferroelectric material CaBi2Nb2O9 (CBNO). Ferroelectric polarization of CBNO nanodomains can serve as a robust source of physical unclonable entropy. Through the application of high‐speed voltage pulses, the inherent randomness of ferroelectric polarizations can be enhanced, thereby yielding cryptographic keys characterized by remarkable uniformity, uniqueness, and negligible environmental sensitivity. More importantly, the voltage pulse operations facilitate the configurability of the ferroelectric cryptographic keys with no correlation. An unprecedented data density of 435 Gbit µm−2 is therefore achievable with a miniaturized CBNO of less than 1 um2. Notably, the reconfigured keys successfully pass the National Institute of Standards and Technology random number tests without requiring additional post‐processing steps. Emanating from the inherent attributes of the material, these high‐density ferroelectric keys confer intrinsic advantages to information security, evincing substantial resistance to duplication or cloning. [ABSTRACT FROM AUTHOR]

In recent years, relaxor ferroelectric single crystals have attracted people's attention and research because of their excellent piezoelectric properties at morphotropic phase boundary(MPB). The ternary system Pb(In1/2Nb1/2)O 3 -Pb(Mg1/3Nb2/3)O 3 -PbTiO 3 (PIN-PMN-PT) crystals have higher Curie temperature and coercive field, which have the opportunity to be applied in high-temperature devices. The crystals of the rhombohedral phase have better stability, but their performance is not as good as that of the MPB component crystals. In this paper, the piezoelectric properties of rhombohedral PIN-PMN-28PT single crystals are improved by Sm3+ doping. The piezoelectric coefficient d 33 after AC polarization along [001] direction can reach 3125pC/N, which is 60% higher than that of undoped crystals. Meanwhile, the crystal exhibits excellent optical performance after DC polarization along [110] direction. The crystal has an effective electro-optic coefficient of 386 pm/V at room temperature and a stable frequency-dependent characteristic, which is expected to be an ideal material for electro-optic devices. [ABSTRACT FROM AUTHOR]

This paper investigates the self-pulsing of dielectric barrier discharges (DBDs) at low driving frequencies. In particular, (a) the dependence of current on the product pd of gas pressure p and the gas gap length d, (b) the effects of lossy dielectrics (in resistive discharges) and large dielectric permittivity (in ferroelectrics) on current dynamics, (c) the transition from Townsend to a dynamic capacitively coupled plasma (CCP) discharge with changing pd values, and (d) the transition from Townsend to a high-frequency CCP regime with increasing the driving frequency. A one-dimensional fluid model of argon plasma is coupled to an equivalent RC circuit for lossy dielectrics. Our results show multiple current pulses per AC period in Townsend and CCP discharge modes which are explained by uncoupled electron–ion transport in the absence of quasineutrality and surface charge deposition at dielectric interfaces. The number of current pulses decreases with an increasing applied frequency when the Townsend discharge transforms into the CCP discharge. The resistive barrier discharge with lossy dielectrics exhibits Townsend and glow modes for the same pd value (7.6 Torr cm) for higher and lower resistances, respectively. Finally, we show that ferroelectric materials can amplify discharge current in DBDs. Similarities between current pulsing in DBD, Trichel pulses in corona discharges, and subnormal oscillations in DC discharges are discussed. [ABSTRACT FROM AUTHOR]

Bulk or anomalous photovoltaic effect in ferroelectrics has recently sparked interest due to the generation of switchable photovoltages that are not limited by the bandgap of the material. The development of strategies to tune its magnitude is a key for the development of light-driven devices, e.g., photostrictive actuators, photostrictive sensors, or reconfigurable waveguides. In this paper, the bulk photovoltaic effect of polycrystalline solution-deposited bismuth ferrite thin films is studied under different stress conditions induced by different substrates and quantified using a direct strain assessment via x-ray diffraction. An increase in the short-circuit bulk photovoltaic current of 150% is observed with a change from a compressive stress of 0.54 GPa to a tensile stress of 0.93 GPa. This change is attributed to intrinsic piezophotovoltaic effect, demonstrating the potential to strain engineer the bulk photovoltaic effect in thin films. [ABSTRACT FROM AUTHOR]

This contribution focuses on two effects causing a temperature change in electrically loaded ferroelectrics. These materials are often subjected to cyclic loading, where viscoelasticity prevails at lower electric fields, whereas dissipative heating by domain switching dominates above the coercive field. While viscoelasticity is modeled within a phenomenological, rheological framework, the ferroelectric constitutive behaviour is described based on a microphysical model. Merging both approaches results in the hybrid model presented in this paper. [ABSTRACT FROM AUTHOR]

The novel single component molecular ferroelectric single crystal of 1,3,5-trimethylnitrobenzene (TMNB) has been investigated in terms of its temperature dependent polar properties. Three phases have been found in the solid state of TMNB: phase I above 161 K, phase II (incommensurate) between 161 and 152 K and phase III below 152 K. The TMNB crystal structures were determined at 100 K (phase III, sp. gr. Pca21) and at 250 K (phase I, sp. gr. Pnma). Ferroelectricity of phase III along the c-axis has been confirmed by the pyroelectric measurements and observations of the hysteresis loops, revealing spontaneous polarization as small as ∼2 × 10−6 C m−2. The crystal is the first example of an origin of spontaneous polarization related to flexibility of the C–H⋯π hydrogen bonds (molecular joints). The TMNB molecules in the dimer can change the mutual orientation of the dipole moments without breaking the C–H⋯π bonds. In this paper, the mechanism of the phase transitions will be discussed, which is governed by the dynamics of the NO2 groups and the flexibility of the C–H⋯π dimer. [ABSTRACT FROM AUTHOR]

In this paper, we studied some ferroelectric properties of archetypal oxide uniaxial ferroelectric single crystals of Pb5Ge3O11 modified by Ba ions. They include dielectric, DSC, ferroelectric polarization, and electrocaloric effect (ECE) measurements. The measurements show that increasing Ba doping considerably influences all the measured parameters, mainly by lowering the Curie temperature, gradually diffusing the phase transition, and decreasing values of polarization as well as the coercive field. The decrease in overall ECE is influenced by decreasing polarization. Compared with the pure PGO single crystals, this decrease is from 1.2 K to 0.2 K. However, the effect of diffusing the phase transition increases the range of its occurrence (up to 30 K), which might be beneficial in applications. [ABSTRACT FROM AUTHOR]

Lead free relaxor ferroelectrics have attracted continuing interest due to their outstanding and eco-friendly properties. In this paper, dielectric relaxation behavior of the 0.6BaTiO3-0.4Bi(Mg1/2Ti1/2)O3 ceramic (BT-40BMT), which is a typical lead free relaxor ferroelectric, is theoretically and experimentally investigated. At first, the observed dielectric relaxation was quantitatively characterized by a statistical model, indicating that the minority co-related polar nano regions (PNRs) dominate the total polarization. Kinetics of the PNRs were subsequently studied by micro-Raman measurements performed at various temperatures. Here, the relaxation of written domains formed by the piezoresponse force microscopy (PFM) tip-bias induced electric field was also studied, which describes the polarization retention performance of BT-40BMT. The absence of ferroelectric signal contribution in local switching was also confirmed by the contact mode Kelvin PFM technique, indicating the lack of local ferroelectricity. Moreover, the temperature insensitive energy storage property from 293K to 443K was obtained. High voltage pulsed discharge behavior was also investigated by using the pulsed current. A power density of 7.9 x 108W/kg is obtained under a pulsed voltage of 50 kV. Combined with the fast discharge time, the 0.6BaTiO3-0.4Bi(Mg1/2Ti1/2)O3 ceramic is considered as a candidate material for high voltage pulse power applications. [ABSTRACT FROM AUTHOR]

One-dimensional ferroelectric photonic crystals have been produced by filling porous anodic aluminum oxide with sodium nitrite. Introducing sodium nitrite into the pores of the photonic crystals has been shown to cause a 40-nm bathochromic shift in the spectral position of their bandgap. The results of this study demonstrate the feasibility of using aluminum oxide-based composite photonic crystals as narrow-band selective mirrors. [ABSTRACT FROM AUTHOR]

Thermosensitive strontium titanate (SrTiO3) as a ferroelectric crystal with great tunability in microwave and terahertz band shows unparalleled potential value. Utilizing the thermal electromagnetic tunability to achieve the intelligent manipulation, a thermal-tunable metamaterial with terahertz-band absorption based on SrTO3 crystal was proposed in this paper. The absorbent metamaterial (AM) is formed by Floquet's linear periodic arranged unit, which is composed of a metallic ground plane and embedded cross SrTO3 material in rhombic metallic patch, and separated by FR-4 dielectric spacer. The broadband frequency tunability of AM was operated by changing the temperature. The permittivity of SrTO3 was discussed in detail to illustrate how the reconfigurability with thermal transformation is generated. The numerical results show that the tunable broadband of the absorbent band has reached 90 GHz and the corresponding absorptivity is above 99% when the temperature increases from 280 K to 360 K. The resonance frequency will produce a blue-shirt with the increase of the temperature. This paper presents a passive thermal-tunable metamaterial as a potential candidate for sensing, materials detection and frequency selective thermal emitters. [ABSTRACT FROM AUTHOR]