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The nanocomposites consisting of graphene oxide (GO) and ferroelectric copolymer poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] have been successfully synthesized by a co-evaporation method. The structural, dielectric and ferroelectric properties of the composite papers are investigated. The Raman spectroscopy analyses on the nanocomposites GO/P(VDF-TrFE) reveal that the defects in GOs are reduced significantly by the loading of ferroelectric P(VDF-TrFE). The IG/ID ratio increases from 1.02 (for pure GO) to 1.17 [for GO/P(VDF-TrFE)-10%], revealing that the defects are reduced by the introduction of the nano-fillers due to a strong interaction between GO and P(VDF-TrFE) in the nanocomposites. The permittivity of the nanocomposites is enhanced by almost 3-times as compared to that of the pristine GOs. The nanocomposites show a notably raised polarization with high applied electric field. Furthermore, due to the high dielectric constants, the electrical energy storage density of the nanocomposites is as high as ~ 39.89 J cm−3 at 2.8 MV cm−1. The large energy density and high dielectric break down strength suggest that GO/P(VDF-TrFE) could be the promising novel materials for electrical energy storage. [ABSTRACT FROM AUTHOR]

Continuous carbon fiber polymer-matrix composites in unprecedented antiferroelectric coupling, as enabled by stacking composites with positive value (up to 400) and negative value (down to −600) of the electric permittivity, provide exceptionally high through-thickness permittivity up to 78,000 (≤2.0 MHz), corresponding to a capacitance of 370 μF/m. The high capacitance is consistent with the equation for negative and positive capacitors in series. The permittivity tailoring of the composites involves dielectric cellulosic tissue paper interlaminar interlayers. Negative permittivity (not previously reported for carbon fiber composites) requires the paper to be wet with tap water (resistivity 1.5 kΩ cm) during incorporation in the composite, though the water evaporates and leaves ions at very low concentrations during composite fabrication, and also requires optimum through-thickness resistivity (e.g., 1 kΩ cm, as given by paper thickness 35 μm); it is probably due to interactions between the functional groups on the carbon fiber surface and the residual ions (mainly chloride) left after tap water evaporation. [ABSTRACT FROM AUTHOR]

This article is in response to the comments raised on our paper “Remarkable enhancement in dielectric, piezoelectric, ferroelectric and SHG properties by iron doping in sodium para-nitrophenolate dihydrate single crystal” published in Materials Letters (Dalal and Kumar, 2016 [1]). In the ferroelectric studies, we performed PUND studies to establish that an unsaturated P-E loop may also contain intrinsic ferroelectric polarization. In dielectric studies, it has been shown that the variation did follow Curie-Wiess law confirming the transition to be related to ferroelectric to paraelectric phase. In respect of the comment on piezoelectric enhancement, it has been shown that the achieved enhancement in d 33 -value due to Fe-doping is well within the possible change in piezo-response by doping in different types of systems. [ABSTRACT FROM AUTHOR]

In spite of the flexoelectric effect being a universal phenomenon in the ferroelectric perovskites, the current understanding of flexoelectric aging in ferroelectrics is, actually, rather incomplete. In this paper, we have fabricated a series of Mn-doped BaTiO3 perovskite ceramics (BaTi1–xMnxO3, x = 0.1% and 1%, BTMO) to systematically investigate the corresponding flexoelectric aging behavior by controlling the concentration of Mn. We found that the variation of Mn dopant significantly effects the Curie temperature, dielectric constant, flexoelectric aging, and flexoelectric coefficient of the BTMO ceramics. Especially for the BTMO (0.1%) ceramics, obvious ferroelectric aging and flexoelectric aging phenomenon are observed at room temperature. The main reason for aging of BTMO ceramics is that the doping of Mn introduces oxygen vacancies, which tend to be stable under the action of strain gradient and electric field. Therefore, the results presented in this paper verify that the flexoelectric aging in Mn-doped BTO ceramics is closely related to ferroelectric fatigue. [ABSTRACT FROM AUTHOR]

In this paper, the optical and static permittivities of CaCu3Ti4O12 supercells are calculated based on the Skanavi model by decomposing the electric field of molecules into the electric field of ions. The results show that the Skanavi model's theoretical predictions are significantly more accurate than those of the Clausius–Mossotti equation and Born model and are in good agreement with the experimental data. In addition, the absence of ferroelectricity in CaCu3Ti4O12 is also revealed by investigating the changes in the structural coefficients of the effective electric field caused by the displacement of Ti4+ along the z-axis. Finally, by analyzing the contribution of TiO6 octahedra or CuO4 planar squares to the static permittivity, the main polarization unit in the structure of CaCu3Ti4O12 has been discovered. This study not only makes up for the insufficient research on the polarization mechanism of CaCu3Ti4O12 but also provides a new tool to explore the polarization mechanism of other materials. [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]

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

This paper presents the experimental evidence of reversible insulator–metal transition (IMT) in thin-film amorphous molybdenum trioxide (MoO3) induced by electric fields of just a few volts. The presence of oxygen vacancies in MoO3 is considered to play a significant role in the reported reversible IMT. The oxygen vacancies not only impact MoO3 stoichiometry but also the optical bandgap. The subthreshold slope for IMT in 10 nm-thick MoO3-based devices is 48.3 mV/decade, which represents a transition from an insulator to a metallic state, and the electric field threshold for such a transition was found to be equal to 0.034 V/Å. Following the IMT in MoO3, there are six orders of magnitude differences between the resistivity of the insulator state (27.5 M Ω at −9 V) and the metallic state (80 Ω between +5 and +9 V). In addition, we reported stabilization of a nanocrystalline hexagonal MoO3 (h-MoO3) phase in thicker MoO3 (150 nm-thick) in the presence of oxygen vacancies that behave as a wide bandgap (3.1 eV) ferroelectric semiconductor with a coercive field of about 50 kV/cm, a saturation polarization of about 30 μC/cm2, and a remanent polarization of about 10 μC/cm2. This ferroelectricity in nanocrystalline h-MoO3 (150 nm-thick) remains stable even after 8 months of storage of the sample in ambient conditions, with remanent polarization increasing up to 20 μC/cm2. These are unexpected results from MoO3. [ABSTRACT FROM AUTHOR]

In this paper, the field-induced residual ferroelectricity in antiferroelectric lead zirconate thin films has been studied by impedance measurements together with a hyperbolic law analysis, which permits us to extract the different contributions to the material's complex permittivity. By measuring the Rayleigh coefficient α r , it appears that the residual ferroelectricity is considerably enhanced when the sample has been previously exposed to an electric field close to the antiferroelectric to ferroelectric transition field. This indicates that a part of the material remains ferroelectric after the antiferroelectric–ferroelectric backward transition, which constitutes an additional contribution to polarization. Consequently, a higher domain wall density and mobility can be observed. Measurements after exposition to thermal treatment show that this ferroelectric response is metastable. [ABSTRACT FROM AUTHOR]

Ferroelectric HfO2 has attracted much attention owing to its superior ferroelectricity at an ultra-thin thickness and good compatibility with Si-based complementary metal–oxide–semiconductor (CMOS) technology. However, the crystallization of polar orthorhombic phase (o-phase) HfO2 is less competitive, which greatly limits the ferroelectricity of the as-obtained ferroelectric HfO2 thin films. Fortunately, the crystallization of o-phase HfO2 can be thermodynamically modulated via interfacial stress engineering. In this paper, the growth of improved ferroelectric Al doped HfO2 (HfO2:Al) thin films on (111)-oriented Si substrate has been reported. Structural analysis has suggested that nonpolar monoclinic HfO2:Al grown on (111)-oriented Si substrate suffered from a strong compressive strain, which promoted the crystallization of (111)-oriented o-phase HfO2 in the as-grown HfO2:Al thin films. In addition, the in-plane lattice of (111)-oriented Si substrate matches well with that of (111)-oriented o-phase HfO2, which further thermally stabilizes the o-phase HfO2. Accordingly, an improved ferroelectricity with a remnant polarization (2 P r) of 26.7 μC/cm2 has been obtained. The results shown in this work provide a simple way toward the preparation of improved ferroelectric HfO2 thin films. [ABSTRACT FROM AUTHOR]

Viscosity, elasticity, and viscoelastic properties are one of the most fundamental properties of liquid crystalline materials; the main problem in determining these properties is the multitude of physical parameters needed to determine the values of elasticity and viscosity constants. In this paper, a number of different measurement methods for the complete characterization of viscoelastic properties for smectic liquid crystalline materials and their mixtures are analyzed, both theoretically and experimentally. The way in which viscoelastic material constants are determined depends mainly on the application/purpose of the materials under study. The subject of this work was to review the methods used to determine viscoelastic effects in ferroelectric and antiferroelectric chiral liquid crystals, their mixtures, composite materials, and even in dielectric systems, which would bear the hallmark of a universal method allowing the application of sufficiently low electric fields. In the case of chiral liquid crystals with ferroelectric and antiferroelectric phases and their subphases, the following assumption applies: fulfilment of Hooke's law (in the case of elastic coefficients) and preservation of laminar flow (in the case of viscosity coefficients). [ABSTRACT FROM AUTHOR]

The ever-increasing demand for high-speed data transmission in telecommunications and data centers has driven the development of advanced on-chip integrated electro-optic modulators. Silicon modulators, constrained by the relatively weak carrier dispersion effect, face challenges in meeting the stringent requirements of next-generation photonic integrated circuits. Consequently, there has been a growing interest in Pockels effect-based electro-optic modulators, leveraging ferroelectric materials like LiNbO3, BaTiO3, PZT, and LaTiO3. Attributed to the large first-order electro-optic coefficient, researchers have delved into developing modulators with expansive bandwidth, low power consumption, compact size, and linear response. This paper reviews the working principles, fabrication techniques, integration schemes, and recent highlights in Pockels effect-based modulators. [ABSTRACT FROM AUTHOR]

Ferroelectric photovoltaic (PV) materials have garnered considerable interest because of their distinctive switchable PV characteristics. Nevertheless, their ability to function within a wide range of ambient temperatures was previously constrained. This paper describes the construction of ferroelectric capacitors featuring an Au/PZT (Pb(Zr 0. 40 Ti 0.60)O 3)/FTO (SnO 2 :F) heterojunction through the utilization of the sol-gel technique. The performance analysis findings indicate that the PZT material, following optimization of annealing temperature, displayed strong ferroelectric properties and notable frequency-dependent dielectric behavior. An increase in temperature (25°C∼300°C) revealed that short-circuit current density J sc exhibited an upward → downward → upward trend and reached 399.6 μA/cm2 at 300°C. Energy band analysis showed the presence of spontaneous polarization and a large work function difference between the bottom electrode FTO and the top electrode Au (∼0.42 eV) created a strong built-in electric field in the PZT films, which was conducive to the photogenerated carriers' separation and greatly improved the PZT film ferroelectric PV. In this paper, transparent ferroelectric materials were demonstrated for the first time to exhibit a photoelectric responsivity of up to 1.77 mA/W at a temperature of 300°C, offering a practical strategy for the implementation of transparent ferroelectric photovoltaic devices in high-temperature environments, particularly those subjected to intense solar energy harvesting and conversion. [ABSTRACT FROM AUTHOR]

This paper investigates In 0. 7 Ga 0. 3 As/Ga 0. 5 As 0. 5 Sb-based Heterojunction Tunnel Field Effect Transistor with ferroelectric dielectric as stack layer, namely Ferroelectric Dual Material Stacked Double Gate Heterojunction TFET (FDMSDG-HJTFET) for the first time for performance and reliability. Ferroelectric gate dielectric has been inculcated in the device design in addition to the doping of Ga 0. 5 As 0. 5 Sb in the source region and In 0. 7 Ga 0. 3 As in the drain region, respectively. The performance of the proposed device is quantified in terms of DC electrical parameters and short channel parameters. The reliability analysis of the proposed device has been carried out in terms of influence of variations of interface trap charges, gate-source overlap length and temperature on the device transfer characteristics. From the simulation results, it can be manifested that the proposed device presents superior DC electrical characteristic and reduced short channel effects as compared to the GaSb/Si Dual Material Stacked Double Gate Heterojunction TFET (GaSb/Si DMSDG-HJTFET), under the influence of group III–V materials and ferroelectric gate dielectric. In addition to this, the proposed device depicts elevated immunity to presence of interface trap charges at the interface, variations in gate-source overlap length and temperature variations as well. The implication of TiO2 as dielectric stack over SiO2 provides exceptional capacitive coupling at the interface and thus assists in the improvement of electrical characteristics of the device by enhancing the electric field. The outcome of the simulation results presents that Ga 0. 5 As 0. 5 Sb/In 0. 7 Ga 0. 3 As-based Ferroelectric Dual Material Stacked Double Gate Heterojunction TFET (FDMSDG-HJTFET) can prove to be a competitive alternative for high performance applications with improved reliability. The design and simulation of the proposed device structure has been executed using technology computer-aided design (TCAD) tool. [ABSTRACT FROM AUTHOR]

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]

The purpose of this paper is to study the intrinsic mechanical contributions of poled piezoelectric ceramics under the three ferroelectric phases [tetragonal (4 mm), rhombohedral (3 m) and orthorhombic (mm2)]. The intrinsic elastic coefficients and spontaneous strains of saturated and unsaturated poling piezoelectric ceramics are analyzed and calculated by probability density functions of orientation (PDFOs) and Reuss or Voigt average, and the analytical results of the intrinsic mechanical properties of piezoelectric ceramics with the poling degree are obtained. In addition, this paper also calculates the Young's modulus and shear modulus of barium titanate (BaTiO3) piezoelectric ceramics by PDFO which are based on the Reuss, Voigt and Hill averages. Comparing them with the published theoretical calculation data shows that the results calculated by the finite element method under the saturated and unsaturated poling states are within the range of the results calculated by us using the three average theories through PDFO, and it shows the accuracy of calculation by PDFO. [ABSTRACT FROM AUTHOR]

Ferroelectricity in biological system has been anticipated both theoretically and experimentally over the past few decades. Claims of ferroelectricity in biological systems have given rise to confusion and methodological controversy. Over the years, a "loop" of induced polarization in response to a varying applied electrical field and a consequent polarization reversal has prompted many researchers to claim ferroelectricity in biological structures and their building blocks. Other observers were skeptical about the methodology adopted in generating the data and questioned the validity of the claimed ferroelectricity as such, "loop" can also be obtained from linear capacitors. In a paper with somewhat tongue-in-cheek title, Jim Scott showed that ordinary banana peels could exhibit closed loops of electrical charge which closely resemble and thus could be misinterpreted as ferroelectric hysteresis loops in barium sodium niobate, BNN paraphrasing it as "banana". In this paper, we critically review ferroelectricity in biological system and argue that knowing the molecular and crystalline structure of biological building blocks and experimenting on such building blocks may be the way forward in revealing the "true" nature of ferroelectricity in biological systems. [ABSTRACT FROM AUTHOR]

Ferroelectricity in hafnium zirconium oxide (Hf1 − xZrxO2) and the factors that impact it have been a popular research topic since its discovery in 2011. Although the general trends are known, the interactions between fabrication parameters and their effect on the ferroelectricity of Hf1 − xZrxO2 require further investigation. In this paper, we present a statistical study and a model that relates Zr concentration (x), film thickness (tf), and annealing temperature (Ta) with the remanent polarization (Pr) in tungsten (W)-capped Hf1 − xZrxO2. This work involved the fabrication and characterization of 36 samples containing multiple sets of metal-ferroelectric-metal capacitors while varying x (0.26, 0.48, and 0.57), tf (10 and 19 nm), and Ta (300, 400, 500, and 600 ° C). In addition to the well-understood effects of x and Ta on the ferroelectricity of Hf1 − xZrxO2, the statistical analysis showed that thicker Hf1 − xZrxO2 films or films with higher x require lower Ta to crystallize and demonstrated that there is no statistical difference between samples annealed to 500 and 600 ° C, thus suggesting that most films fully crystallize with Ta ∼ 500 ° C for 60 s. Our model explains 95% of the variability in the Pr data for the films fabricated, presents the estimates of the phase composition of the film, and provides a starting point for selecting fabrication parameters when a specific Pr is desired. [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]

Obituary for Sidney C. Abrahams [ABSTRACT FROM AUTHOR]

This paper reports the onset of ferroelectricity in NiO by breaking the crystallographic symmetry with oxygen vacancies created by N doping. Nitrogen-doped NiO was grown at room temperature by RF sputtering of Ni target in Ar–O2–N2 plasma on silicon and fused silica substrates. The impact of the nitrogen doping of NiO on microstructural, optical, and electrical properties has been investigated. According to x-ray diffraction investigations, by increasing the N doping level in NiO, a transition from (002) to a (111) preferential orientation for the cubic NiO phase was observed, as well as a lattice strain relaxation, that is usually ascribed to structural defect formation in crystal. The x-ray diffraction pole figures the presence of a distorted cubic structure in NiO and supports the Rietveld refinement findings related to the strain, which pointed out that nitrogen doping fosters lattice imperfections formation. These findings were found to be in agreement with our far-infrared measurements that revealed that upon nitrogen doping a structural distortion of the NiO cubic phase appears. X-ray photoemission spectroscopy measurements reveal the presence of oxygen vacancies in the NiO film following nitrogen doping. Evidence of ferroelectricity in nitrogen-doped NiO thin films has been provided by using the well-established Sawyer–Tower method. The results reported here provide the first insights on oxygen-vacancy induced ferroelectricity in nitrogen-doped nickel oxide thin films. [ABSTRACT FROM AUTHOR]

Ferroelectricity and magnetism seldom coexist due to mutual exclusiveness. Recent attempts have been made to achieve the coexistence of ferroelectricity and magnetism in polar magnets. In this paper, we investigated the magnetic properties, dielectric relaxation, and magnetodielectric (MD) effect of polar Dy2Cu2O5 ceramic. At the antiferromagnetic ordering temperature, the dielectric constant (ɛ) curves exhibit a spontaneous change in slope, indicating strongly coupled charge and spin degrees of freedom. With increase in the magnetic field intensity, the simultaneous suppression of the dielectric anomaly and the antiferromagnetic transformation demonstrates the existence of the MD effect. It is important to note that ɛ varies nonmonotonically with the magnetic field. Below the magnetic ordering temperature, ɛ increases continuously before the metamagnetic transition and then decreases after that. The results are discussed in terms of the magnetic field-induced change of spin configuration and spin–phonon coupling. Moreover, two dielectric relaxation-related steps are observed, which are correlated with the electrons hopping within and among the zigzag chains of Cu2+, respectively. This work helps understand the dielectric behavior and the MD effect in materials with complicated spin structures. [ABSTRACT FROM AUTHOR]

This review reports the latest trends in the ceramic composite matrix used for the magnetoelectric (ME) effect. In the last few years, ME composite has become the center of attraction for use in various electrically and magnetically coupled devices. The growth and use of electronic components everywhere have propulsively accelerated the exploration of self-powered electronic and sensor network devices. ME is a feasible technique for addressing difficulties of traditional batteries such as short life span and frequent recharge difficulties. Self-charging multiferroic components have been found for the constant working of mobile electronics that use multiferroic composites in response to magnetoelectric energy transformation. Researchers have rigorously studied the rigid and flexible magnetoelectric composites for their suitability in applications. This paper gives a comparative study between rigid and flexible magnetoelectric composites based on their properties and provides knowledge about the materials for such types of composites. It reviews the latest polymer-based ME materials as well as the related fabrication and polarization methods. The review finally encapsulates the applications in biomedicine, ranging from mechanical energy harvesters to sensors and actuators. [ABSTRACT FROM AUTHOR]

Pyroelectric materials are naturally electrically polarized and exhibits a built-in spontaneous polarization in their unit cell structure even in the absence of any externally applied electric field. These materials are regarded as one of the ideal detector elements for infrared applications because they have a fast response time and uniform sensitivity at room temperature across all wavelengths. Crystals of the perovskite lead titanate (PbTi O 3 ) family show pyroelectric characteristics and undergo structural phase transitions. They have a high Curie temperature (the temperature at which the material changes from the ferroelectric (polar) to the paraelectric (nonpolar) phase), high pyroelectric coefficient, high spontaneous polarization, low dielectric constant, and constitute important component materials not only useful for infrared detection, but also with vast applications in electronic, optic, and MEMS devices. However, the preparation of large perfect and pure single crystals PbTi O 3 is challenging. Additionally, difficulties arise in the application of such bulk crystals in terms of connection to processing circuits, large size, and high voltages required for their operation. In this part of the review paper, we explain the electrical behavior and characterization techniques commonly utilized to unravel the pyroelectric properties of lead titanate and its derivatives. Further, it explains how the material preparation techniques affect the electrical characteristics of resulting thin films. It also provides an in-depth discussion of the measurement of pyroelectric coefficients using different techniques. [ABSTRACT FROM AUTHOR]

An intrinsically switchable and frequency reconfigurable bulk acoustic wave filter bank based on ferroelectric barium strontium titanate (BST) is presented. Ferroelectric BST possesses electric-field-induced piezoelectricity, enabling the design of voltage-controlled acoustic devices, including thin-film bulk acoustic resonators and solidly mounted resonators. In this paper, a triple-band switchable filter bank, consisting of three 2.5-stage filters based on BST FBARs, is designed, simulated, and fabricated for the first time. The bandpass filters have center frequencies at 1.85, 1.96, and 2.04 GHz and are selectively turned on based upon the external dc bias voltage applied to each filter. Turning off all the filters provide an isolation of more than 27 dB between the input and output ports. The presented intrinsically switchable ferroelectric filter bank potentially simplifies future radio frequency front ends by integrating both switching and filtering functionalities onto a single device and reduces the overall circuit area. [ABSTRACT FROM AUTHOR]

The function of conductive particles on the insulator for a simple case is analyzed in this paper. In a certain insulator containing conductive particles, the electric dipoles in the conductive particles are induced by the external electric field, and the polarization orientation is along the direction of electric field. Macroscopically, the insulator containing conductive particles can be equivalent to a high-permittivity (εeff) insulator. Meanwhile, the maximum electric field (Emax) in the insulator containing conductive particles is enhanced. The εeff and Emax are determined not only by the geometric shape, size, and the packing modes of conductive particles. This paper presents several packing modes of conductive particles in the insulator. Simulation results indicate that when cubic conductive particles with side length 2R are stacked in the form of cubic close packing, the εeff and the Emax of the insulator containing conductive particles at R/d = 0.495 (d is the distance between the centers of the mass of closet conductive particles) are increased to 67.1 times and 97.5 times, respectively, compared with the insulator without conductive particles inside. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials are considered attractive semiconducting layers for emerging field-effect transistors owing to their unique electronic and optoelectronic properties. Polymers have been utilized in combination with 2D semiconductors as gate dielectric layers in field-effect transistors (FETs). Despite their distinctive advantages, the applicability of polymer gate dielectric materials for 2D semiconductor FETs has rarely been discussed in a comprehensive manner. Therefore, this paper reviews recent progress relating to 2D semiconductor FETs based on a wide range of polymeric gate dielectric materials, including (1) solution-based polymer dielectrics, (2) vacuum-deposited polymer dielectrics, (3) ferroelectric polymers, and (4) ion gels. Exploiting appropriate materials and corresponding processes, polymer gate dielectrics have enhanced the performance of 2D semiconductor FETs and enabled the development of versatile device structures in energy-efficient ways. Furthermore, FET-based functional electronic devices, such as flash memory devices, photodetectors, ferroelectric memory devices, and flexible electronics, are highlighted in this review. This paper also outlines challenges and opportunities in order to help develop high-performance FETs based on 2D semiconductors and polymer gate dielectrics and realize their practical applications. [ABSTRACT FROM AUTHOR]

DaltonTransactions An international journal of inorganic chemistry rsc. li/ dalton Volume 53 Number 45 7 December 2024 Pages 18057- 18386 ISSN 1477- 9226 PAPER Minoru Osada et al. Ferroelectricity in CsPb 2 Nb 3 O 10 and exfoliated 2D nanosheets [Extracted from the article]

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]

In this paper, the calcium-doped nickel-zinc nano-ferrites [Ni 0.5 Zn 0.5 Ca x Fe 2-x O 4 ; x = 0.00, 0.10, and 0.30] were prepared using the chemical co-precipitation synthesis route and studied for switching field high-frequency device applications. The structural analysis has been completed by analyzing X-ray diffraction (XRD) patterns. The Rietveld refined XRD patterns confirmed the formation of cubic spinel structure of Ca2+ substituted nickel-zinc ferrites. The detection of metal-oxygen bonds present at A and B lattice sites has been unveiled by Fourier transform infrared (FTIR) spectroscopy. The morphological studies obtained through FESEM (Field emission scanning electron microscopy) analysis showed a reduction in the particle size from 70 nm to 53 nm when the concentration of Ca2+ ions in Ni-Zn ferrites was increased. Energy dispersive spectra (EDS) confirmed the presence of elements present in the prepared composition. The structure of a cubic spinel-shaped unit cell has been verified from three active prominent Raman modes (A 1g , A 2g , and T 2g). Diffuse-reflectance spectroscopy (DRS) exhibits the increment in the bandgap values (from 1.55 eV to 1.63 eV) which helps fabricate highly efficient photovoltaic devices. The ferroelectric measurements yielded a rise in polarization values from 1.461 μC/cm2 to 18.228 μC/cm2 for 10 % Ca2+ ion substitution. The tangent loss values declined from 24 to 3 in Ni-Zn ferrites upon substituting Ca2+ ions. The Vibrating sample Magnetometer (VSM) technique found the increment in the saturation magnetization (M s) values from 34.724 emu/g to 54.662 emu/g on substituting up to 30 % Ca2+ ions in Ni-Zn ferrites. These obtained results support the material in switching field distribution for high-frequency applications. The results exhibited that the prepared samples can be applicable for switching devices, filters, and microwave absorption devices. The results revealed the maximum frequency between 12 and 18 GHz which is useful for Ku band absorption. [ABSTRACT FROM AUTHOR]

With lots of interest in negative capacitance field-effect transistors for ultralow-power complementary metal-oxide-semiconductor technology, negative capacitance thin-film transistors (NCTFTs) have also received much attention. Although previous studies on NCTFTs were done, the NC effect in organic-based TFTs was not studied yet. In this paper, P(VDF-TrFE) ferroelectric-gated P3HT semiconductor channel TFTs are experimentally demonstrated with solution-based fabrication process. Especially, this paper shed light on the NC effect in the organic based TFTs. The step-up current-voltage characteristics are repeatedly and reliably observed in diverse TFTs, and then, with the results, transconductance (gm) amplification implemented by the negative capacitance was delved. Moreover, with the aid of ferroelectric polarization switching, super steep-switching characteristic of the organic-based TFT was experimentally confirmed. These experimental results and discussion would be helpful in understanding NC effects in TFTs. [ABSTRACT FROM AUTHOR]

This paper presents data on the macroscopic polarization of copolymer films of vinylidene fluoride with tetrafluoroethylene obtained with a modified apparatus assembled according to the Sawyer–Tower Circuit. The kinetics of the polarization process were analyzed taking into consideration the contributions of both bound and quasi-free (impurity) charges. It was shown that an "abnormal" decrease in conductivity was observed in fields near the coercive fields. This could be associated with the appearance of deep traps of the impurity charge carriers formed by the polar planes of β-phase crystals. The conductivity data obtained from the charge and current responses differed. It was concluded that chain segments contributing to polarization with sufficiently low fields were present in the amorphous phase. A comparison showed that the average size of β-phase crystals (crystals of X-ray diffraction reflection width) was almost one order of magnitude lower than the domain size obtained using piezoresponse force microscopy (PFM). The analysis of the fast-stage dielectric response before and after polarization indicated that as the external polarizing field increased in the ferroelectric polymer chains, conformational transitions occurred according to the T3GT3G− → (-TT-)n и TGTG → (-TT-)n types. This was accompanied by an increase in the effective dipole moment in the amorphous phase chains. The analysis of the IR spectroscopy data obtained in transmission and ATR modes revealed a difference in the conformational states of the chains in the core and surface parts of the film. [ABSTRACT FROM AUTHOR]

Recently, two-dimensional (2D) bilayer magnetic systems have been widely studied. Their interlayer magnetic interactions play a vital role in the magnetic properties. In this paper, we theoretically studied the interlayer magnetic interactions, magnetic states, and ferroelectricity of π / 3 -twisted CrX2 (X = Se, Te) bilayers (π / 3 -CrX2). Our study reveals that the lateral shift could switch the magnetic state of the π / 3 -CrSe2 between interlayer ferromagnetic and antiferromagnetic, while just tuning the strength of the interlayer antiferromagnetic interactions in π / 3 -CrTe2. Furthermore, the lateral shift can alter the off-plane electric polarization in both π / 3 -CrSe2 and π / 3 -CrTe2. These results show that stacking is an effective way to tune both the magnetic and ferroelectric properties of 1T-CrX2 bilayers, making the 1T-CrX2 bilayers hold promise for 2D spintronic devices. [ABSTRACT FROM AUTHOR]

The metastable polar orthorhombic phase is believed to be the origin of the ferroelectricity of hafnia-based films. The adjustment of stain, oxygen vacancies and dopant during film deposition and the wake-up electric cycling are common strategies to induce the ferroelectricity in hafnia. However, none of them could independently render the ferroelectric phase to be the most stable phase from the theoretical calculation results. The exact external conditions to stabilize orthorhombic phase still remain elusive. In this paper, we investigate the effects of the type, distribution, concentration, and charge state characteristics of oxygen vacancies and the uniaxial strain on the crystal' energy, dielectric constant and spontaneous polarization (Ps); In addition, the impact of the applied electric field parallel to the Ps on the crystal' energy is explored by first-principles calculations. It is challenging to independently stabilize the ferroelectric phase of hafnia-based films by a single component owing to the rather strict conditions. Surprisingly, the ferroelectricity can be easily obtained when simultaneously considering the effects of oxygen vacancies, uniaxial strain, and applied electric fields, suggesting the extremely important mechanical-electrical-chemical coupling effects. This work provides an explanation for the typical wake-up phenomenon in hafnia and a guidance for film applications. [ABSTRACT FROM AUTHOR]

Investigation of the polarization switching mechanism in ferroelectric hafnium zirconium oxide (HZO) film is of great importance for developing high-quality ferroelectric memory devices. Recently, several works have been reported to describe the switching process of polycrystalline HZO film using the inhomogeneous field mechanism (IFM) model. However, no report has recorded the effect of high pressure annealing (HPA) on the polarization switching process. In this paper, we have carried out a careful investigation on the switching properties of HZO capacitors annealed at 600 °C with various high pressure conditions (1, 50, and 200 atm) using the IFM model. As pressure increases to 200 atm, the ferroelectric properties were enhanced in the HZO films, and, as a result, highest remanent polarization (Pr of 24.5 μC/cm2) was observed when compared with 1 and 50 atm. Similarly, as HPA increases, the HZO capacitors showed a decrement of the coercive field, which significantly improved the switching properties. The time consumed for reversing 80% polarization was 113.1, 105.7, and 66.5 ns for the sample annealed at 1, 50, and 200 atm, respectively. From the IFM model, the smallest active field (2.997 MV/cm) and a uniform distribution of the local electric field (0.304) were observed at 200 atm. Furthermore, the characteristic time constant (τ 0) showed a decreasing trend (34.7, 18.1, and 11.7 ps) with increasing HPA. The improved switching properties and detailed findings recorded in this study may be helpful for developing the ferroelectric hafnia based non-volatile memory applications. [ABSTRACT FROM AUTHOR]

This paper is devoted to a comprehensive study on a new type of microwave structures named magnetoelectric (ME) gradient structures. These structures are studied in this paper to understand the possibilities and application principles in feasible devices. The structure under study was calculated at different values of the applied electric field and different values of the relative permittivity of the artificial dielectric layer. The layered multiferroic structure in inhomogeneous electric and magnetic fields was calculated on the basis of the previously proposed mathematical model. The eigenwaves spectrum for several considered cases was the result of the performed calculation. The concept of using ME gradient structures in the design of electronically controlled microwave devices is formed on the basis of the results of a numerical experiment. Structures of this type will preferably be used in electronically controlled devices for the directional transmission of microwave signals, as it was shown in the theoretical part of the paper. [ABSTRACT FROM AUTHOR]

Ferroelectrics are a class of materials that possess a variety of interactions between electrical, mechanical, and thermal properties that have enabled a wealth of functionalities. To realize integrated systems, the integration of these functionalities into semiconductor processes is necessary. To this end, the complexity of well-known ferroelectric materials, e.g., the perovskite class, causes severe issues that limit its applications in integrated systems. The discovery of ferroelectricity in hafnium oxide-based materials brought a renewed interest into this field during the last decade. Very recently, ferroelectricity was also verified in aluminum scandium nitride extending the potential of seeing a wealth of ferroelectric functions in integrated electronics in the future. This paper discusses the prospects of both material systems in various applications. [ABSTRACT FROM AUTHOR]