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The development of large-scale, high-quality ferroelectric semiconductor nanowire arrays with interesting light-emitting properties can address limitations in traditional wide-bandgap ferroelectrics, thus serving as building blocks for innovative device architectures and next-generation high-density optoelectronics. Here, we investigate the optical properties of ferroelectric CsGeX3 (X = Br, I) halide perovskite nanowires that are epitaxially grown on muscovite mica substrates by vapor phase deposition. Detailed structural characterizations reveal an incommensurate heteroepitaxial relationship with the mica substrate. Furthermore, photoluminescence that can be tuned from yellow-green to red emissions by varying the halide composition demonstrates that these nanowire networks can serve as platforms for future optoelectronic applications. In addition, the room-temperature ferroelectricity and ferroelectric domain structures of these nanowires are characterized using second harmonic generation (SHG) polarimetry. The combination of room-temperature ferroelectricity with photoluminescence in these nanowire arrays unlocks new avenues for the design of novel multifunctional materials.

The multiferroics with remarkable magnetoelectric (ME) coupling and technological application have drawn significant attention. Here, we report a chemical doping tunable effect on the magnetic, ferroelectric, and dielectric properties in type-II multiferroic Gd 2 BaCuO 5. The magnetic measurement results show that a long-range antiferromagnetic ordering forms at the Néel temperature (T N1) of ∼12.1 K, and a second magnetization anomaly occurs at a lock-in transition temperature (T N2) of ∼6.4 K. Sharp peaks in the pyroelectric and dielectric curves are observed at the magnetic transition temperatures, indicating intrinsic coupling between magnetic and ferroelectric orderings. The doping of Zn2+ results in a gradual enhancement of magnetization due to the increase of uncompensated spins, and large magnetodielectric (MD) coupling parameter up to ∼7.65 % is obtained in Gd 2 BaCu 0.7 Zn 0.3 O 5 because of strong spin-phonon coupling. The ferroelectric property is weakened in Zn2+ doped samples, suggesting the critical role of the 4 f -3 d magnetic interactions in determining the ME coupling effect. Moreover, an effective manipulation of electric field on magnetization is observed in Gd 2 BaCuO 5. This work helps understand the importance of 4 f -3 d magnetic interactions in inducing ferroelectricity and explore the ME and MD coupling effects with multiple magnetic orderings. [ABSTRACT FROM AUTHOR]

The crystallographic, microstructural, and dielectric properties of Sr 2.1 Na 0.8-x Ca x Nb 5-x Sn x O 15 (x = 0.00, 0.01, 0.05, 0.10) polycrystalline ceramics have been studied by X-ray diffraction, scanning electron microscopy, dielectric spectroscopy (DS) and impedance spectroscopy (IS). For x = 0.00, 0.05, and 0.10, samples are single phase with P 4 bm symmetry at room temperature with x = 0.01 showing a small quantity of secondary phase(s). All compositions show typical ceramic microstructures and d 50 grain sizes ranging from 5.1 to 26.6 μm. DS shows a clear trend in the high temperature ferroelectric-paraelectric transition with the Curie temperature, T 0 , decreasing from ∼ 160 to ∼ 110 °C, and an additional relaxation at approximately 120 °C with increasing CaSnO 3. IS reveals all samples have a homogeneous electrical microstructure with predominantly electronic conduction. The activation energy of conduction calculated from Arrhenius plots of the conductivity increases with CaSnO 3 content from 1.27 to 1.38 eV likely due to the expansion of the band gap. [ABSTRACT FROM AUTHOR]

Flexible or wearable devices are of great interests in the modern technologies, and oxide thin films are critical components for such applications. In this work, epitaxial LiNbO 3 (LNO) thin film integrated on flexible mica substrate has been achieved. Al-doped ZnO (AZO) layer has been first deposited as buffer layer to obtain the epitaxial LNO film, furthermore AZO serves as bottom electrode for electrical measurement. The as-deposited LNO film exhibits high epitaxial quality with c-direction growth. The transmittance measurement indicates the high transparency of the film, ～85 % in visible range and ～90 % in near infrared region up to 1500 nm. The second harmonic generation (SHG) measurement confirms the nonlinearity of the flexible LNO film. The LNO/AZO/mica film also presents apparent ferroelectric response. Overall, the high-quality LNO integrated on flexible mica could be potentially applied in wearable optical and electrical devices. [ABSTRACT FROM AUTHOR]

HfO2-based ferroelectric materials as the most promising candidate for the ferroelectric memories, have been widely studied for more than a decade due to their excellent ferroelectric properties and CMOS compatibility. In order to realize its industrialization as soon as possible, researchers have been devoted to improving the reliability performance, such as wake up, imprint, limited endurance, et al. Among them, the breakdown characteristic is one of main failure mechanisms of HfO2-based ferroelectric devices, which limits the write/read reliability of the devices. Based on this, we systematically studied the effect of thickness on the time-dependent dielectric breakdown (TDDB) tolerate capability of HfO2–ZrO2 (HZO) FE films under both forward and reverse electrical stress conditions. The thickness of HZO FE film ranged from 6 to 20 nm. Our findings reveal that decreasing the thickness of the HZO FE film leads to an improvement in TDDB tolerance capability which is attributed to the fact that higher density of oxygen vacancies in thinner HZO FE films can effectively inhibit the generation of new oxygen vacancies and the growth of conductive filaments, thus effectively improving the TDDB characteristics. These results provide a potential solution for mitigating breakdown characteristics of HfO2-based ferroelectric devices in memory applications. [ABSTRACT FROM AUTHOR]

In this study, lead-free Ba 0.85 Ca 0.15 Ti 0.95 (Nb 0.5 Yb 0.5) 0.05 O 3 (BC15TYN5) ceramic has been successfully obtained through the conventional solid-state reaction. It has been found the multifunctionality of the BC15TYN5 ceramic. It exhibits ferroelectric properties, with a significant remanent polarization value of about P r = 9.36 μC/cm2, and a recoverable energy storage density value of about W rec = 42.21 mJ/cm3. Additionally, it displays a dielectric permittivity of about ε ′ r = 7230 around T C = 80 °C, and an electro-caloric strength value of about ξ = 0.12 K mm/kV. It's worth noting that these values surpass those typically found in BaTiO 3 ceramics elaborated with similar experimental conditions. Electrical study (impedance, modulus, and conductivity characteristics) is essential for characterizing the BC15TYN5 material, determining its suitability for various technological applications, and optimizing manufacturing processes. The Cole-Cole plots exhibited two relaxations associated with the contribution of the grains and grain boundaries. The relaxation times for both grains and grain boundaries showed temperature-dependent variation following Arrhenius relation. The measured AC conductivity was evaluated by applying the Jonsher power law. Based on the thermal evolution of the exponent S , it was confirmed that the conduction mechanism follows the Correlated Barrier Hopping (CBH) model. These properties make BC15TYN5 ceramic suitable for applications such as dielectric capacitors, ferroelectric random-access memories, electrical energy storage units, and electro-caloric refrigeration systems. [ABSTRACT FROM AUTHOR]

The dielectric gap between the scanning probe microscopy (SPM) tip and the surface of a ferroelectric using conductive atomic force microscopy and piezoresponse force microscopy (PFM) is investigated. While the gap functions as a dielectric layer, it also allows tunneling current to inject charges into the ferroelectric when a critical loading force between 10–20 µN is applied to a tip with a radius of 25 nm under a bias voltage of 0.5 V. It is observed that the permittivity of the dielectric gap determines the coercive voltage measured by the piezoresponse hysteresis loop. While such studies done in air often produce coercive voltages much larger than those studied for the same materials in capacitor‐based studies, the use of high permittivity media such as water (ɛr = 79) or silicone oil (ɛr = 2.1‐2.8) produces coercive fields that more closely match those measured in conventional capacitor‐based polarization hysteresis loop measurements. Furthermore, using water as a dielectric medium in PFM imaging enhances the accuracy in extracting the amplitude and phase data from periodically poled lithium niobate crystals. These findings provide insight into the nanoscale phenomena of polarization switching instigated by the SPM tip and provide a pathway to improved quantitative studies. [ABSTRACT FROM AUTHOR]

This study investigates the magnetoelectric coupling effect in dual‐phase multiferroic composites prepared using a solid‐state reaction method. The composites were fabricated with the formula (1−x)Ba₀.₇₇Ca₀.₂₃TiO₃(BCT) + xNi₀.₆Zn₀.₂₅La₀.₁₅Fe₂O₄(NZLFO), where x varied from 0% to 100% in 10% increments. Ca‐doped BaTiO₃ served as the ferroelectric phase, while La‐doped Ni–Zn ferrite acted as the ferromagnetic phase. The effects of varying ferrite content (x) on structural, optical, ferroelectric, electrical, and magnetoelectric properties were comprehensively analyzed. X‐ray diffraction (XRD) with Rietveld refinement revealed a spinel cubic structure for the ferrite phases and a tetragonal structure for the perovskite phases. The study observed a moderate influence of ferrite concentration on the lattice parameters of BCT and an opposing effect on the lattice parameters of NZLFO. Optical measurements indicated higher light absorption in the visible range compared to the UV region and wide optical bandgap. Magnetic properties, characterized by saturation magnetization, exhibited a dependence on temperature, with a Curie temperature (Tc) of 700 K. Electrical resistivity displayed a maximum at x = 50% and remained constant at high frequencies. The study also confirmed the presence of electric polarization induced by a magnetic field, with the highest magnetoelectric coefficient observed at x = 10%. These findings demonstrate the successful fabrication of dual‐phase multiferroic composites with tunable properties through controlled ferrite content. The observed magnetoelectric coupling suggests potential applications in multifunctional devices. [ABSTRACT FROM AUTHOR]

Recombination of charge carriers is the major issue for the sustainable operation of dye-sensitized solar cells (DSSC). Generally, an external voltage bias is necessary to efficiently segregate the excitons and restrict recombination. A ferroelectric An organic ferroelectric DSSC has been fabricated, and the performance was examined by altering the thickness of the ferroelectric polyvinylidene fluoride (PVDF) thin film stratum. The PVDF was coated using the spin-coating method, and the TiO2 anode and nitrogen-doped reduced graphene nanosheet cathode layers were coated using the doctor blade method. An enhancement in Jsc and Voc has been noted by a decrease in PVDF film thickness. A maximum efficiency of 3.9%, along with a 70.9% fill factor, was achieved for the irradiation of 10 mW/cm2 for the DSSC made with an 80-nm-thick ferroelectric PVDF layer. Further, the performance has been tested by coating the TiO2 anode using spin coating. After evaluating the current–voltage characteristics with a single diode model, it was found that low series and high shunt resistances are responsible for the observed enhancement in Voc, leading to an overall increase in device efficiency. [ABSTRACT FROM AUTHOR]

Lead-free 0.96(K0.48Na0.52)(Nb0.965Sb0.035−xErx)O3-0.04(Bi0.5Na0.5)ZrO3 (KNNS0.035−xEx-BNZ) multifunctional ceramics were prepared by the conventional solid-state reaction method combined with the two-step sintering method. The results show that the ceramics doped with a moderate amount of Er3+ show good piezoelectric properties and excellent temperature stability, while displaying bright up-conversion photoluminescence. Er3+-doping shifts the orthorhombic–tetragonal phase transition temperature (TO-T) down to below room temperature and enhances the temperature stability of the ceramics. For a 0.2 mol%Er3+-doped sample, the room-temperature piezoelectric constant d33 reached 343 pC/N. The sample shows good resistance to thermal depoling as noted that the d33 value remaining at more than 95% of that at room temperature when the temperature was increased to 230 °C. Relying on the luminescence behavior of rare earth Er3+ ions, Er3+-doped samples exhibit a strong photoluminescence with a bright green up-conversion emission under excitation at 980 nm. Two green emissions, at 525 nm and 550 nm, corresponded to the transitions from 2H11/2 → 4I15/2 to 4S3/2 → 4I15/2, and a weak red emission at 660 nm was assigned to the 4F9/2 → 4I15/2 transition obtained under the excitation of a 980-nm laser. The multifunctional properties in the Er-doped samples make them promising for multifunctional device applications. [ABSTRACT FROM AUTHOR]

This paper reports the structural, dielectric, electrical, and multiferroic properties of Bi2FeNiO6 (BFNO) double perovskite synthesised using a sol-gel modified combustion technique. Its calcination temperature, 873 K, was determined using the mass variation in the TGA curve. Structural characterisation was conducted with the X-ray diffraction technique and the perovskite was found to adopt a cubic structure with space group Fm 3 ¯ m (#225). Synchrotron-based powder angle dispersive X-ray diffraction (ADXRD) measurements were carried out to analyze the structural stability with temperature variation (RT-773 K). SEM studies revealed nearly cubic nanostructures with an average grain size of ~54 nm. EDS and XPS studies confirm the stoichiometric and electrical neutrality of the compound, respectively. The ε vs T curve shows the ferroelectric Curie temperature to be around 732 K, corroborating an exothermic peak observed in the DSC curve around the same temperature. The M-H curve and PE loop show the coexistence of ferroelectric and ferromagnetic properties in the as-prepared Bi2FeNiO6 at room temperature. Highlights: Citric acid-assisted Sol-gel modified combustion technique was implemented to synthesise Bi2FeNiO6 double perovskite. Strong coupling between unpaired electrons of the t2g and eg subshells in the Fe and Ni ions, respectively, is responsible for the magnetic phase transition shift to a higher temperature. The PE loop shows the sample is ferroelectric with remanent polarisation Pr = 1.6 μC/cm2. The ferroelectric transition was found at 733 K and is shown with a temperature-dependent dielectric constant curve. It exhibits room-temperature multiferroic properties with a semiconducting nature. [ABSTRACT FROM AUTHOR]

Ferroelectric photoelectric devices show promising applications in artificial vision systems. However, this type of devices used in artificial vision systems exhibits low photoresponsivity and this limited cyclability of photocurrents, which hinders the progress of artificial vision systems. In this study, an artificial vision system is constructed with high photoresponsivity, fast photoresponse speed, and high read/write speed based on the Pd/PbZr0.4Ti0.6O3/La0.3Sr0.7MnO3/LaAlO3 ferroelectric photomemristor. The high optical response (18.86 nanoamperes) and read/write speeds (50 nanoseconds) of the device significantly improve the robustness and speed of the neuromorphic visual system while reducing power consumption for recognition. The artificial vision system developed in this study provides excellent real‐time image processing capabilities, including edge detection and classification with 100% accuracy for musical key patterns, and it is expected to offer great potential for the development of high‐performance self‐powered artificial vision systems. [ABSTRACT FROM AUTHOR]

Bismuth sodium titanate (Bi0.5Na0.5TiO3, BNT) ceramics are expected to replace traditional lead-based materials because of their excellent ferroelectric and piezoelectric characteristics, and they are widely used in the industrial, military, and medical fields. However, BNT ceramics have a low breakdown field strength, which leads to unsatisfactory energy storage performance. In this work, 0.85Bi0.5Na0.5TiO3-0.15LaFeO3 ceramics are prepared by the traditional high-temperature solid-phase reaction method, and their energy storage performance is greatly enhanced by improving the process of buried sintering. The results show that the buried sintering method can inhibit the formation of oxygen vacancy, reduce the volatilization of Bi2O3, and greatly improve the breakdown field strength of the ceramics so that the energy storage performance can be significantly enhanced. The breakdown field strength increases from 210 kV/cm to 310 kV/cm, and the energy storage density increases from 1.759 J/cm3 to 4.923 J/cm3. In addition, the energy storage density and energy storage efficiency of these ceramics have good frequency stability and temperature stability. In this study, the excellent energy storage performance of the ceramics prepared by the buried sintering method provides an effective idea for the design of lead-free ferroelectric ceramics with high energy storage performance and greatly expands its application field. [ABSTRACT FROM AUTHOR]

Since the study of short‐wave ultraviolet nonlinear optical crystals based on the quasi‐phase‐matching principle will effectively expand the development field of nonlinear optical materials, it is urgent to achieve their directional design. Here, it is proposed and implemented on account of the hexagonal wurtzite structure. Thus, the LiRbSeO4 crystal is obtained with [SeO4] groups as the main tetrahedra and [LiO4] as the separation. It exhibits a wide transparency window (0.22–5.57 µm) and an excellent nonlinear optical effect (≈1.7 × KH2PO4), which originates from the synergy of distorted tetrahedral groups and their uniform arrangement. More importantly, the LiRbSeO4 crystal is confirmed to be a ferroelectric with a typical polarization‐electric field hysteresis loop (a coercive field of 27.71 kV cm−1, a remanent polarization of 8.60 µC cm−2 at 373 K). Its ferroelectricity is further identified by the domain engineering studies, involving piezoelectricity and the chirality. Besides, ferroelectricity is attributed to the ordered arrangement of tetrahedra with the polarization reversal involving atomic displacements. Therefore, the LiRbSeO4 crystal is a promising short‐wave ultraviolet nonlinear optical candidate based on the quasi‐phase‐matching principle. This work also provides a new horizon for the design of nonlinear optical crystals. [ABSTRACT FROM AUTHOR]

Over the last decade, an increasing body of evidence has emerged, supporting the existence of a metastable liquid-liquid critical point in supercooled water whereby two distinct liquid phases of different densities coexist. Analyzing long molecular dynamics simulations performed using deep neural-network force fields trained to accurate quantum mechanical data, we demonstrate that the low-density liquid phase displays a strong propensity toward spontaneous polarization, as witnessed by large and long-lived collective dipole fluctuations. Our findings suggest that the dynamical stability of the low-density phase, and hence the transition from high-density to low-density liquid, is triggered by a collective process involving an accumulation of rotational angular jumps, which could ignite large dipole fluctuations. This dynamical transition involves subtle changes in the electronic polarizability of water molecules which affects their rotational mobility within the two phases. These findings hold the potential for catalyzing activity in the search for dielectric-based probes of the putative second critical point. [ABSTRACT FROM AUTHOR]

The present study elucidates the role of annealing with electric field on lamellar crystalline structure and molecular orientation of polymer chains in ferroelectric copolymer (P(VDF‐TrFE)) and ferroelectric terpolymer (P(VDF‐TrFE‐CFE)) spin‐coated thin films. The ferroelectric polymer thin films annealed under an electric field support the growth of nanostructure with an “edge‐on” lamellar crystalline structure having in‐plane molecular chain orientation. The poled P(VDF‐TrFE) thin films have higher remnant polarization (Pr) ≈6.2 µC cm−2 and saturation polarization (Ps) ≈8.2 µC cm−2 at an applied electric field of 250 MV/m compared to unpoled thin films having Pr ≈4.7 and Ps ≈6.2 µC cm−2. Also, poled P(VDF‐TrFE) thin films show lower coercive field (Ec) ≈94 MV/m compared to an unpoled thin film having Ec ≈105 MV/m. Similarly, poled PVDF‐TrFE‐CFE thin film shows better ferroelectric properties having Pr ≈0.4 and Ps ≈5.7 µC cm−2 at an applied electric field of 200 MV m−1 compared to unpoled thin films having Pr ≈0.4 and Ps ≈4.1 µC cm−2. The storage energy efficiency of unpoled and poled P(VDF‐TrFE‐CFE) thin films is measured to be ≈75% and 80%. Annealing of ferroelectric P(VDF‐TrFE) polymer thin films under an electric field demonstrates improved ferroelectric and electroactive properties. [ABSTRACT FROM AUTHOR]

Ferroelectric polymers have emerged as crucial materials for the development of advanced organic electronic devices. Their recent high‐end commercial applications as fingerprint sensors have only increased the amount of scientific interest around them. Despite an ever‐larger body of studies focusing on optimizing the properties of ferroelectric polymers by physical means (e. g. annealing, stretching, blending or nano‐structuring), post‐polymerization chemical modification of such polymers has only recently become a field of active study with great promise in expanding the scope of those polymers. In this work, a solution‐based post‐polymerization modification method was developed for the safe and facile grafting of a plethora of functional groups to the backbone of commercially available Poly(vinylidene fluoride‐co‐trifluoroethylene P(VDF‐co‐TrFE) ferroelectric polymers. To showcase the versatility of this approach, photosensitive groups were grafted onto the polymeric backbone, enabling them to undergo photo‐cross‐linking. Finally, these modified polymers were used as functional negative photoresists in a photolithographic process, highlighting the potential of this method to integrate ferroelectric fluorinated electroactive polymers into standard electronic microfabrication production lines. [ABSTRACT FROM AUTHOR]

The flexoelectric effect describes the interplay between material polarization and strain gradient. While much research has focused on control strategies for flexoelectricity, the impact of ferroelectric domain structure on the flexoelectric effect remains elusive. Through phase field simulations, we conduct a comparative study on the flexoelectric response of two types of BaTiO3–SrTiO3 binary films: BaTiO3–SrTiO3 multilayers and (Ba,Sr)TiO3 solid solutions. Our findings reveal that the flexoelectric response of these two systems, at the same Ba/Sr ratio, differs not only in magnitude but also in other aspects like temperature dependence, linearity, and hysteresis, due to their different ferroelectric domain structures and evolution dynamics. Our study deepens our current understanding of flexoelectricity in ferroelectrics and suggests "domain engineering" as a potential way to tailor this effect. [ABSTRACT FROM AUTHOR]

A series of novel lead free tungsten bronze (T-B) structured Ba4(La2-xBix)Fe2Nb8O30(x = 0, 0.05, 0.1, 0.15, 0.2, and 0.25) were formulated by traditional high temperature solid-state method and calcined at 1200 °C. The structural property was investigated by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Tetragonal structure was confirmed from Rietveld analysis. The scanning electron micrograph (SEM) shows uniform distribution of rod-shaped grains with less porosity. The UV–vis analysis shows that the materials have band gaps in the range 2.17–2.29 eV which makes them useful for photocatalytic applications. The dielectric measurement of the samples was carried out in a broad range of frequency as well as temperature. The impedance of the materials falling off with the rise in temperature showing their negative temperature coefficient (NTCR) behavior. The variation of polarization with electric field confirms the ferroelectric nature of the samples. [ABSTRACT FROM AUTHOR]

The effect of randomly distributed Ca dopants within the BaTiO3 lattice was investigated using first principle calculations. We examined electronic properties to understand how different orbitals contribute to the conduction and valence bands in doped materials. Our findings indicate that the valence band is primarily composed of Ti-3d and O-2p orbital states, while the conduction band is influenced by the collective contributions of Ba-4d, Ti-3d, and Ca-3d orbital states. Additionally, our results demonstrate a reduction in the bandgap due to Ca doping, with the extent of variation depending on the substituted sites of the Ca atoms. Furthermore, we investigated modifications in optical properties such as absorption, conductivity, dielectric function, refractive index, extinction coefficient, loss function, and reflectivity in the energy range from 0 to 40 eV. The findings reveal the stability of these characteristics in the infrared and visible light regions, and they also depend on the site substitution of Ca cations within the BaTiO3 lattice. We expected that our findings would deepen the understanding of the mechanism and site effect of Ca dopant on the properties of BaTiO3 materials, thereby contributing to the development of lead-free ferroelectric materials with enhanced properties for multifunctional applications. [ABSTRACT FROM AUTHOR]

This report is on magneto-electric (ME) interactions in bulk composites with coaxial fibers of nickel–zinc ferrite and PZT. The core–shell fibers of PZT and Ni1−xZnxFe2O4 (NZFO) with x = 0–0.5 were made by electrospinning. Both kinds of fibers, either with ferrite or PZT core and with diameters in the range of 1–3 μm were made. Electron and scanning probe microscopy images indicated well-formed fibers with uniform core and shell structures and defect-free interface. X-ray diffraction data for the fibers annealed at 700–900 °C did not show any impurity phases. Magnetization, magnetostriction, ferromagnetic resonance, and polarization P versus electric field E measurements confirmed the ferroic nature of the fibers. For ME measurements, the fibers were pressed into disks and rectangular platelets and then annealed at 900–1000 °C for densification. The strengths of strain-mediated ME coupling were measured by the H-induced changes in remnant polarization Pr and by low-frequency ME voltage coefficient (MEVC). The fractional change in Pr under H increased in magnitude, from +3% for disks of NFO–PZT to −82% for NZFO (x = 0.3)-PZT, and a further increase in x resulted in a decrease to a value of −3% for x = 0.5. The low-frequency MEVC measured in disks of the core–shell fibers ranged from 6 mV/cm Oe to 37 mV/cm Oe. The fractional changes in Pr and the MEVC values were an order of magnitude higher than for bulk samples containing mixed fibers with a random distribution of NZFO and PZT. The bulk composites with coaxial fibers have the potential for use as magnetic field sensors and in energy-harvesting applications. [ABSTRACT FROM AUTHOR]

Monolithic three‐dimensional (M3D) integration advances integrated circuits by enhancing density and energy efficiency. Ferroelectric thin‐film transistors (Fe‐TFTs) attract attention for neuromorphic computing and back‐end‐of‐the‐line (BEOL) compatibility. However, M3D faces challenges like increased runtime temperatures due to limited heat dissipation, impacting system reliability. This work demonstrates the effect of temperature impact on single‐gate (SG) Fe‐TFT reliability. SG Fe‐TFTs have limitations such as read‐disturbance and small memory windows, constraining their use. To mitigate these, dual‐gate (DG) Fe‐TFTs are modeled using technology computer‐aided design, comparing their performance. Compute‐in‐memory (CIM) architectures with SG and DG Fe‐TFTs are investigated for deep neural networks (DNN) accelerators, revealing heat's detrimental effect on reliability and inference accuracy. DG Fe‐TFTs exhibit about 4.6x higher throughput than SG Fe‐TFTs. Additionally, thermal effects within the simulated M3D architecture are analyzed, noting reduced DNN accuracy to 81.11% and 67.85% for SG and DG Fe‐TFTs, respectively. Furthermore, various cooling methods and their impact on CIM system temperature are demonstrated, offering insights for efficient thermal management strategies. [ABSTRACT FROM AUTHOR]

Ferroelectric hafnium and zirconium oxides have recently garnered significant attention due to their potential applications in in-memory computing. In this study, we present an optimized process design for a wake-up free 15 nm thick Hf0.5Zr0.5O2 (HZO) ferroelectric capacitor by fine-tuning the dual-oxygen process and incorporating oxygen annealing after post-metallization annealing (PMA). The optimized approach resulted in a competitive polarization of 28.6 μC/cm2, consistently exceeding 25 μC/cm2 at 3 V after 2 × 107 cycles, showcasing a current density of 3.2 mA/cm2 at 2 V after 105 cycles. The synergistic effect of oxygen vacancies and grain properties (grain size, phase proportion) enables competitive ferroelectric polarization at lower voltages, while the generation of WOx near the top electrode and increased grain size further ensure the reliability of the HZO ferroelectric capacitor. This work presents innovative perspectives for the development of non-volatile devices characterized by low leakage current and low power consumption. [ABSTRACT FROM AUTHOR]

We report the growth of AlBN/β‐Nb2N nitride epitaxial heterostructures in which the AlBN is ferroelectric, and β‐Nb2N with metallic resistivity ≈40 μΩ cm$$ \text{μΩ\hspace{0.17em}cm}$$ at 300 K becomes superconducting below TC ≈ 0.5 K. Using nitrogen plasma molecular beam epitaxy, we grow hexagonal β‐Nb2N films on c‐plane Al2O3 substrates, followed by wurtzite AlBN. The AlBN is in epitaxial registry and rotationally aligned with the β‐Nb2N, and the hexagonal lattices of both nitride layers make angles of 30° with the hexagonal lattice of the Al2O3 substrate. The B composition of the AlBN layer is varied from 0 to 14.7%. It is found to depend weakly on the B flux, but increases strongly with decreasing growth temperature, indicating a reaction rate‐controlled growth. The increase in B content causes a non‐monotonic change in the a‐lattice constant and a monotonic decrease in the c‐lattice constant of AlBN. Sharp, abrupt epitaxial AlBN/β‐Nb2N/Al2O3 heterojunction interfaces and close symmetry matching are observed by transmission electron microscopy. The observation of ferroelectricity and superconductivity in epitaxial nitride heterostructures opens avenues for novel electronic and quantum devices. [ABSTRACT FROM AUTHOR]

Highlights: The capacity fading mechanism of the conventional Na3V2(PO4)3//Na3V2(PO4)3 (NVP//NVP) cell has been investigated. All-solid-state ferroelectric-engineered composite electrolyte could improve the electrolyte–electrode interfacial stability as well as the interfacial ion conduction of the Na-ion battery using the NVP anode. Outstanding cyclic stability has been achieved in the all-solid-state Na-ion battery using the NVP anode, with a capacity fading rate as low as 0.005% per cycle. Symmetric Na-ion cells using the NASICON-structured electrodes could simplify the manufacturing process, reduce the cost, facilitate the recycling post-process, and thus attractive in the field of large-scale stationary energy storage. However, the long-term cycling performance of such batteries is usually poor. This investigation reveals the unavoidable side reactions between the NASICON-type Na3V2(PO4)3 (NVP) anode and the commercial liquid electrolyte, leading to serious capacity fading in the symmetric NVP//NVP cells. To resolve this issue, an all-solid-state composite electrolyte is used to replace the liquid electrolyte so that to overcome the side reaction and achieve high anode/electrolyte interfacial stability. The ferroelectric engineering could further improve the interfacial ion conduction, effectively reducing the electrode/electrolyte interfacial resistances. The NVP//NVP cell using the ferroelectric-engineered composite electrolyte can achieve a capacity retention of 86.4% after 650 cycles. Furthermore, the electrolyte can also be used to match the Prussian-blue cathode NaxFeyFe(CN)6−z·nH2O (NFFCN). Outstanding long-term cycling stability has been obtained in the all-solid-state NVP//NFFCN cell over 9000 cycles at a current density of 500 mA g−1, with a fading rate as low as 0.005% per cycle. [ABSTRACT FROM AUTHOR]

Ferroelectric field‐effect transistors (FeFETs) are increasingly important for in‐memory computing and monolithic 3D (M3D) integration in system‐on‐chip (SoC) applications. However, the high‐temperature processing required by most ferroelectric memories can lead to thermal damage to the underlying device layers, which poses significant physical limitations for 3D integration processes. To solve this problem, the study proposes using a nanosecond pulsed laser for selective annealing of hafnia‐based FeFETs, enabling precise control of heat penetration depth within thin films. Sufficient thermal energy is delivered to the IGZO oxide channel and HZO ferroelectric gate oxide without causing thermal damage to the bottom layer, which has a low transition temperature (<250 °C). Using optimized laser conditions, a fast response time (<1 µs) and excellent stability (cycle > 106, retention > 106 s) are achieved in the ferroelectric HZO film. The resulting FeFET exhibited a wide memory window (>1.7 V) with a high on/off ratio (>105). In addition, moderate ferroelectric properties (2·Pr of 14.7 µC cm−2) and pattern recognition rate‐based linearity (potentiation: 1.13, depression: 1.6) are obtained. These results demonstrate compatibility in HZO FeFETs by specific laser annealing control and thin‐film layer design for various structures (3D integrated, flexible) with neuromorphic applications. [ABSTRACT FROM AUTHOR]

2D Ruddlesden–Popper perovskites exhibit significant ferroelectricity due to the spontaneous polarization of organic molecules. By modulating the quantum well width in 2D Ruddlesden–Popper perovskites BA2MAn‐1PbnBr3n+1, a series of perovskites are adopted to realize adjustable polarization intensity and bandgap width. It is found that when n = 3, perovskite has the maximum polarization strength and optimal optoelectronic performance. In addition, flexible photodetectors with high mechanical stability are successfully fabricated based on n = 3 perovskite microplates. The fabricated flexible photodetectors exhibit high responsivity of 920 mA W−1 and detectivity of 1.02 × 1011 Jones, along with excellent flexibility and stability. After 3000 bending cycles, the photocurrent of n = 3 perovskites photodetector remains 81.8% of initial state. Besides, the photocurrent of n = 3 perovskites increase by 33 and 34 times after polarization at 0 and 3 V, respectively. And n = 3 perovskites exhibit a high polarization sensitivity with a current ratio of 2.09. On the basis of controllable regulation of the photocurrent through polarization, the application of flexible decoding optoelectronic devices by utilizing the correspondence between optical signals before and after polarization and binaries is achieved. These findings highlight the potential of modulating quantum well width in 2D Ruddlesden–Popper perovskites as a promising strategy for designing next‐generation flexible optoelectronic devices. [ABSTRACT FROM AUTHOR]

Most of the applied research on BiFeO3 (BFO) focuses on magnetoelectric and spintronic applications. This calls for a detailed grasp of multiferroic and conduction properties. BFO thin films with (100) epitaxial growth has been deposited on a LaNiO3 (LNO) buffered Pt/Ti/SiO2/Si(100) substrate using RF magnetron sputtering. The film formed at 15 mTorr, 570 °C, and with Ar/O2 4:1 had a reasonably high degree of (100)-preferential orientation, the least surface roughness, and a densely packed structure. We obtained ferroelectric loops with strong polarization (150 μ C cm−2). The leakage current density is as low as 10–2 A cm−2 at 100 kV cm−1, implying that space-charge-limited bulk conduction (SCLC) was the primary conduction channel for carriers within BFO films. Local electrical conduction behavior demonstrates that at lower voltages, the grain boundary dominates electrical conduction and is linked to the displacement of oxygen vacancies in the grain boundary under external electric fields. We hope that a deeper understanding of the conduction mechanism will help integrate BFO into viable technologies. [ABSTRACT FROM AUTHOR]

Lead halide molecular ferroelectrics represent an important class of luminescent ferroelectrics, distinguished by their high chemical and structural tunability, excellent processability and distinctive luminescent characteristics. However, their inherent instability, prone to decomposition upon exposure to moisture and light, hinders their broader ferroelectric applications. Herein, for the first time, we present a series of isoreticular metal–organic framework (MOF)‐type lead halide luminescent ferroelectrics, demonstrating exceptional robustness under ambient conditions for at least 15 months and even when subjected to aqueous boiling conditions. Unlike conventional metal‐oxo secondary building units (SBUs) in MOFs adopting highly centrosymmetric structure with limited structural distortion, our lead halide‐based MOFs occupy structurally deformable [Pb2X]+ (X=Cl−/Br−/I−) SBUs that facilitate a c‐axis‐biased displacement of Pb2+ centers and substantially contribute to thermoinducible structural transformation. Importantly, this class of MOF‐type lead halide ferroelectrics undergo ferroelectric‐to‐paraelectric phase transitions with remarkably high Curie temperature of up to 505 K, superior to most of molecular ferroelectrics. Moreover, the covalent bonding between phosphorescent organic component and the light‐harvesting inorganic component achieves efficient spin‐orbit coupling and intersystem crossing, resulting in long‐lived afterglow emission. The compelling combination of high stability, ferroelectricity and afterglow emission exhibited by lead halide MOFs opens up many potential opportunities in energy‐conversion applications. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) materials have attracted extensive attention in the field of photodetection thanks to their unique physical properties. Among them, the PdSe2 nanoflake shows great potential. However, the performance of the PdSe2‐based photodetector with a hetero‐type heterojunction remains poor due to the severe tunneling‐assisted interfacial recombination of photogenerated electron‐hole pairs in the thin bilateral‐depletion heterojunctions. In this work, a novel photodetector with a α‐In2Se3/PdSe2 homo‐type heterojunction for both high‐performance and broadband detection from visible to short‐wave infrared is constructed. The high‐performance of the photoresponsivity of 4.64 × 103 A·W−1, the external quantum efficiency of 1.08 × 106%, and the specific detectivity of 1.55 × 1014 Jones at 532 nm is the result of the homo‐type unilateral‐depletion junction which can promote the effective separation of photogenerated electron‐hole pairs compared to the hetero‐type. Also, adjusting the α‐In2Se3 ferroelectric polarization state further optimizes the unilateral depletion region. In addition, the photodetector can work in a self‐powered mode. This study suggests that the PdSe2‐based homo‐type device has great application potential in the field of 2D optoelectronics. [ABSTRACT FROM AUTHOR]

In this study, gadolinium (Gd) and chromium (Cr) co-doped yttrium iron garnet (Y3Fe5O12) nanoparticles were prepared by the sol–gel method. The X-ray diffraction (XRD) data, which was further refined by Rietveld analysis, proved the cubic (Ia-3d) structure without any secondary phase. Surface morphology and microstructure analysis were investigated utilizing field emission scanning electron microscopy (FESEM). FESEM images show how dopants (both Gd and Cr) particles have dispersed non-uniformly in the Y3Fe5O12 matrix and the nanostructured particles with size range from 97 to 284 nm for different Gd and Cr levels. Ferroelectric measurements present a substantial improvement in polarization under a saturated applied field of ± 5 kV/cm for doped, and co-doped Y3Fe5O12. At room temperature magnetic properties are measured by VSM, and it is found that the magnetic properties (saturation and remnant magnetization) are reduced (enhanced) with Gd3+ (Cr3+) doping substantially. UV–VIS spectrophotometry revealed a significant reduction in optical band gap energy from 2.23 to 1.99 eV due to Gd and Cr co-doping in Y3Fe5O12. The dielectric behavior of Y3Fe5O12 is studied in the 100 Hz to 1 MHz frequency range. The frequency-dependent dielectric constant displays the normal dielectric dispersion response, which is explained in terms of polarization concentration using Maxwell–Wagner theory. The dielectric constant is independent of the frequency at longer wavelengths (˃ 105 Hz), owing to only ionic and electronic polarizations. The AC conductivity (σAC) complies with the power law, and the linearity of log2 versus logσAC plot shows that the conduction mechanism is due to limited polar hopping. The obtained results anticipated that Gd3+- and Cr3+-doped Y3Fe5O12 exhibit improved properties for application compared to pure Y3Fe5O12. The synthesized ceramics may find potential applications in sensors, capacitors, actuators, transducers, and memory devices. [ABSTRACT FROM AUTHOR]

Emerging tribovoltaic nanogenerator (TVNG) technology, which can capture mechanical energy at dynamic semiconductor interfaces and generate instant direct current (DC) outputs, is considered promising to mitigate growing energy demand. However, the unsatisfactory charge excitation and extraction efficiency limit its electrical output stability and even practicability. Here, a novel strategy is proposed to synergistically modulate charge generation and transfer dynamics by integrating ferroelectric and photovoltaic effect with tribovoltaic effect, and thus a multi‐effect coupled Schottky TVNGs is, for the first time, developed. Research indicates that such coupling mechanism involving ferroelectric polarization, photoexcitation, and triboelectricity can allow TVNGs to jointly collect light and mechanical energy to excite more charges, and meanwhile, incorporation of strong electric fields can also be induced by controlled polarization to assist Schottky junction in modulating separation/extraction efficiencies of these charges. Ultimately, this multi‐effect coupled devices deliver impressive DC output of 7.3 V and 69.8 µA, outperforming similar coupled Schottky junction TVNGs. Besides that, its feasibility for multifunctional sensing and photodetection is also demonstrated. This study proposes an effective strategy for modulating performance while extending its functionality, which can expedite the development and potential application of advanced TVNGs. [ABSTRACT FROM AUTHOR]

Out‐of‐plane polarization is a highly desired property of two‐dimensional (2D) ferroelectrics for application in vertical sandwich‐type photoferroelectric devices, especially in ultrathin ferroelectronic devices. Nevertheless, despite great advances that have been made in recent years, out‐of‐plane polarization remains unrealized in the 2D hybrid double perovskite ferroelectric family. Here, from our previous work 2D hybrid double perovskite HQERN ((S3HQ)4EuRb(NO3)8, S3HQ=S‐3‐hydroxylquinuclidinium), we designed a molecular strategy of F‐substitution on organic component to successfully obtain FQERN ((S3FQ)4EuRb(NO3)8, S3FQ=S‐3‐fluoroquinuclidinium) showing circularly polarized luminescence (CPL) response. Remarkably, compared to the monopolar axis ferroelectric HQERN, FQERN not only shows multiferroicity with the coexistence of multipolar axis ferroelectricity and ferroelasticity but also realizes out‐of‐plane ferroelectric polarization and a dramatic enhancement of Curie temperature of 94 K. This is mainly due to the introduction of F‐substituted organic cations, which leads to a change in orientation and a reduction in crystal lattice void occupancy. Our study demonstrates that F‐substitution is an efficient strategy to realize and optimize ferroelectric functional characteristics, giving more possibility of 2D ferroelectric materials for applications in micro‐nano optoelectronic devices. [ABSTRACT FROM AUTHOR]

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Composites derived from polyvinylidene fluoride (PVDF) play an important role in advanced dielectric energy storage due to their outstanding characteristics, including remarkable flexibility, low density, high dielectric permittivity, and superior dielectric breakdown strength. The strategically designed composition significantly enhances the energy storage performance, such as discharge energy density (Ue) and charge–discharge energy efficiency (η). Consequently, we employed the solution cast method to create flexible composite films, combining PVDF polymer with strontium tungstate (SrWO4) ceramic. X-ray diffraction analysis revealed the coexistence of α and electroactive β phases in PVDF. These phases have a substantial effect on the dielectric characteristics and energy storage density of composites. Flexible nanocomposites of PVDF and SrWO4 exhibit high dielectric constant and low tangent loss. Micrographs obtained using scanning electron microscopy (SEM) showed that the morphology of the composite varies according to the amount of filler present in the matrix. The impedance spectroscopy method yielded intriguing findings regarding the roles of both grain and grain boundaries in the overall resistance characteristics of the composites. The frequency-dependent behavior of alternating conductivity follows Jonscher's power law. The hysteresis loops indicate that the nanocomposite film maintains favorable ferroelectric properties. The present study suggests some promising applications for advanced dielectric capacitors and energy storage devices. [ABSTRACT FROM AUTHOR]

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0–3 type ferroelectric–phosphor composite ceramics cannot be prepared by the traditional solid-state sintering (SSS) method due to the strong chemical reaction between ferroelectrics and phosphors during high-temperature sintering. The cold sintering process (CSP) may solve this issue by densifying ceramics at ultralow sintering temperatures. In this work, dense 0–3 type 0.8BaTiO3–0.2CaTiO3:Pr3+ (0.8BT–0.2CT:Pr3+) binary composite ceramics were fabricated at an ultralow temperature of 225 °C via CSP with the Ba(OH)2·8H2O hydrated flux. The effects of the Ba(OH)2·8H2O content, sintering temperature, and sintering time on the microstructure and densification of the ceramics were investigated. The density of the composite ceramics prepared by the optimized sintering parameters reaches 89%. Both energy-dispersive X-ray (EDX) spectroscopy and X-ray diffraction (XRD) confirm the existence of BT and CT:Pr3+ phases in the prepared ceramics. A strong ferroelectric performance is obtained, and the luminescent properties of CT:Pr3+ are preserved for the ceramics. Furthermore, the 0.8BT–0.2CT:Pr3+ composite ceramics prepared by CSP have stronger photoluminescence and photo-stimulated luminescence than their counterparts prepared by cold sintering assistance (CSA) and SSS methods. Therefore, CSP is a promising method for combining luminescent and ferroelectric properties into 0–3 type composite ceramics.

In this work, dielectric ultracapacitors were designed and fabricated using a combination of phase boundary and nanograin strategies. These ultracapacitors are based on submicron-thick Ba(Zr0.2Ti0.8)O3 ferroelectric films sputter-deposited on Si at 500 °C. With a composition near a polymorphic phase boundary (PPB), a compressive strain, and a high nucleation rate due to the lowered deposition temperature, these films exhibit a columnar nanograined microstructure with gradient phases along the growth direction. Such a microstructure presents three-dimensional polarization inhomogeneities on the nanoscale, thereby significantly delaying the saturation of the overall electric polarization. Consequently, a pseudolinear, ultraslim polarization (P)–electric field (E) hysteresis loop was obtained, featuring a high maximum applicable electric field (~5.7 MV/cm), low remnant polarization (~5.2 μC/cm2) and high maximum polarization (~92.1 μC/cm2). This P–E loop corresponds to a high recyclable energy density (Wrec ~208 J/cm3) and charge‒discharge efficiency (~88%). An in-depth electron microscopy study revealed that the gradient ferroelectric phases consisted of tetragonal (T) and rhombohedral (R) polymorphs along the growth direction of the film. The T-rich phase is abundant near the bottom of the film and gradually transforms into the R-rich phase near the surface. These films also exhibited a high Curie temperature of ~460 °C and stable capacitive energy storage up to 200 °C. These results suggest a feasible pathway for the design and fabrication of high-performance dielectric film capacitors.

Highlights The capacity fading mechanism of the conventional Na3V2(PO4)3//Na3V2(PO4)3 (NVP//NVP) cell has been investigated. All-solid-state ferroelectric-engineered composite electrolyte could improve the electrolyte–electrode interfacial stability as well as the interfacial ion conduction of the Na-ion battery using the NVP anode. Outstanding cyclic stability has been achieved in the all-solid-state Na-ion battery using the NVP anode, with a capacity fading rate as low as 0.005% per cycle.