Polarization Values Research Articles

Innovative Ultralow Thermal Budget ZrHfOx Ferroelectric Films with Low-Temperature Phase Transition for Next-Generation High-Speed Multifunctional Devices.

By design of the element concentration, regulating the ratio of the t phase and the energy difference between t and o phases, the ZrHfOx (ZHO) film demonstrated the highest polarization value at a maximum processing temperature of only 280 °C without an annealing process, and it can withstand over 1010 polarization cycles without breakdown. The ZHO film maintains good ferroelectric performance in extreme temperature environments (4.55 to 473 K). Even under high-temperature conditions, the ZHO film shows exceptional endurance performance (>1010 at 423 K). These parameters represent the best overall performance reported in the literature to date. The polarization switching process can be accurately described by the nucleation limited switching (NLS) model, and the polarization switching time is expected to reach the sub-ns level as the device size decreases. The ZHO film demonstrates great potential in both process simplification and performance optimization, providing new possibilities for the application of ferroelectric devices.

First-principles study of robust half-metallic ferromagnetism and electronic structure of the Heusler compounds Co2-xCrxMnGe

Abstract Half-metallic ferromagnets (HMFs) are among the most promising materials in 
the field of spintronics because of their distinct band structures, which consist of two 
characteristic subbands, one with semiconductor-like behaviour and the other with metallic 
features. Using density functional theory-based calculations, we have carried out in-depth 
studies to predict the effects of Co replacement by Cr on electronic structure as well as the 
magnetic properties of Co2-xCrxMnGe with 0 ≤ x ≤ 1. The results demonstrate that the alloys 
are stable in the ferromagnetic phase with half-metallic nature. The origin of ferromagnetism 
can be explained by Ruderman-Kittel-Kasuya-Yosida (RKKY), like exchange interaction. Due 
to their high Curie temperatures, which increase linearly with the total magnetic moment, all 
alloys are suitable for applications at and above room temperature. Besides, the electronic 
properties have revealed a transition from half-metallic to semi-metallic character for higher 
doping concentration (x=0.75, x=1.0). The calculated total magnetic moments, however, 
decrease with increasing doping concentration, consistent with the Slater-Pauling rule. The 
observed high value of spin polarisation of all the studied compounds suggests their futuristic 
roadmaps for possible spintronics applications beyond room temperature.

Studies on Multifunctional Nanostructured Materials

Multifunctional materials are of today’s quest. Miniaturization, i.e. development of these materials in the form of nanomaterials is of primary need considering their application in devices. Moreover, if these are obtained in nanostructured form, they can bring wonders. We have adopted a method for developing multiferroic BiFeO3 (BFO) with simultaneous antiferromagnetic, ferroelectric & ferroelastic behaviour in form of nanostructures like nanorods, nanowire etc. by employing Anodised Alumina (AAO) template with various pore sizes from 20nm with solution route followed by controlled vacuum filtration and sintering. Diameters of nanorods are in the range of 20-100 nm as observed by FESEM. Capacitance assayed by cyclic voltammetry (CV) and charge discharge processes reveals a very high value of specific capacitance of 450F/gm. Capacitance has been estimated by extrapolating the charge collected at the electrode to that at scanning rate of infinity which is relevant for the charge collected at the nanorods protruding out of the template. Charging and discharging times are quite constant over a large number of cycles. This large value of specific capacitance can be attributed to the nanostructure form of BFO nanorod. The high value of specific capacitance of BFO nanorods brings forth its use as electrode in storage energy devices. Also, a high value of polarization as well as a significant magnetic susceptibility are observed in multiferroic Bismuth Ferrite (BFO) in the form of nanorods protruding out. The high values of polarization and magnetic susceptibility are attributed to the structured form of BFO nanorods giving rise to the directionality. There is no leakage current in P-E loop examined at various fields and frequencies. Magnetocapacitance measurements reflect a significant enhancement in magnetoelectric coupling also.

Sol-gel fabrication of transparent ferroelectric (K,Na)NbO3/La0.06Ba0.94SnO3 heterostructure

Lead-free K0.5Na0.5NbO3 (KNN) ferroelectric film and transparent La0.06Ba0.94SnO3 (LBSO) bottom electrode are fabricated on (001)-oriented SrTiO3 (STO) substrate by sol-gel. The characterization results confirm an epitaxial relationship between the films and the substrate, as well as a uniform structure and good crystallization quality of the films. The optical measurement shows that the film heterostructure exhibit a high transmittance with a maximum transmittance of ∼80%. The polarization-electric field (P-E) curves demonstrate that the twice remanent polarization value of the ∼500 nm thick KNN film reaches up to 28 μC/cm2 under an electric field of 800 kV/cm, and the effective piezoelectric strain constant (d33*) is measured as 24.8 pm/V. The dielectric properties of the film are displayed, and the leakage behavior can be divided into three stages of Ohmic conduction, Schottky emission and Poole-Frenkel emission with increasing the applied electric field. This study indicates that transparent lead-free ferroelectric KNN heterostructures can be prepared using a cost-effective sol-gel method and shows promise for future applications.

Ag-decorated hollow copper microtubes as a photocathode for the hydrogen evolution reaction

This paper presents the results of a photoelectrocatalytic study for a copper-silver system obtained in the form of microtubes using electrochemical template synthesis. CuOx/Cu hollow microtubes (HT) decorated with nanoscale silver particles by electrodeposition demonstrate the cathode photocurrent in 7.6 uAcm–2 when using LED light sources in the UVA-Vis spectral region and low polarization values. It was shown that the highest intensity of the photoresponse is achieved in the visible region at a wavelength of 450 nm. The stability test suggests that the retention of Ag/CuOx-HT is 95% after 12 hours of functioning.

Next-generation hybrid nanogenerators using giant piezoelectric lead-free KNNS composites for sustainable self-powered electronics

This study presents a flexible hybrid nanogenerator that utilizes lead-free KNNS-BF-xBNZ materials integrated with polydimethylsiloxane (PDMS) to enhance energy harvesting performance. The findings demonstrate that by combining piezoelectric and triboelectric effects, the energy conversion efficiency of the nanogenerator is significantly improved, resulting in high output voltage and current, suitable for real-world applications. Specifically, the optimal composition of KNNS-BF-xBNZ ceramics, with x = 0.03 mol.%, yields superior piezoelectric, ferroelectric, and dielectric properties, with remnant polarization (Pr), spontaneous polarization (Ps), and piezoelectric coefficient (d33) values reaching 18.8 μmC/cm², 30.3 μmC/cm², and 358 pC/N, respectively. In the hybrid device, incorporating 15 wt% of KNNS-BF-3BNZ into PDMS resulted in the highest open-circuit voltage (VOC) of 107 V and short-circuit current (ISC) of 4.68 μA. The developed hybrid nanogenerator effectively charges capacitors for energy storage, powers LEDs, and drives small electronic devices, such as watches, showcasing its potential for practical energy harvesting applications. The findings suggest that the integration of KNNS-BF-3BNZ with PDMS provides an efficient and scalable pathway for fabricating high-performance nanogenerators, paving the way for advancements in self-powered devices and sustainable energy solutions.

Achieving High Piezoelectric Performance Across Multidomains Design in K(Ta,Nb)O3-Based Lead-free Single Crystals.

In light of environmental issues, the lead-free ferroelectric single crystal K(Ta1-xNbx)O3 (KTN) has attracted considerable interest due to its excellent piezoelectric properties. This research focus on improving the piezoelectric performance of KTN by engineering domains through polarization in the [011]c direction. The full-matrix parameters of KTN crystals after polarization along the [011] direction were determined. The finding reveal that KTN polarized in the nonspontaneous polarization direction [011]c exhibits higher piezoelectric constants (d33 = 156 pC/N, d15 = 155 pC/N) and dielectric constants (ε33T ∼ 2337). Additionally, tensor matrix transformation techniques were utilized to analyze the directional dependence of the piezoelectric (d33*), dielectric (ε33T*), elastic (s33E*) constants, and electromechanical coupling coefficient (k33*). The results indicate that these constants reach their maximum values along the polarized [011]c direction. A comparison of the experimental polarization values in the [011]c direction with those calculated for a single-domain state, demonstrates that ferroelectric domains in KTN crystals contribute significantly to the piezoelectric properties. Finally, polarized light microscopy was used to conduct a detailed analysis of the domain structure in KTN single crystals, revealing various orientations and sizes of domain walls. This research offers strategies for optimizing piezoelectric performance.

Embedding Plate‐Like Pyrochlore in Perovskite Phase to Enhance Energy Storage Performance of BNT‐Based Ceramic Capacitors

AbstractNext‐generation electrical and electronic systems rely on the development of efficient energy‐storage dielectric ceramic capacitors. However, achieving a synergistic enhancement in the polarization and in the breakdown field strength (Eb) presents a considerable challenge. Herein, a heterogeneous combination strategy involving embedding a high Eb plate‐like pyrochlore phase in a high‐polarization perovskite phase is proposed. The embedded plate‐like pyrochlore increases the breakdown field strength and promotes the dynamic polarization response. Meanwhile, the strong spin–orbit coupling effect of the 5d electrons is conducive to the maintenance of the high polarization value of the perovskite. Consequently, the prepared multilayer ceramic capacitor (MLCC) exhibits an ultrahigh Eb and a high polarization. More specifically, an energy storage density (Wrec) of 14.9 J cm−3 with an efficiency of up to 93.4% is achieved for the optimized pyrochlore/perovskite phase. Furthermore, the MLCCs also exhibits an Wrec of ≈ 7.7 J cm−3 ± 4.5% in the temperature range of −50–180 °C. Therefore, this heterogeneous combination strategy therefore provides a simple and effective method for improving the energy‐storage performances of dielectric ceramic capacitors.

Mapping membrane biophysical nano-environments

The mammalian plasma membrane is known to contain domains with varying lipid composition and biophysical properties. However, studying these membrane lipid domains presents challenges due to their predicted morphological similarity to the bulk membrane and their scale being below the classical resolution limit of optical microscopy. To address this, we combine the solvatochromic probe di-4-ANEPPDHQ, which reports on its biophysical environment through changes in its fluorescence emission, with spectrally resolved single-molecule localisation microscopy. The resulting data comprises nanometre-precision localisation coordinates and a generalised polarisation value related to the probe’s environment – a marked point pattern. We introduce quantification algorithms based on topological data analysis (PLASMA) to detect and map nano-domains in this marked data, demonstrating their effectiveness in both artificial membranes and live cells. By leveraging environmentally sensitive fluorophores, multi-modal single molecule localisation microscopy, and advanced analysis methods, we achieve nanometre scale mapping of membrane properties and assess changes in response to external perturbation with methyl-β-cyclodextrin. This integrated methodology represents an integrated toolset for investigating marked point pattern data at nanometre spatial scales.

A ferroelectric capacitor with an asymmetric double-layered ferroelectric structure comprising a liquid-delivery MOCVD Pb(Zr, Ti)O3 layer and a sputter-deposited La-doped Pb(Zr, Ti)O3 for highly reliable FeRAM

We have developed a double-layered ferroelectric capacitor comprising a liquid-delivery metal–organic chemical vapor deposition-based Pb(Zr, Ti)O3 (PZT) lower layer and a sputter-deposited La-doped Pb(Zr, Ti)O3 (PLZT) upper layer. This structure is designed to achieve a large polarization in the stacked-type capacitor of FeRAM. Ferroelectric capacitors with noble metal electrodes, which are patterned by sputter-etching due to the difficulty of standard chemical reactive etching typically exhibit sloped sidewalls. Consequently, their polarization values, determined by the actual capacitor area, depend on their geometric shape. Our developed capacitor exhibits a 35% increase in polarization compared to an all-sputter-deposited PLZT capacitor. This improvement is due to the reduced total thickness of the developed capacitor achieved by simplifying the bottom electrode structure, which results in steeper capacitor sidewalls. Furthermore, our developed capacitor demonstrates excellent retention margin even after 3000 h of baking at 150 °C, and with a potential endurance of 1014 cycles as predicted by voltage acceleration measurements.

Improved lateral figure-of-merit of heteroepitaxial α-Ga2O3 power MOSFET using ferroelectric AlScN gate stack

In this Letter, we demonstrate heteroepitaxial α-Ga2O3 MOSFETs using an aluminum scandium nitride (AlScN) ferroelectric gate stack. Owing to ferroelectric effects, α-Ga2O3 MOSFETs with the AlScN/HfO2 gate stack (FGFET) exhibited enhanced electrical performance compared with a HfO2 gate dielectric (IGFET) for variable gate–drain lengths (10, 15, 20 μm). A remnant polarization value of the AlScN deposited on a HfO2 layer was measured to be about 30 μC/cm2. The subthreshold swing (SS) and field-effect mobility (μFE) of IGFET was extracted at 1814 mV/dec and 13.9 cm2/V s, respectively. However, the FGFET exhibits a reduced SS of 552 mV/dec with enhanced μFE of 42.7 cm2/V s owing to the negative capacitance of the ferroelectric AlScN. Furthermore, a lateral figure-of-merit of 17.8 MW/cm2 was achieved for the FGFET, far surpassing the 8.3 MW/cm2 of the IGFET. The proposed ferroelectric AlScN/HfO2 stack can be a promising gate structure for improving both transfer and breakdown characteristics in heteroepitaxial α-Ga2O3 power devices.

Piezo-traces of ferroelectrics and multiferroics of BiFeO3 -embedded substrate-free Ti3C2Tx MXene films for high throughput data storage application

Ferroelectrics and multiferroics have added flexibility in device design as they can couple with either electric or magnetic polarization. Here, we report a simple approach to observe ferroelectric and multiferroic behavior in BFO embedded Ti3C2Tx MXene free standing film. Structural, morphological, optical and domain analyses were done using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Raman spectroscopy, and Piezoresponse Force Microscopy (PFM) respectively. The hysteresis polarization curves obtained at various frequencies, both with and without a static magnetic field, provide confirmation of the frequency-dependent ferroelectric behavior within BFO embedded Ti3C2Tx MXene free standing film. Magneto-electric couplings have demonstrated the film's ability to manipulate electric polarization using a magnetic field. Recently, researchers have unveiled ferroelectric properties in Ti3C2Tx MXene triggered through heat treatment because of oxidation. To investigate this phenomenon, we applied heat treatment to our film which resulted in an amplified polarization value and notably improved results. The fabricated composite film was used in tri-layered device consisting of heated BFO-embedded Ti3C2Tx MXene as middle layer that showed excellent data storage capability controlled by ferroelectricity of the middle layer itself. The simultaneous presence of ferroelectric and multiferroic coupling highlights the promising application of MXene-assisted films in data storage applications.

Harnessing the half-metallicity and thermoelectric insights in Cs2AgMBr6 (M = V, Mn, Ni) double halide perovskites: A DFT study

Herein, we undertake a detailed exploration of the structural stability, magneto-electronic behavior, and thermoelectric properties of Cs₂AgMBr₆ (M = V, Mn, Ni) halide double perovskites using first-principles approach. The study commences with a meticulous assessment of both structural stability and thermodynamic properties employing various metrics. Energy minimization across different phases, utilizing the Birch-Murnaghan equation of state, confirms the ferromagnetic phase as energetically favoured, supported by Curie-Weiss constants of 98 K, 100 K, and 150 K for V, Mn, and Ni-based perovskites, respectively. Mechanical properties, including hardness, stiffness, ductility, and fracture strength, are derived from the simulated elastic constants, ensuring the mechanical stability of the materials. Electronic structure analysis, performed using the PBE-GGA and GGA + mBJ functionals, reveals that Cs₂AgMBr₆ compounds exhibit half-metallic ferromagnetism, with 100 % spin polarization at the Fermi level. Analysis of the partial density of states highlights the half-metallic ferromagnetic mechanism, confirming predominant ferromagnetic order through parameters such as the exchange splitting energy (Δx), p-d exchange interaction energy (Δx(p-d)), crystal-field energy (Ecrys), and exchange constants (N₀α and N₀β). The negative values of the exchange constants further validated the dominant ferromagnetic order in both s-d and p-d interactions, with unpaired electrons contributing magnetic moments of 2 μB for V, 4 μB for Mn, and 1 μB for Ni-based perovskites. Also, the Curie temperatures are calculated as 385 K, 747 K, and 204 K for V, Mn, and Ni-based perovskites. The overall findings, which reveal 100 % spin polarization and high zT values, underscore the significant potential of Cs₂AgMBr₆ halide perovskites for advancing spintronics and thermoelectric applications.

Low-Cost Purpose-Built Ultra-Low-Field NMR Spectrometer.

Low-field NMR has emerged as a new analytical technique for the investigation of molecular structure and dynamics. Here, we introduce a highly integrated ultralow-frequency NMR spectrometer designed for the purpose of ultralow-field NMR polarimetry of hyperpolarized contrast media. The device measures 10 cm × 10 cm × 2.0 cm and weighs only 370 g. The spectrometer's aluminum enclosure contains all components, including an RF amplifier. The device has four ports for connecting to a high-impedance RF transmit-receive coil, a trigger input, a USB port for connectivity to a PC computer, and an auxiliary RS-485/24VDC port for system integration with other devices. The NMR spectrometer is configured for a pulse-wait-acquire-recover pulse sequence, and key sequence parameters are readily controlled by a graphical user interface (GUI) of a Windows-based PC computer. The GUI also displays the time-domain and Fourier-transformed NMR signal and allows autosaving of NMR data as a CSV file. Alternatively, the RS485 communication line allows for operating the device with sequence parameter control and data processing directly on the spectrometer board in a fully automated and integrated manner. The NMR spectrometer, equipped with a 250 ksamples/s 17-bit analog-to-digital signal converter, can perform acquisition in the 1-125 kHz frequency range. The utility of the device is demonstrated for NMR polarimetry of hyperpolarized 129Xe gas and [1-13C]pyruvate contrast media (which was compared to the 13C polarimetry using a more established technology of benchtop 13C NMR spectroscopy, and yielded similar results), allowing reproducible quantification of polarization values and relaxation dynamics. The cost of the device components is only ∼$200, offering a low-cost integrated NMR spectrometer that can be deployed as a plug-and-play device for a wide range of applications in hyperpolarized contrast media production─and beyond.

Unveiling the NLO Potential of New Zn (II) Complex of 6‐Methylpyridine‐2‐Carboxaldehyde: Experimental/DFT Study on Spectral, Static, and Frequency‐Dependent Linear/Nonlinear Optical Parameters

ABSTRACTOngoing exploration focuses on synthesizing and characterizing coordination compounds to improve the design of nonlinear optical (NLO)‐based materials. In this regard, to examine spectral and static/frequency–dependent linear/NLO parameters, the new Zn (II) complex {[Zn(6‐MePyAld)2(Cl)]; 6‐MePyAld: 6‐methylpyridine‐2‐carboxaldehyde} was synthesized and characterized by using 1H and 13C NMR, mass (LC‐HRMS), powder XRD, and FTIR spectra. The electronic features of synthesized complex were investigated by considering the TD‐CAM‐B3LYP/ and TD‐M06L/6‐311G(d,p)//LanL2DZ levels of time‐dependent density functional theory (TD‐DFT). Moreover, the theoretical linear optical (LO), second‐, and third‐order NLO susceptibility tensors/polarization (χ(1)/P(1), χ(2)/P(2), χ(3)/P(3)) parameters for the Zn (II) complex were computed using the DFT/M06L and DFT/CAM‐B3LYP levels. The external electric field (E), polarization (P), and electric displacement (D) values of the Zn (II) complex were also calculated using the same DFT levels. To investigate microscopic LO (isotropic polarizability <α(0;0)>/<α(−ω;ω)>, and anisotropic polarizability (∆α (0;0)/∆α (−ω;ω)) and second‐/third‐order NLO (<β(0;0,0)>/<β(−ω;ω,0), <β(−2ω;ω,ω)>/<γ(0;0,0,0)>/<γ(−ω;ω,0,0)> and <γ(−2ω;ω,ω,0)>) parameters for the Zn (II) complex, the DFT/M06L and DFT/CAM‐B3LYP levels in the gas phase were used. The ∆α (0;0), ∆α (−ω;ω), <β(0;0,0)>, <β(−ω;ω,0)>, and <β(−2ω;ω,ω)> for Zn (II) complex were computed at 17.288 × 10−24, 21.782 × 10−24, 14.692 × 10−30, 466.80 × 10−30, and 210.79 × 10−30 esu, respectively, by using the DFT/CAM‐B3LYP level. Moreover, the <γ(0;0,0,0)>/<γ(−ω;ω,0,0)> and <γ(−2ω;ω,ω,0)> in the gas phase computed at the DFT/CAM‐B3LYP level for Zn (II) complex were obtained at 129.74 × 10−36, 3997.6 × 10−36, and −886.60 × 10−36 esu, in turn. According to the CAM‐B3LYP level, the <γ(0;0,0,0)> value is 8.65 and 18.53 times higher than the values of para‐nitroaniline (pNA) and urea, respectively. The obtained static/dynamic β and γ values of Zn (II) complex are greater than those of urea and pNA. Zn (II) complex exhibited remarkably microscopic second‐order and particularly third‐order NLO features. It is predicted that our study will shed light on NLO materials that might be used in telecommunication and optoelectronics.

Chemically diverse antimicrobial peptides induce hyperpolarization of the E. coli membrane

The negative membrane potential within bacterial cells is crucial in various essential cellular processes. Sustaining a hyperpolarised membrane could offer a novel strategy to combat antimicrobial resistance. However, it remains uncertain which molecules are responsible for inducing hyperpolarization and what the underlying molecular mechanisms are. Here, we demonstrate that chemically diverse antimicrobial peptides (AMPs) trigger hyperpolarization of the bacterial cytosolic membrane when applied at subinhibitory concentrations. Specifically, these AMPs adopt a membrane-induced amphipathic structure and, thereby, generate hyperpolarization in Escherichia coli without damaging the cell membrane. These AMPs act as selective ionophores for K+ (over Na+) or Cl− (over H2PO4− and NO3−) ions, generating diffusion potential across the membrane. At lower dosages of AMPs, a quasi-steady-state membrane polarisation value is achieved. Our findings highlight the potential of AMPs as a valuable tool for chemically hyperpolarising bacteria, with implications for antimicrobial research and bacterial electrophysiology.

High ferroelectric polarization and bandgap modulation in Sol-gel-Synthesis BiFe1–2xAxCoxO3 (A=Mn2+, Ti4+) polycrystalline films

Co-doping of Fe sites in BiFeO3 polycrystalline films effectively suppresses leakage current. Polycrystalline BiFe1–2xMnxCoxO3 and BiFe1–2xTixCoxO3 (x = 0, 0.01, 0.02, 0.03) films were prepared using the sol-gel spin-coating method. A systematic investigation was conducted to determine the impact of (Mn2+/Ti4+, Co2+) co-doping on the structural, leakage current, ferroelectric, dielectric, and optical properties of BiFeO3 films. Results reveal that BiFe1–2xAxCoxO3 (A=Mn2+, Ti4+) films maintain a stable tripartite structure, with (Mn2+/Ti4+, Co2+) co-doping inducing lattice distortion. The leakage current density of BiFe0.98Mn0.01Co0.01O3 (3.45×10−7 A/cm2) and BiFe0.96Ti0.02Co0.02O3 (2.05×10−6 A/cm2) is reduced by 2–3 orders of magnitude relative to pure BiFeO3. Additionally, these films exhibit high remanent polarization values of 188.4 μC/cm2 and 186.8 μC/cm2, respectively. Optical band gaps decrease with (Mn, Co) co-doping and increase with (Ti, Co) co-doping. The magnetic properties are enhanced with increased (Mn, Co) doping but are reduced as (Ti, Co) doping increases. This study provides enhanced understanding of Fe-site co-doping's role in reducing leakage current and improving ferroelectricity in BiFeO3 films, offering valuable insights for photovoltaic applications involving BiFeO3 thin films.

Corrosion Susceptibility and Microhardness of Al-Ni Alloys with Different Grain Structures

The development of Al-Ni alloys with a controlled microstructure has had a great impact on the field of study of aluminum-based alloys. In the present research, the influence of thermal parameters on the grain structures resulting from the directional solidification process of Al-Ni alloys with different alloy content has been studied. It has also been evaluated how different structures and the distribution of second phases influence the corrosion behavior and microhardness of alloys. The columnar-to-equiaxed transition (CET) was observed to occur when the temperature gradient in the melt decreased to values between 1.3 and 2.9 °C/cm. In addition, a small increase in the microhardness values was observed as a function of the Ni content. When the Ni content increases, the resistance to polarization decreases for samples with equiaxed grain structure throughout the range of compositions studied. Furthermore, the equiaxed grain structure presents higher resistance to polarization values than the columnar grain zone for alloys with a composition equal to or lower than the eutectic composition.

Polarization and hate speech based on fuzzy logic and transformers: the case of the 2023 Spanish general elections

ABSTRACT Affective polarization in the digital debate of the Spanish presidential election campaign (2023), following the sudden call of the Spanish president on July 23, was measured. Using transformers, topics were detected, and sentiment analysis techniques were applied in the political debate during the elections to measure the emotional valence of the debate. The topics that dominate most of the debate are Candidates (n1 = 17170) and Opposition (n3 = 15327). These topics also show the highest typical polarization deviances. Based on affective polarization, a polarization measure (JDJ) grounded in the fuzzy sets was applied. The topic activism has the highest polarization value, while the topic of voting has the lowest. This analysis highlights a dichotomy that defines the Spanish political reality: the positive image of conventional political participation in the face of the rejection of collective action processes.

Dibenzodioxin-Based Polymers of Intrinsic Microporosity with Enhanced Transport Properties for Lithium Ions in Aqueous Media.

Boosting the transport and selectivity properties of membranes based on polymers of intrinsic microporosity (PIMs) toward one specific working analyte of interest is challenging. In this work, a novel family of PIM membranes, prepared by casting and exhibiting optima mechanical properties and high thermal stability, was synthesized from 4,4'-(2,2,2-trifluoro-1-phenylethane-1,1-diyl) bis(benzene-1,2-diol) and two tetrafluoro-nitrile derivatives. Gas permeability measurements evidenced a CO2/CH4 selectivity up to 170% relative to the reference polymer, PIM-1, in agreement with their calculated fractional free volume and the analysis of the textural properties by N2 and CO2 gas adsorption. Besides, the chemical modification by acid hydrolysis of the PIM membranes favored the permeability for lithium ions (LiCl 2M, 6 × 10-9 cm2·s-1) compared to other alkali metal analogs such as sodium (NaCl 2M, 7.38 × 10-10 cm2·s-1) and potassium (KCl 2M, 1.05 × 10-9 cm2·s-1). Moreover, the complete mitigation of the crossover of redox species with higher molecular sizes than the ions from alkali metal salts was confirmed by using in-line benchtop NMR methods. Additionally, the modified PIM membranes were measured in a symmetric electrochemical flow cell using an aqueous electrolyte by combining lithium ferro/ferricyanide redox compounds and lithium chloride. The electrochemical tests showed low polarization, high-rate capability, and capacity retention values of 99% when cycled at 10 mA·cm-2 for over 50 cycles. Based on these results, these polymers could be used as highly selective and conducting membranes in electrodialysis for lithium separation and lithium-based redox flow batteries and as a protective layer in high-energy density lithium metal batteries.