A Co-nitronyl nitroxide two-dimensional coordination network with formula {[Co(hfac)2]3(NITPh-2F-4CN)2}n·nC6H14 (hfac = hexafluoroacetylacetonate; NITPh-2F-4CN = 2-(2'-fluoro-4'-cyanophenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) has been synthesized through the reaction of NITPh-2F-4CN radical with Co(hfac)2·2H2O. The crystal structure reveals that NITPh-2F-4CN acts as a tridentate ligand to bridge three Co(II) ions, resulting in a 2D coordination polymer of interlinked [Co-NIT]n chains. Noteworthy, the bridging NIT moieties have rare trans position in the coordination sphere of the Co(II) center. Magnetometry studies indicate strong antiferromagnetic Co-aminoxyl exchange and the absence of detectable interchain interactions, resulting in a ferrimagnetic chain with bistable SCM behavior. Magnetization becomes blocked below 10.5 K, resulting in a M versus H hysteresis loop with a coercive field up to 4.65 kOe for 5 K. These chains are characterized by an activation barrier for spin flipping of Δτ/kB = 298 K. This 2D compound is the first example of a Co-NIT SCM-based coordination network and its magnetic properties confirm a strictly 1D ferrimagnetic system exhibiting single-chain magnet behavior.

This study systematically examines the dynamic magnetic hysteresis behavior of a mixed-spin (3/2, 7/2) Blume–Capel Ising system on a hexagonal lattice, using the Path Probability Method (PPM). We analyze the effects of temperature, oscillating magnetic field frequency, crystal field and kinetic rate constants on coercive fields (CFs), remanent magnetizations (RMs) and the shape of hysteresis loops. Our results show complex and varied hysteresis behaviors, including single, double, triple and quintuple loops, with a strong dependence on these parameters. Notably, the kinetic rate constant, similar to the cooling rate in rapid solidification, significantly influences loop shape and area, emphasizing PPM’s strength in linking theoretical insights with practical material synthesis.

Visual memristors, which integrate resistive switching with optical feedback, are attracting growing interest for neuromorphic computing, nonvolatile storage, and human-machine interfaces. By directly coupling electrical states with optical outputs, such devices enable both data processing and intuitive visualization, providing new opportunities for interactive and multifunctional systems. Here, we innovatively demonstrate a carbon dot (CD)-based visual memristor that combines reliable resistive switching with tunable electroluminescence. The device exhibits stable storage, reproducible hysteresis loops, and multilevel conductance control, while its emission spectra systematically evolve with resistive states, enabling "visible" memory and computation. This dual-mode behavior bridges the electrical and optical domains, closely resembling synaptic plasticity and supporting artificial neuromorphic functions. Benefiting from the unique properties of CDs, including strong luminescence, abundant surface functionalities, and facile solution processing, the proposed device represents a new platform for multifunctional optoelectronic systems. These results open pathways toward next-generation neuromorphic optoelectronics that unify perception, memory, and processing.

Achieving high recoverable energy density (Wrec) with near-unity efficiency (η) in lead-free dielectrics remains a major challenge for advanced pulse power capacitors, given their central role in emerging pulsed power systems and high-voltage electronics. Here, we show that targeted engineering of dynamic dipole behavior provides an effective route to remarkable energy storage performance. Guided by phase-field simulations, we design (Bi0.5Na0.5)TiO3 (BNT)-based multilayer ceramic capacitors that transform a continuous network of strongly correlated dipoles into discrete nano-domains. Within each nano-domain, dipoles retain strong local cooperativity, which maintains high polarization while markedly suppressing hysteresis losses. As a result, the optimized multilayer ceramic capacitors (MLCCs) achieve a recoverable energy density of 16.2 J cm-3, an η below 1.5%, and a record-high figure of merit (WF) of 1080 at 650kV cm-1. This moderate operating field also produces an ultrahigh energy storage strength (ξ) of 249 J kV-1 m-2, highlighting the efficiency of the dipole-regulation strategy. These findings demonstrate that weakly correlated and dynamic dipoles can be harnessed to advance high-performance, lead-free energy storage devices and offer a viable design principle for next-generation capacitive technologies.

Aiming at analyzing the load characteristics and friction torque of triple-row hub bearings for new energy vehicles, this work established a comprehensive theoretical and experimental methodology for predicting the internal load distribution and friction torque. Firstly, considering the preload effect via an initial negative clearance, deformation coordination and force balance equations for the triple-row bearing under axial load were formulated, to analyze the external loads under various driving conditions. Based on contact deformation theory, a quasi-static model was developed to combine radial, axial, and moment loads. The Newton–Raphson iterative algorithm was employed to solve the ball load distribution equations, and the correctness was verified by using the finite element method. Furthermore, accounting for the elastic hysteresis, differential sliding, and spin sliding, the theoretical models for friction torque components were established, to investigate the influence of structural parameters and the total friction torque under different driving conditions. Finally, to confirm the effectiveness and the precision of the model, a finite element simulation and experimental measurements of friction torque were conducted, respectively, which showed good agreement with theoretical calculations. The main innovations include proposing a mechanical modeling method for triple-row hub bearings that accounts for preload effects, and establishing an integrated friction torque analysis model applicable to multiple driving conditions. This work provides theoretical support and a methodological foundation for the design of next-generation hub bearings for new energy vehicles.

Dielectric capacitors are essential for high-power, fast-response electronics, but their performance is limited by trade-offs between high polarization, low hysteresis loss, and high breakdown strength. The urgent need for eco-friendly materials has spurred intense interest in lead-free oxide dielectrics. Recent advances in synthesis and advanced characterization have revealed that atomic- and nanoscale local structures exert a profound influence on energy-storage performance. Specifically, local polar nanoregions, chemical inhomogeneities, lattice distortions, and interfacial architectures play a pivotal role in regulating polarization configuration, leakage behavior, and breakdown pathways. This review systematically summarizes recent progress in lead-free dielectric oxides through local structural design. After a concise overview of dielectric energy-storage principles and classification, representative systems are discussed, with a focus on how specific local structural motifs correlate with macroscopic performance. The emerging strategies, such as local chemical framework design, high-entropy approaches, polar nanodomain engineering, local microstructure architectures, multiphase/heterogeneous interfaces, and local amorphous design, are summarized. By integrating key advances in this field, the review clarifies intrinsic structure-property relationships, identifies current challenges, and outlines opportunities for future breakthroughs, which could deliver timely guidance for designing high-performance and environmentally benign dielectric capacitors.

Relaxor ferroelectrics (RFEs) exhibit complex heterogeneity of polarity at the nanoscale due to polar nano-regions (PNRs). They are commonly crystalline-based materials and widely applied for energy storage, electrostrictive actuators, and electrocaloric devices. In this work, we find a fluid-based relaxor-like ferroelectric in single-component polar nematic fluids, which intrinsically appears as a precursor of emerging ferroelectric fluids with nematic order, dubbed as nematic relaxor-like ferroelectric (nRFE) liquid crystals. The characteristic relaxor-like behaviors, including high permittivity, diffuse phase transitions, frequency dispersion in dielectric response, and slim polarization-electric field hysteresis loop, are identified in all polar nematic fluids experiencing N-NF phase transition. These unique dielectric responses would be attributed to the short-range polar order in the high-temperature N phase, triggered by strong local dipole-dipole interaction. The chemical structure influences the thermal range and stability of the relaxor-like state, the incorporation of thioester linkages proving advantageous for promoting relaxor-like behavior. Furthermore, the relaxor-like polar nematic demonstrates impressive performance under low electric field conditions, presenting notable benefits for various electro-optic devices that necessitate relatively high driving voltages.

Accurate prediction of magnetic core loss is a key challenge for improving the efficiency and reliability of power electronic systems. Traditional empirical models such as the Steinmetz equation are only applicable to sinusoidal steady-state conditions and struggle with the complex non-sinusoidal waveforms and variable operating conditions in modern power electronics. While existing deep learning methods have shown improvements, they still face fundamental limitations in handling the nonlinear mismatch between B(t) and H(t) waveforms, coupling of multi-scale loss mechanisms, and generalization under extreme operating conditions. This paper proposes an Enhanced Memory Augmented Mamba (EMA-Mamba) model that achieves breakthrough progress in magnetic core loss prediction. It utilizes a state-space memory augmentation mechanism that stores and retrieves typical magnetization patterns through a trainable external memory matrix, endowing the model with a capability similar to the “magnetic memory” of magnetic materials, effectively solving the gradient vanishing problem in long sequence modeling. Combined with an attention-guided intelligent feature selection mechanism, it adaptively identifies critical turning points in hysteresis curves through a Top-K strategy, fundamentally solving the temporal mismatch problem between B(t) and H(t) waveforms. Finally, through a physics-constrained multi-objective optimization framework, it achieves decoupled modeling of hysteresis loss, eddy current loss, and residual loss through loss function combination, overcoming the optimization difficulties caused by data spanning six orders of magnitude. Experiments on the MagNet dataset containing 10 materials and over 150,000 data points show that EMA-Mamba achieves an average prediction error of 4.50% and a coefficient of determination of 99.9947%, reducing error by 34.2% compared to state-of-the-art baseline methods, with a 36.2% reduction in 95th percentile error under extreme conditions. The model demonstrates excellent temperature robustness and cross-material generalization capability, providing a reliable theoretical tool for intelligent design and optimization of magnetic components.

Na0.5Bi0.5TiO3 (NBT) is a promising lead-free ferroelectric material and has a unique A-site substitution structure with rhombohedral (R3c) symmetry at ambient conditions. Combining in situ polarization–electric field (P–E) hysteresis loops, Raman spectroscopy, x-ray diffraction measurements, and ab initio calculations, here we report a pressure-induced polar–nonpolar–polar phase crossover in NBT with a two-stage structural transition from R3c to P21/m and then to Pmn21 symmetry. Electrical resistance and absorption spectroscopy measurements demonstrate the abnormal changes around 5 and 13 GPa, corresponding to the two-stage phase transitions. Detailed charge density difference analyses reveal that the structural transition causes a synergistic change of Ti cation off-center displacement and octahedron tilting angle, leading to the ferroelectric–paraelectric–ferroelectric transition under pressure. These results establish a phase transition sequence of NBT with intriguing ferroelectric and electronic evolution, which helps to resolve the controversial structural conversion process in NBT and expand our understanding of lead-free ferroelectric under extreme conditions.

Lead-free relaxor ferroelectric ceramics are promising candidates for advanced pulsed power systems owing to their combination of exceptional power density and ultrafast charge-discharge capabilities. However, the simultaneous realization of ultrahigh recoverable energy density (Wrec) and high efficiency (η) remains a persistent challenge, as strategies to enhance polarization typically increase hysteresis losses. To address this issue, we propose a strategy actively constructing a superrelaxor critical state-a crossover from dynamic to static/frozen relaxor states-through targeted compositional tuning and polarization configuration control. Guided by phase-field simulations and first-principles calculations, we introduce BaHfO3 into a Sr0.5Bi0.25Na0.25TiO3 relaxor matrix. This approach successfully shifted the dielectric maximum temperature to room temperature and enhanced the strength of relaxor behavior. Atom-scale structural characterization reveals that this structure weakens local domain interactions within 3 - 5 nm refined polar nanoregions yet preserving robust polar atomic displacements, effectively bridging the kinetic advantage of superparaelectrics with the dipole magnitude of classical relaxors. As a result, the superrelaxor critical state delivers a giant energy-storage capability, including Wrec of 16.2 J/cm3 with a high η of 92%, outperforming most reported lead-free ceramics. This work establishes a generalizable strategy for engineering critical polarization states in dielectric oxides toward next-generation capacitive energy storage.

Ferroelectric ultrathin films tend to favor a homogeneous polar state at strong interfacial bound charge screening conditions. Reducing screening parameter (β) may induce topological textures such as vortices, labyrinth stripes, and skyrmion bubbles. Here, we explore β-and temperature-induced phase transitions of polarization reversal in ferroelectric PbZr 0.2 Ti 0.8 O 3 (PZT) thin films using phase-field simulations under a 1% compressive strain. The results unveil a phase diagram comprising polarization reversal, hysteresis loop and topological structures. At room temperature, a phase transition from ferroelectric (FE) to antiferroelectric-like (AFE*) state occurs at β ∼ 0.53. At increasing temperatures, the FE and AFE* phases convert to a paraelectric (PE) state and form a tricritical point at β ∼0.78 and T∼ 770 K. Notably, at the phase boundary, a coexistence region of uniform polarization and isolated skyrmion bubbles emerges in a narrow screening range, which can be modulated by an applied electric field. Moreover, simulations of thermal effects on the FE to AFE* phase transition via the indirect method reveal a large electrocaloric effect around room temperature at low electric fields. Our findings uncover rich phenomena and elucidate underlying mechanisms in ferroelectric thin films, which hold promise for advanced device applications.

The transition to sustainable energy is crucial for mitigating climate change impacts, with hydrogen and carbon storage and utilization technologies playing pivotal roles. This review highlights the integral and useful role of microfluidic technologies in advancing subsurface fluid dynamics for carbon capture, utilization, and storage (CCUS), enhanced oil recovery (EOR), and underground hydrogen storage (UHS). In particular, microfluidic platforms provide clear and insightful visualization of fluid-fluid and fluid-solid interactions at the pore scale, crucial for understanding and further optimizing processes for CO2 sequestration, hydrogen storage, and oil displacement in various geological formations. We first discuss the development of lab-on-a-chip devices that accurately mimic subsurface conditions, allowing detailed studies of complex phenomena including viscous fingering, capillary trapping, phase behavior during CCUS and EOR processes, and the hysteresis effects unique to hydrogen storage cycles. We also discuss the dynamics of CO2 gas and foam in enhancing oil recovery and the innovative use of hydrogen foam to mitigate issues associated with pure hydrogen gas storage. The integration of advanced imaging, spectroscopic techniques, and machine learning (ML) with microfluidic experiments has enriched our understanding and opened new pathways for predictive capabilities and operational optimization in CCUS, EOR, and UHS applications. We further emphasize the critical need for continued research into microfluidic applications, e.g., incorporating state-of-the-art ML to optimize microfluidic experiments and parameters, and UHS enhancement through favorable microbial activities and suppression of reactions in H2 foam, aiming at refining storage strategies and exploiting the full potential of these technologies towards a sustainable energy future.

Due to the hysteresis phenomenon of ferromagnetic materials, an unknown remanence BR will be generated after the material is disconnected from the power supply, which can cause a considerable inrush current, so that the safety of electrical equipment can be seriously affected. Therefore, various methodologies for evaluating the remanence have been proposed to achieve more effective demagnetization of ferromagnetic materials. However, the proposed remanence evaluation only applies in certain exceptional cases due to the lack of physical significance. In this study, based on the maximum irreversible differential magnetization [max(dMirr/dH), MIDM], a new remanence evaluation method is proposed. First, based on the Jiles-Atherton (J–A) hysteresis theory, a relationship between the MIDM and the remanence is investigated. Then, hysteresis loops under the different remanence are used to obtain the MIDM for the remanence estimation in practice. Finally, an experimental platform based on the Epstein frame is used to examine the reliability of this approach. The obtained results indicate that the proposed method has an error range of 2.72%–9.67% in experiments. This study provides a new theoretical basis for the remanence evaluation, which has essential scientific theoretical significance.

Lightweight thin aluminium sheets are increasingly used in transportation and packaging industries, but their reliable joining remains challenging due high residual stresses, and poor fatigue resistance in conventional fusion welding. This study addresses these limitations by employing pinless friction stir welding to fabricate 0.5 mm thin commercially pure aluminium lap joints, and systematically investigating their microstructural, mechanical, residual stress, and fatigue behaviour. Defect-free welds were obtained without hook or cold lap formation, though limited flash and thickness reduction were observed. X-ray diffraction residual stress analysis revealed predominantly compressive stresses, limited to −3.8 ± 8 MPa. Low-cycle fatigue tests demonstrated stable cyclic response at 0.2% strain amplitude, while higher amplitudes (0.3–0.7%) caused strong cyclic softening linked to grain coarsening. Hysteresis loop analysis confirmed strain-dependent energy dissipation, with widening and rotation at higher amplitudes. Overall, the study establishes that pinless FSW enables sound joints in ultra-thin aluminium sheets with low residual stresses, reasonable lap shear strength, and cyclic deformation response, making it a promising technique for lightweight structural applications.

We report a combinedexperimental and numerical investigationofspin-wave dynamics in a hybrid magnonic crystal consisting of a CoFeBartificial spin ice (ASI) of stadium-shaped nanoelements patternedatop a continuous NiFe film separated by a 5 nm Al2O3 spacer. Using Brillouin light scattering spectroscopy, weprobe the frequency dependence of thermal spin waves as functionsof applied magnetic field and wavevector, revealing the decisive roleof interlayer dipolar coupling in the magnetization dynamics. Micromagneticsimulations complement the experiments, showing a strong interplaybetween ASI edge modes and backward volume modes in the NiFe film.The contrast in saturation magnetization between CoFeB and NiFe enhancesthis coupling, leading to a pronounced hybridization manifested asa triplet of peaks in the BLS spectrapredicted by simulationsand observed experimentally. This magnon–magnon coupling persistsover a wide magnetic field range, shaping both the spin-wave dispersionat fixed fields and the full frequency-field response throughout themagnetic hysteresis loop. Our findings establish how ASI geometrycan selectively enhance specific spin-wave wavelengths in the underlyingfilm, thereby boosting their amplitude and identifying them as preferentialchannels for spin wave transmission and manipulation.

Two-dimensional (2D) ferromagnetic materials with high magnetic crystalline anisotropy energy and high Curie temperature are in high demand for magnetic storage devices. In this work, we employ first-principles calculations and Monte Carlo simulations to systematically investigate the crystalline structure, and electronic and magnetic properties of the Janus VSeTe monolayer at different carrier concentrations. It is found that with appropriate carrier doping, the Janus VSeTe monolayer undergoes a transition from a semiconductor to a half-metal with 100% spin polarization. The obtained magneto crystalline anisotropy energy is 1157.72 µeV, and the easy magnetic axis undergoes a transition from the in-plane to out-of-plane with hole doping. In addition, the Janus VSeTe monolayer exhibits a valley splitting of 86 meV and a Curie temperature of 454 K. With hole doping, the valley splitting increases to 110 meV and the Curie temperature rises to 510 K. The coercivity calculated from the hysteresis loop is 0.13 T, and its hysteresis loss is low, showing its rapid response to external magnetic fields. Our work demonstrates the broad application potential of the Janus VSeTe monolayer in spintronic devices and provides theoretical support for future experiments.

Finite-time and fixed-time self-triggered synchronization of stochastic memristive neural networks and applications in secure communication.

The creation of adaptive memory based on soft matter, similar to the brain, is an attractive and challenging research area. Hysteresis is closely related to adaptive memory because it involves a system's ability to retain and utilize information about its past states or inputs to influence its current and future behavior. To achieve adaptive memory control, it is highly desirable to develop stimuli-responsive hydrogels with a tunable hysteresis in the volume phase transition. Herein, we propose a one-pot synthesis method to develop environmentally adaptive memory by preparing dual-responsive hydrogels (e.g., poly(N-isopropylacrylamide-co-acrylic acid)-g-methylcellulose). The range of the hysteresis window in temperature-dependent shape morphing can be adjusted from approximately 0 °C to 17.6 °C by changing the pH stimulus. Furthermore, the thermal hysteresis windows adapt to the surrounding temperature autonomously. The P(NIPAm-co-AAc)-g-MC hydrogel can maintain a series of small hysteresis loops, which are suitable for memorizing multiple states. Applications in microvalves, hydrogel patterns and smart windows are successfully demonstrated, leveraging the intrinsic hysteresis behavior of the hydrogels. The memory function can switch between memorizing and forgetting behavior, and the memory window adapts to environmental stimuli autonomously. This work contributes an innovative strategy to the development of adaptive memory based on soft materials, paving the way for more intelligent systems.

Al<sub>1–<i>x</i></sub>Sc<sub><i>x</i></sub>N, as a new generation of wurtzite-type ferroelectric material, has become a focal point in ferroelectric materials research in recent years, due to its high remnant polarization, nearly ideal rectangular polarization-electric field hysteresis loops, inherent compatibility with back-end-of-line (BEOL) CMOS processes, and stable ferroelectric phase structure. The systematic and in-depth studies on the preparation, property modulation, and device applications of this material have been conducted. This paper provides a comprehensive review of the research progress of Al<sub>1–<i>x</i></sub>Sc<sub><i>x</i></sub>N ferroelectric thin films. Regarding the factors influencing ferroelectric properties, it emphasizes the regulatory effects of Sc doping concentration on phase transition and coercive field, explores the influences of substrate (such as Si and Al<sub>2</sub>O<sub>3</sub>) and bottom electrode (such as Pt, Mo, and HfN<sub>0.4</sub>) on thin-film orientation, stress, and interface quality, and systematically summarizes the influences of deposition conditions, film thickness, testing frequency, and temperature on ferroelectric performance. At the level of physical mechanisms governing polarization switching, this review elaborates on the domain structure, domain wall motion dynamics, nucleation sites and growth mechanisms in the Al<sub>1–<i>x</i></sub>Sc<sub><i>x</i></sub>N switching process, revealing its microscopic response behavior under external electric fields and the mechanisms underlying fatigue failure. In terms of application prospects, Al<sub>1–<i>x</i></sub>Sc<sub><i>x</i></sub>N thin films show significant advantages in memory devices such as ferroelectric random-access memory (FeRAM), ferroelectric field-effect transistors (FeFETs), and ferroelectric tunnel junctions (FTJs). Their high performance and integration compatibility provide strong technical support for developing next-generation, high-density, low-power ferroelectric memory and nanoelectronic devices.

A genetic algorithm-based calibration procedure for hysteresis loops in timber structures