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Mn+1AXn-phase Ti2AlN thin-films were synthesized using reactive sputtering-based methods involving the deposition of single-layer TiAlN, and Ti/AlN and TiN/TiAl multilayers of various modulation periods at ambient temperature and subsequent annealing at elevated temperatures. Ex situ and in situ x-ray diffraction measurements were used to characterize the Ti2AlN formation temperature and phase fraction. During annealing, Ti/AlN multilayers yielded Ti2AlN at a significantly lower in situ temperature of 650 °C compared to TiN/TiAl multilayers or single-layer TiAlN (750 °C). The results suggest a reactive multilayer mechanism whereby distinct Ti and AlN layers react readily to release exothermic energy resulting in lower phase transition temperatures compared to TiN and TiAl layers or mixed TiAlN. With a modulation period of 5 nm, however, Ti/AlN multilayers yielded Ti2AlN at a higher temperature of 750 °C, indicating a disruption of the reactive multilayer mechanism due to a higher fraction of low-enthalpy interfacial TiAlN within the film. [ABSTRACT FROM AUTHOR]

Epitaxial W–Mo multilayers are employed as a model system to demonstrate how resistivity measurements parallel to metal–metal interfaces can be used to quantify the specific interface resistance without sub-10-nm patterning that would be required for direct transport measurements across the interface. 50-nm-thick epitaxial multilayer stacks containing 2–60 individual W(001) and Mo(001) layers are deposited on MgO(001) substrates and their resistivity ρ measured as a function of superlattice period Λ at 293 and 77 K. The measured room temperature ρ increases from 7.10 to 8.62 μΩ cm with decreasing Λ = 50–1.7 nm, which is attributed to the increasing electron-interface scattering. The semiclassical Fuchs–Sondheimer model for surface scattering dramatically overestimates the resistivity, which is attributed to coherent electron transmission across multiple interfaces. A new Boltzmann transport model treats each interface as a boundary condition where electrons either scatter diffusely or traverse without momentum loss with a probability T for the first encountered interface and with 100% transmission at subsequent interfaces until they are relaxed by a bulk scattering event. This model has a single unknown parameter T, which becomes the fitting parameter for experimental data analysis, yielding a temperature-independent T = 0.8 ± 0.1 and a corresponding contact resistance at the W(001)–Mo(001) interface of 2.6 × 10−16 Ω m2. [ABSTRACT FROM AUTHOR]

The Ruderman–Kittel–Kasuya–Yosida (RKKY) theory of oscillatory exchange interaction in synthetic antiferromagnetic multilayers results in the oscillation behavior of giant magnetoresistance ratio. In addition, the formation of Yu–Shiba–Rusinov (YSR) bound states will induce an extra antiferromagnetic interaction, which is expected to mediate stronger exchange coupling than conventional RKKY interaction. However, the YSR bound states have only been studied in some superconducting hosts with magnetic impurities. The narrow range of material systems that are not compatible with the device integration architecture limits the practical application of YSR interaction. Here, we observe the RKKY interaction and provide the evidence for YSR interaction in Pt/(Co/Pt)2/Nb/(Pt/Co)2/Pt synthetic antiferromagnetic multilayers by quantitatively determining the coupling energy via ferromagnetic resonance technique. [ABSTRACT FROM AUTHOR]

Electronic relaxation dynamics of solution-phase redox-exfoliated molybdenum disulfide (MoS2) monolayer and multilayer ensembles are described. MoS2 was exfoliated using polyoxometalate (POM) reductants. This process yields a colloidal heterostructure consisting of MoS2 2D sheet multilayers with surface-bound POM complexes. Using two-dimensional electronic spectroscopy, transient bleaching and photoinduced absorption signals were detected at excitation/detection energies of 1.82/1.87 and 1.82/1.80 eV, respectively. Approximate 100-fs bandgap renormalization (BGR) and subsequent defect- and phonon-mediated relaxation on the picosecond timescale were resolved for several MoS2 thicknesses spanning from 1 to 2 L to ∼20 L. BGR rates were independent of sample thickness and slightly slower than observations for chemical vapor deposition-grown MoS2 monolayers. However, defect-mediated relaxation accelerated ∼10-fold with increased sample thicknesses. The relaxation rates increased from 0.33 ± 0.05 to 1.2 ± 0.1 and 3.1 ± 0.4 ps−1 for 1–2 L, 3–4 L, and 20 L fractions. The thicknesses-dependent relaxation rates for POM-MoS2 heterostructures were modeled using a saturating exponential function that showed saturation at thirteen MoS2 layers. The results suggest that the increased POM surface coverage leads to larger defect density in the POM-MoS2 heterostructure. These are the first descriptions of the influence of sample thickness on electronic relaxation rates in solution-phase redox-exfoliated POM-MoS2 heterostructures. Outcomes of this work are expected to impact the development of solution-phase exfoliation of 2D metal-chalcogenide heterostructures. [ABSTRACT FROM AUTHOR]

Despite the potential use of polyelectrolyte multilayers for biomedical, separation, and energy applications, their dynamic properties are not sufficiently understood. In this work, center-of-mass diffusion of a weak polyacid—poly(methacrylic acid) (PMAA) of linear and 8-arm architecture (L-PMAA and 8-PMAA, respectively) and matched molecular weight—was studied in layer-by-layer (LbL) assemblies with poly(diallyldimethylammonium) chloride (PDADMAC) of varied molecular weight. The film deposition at low-salt, acidic conditions when PMAA was only partially ionized yielded thicker, more diffused layers with shorter PDADMAC chains, and bilayer thickness decreased for multilayers constructed with longer PDADMAC. The molecular architecture of PMAA had a weak effect on film growth, with bilayer thickness being ∼20% larger for L-PMAA for the films constructed with the shortest PDADMAC (35 kDa) and identical film growth for L-PMAA and 8-PMAA with the longest PDADMAC (300 kDa). The exposure of the multilayer films to 0.2M NaCl triggered a reduction in PMAA ionization and significant lateral diffusivity of fluorescently labeled PMAA molecules (PMAA*), with diffusion coefficients D ranging from 10−13 to 10−12 cm2/s, as determined by the fluorescence recovery after photobleaching technique. For all the films, polymer mobility was higher for star polyacids as compared to their linear counterparts, and the dependence of PMAA diffusion coefficient D on PDADMAC molecular weight (D ∼ M−n) was relatively weak (n < 0.6). However, 8-PMAA demonstrated an approximately doubled power exponent compared to the L-PMAA chains, suggesting a stronger effect of the molecular connectivity of the partner polycation molecules on the diffusion of star polyelectrolytes. [ABSTRACT FROM AUTHOR]

Due to their nanoscale features, nanometric multilayers can have a large variation in properties for varying bilayer heights. While the hardening at small feature sizes and the consequent softening at even smaller feature sizes have been observed for decades, the underlying mechanisms are still under debate. In this study, molecular dynamics uniaxial compression simulations are employed to study the mechanical properties of Al/Ni multilayers for bilayer heights h from 100 nm down to 5 nm. The effect of the microstructure on Young's modulus and the yield strength was investigated. Furthermore, the mechanical properties of equiatomic and equivolumetric multilayers were compared. A comparison with experimental results from the literature showed good agreement. Both the hardening at intermediate bilayer heights as well as the softening at very small bilayer heights were observed. The results are discussed in the context of possible hardening and softening mechanisms. While the Hall–Petch effect with a h − 1 / 2 scaling is not contradicted, it is shown that, although the underlying mechanisms are different, both the hardening as well as the softening are based on a general size effect with a scaling of ln (h) / h. [ABSTRACT FROM AUTHOR]

In the present paper, we apply a blind fitting algorithm to model two-dimensional energy-incidence angle maps of soft x-ray resonant reflectivity measured in nanoscale epitaxial multilayers of multiferroic ε-Fe2O3 grown by pulsed laser deposition. The possibility of fitting the spectral shape of the complex refraction index across the Fe L3 absorption edge without having an initial guess about the optical constants has been demonstrated. The spectral shape fitting of the real (f1) and imaginary (f2) parts of the atomic scattering factor has been carried out by using a specially designed software utilizing OpenCL fast calculations on graphical processing units. The Kramers-Kronig relations between f1 and f2 are automatically taken into account by the fitting algorithm. A reasonable agreement between blindly generated and reference scattering factor spectra derived independently from an x-ray absorption spectroscopy experiment has been demonstrated. The blind fitting has been compared with the alternative refinement routines, in which small free variations of the reference spectral shapes (or no variations at all) have been allowed. The presented approach to the resonant x-ray reflectometry modeling makes it unnecessary to acquire the optical constant spectral shapes in advance and, thus, is especially helpful when such spectra cannot be physically measured, e.g., for a buried layer of a multilayer system. [ABSTRACT FROM AUTHOR]

Short-period 2.5 nm W/B4C multilayers are useful as dispersive Bragg reflectors in wavelength-dispersive x-ray fluorescence. However, high roughness at the W–B4C interfaces deteriorates optical performance. To improve this, low-energy neon ion beam polishing (IBP) has been applied in sputter-deposited 2.5 nm W/B4C multilayers. Two energies, 200 and 50 eV, were investigated to study the effects of polishing by sputter removal (200 eV) and polishing by the mobilization of weakly bound surface atoms (50 eV). Atomic force microscopy and x-ray scattering showed reduced interface roughness for both IBP energies. However, the optical constant profile of 200 eV IBP showed strong W–B4C intermixing and interface asymmetry, leading to significant reflectance loss. In contrast, 50 eV IBP resulted in sharp, symmetric interfaces and increased optical contrast. A 43% peak reflectance at θ = ⁓9.7° grazing for W/B4C with 50 eV IBP was measured at λ = 0.834 nm—a 6.4% increase relative to non-polished W/B4C, corresponding to a 25% increase in integrated reflectance. These results highlight the necessity of using low-energy ion polishing by the mobilization of weakly bound surface atoms in short-period multilayers—rather than polishing by sputter removal. [ABSTRACT FROM AUTHOR]

Bimetallic, reactive multilayers are uniformly structured materials composed of alternating sputter-deposited layers that may be ignited to produce self-propagating mixing and formation reactions. These nanolaminates are most commonly used as rapid-release heat sources. The specific chemical composition at each metal/metal interface determines the rate of mass transport in a mixing and formation reaction. The inclusion of engineered diffusion barriers at each interface will not only inhibit solid-state mixing but also may impede the self-propagating reactions by introducing instabilities to wavefront morphology. This work examines the effect of adding diffusion barriers on the propagation of reaction waves in Co/Al multilayers. The Co/Al system has been shown to exhibit a reaction propagation instability that is dependent on the bilayer thickness, which allows for the occurrence of unstable modes in otherwise stable designs from the inclusion of diffusion barriers. Based on the known stability criteria in the Co/Al multilayer system, the way in which the inclusion of diffusion barriers changes a multilayer's heat of reaction, thermal conductivity, and material mixing mechanisms can be determined. These factors, in aggregate, lead to changes in the wavefront velocity and stability. [ABSTRACT FROM AUTHOR]

Short-period multilayer mirrors are used in wavelength-dispersive x-ray fluorescence to reflect and disperse elements in the O-Kα– Al-Kα range. In this work, we investigated sputter-deposited 2.5 nm W/Al with 20 periods. Our results show that W/Al is a poor reflector due to a combination of high interfacial roughness and strong W–Al intermixing. To address this, we introduced 0.5 nm Si seed layers at the W-on-Al and Al-on-W interfaces each consecutive period, while reducing the Al thickness from ∼2.0 to ∼1.0 nm. The Si seed layers significantly reduced interfacial roughness and W–Al intermixing, which led to an increase in the reflectance of the first Bragg peak at λ = 0.154 nm. To further reduce interfacial roughness, ion beam polishing of the top Si layer was applied at each period. The resulting structure of W/Si/Al/Si with ion beam polishing showed that the reflection coefficient of the first Bragg peak at λ = 0.154 nm was comparable to that of standard W/Si. These findings demonstrate the effectiveness of seed layers combined with polishing techniques in synthesizing smooth, high-reflectance multilayers containing two materials that are otherwise challenging to synthesize. [ABSTRACT FROM AUTHOR]

Exceptional points (EPs) are critical phase points in non-Hermitian systems, exhibiting fantastic physical phenomena and plenty of applications, such as unidirectional reflectionless and ultrahigh-sensitive detection of perturbations. Here, a non-Hermitian metasurface based on multilayers split-ring resonators (SRRs) is proposed with specific EP effects. By changing the angle of the SRRs and adjusting the geometric parameters of the metasurface, EPs are generated with topologically protected 2π-phase accumulation. A unique EP effect can be achieved in the THz region, and high-performance sensing of environment refractive index can be realized around the EP position. Therefore, this work demonstrates an EP-based sensing enhancement at non-Hermitian systems compared to Hermitian ones and paves the way for the design of high-performance THz sensors based on topological polaritonic effects. [ABSTRACT FROM AUTHOR]

A nano-multilayered ZrN/TiAlN was deposited as the interlayer to enhance the coating hardness and wear resistance between the inner TiAlN and outer ZrN layers. The structural evolution and mechanical performance of the multilayer coatings were significantly achieved. High-resolution transmission electron microscopy (HRTEM) revealed a local epitaxial growth between the nano multilayers, in which (111) crystal planes for TiAlN was parallel to (111) crystal planes for ZrN. Nanoindentation experiments were conducted to evaluate the mechanical properties. TiAlN-ZrN/TiAlN-ZrN and ZrN-TiAlN-ZrN/TiAlN-ZrN featuring a multilayered architecture, exhibited the higher hardness values of 24.68 ± 3.27 GPa and 25.34 ± 3.42 GPa respectively. Additionally, The wear mechanism for coatings under a load of 10N was dominated by abrasive wear, whereas that under a load of 15N was mainly oxidation wear and abrasive wear. Furthermore, in comparison to TiAlN-ZrN, the wear tracks on TiAlN-ZrN/TiAlN-ZrN exhibited a lower width value about 423 μm, indicating a better wear resistance. This enhancement could attribute to the alternating stress fields hindering the dislocation movement, which arose from coherency strains due to a mismatch in the lattice differences between nano multilayers. Simultaneously, the interface of nano layers inhibited oxygen diffusion, enhanced the antioxidant effects and further improved the wear behavior. [ABSTRACT FROM AUTHOR]

This article reports the synthesis of a novel perfluoropolyalkylether (PFPAE) vinylether monomer and its use as a comonomer in the thiol‐ene photopolymerization of a trifunctional thiol together with a trifunctional vinylether. The crosslinked copolymers are obtained in the form of few mm thick layers and characterized. By changing the thiol/ene ratio, the polymers are optimized to tailor their surface composition and obtain adhesion between two thick layers despite the presence of the fluorinated monomer. The final bilayered structures are adhesive, and appeared chemically resistant, with good dimensional stability: therefore, these fluorinated thiol–ene based copolymers are likely to be of interest for applications based on layer‐by‐layer processes, such as additive manufacturing and microfluidics. [ABSTRACT FROM AUTHOR]

NiAl bi‐ and trilayers are prepared by alternating evaporation of aluminum and nickel on float glass substrates under high vacuum, with individual layer thicknesses between 20 and 100 nm. The samples are subjected to an annealing procedure to temperatures of up to 300 °C in vacuum, and the structural changes induced by the heat treatments are followed by in situ grazing incidence X‐ray absorption spectroscopy experiments at the Ni K‐edge. The results show that the elemental metallic deposits are stable up to 180 °C, while a slow formation of the intermetallic NiAl compound occurs at temperatures above 200 °C. No additional reaction intermediates are detected. Linear combination fits employing spectra of face‐centered metallic Ni and body‐centered NiAl as references allow to quantify the contributions of the respective phases as a function of the temperature and the depth in the multilayer. In general, an increase of the phase fraction of the intermetallic NiAl phase is detected. While the deposited elemental metals cannot completely be transformed into this intermetallic compound for the Al–Ni bilayer system even after prolonged annealing at 240 °C, the analysis of the spectra of the Al–Ni–Al trilayer suggests almost complete conversion to NiAl with body‐centered‐cubic structure. [ABSTRACT FROM AUTHOR]

Magneto-electro-elastic (MEE) materials are a specific class of advanced smart materials that simultaneously manifest the coupling behavior under electric, magnetic, and mechanical loads. This unique combination of properties allows MEE materials to respond to mechanical, electric, and magnetic stimuli, making them versatile for various applications. This paper investigates the static and time-harmonic field solutions induced by the surface load in a three-dimensional (3D) multilayered transversally isotropic (TI) linear MEE layered solid. Green's functions corresponding to the applied uniform load (in both horizontal and vertical directions) are derived using the Fourier-Bessel series (FBS) system of vector functions. By virtue of this FBS method, two sets of first-order ordinary differential equations (i.e., N-type and LM-type) are obtained, with the expansion coefficients being Love numbers. It is noted that the LM-type system corresponds to the MEE-coupled P-, SV-, and Rayleigh waves, while the N-type corresponds to the purely elastic SH- and Love waves. By applying the continuity conditions across interfaces, the solutions for each layer of the structure (from the bottom to the top) are derived using the dual-variable and position (DVP) method. This method (i.e., DVP) is unconditionally stable when propagating solutions through different layers. Numerical examples illustrate the impact of load types, layering, and frequency on the response of the structure, as well as the accuracy and convergence of the proposed approach. The numerical results are useful in designing smart devices made of MEE solids, which are applicable to engineering fields like renewable energy. [ABSTRACT FROM AUTHOR]

Ultrafast thermally induced magnetization switching (TIMS) with femtosecond lasers has attracted much attention due to its ability to trigger a single switching on the picosecond time scale. Currently, most of the studies on TIMS have focused on various ferrimagnetic alloys. In this paper, TIMS of Gd/Fe multilayers in different monolayer ratios is investigated by atomic spin dynamics. The results show that an increase in the monolayer Gd ratio narrows the energy density window of the switching. Further studies found that a lower damping ratio decreases the laser energy density threshold for magnetization reversal. Moreover, reducing the ratio of Gd in the monolayer at the appropriate energy density can shorten the duration of the transient ferromagnetic-like state, which can lead to faster realization of TIMS. Our simulation results provide new insights to explore the physical mechanism of TIMS in Gd/Fe multilayers. [ABSTRACT FROM AUTHOR]

Ion bombardment with 30 keV Ga+ ions can locally change the magnetic properties of perpendicular magnetic anisotropy ferrimagnetic Tb/Co based multilayers. The induced changes in the effective magnetization create high gradients of magnetic fields in the proximity of the perimeters of the bombarded areas. Superparamagnetic, micrometer-sized beads floating in an aqueous suspension over such a patterned structure respond to the ensuing magnetostatic energy landscape. This landscape, and its associated forces on the beads, can be controlled with a time varying, external, homogeneous magnetic field. It is shown that with a 3.37 kA/m (approx. 4.2 mT) field and switching the direction at 10 Hz frequencies the beads can be driven with average forward velocities reaching 40 μ m/s. This has the potential for use in lab-on-a-chip type assays. [ABSTRACT FROM AUTHOR]

Spin‐orbit coupling refers to the relativistic interaction between the spin and orbital motions of electrons. This interaction leads to numerous intriguing phenomena, including spin‐orbit torques, spin–momentum locking, topological spin textures, etc., that have recently gained prominence in the field of spin‐orbitronics. In particular, the emerging ferroelectric control is recognized and validated as an effective means to enhance energy efficiency across a broad spectrum of spin‐orbitronic devices. Here, cutting‐edge research on ferroelectric control of spin‐orbitronics (FECSO) by means of spontaneous polarization, reversible ferroelectric switching, and multiferroic coupling, are comprehensively reviewed. Two fascinating topics are mainly discussed: topological spin texture and spin‐charge interconversion. The classification of control mechanisms for different interactions in FECSO is summarized first. Then, from the perspective of material classification, the ferroelectric‐controlled spin‐orbit coupling with tunable topological spin texture in oxide systems, magnetic metal multilayers, and 2D van der Waals materials is reviewed. Subsequently, the ferroelectric‐tunable spin‐charge interconversion on heavy metal layers, oxide interfaces, and ferroelectric Rashba semiconductors is highlighted. In the end, the challenges and forthcoming prospects of FECSO are discussed. This work may provide pertinent and forward‐thinking guidance to accelerate the ongoing advancement of this field. [ABSTRACT FROM AUTHOR]

Wonder was deeply rooted in the Chosŏn Neo-Confucian system. Through this wonder, we can see various layers of consciousness of Neo-Confucian scholars. Exploring the use of the element of wonder in political and scholarly areas requires more than just looking at aspects that have been neglected. This task is meaningful in that it shows the multi-layers of Neo-Confucianism in the Chosŏn era. It also provides an opportunity to examine how Confucianism intersected with other religions of the time. This allowed Neo-Confucianism to be more closely aligned with the general views of Chosŏn society. [ABSTRACT FROM AUTHOR]

Microlayer coextrusion is capable of producing multilayer composites with anywhere from 30 to 1000 layers, each layer having a thickness of 20 − 5000 nm. Microlayer coextrusion assembles such layers into monolithic products by repeated splitting and stacking a small number of input melt streams. Owing to the superlattice multilayer configuration, microlayer composites usually show outstanding mechanical, barrier, and optical properties and thus have broad application prospects in the industry. Therefore, microlayer coextrusion has been attracting both academic and industrial interest. This review focuses on the progress of microlayer coextrusion and its derivative technologies, including (i) the development and optimization of microlayer coextrusion; (ii) excellent properties conferred by the microlayer structure; (iii) derivative technologies to build microlayer structures in more types polymer products like films, pipes, pellets, and fibers; (iv) viscoelastic behavior during microlayer coextrusion to achieve more fine layer structure; (v) future research endeavors and possible directions for further progress in this filed are outlined. [ABSTRACT FROM AUTHOR]

This research concerns the development and implementation of ground-breaking strategies for improving the sorting, separation, and recycling of common flexible laminate packaging materials. Such packaging laminates incorporate different functional materials in order to achieve the desired mechanical performance and barrier properties. Common components include poly(ethylene) (PE), poly(propylene) (PP), and poly(ethylene terephthalate) (PET), as well as valuable barrier materials such as poly(vinyl alcohol) (PVOH) and aluminium (Al) foils. Although widely used for the protection and preservation of food produce, such packaging materials present significant challenges for established recycling infrastructure and, therefore, to our future ambitions for a circular economy. Experience from the field of ionic liquids (ILs) and deep eutectic solvents (DESs) has been leveraged to develop novel green solvent systems that delaminate multilayer packaging materials to facilitate the separation and recovery of high-purity commodity plastics and aluminium. This research focuses on the development of a hydrophobic DES and the application of a Design of Experiments (DoE) methodology to investigate the effects of process parameters on the delamination of PE/Al/PET laminate packaging films. Key variables including temperature, time, loading, flake size, and perforations were assessed at laboratory scale using a 1 L filter reactor vessel. The results demonstrate that efficient separation of PE, Al, and PET can be achieved with high yields for material and solvent recovery. Recovered plastic films were subsequently characterised via Fourier-transform infra-red (FTIR) spectroscopy, Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) to qualify the quality of plastics for reuse. [ABSTRACT FROM AUTHOR]

Magneto‐ionics, as the electrochemical reconfiguration of magnetic materials at low gating voltages, is a highly energy‐efficient alternative to control magnetism. For the fastest magneto‐ionic concept based on hydrogen, fundamental mechanisms are currently under debate, mainly because quantitative compositional information inside the magnetic materials upon gating is lacking. Using the electrochemical hydrogen loading of Co/Pd multilayers with perpendicular anisotropy, this study demonstrates that the hydrogen concentration inside the magnetic material determines its magnetic properties. Hydrogen concentrations up to a maximum of (0.24 ± 0.01) hydrogen atoms per metal atom can be set deterministically by voltage and are quantified via flow‐cell coulometry. With increasing hydrogen concentration, a continuous increase in coercivity of up to 15% and a decrease in magnetic domain‐wall velocity by an order of magnitude are observed using in situ MOKE microscopy. This enables the voltage‐controlled stop‐and‐go of domain walls. These magneto‐ionic effects can be explained by an increasing perpendicular anisotropy with increasing hydrogen content in Co/Pd multilayers, which is supported by theory. Importantly, the approach should be transferable to other ionic systems, such as lithium‐ or oxygen‐based ones, where it can uncover the yet hidden effects of ionic concentration on the magnetic properties and guide the design of functional magneto‐ionic devices. [ABSTRACT FROM AUTHOR]

The last decade has seen significant improvements in our understanding of skyrmions current induced dynamics, along with their room temperature stabilization, however, the impact of local material inhomogeneities still remains an issue that impedes reaching the regime of steady state motion of these spin textures. Here, we study the spin-torque driven motion of skyrmions in synthetic ferrimagnetic multilayers with the aim of achieving high mobility and reduced skyrmion Hall effect. We consider Pt|Co|Tb multilayers of various thicknesses with antiferromagnetic coupling between the Co and Tb magnetization. The increase of Tb thickness in the multilayers reduces the total magnetic moment and increases the spin-orbit torques allowing to reach velocities up to 400 ms−1 for skyrmions with diameters of about 160 nm. We demonstrate that due to reduced skyrmion Hall effect combined with the edge repulsion of the magnetic track, the skyrmions move along the track without any transverse deflection. Further, by comparing the field-induced domain wall motion and current-induced skyrmion motion, we demonstrate that the skyrmions at the largest current densities present all the characteristics of a dynamical flow regime. A major challenge for the use of skyrmions in information processing is getting them to move consistently, due to the presence of defects, and in a straight line, due to the skyrmion Hall effect. Here, Mallick et al overcome these challenges, demonstrating the motion of skyrmions in the dynamical flow regime in synthetic ferrimagnets. [ABSTRACT FROM AUTHOR]

2D materials possess significant potential across various applications, with physical and chemical properties that can be effectively modulated by their thickness, enabling tailored optimization for specific uses. For instance, 2D monolayers are ideal for transparent and flexible electronics, while 2D multilayers are more suitable for solar cells and high‐speed devices. Although scalable methods for synthesizing large‐area 2D materials and their applications have been developed, most research has focused on monolayers, with comparatively limited efforts directed toward multilayers. This review provides an overview of the emerging field of 2D multilayers, revisiting the analysis of layer‐dependent properties to determine the optimal material thickness for various applications. It introduces representative techniques for synthesizing 2D multilayer films and presents applications where multilayer structures demonstrate superior performance compared to monolayers, particularly in electronics and optoelectronics. The review advocates for the development of synthesis and integration methods for 2D multilayers, calling for a shift in research focus toward these materials to enhance their technological impact and unlock new industrial applications. [ABSTRACT FROM AUTHOR]

X‐ray multilayer optics play a vital role in synchrotron optics due to their ability to generate constructive interference. These devices typically consist of several tens to hundreds of periods of alternating layers coated on a substrate. In contrast to single‐layer mirrors that reflect X‐rays within a specific energy range, multilayer optics can be tailored to achieve a high reflection over a broad energy spectrum. This is a sought‐after property for many beamlines and has led to the development of numerous new X‐ray applications and capabilities. This review highlights advances in multilayer optics, including fabrication techniques, layer structure design, material choice, and strategies to enhance performance. This is placed in the context of recent applications of such multilayers as monochromator and gratings, focusing devices, and polarizers. Current challenges and the future outlook within this field are also proposed. This comprehensive summary of a rapidly advancing field highlights recent achievements and is intended to promote practical applications in terms of the use of multilayer synchrotron optics. [ABSTRACT FROM AUTHOR]

It is crucial to study the materials that could effectively facilitate the inter‐conversion between charge, spin, and orbital degrees of freedom. In this work, the conversion among these three types of degrees of freedom in Pt/CoFeB/rare‐earth (RE, represents Nd, Gd, and Ho)/Ti multilayers is manipulated. Through terahertz (THz) emission measurements, it is found that the spin current induced by a femtosecond laser is converted into an orbital current via the spin‐orbit coupling of the RE layer. Notably, the light RE (Nd) and heavy RE (Gd and Ho) induce the orbital current with opposite polarization directions, ultimately leading to a weakening or enhancement of the THz emission intensity, respectively. Moreover, the fast Fourier transform reveals that Gd exerts the most significant influence on increasing the whole THz spectrum within the Pt/CoFeB/RE/Ti structure. The findings of RE‐modulated spin‐to‐orbital conversion provide valuable insights into the fundamental transport mechanism of the orbital current. [ABSTRACT FROM AUTHOR]

The electronic bandgap of a material is often fixed after fabrication. The capability to realize on-demand and nonvolatile control over the bandgap will unlock exciting opportunities for adaptive devices with enhanced functionalities and efficiency. We introduce a general design principle for on-demand and nonvolatile control of bandgap values, which utilizes reversible sliding-induced polarization driven by an external electric field to modulate the irreversible background polarization in asymmetric two-dimensional (2D) multilayers. The structural asymmetry can be conveniently achieved in homobilayers of Janus monolayers and heterobilayers of nonpolar monolayers, making the design principle applicable to a broad range of 2D materials. We demonstrate the versatility of this design principle using experimentally synthesized Janus metal dichalcogenide multilayers as examples. Our first-principles calculations show that the bandgap modulation can reach up to 0.3 eV and even support a semimetal-to-semiconductor transition. By integrating a ferroelectric monolayer represented by 1T″′-MoS2 into a bilayer, we show that the combination of intrinsic ferroelectricity and sliding ferroelectricity leads to multi-bandgap systems coupled to multi-step polarization switching. The sliding-reversible bandgap modulation offers an avenue to dynamically adjust the optical, thermal, and electronic properties of 2D materials through mechanical and electrical stimuli. [ABSTRACT FROM AUTHOR]

Controlling the surface density of heparin in active coatings is important in providing anticoagulation while preventing bleeding. An approach based on tuning the degree of hydrolysis of poly(2‐ethyl‐2‐oxazoline) (PEOX) is presented to control the surface density of heparin in layer‐by‐layer (LbL) assembled films. Multilayers are prepared at pH 5 in 0.5 M aqueous NaCl solutions by electrostatic interactions between negatively charged heparin and the positively charged amine groups in hydrolyzed PEOX. Characterization of the multilayers by quartz crystal microbalance with dissipation (QCM‐D), toluidine blue (TBO) assay and X‐ray Photoelectron Spectroscopy (XPS) all shows that the amount of heparin deposited increases with the degree of hydrolysis. While non‐hydrolyzed PEOX/heparin multilayers do not grow, the average deposited mass per area per bilayer as determined by QCM‐D measurements increases with the degree of hydrolysis. At 50% hydrolysis, TBO assay gives a heparin surface density of 1.03 μg/cm2 and atomic % of sulfur as determined by XPS leveled off at ~14%. These results show the potential of acidic hydrolysis of PEOX combined with LbL assembly of heparin as a reproducible method for controlling the surface density of heparin in anticoagulant coatings. [ABSTRACT FROM AUTHOR]

Precise surface reflectance control at specific deep‐ultraviolet (DUV) wavelengths across wide angles is crucial for semiconductor inspection and lithography tools. The inherent challenges in designing DUV antireflective multilayers stem from limited transparent materials and the resultant fabrication complexity owing to numerous interfaces. Here, wide‐angle antireflective multilayers finely tuned to 248 nm designed using an active learning scheme is presented. The active learning scheme employing factorization machines (FM) identifies the optimal configurations for binary‐material‐based multilayers (AlF3/LaF3, AlF3/MgF2, and AlF3/Al2O3) with varying index contrasts, achieving minimal figure‐of‐merit (i.e., average angular reflectance) values at predetermined total thicknesses. High‐index‐contrast AlF3/Al2O3 multilayers are fabricated via atomic layer deposition, thus enabling the conformal coating of high‐numerical‐aperture (NA) lenses with atomic precision. An optimized AlF3/Al2O3 tri‐layer with a total thickness of 180 nm results in an average (0°–45°) reflectance of 0.4% on a CaF2 planar substrate and 0.6% on a CaF2 convex lens (NA = 0.47), similar to the performance of an ideal single‐layer coating requiring a practically unavailable refractive index. Phasor analysis, which considers only first‐order reflections between adjacent layers, supports the benefits of high‐index‐contrast binary materials and the use of the FM‐based active learning scheme in antireflective multilayer design. [ABSTRACT FROM AUTHOR]

A state‐of‐the‐art multilayer deposition system with a 4200 mm‐long linear substrate translator housed within an ultra‐high vacuum chamber has been developed. This instrument is engineered to produce single and multilayer coatings, accommodating mirrors up to 2000 mm in length through the utilization of eight rectangular cathodes. To ensure the quality and reliability of the coatings, the system incorporates various diagnostic tools for in situ thickness uniformity and stress measurement. Furthermore, the system features an annealing process capable of heating up to 700°C within the load‐lock chamber. The entire operation, including pump down, deposition and venting processes, is automated through user‐friendly software. In addition, all essential log data, power of sputtering source, working pressure and motion positions are automatically stored for comprehensive data analysis. Preliminary commissioning results demonstrate excellent lateral film thickness uniformity, achieving 0.26% along the translation direction over 1500 mm in dynamic mode. The multilayer deposition system is poised for use in fabricating periodic, lateral‐graded and depth‐graded multilayers, specifically catering to the beamlines for diverse scientific applications at Diamond Light Source. [ABSTRACT FROM AUTHOR]

In this paper, using a honeycomb-velcro structure to generate a novel jamming gripper is explored. Each finger of the gripper consists of multi-layers with a honeycomb sandwich structure acting as a core wrapped by a fabric sheet and sealed by a latex membrane. This structure can transit between unjammed (flexible) and jammed (rigid) states thanks to the vacuum pressure. Various materials of honeycomb structure, fabric, and reinforcements are investigated to seek optimal combinations for making the jamming fingers. Then, such fingers are deployed in experiments to evaluate the stiffness and the surface friction with different loads in terms of with or without vacuum. Vacuum pressure boosts the stiffness and friction of all the jamming fingers compared with the without-vacuum case. Attached to a gripper, the jamming finger shows good performance in diverse manipulation with food, a metal component, a toy, a can, and a bottle. Furthermore, the variable-stiffness finger under vacuum pressure can be utilized to perform assembly and installation operations such as pushing a bolt into an aligned hole. [ABSTRACT FROM AUTHOR]

Reactive multilayer nanofoils (RMNFs), comprised of alternating layers of metals such as nickel and aluminum, have emerged as a focal point of interest owing to their distinctive properties and versatile applications across semiconductor and micro-electromechanical systems. This nanoengineered material undergoes a self-contained exothermic reaction, initiated by a small external trigger delivering localized heat up to 1500 ℃ in fractions of a second. It can be a heat source material primarily used to make a bond between electric components by melting solders. However, the volume shrinkage during reaction causes void formation and microcracking in the reaction product, and it reduces the reliability of the bonding. In this study, we systematically investigate 11 different Ni–Al RMNFs, including multilayers with 0, 10, 30, 50, 70, and 90% alloyed regions (polycrystalline B2-NiAl or amorphous-NiAl) using molecular dynamic simulations. We found that samples with alloyed interlayers exhibit reduced reaction temperatures and volume shrinkage after the reaction. By controlling the thickness of the alloyed interlayers and structures, we can reduce the damage caused by volume shrinkage during the reaction while obtaining a sufficient reaction temperature. [ABSTRACT FROM AUTHOR]

A state-of-the-art multilayer deposition system with a 4200 mm-long linear substrate translator housed within an ultra-high vacuum chamber has been developed. This instrument is engineered to produce single and multilayer coatings, accommodating mirrors up to 2000 mm in length through the utilization of eight rectangular cathodes. To ensure the quality and reliability of the coatings, the system incorporates various diagnostic tools for in situ thickness uniformity and stress measurement. Furthermore, the system features an annealing process capable of heating up to 700°C within the load-lock chamber. The entire operation, including pump down, deposition and venting processes, is automated through user-friendly software. In addition, all essential log data, power of sputtering source, working pressure and motion positions are automatically stored for comprehensive data analysis. Preliminary commissioning results demonstrate excellent lateral film thickness uniformity, achieving 0.26% along the translation direction over 1500 mm in dynamic mode. The multilayer deposition system is poised for use in fabricating periodic, lateral-graded and depth-graded multilayers, specifically catering to the beamlines for diverse scientific applications at Diamond Light Source.

In this work, we report on the development and application of a simple reflectivity technique for real-time monitoring of the fabrication of porous-silicon multilayers. The technique allows for high-resolution quantification of the effective optical thickness of the layers during the fabrication process, enabling calibration of attack rates and detection of changes in porosity. Our experiments revealed that the porosity of the layers increases during the attack, indicating incomplete passivation of the pores. By studying thin porous-silicon layers in the absence of applied current, we developed a three-layer model to understand passive chemical etching. Furthermore, our study allowed discrimination between the two mechanisms responsible for the reduction of effective optical thickness with time, with changes in porosity being the dominant one. The technique has the potential to enable real-time control of multilayer fabrication, offering flexibility in controlling environmental conditions and silicon wafer conduction properties. Our results contribute to the understanding of multilayer fabrication and reflectivity-based process monitoring. [ABSTRACT FROM AUTHOR]

We report a theoretical modeling of the flexoelectric response of dielectric–ferroelectric (DE–FE) multilayers based on phase field simulations in the framework of the Landau–Ginzburg–Devonshire (LGD) theory. The correlation between negative capacitance and flexoelectric response is revealed, and the single-domain and multi-domain models are compared. It shows that the dielectric layers drive the ferroelectric layer into a negative capacitance regime, and the flexoelectric response of the multilayer is maximal when the negative capacitance of the ferroelectric layer has a minimal absolute value. Moreover, the flexoelectric response peak will be shifted to a lower temperature by increasing the thickness of dielectric layer, indicating a possibility of achieving a stronger flexoelectric response at room temperature compared with that of pure ferroelectric. However, while the single-domain model shows that the flexoelectric response peak is simply shifted to a lower temperature with near constant peak value and width, the multi-domain model reveals a significant suppressing of the flexoelectric peak by the dielectric layer. This is attributed to the formation of the vortex domain state, which eases the depolarization effect and leads to large absolute value of negative capacitance of the ferroelectric layer. Our work provides new insights into flexoelectricity in ferroelectric heterostructures. [ABSTRACT FROM AUTHOR]

Ultrashort period 1.0 nm W/Si multilayers have potential as dispersive Bragg reflectors in high-resolution x-ray fluorescence. However, formation of WSix leads to poor optical performance. To address this, we introduce ultrathin 0.1 nm B4C diffusion barriers in sputter-deposited 1.0 nm W/Si, inhibiting W–Si interaction. We demonstrate that the peak reflectance at a wavelength of 0.834 nm increased with a factor of 3.4 compared to W/Si. Diffuse scattering measurements reveal no change in interfacial roughness when applying B4C barriers compared to W/Si. X-ray reflectivity analysis shows a substantial increase in optical contrast between Si and W as well as sharper transitions between the layers. Chemical analysis suggests that the B4C barrier reduces formation of WSix through partial substitution of W-silicide bonds with W-carbide/boride bonds, leading to an increase in optical contrast. The resulting structure of W/Si with B4C barriers offers a compelling alternative to the more established W/B4C multilayer at the ultrashort scale due to its superior soft- and hard x-ray reflectance. [ABSTRACT FROM AUTHOR]

Reactive multilayers store large amounts of chemical energy, which can be released through a self-sustaining reaction. One way of triggering the self-sustaining reaction is mechanical ignition, which is a prerequisite for designing a self-healing system. For potential integration into various devices, it is important to understand how Al/Ni reactive multilayers behave under shock compression. In this study, molecular dynamics (MD) simulations are employed to investigate Al/Ni reactive multilayers under shock compression. MD simulations allow for the understanding of what is happening at the atomistic level. Furthermore, they give access to bilayer heights that are difficult to study otherwise. This allows studying the shock wave propagation from bilayer heights of 100 down to 5 nm, while at the same time observing what is happening atomistically. Shock compression is studied both, for interfaces parallel and normal to the shock wave. It is shown that when the shock wave is parallel to the Al–Ni interfaces, there is a clear relationship between bilayer height and effective elastic modulus, which is not true when the interfaces are normal to the shock wave. Furthermore, intermixing of Al and Ni, as a prerequisite for ignition, strongly depends on the bilayer height as well as the impact velocity. Behind the shock wave, a phase transformation occurs, which strongly depends on the impact velocity, with a weak dependence on the bilayer height. Furthermore, void nucleation and fracture are observed, where the voids start nucleating in the Al layers. [ABSTRACT FROM AUTHOR]

In the domain of phase change memories (PCMs), intensive research is conducted to reduce the programming cycle cost. The RESET operation is done by melting the PCM and then quenching the liquid phase to put it back to the amorphous state. In most of the devices, the heating is realized by the Joule effect with a titanium nitride (TiN) component put in contact with the PCM itself. One of the crucial points to improve the efficiency of this technology is to characterize the thermal contact between TiN and PCM. Having a low thermal resistance between the heater and the PCM ensures the heat transfer between the two is as efficient as possible. In this work, the interfacial thermal resistance between Ge-doped G 2 Sb 2 Te 5 (GeGST)/TiN in multilayer systems has been characterized, and the influence of the compressive stress exerted by the TiN layers on the GeGST crystallization has been highlighted. [ABSTRACT FROM AUTHOR]

Neural network potentials (NNPs) can greatly accelerate atomistic simulations relative to ab initio methods, allowing one to sample a broader range of structural outcomes and transformation pathways. In this work, we demonstrate an active sampling algorithm that trains an NNP that is able to produce microstructural evolutions with accuracy comparable to those obtained by density functional theory, exemplified during structure optimizations for a model Cu–Ni multilayer system. We then use the NNP, in conjunction with a perturbation scheme, to stochastically sample structural and energetic changes caused by shear-induced deformation, demonstrating the range of possible intermixing and vacancy migration pathways that can be obtained as a result of the speedups provided by the NNP. The code to implement our active learning strategy and NNP-driven stochastic shear simulations is openly available at https://github.com/pnnl/Active-Sampling-for-Atomistic-Potentials. [ABSTRACT FROM AUTHOR]

Abstract The authors propose a system of closely coupled‐complementary frequency‐selective surfaces (FSSs) based on the four‐arms star geometry with dual‐ and triple‐passbands responses for 5G applications. Four complementary structure configurations are presented, and depending on the chosen configuration, the structure can create two or three transmission bands in one or both polarisations of the electromagnetic waves. The designed FSSs are compact and have stable behaviour at different incident angles. The complementary FSS passes signals around 2.6 and 6.2 GHz, and a structural offset allows the transmission at a third frequency (4.2 GHz). To validate the proposed designs, four prototypes are fabricated and measured. Numerical and experimental characterisations are in good agreement.

Here we investigated the dynamics of OER activity of NiFe (90/10) catalysts over 1000 potential sweep cycles as a function of their mass loading. Over twenty different films with mass loading in the 10 ng/cm2–30 μg/cm2 range were deposited by Supersonic Cluster Beam Deposition (SCBD), allowing to study the progress of OER in sub‐monolayer, monolayer and multilayer regimes. Upon prolonged potential sweeps the electrocatalytic performances of multilayers decreased, while those of monolayers were significantly improved. The best balance in terms of catalytic efficiency and stability in working conditions is found for mass loadings corresponding to a NiFe monolayer, corresponding to a mass loading around 1 μg/cm2 and a thickness of about 3 nm. [ABSTRACT FROM AUTHOR]

Thermal stability of the multilayer (Mg/NbOx)82 nanostructure and the effect of heat treatment on its electrical properties and phase composition depending on the bilayer thickness are studied. The studied (Mg/NbOx)82 samples contain 82 bilayers whose thickness varies in the range from 2.2 to 6.2 nm. The NbOx layer thickness in the multilayers is the same (0.96 nm) in all samples, while the magnesium layers thickness is varied. It is established that the magnesium layers are either discrete (a set of nanosized particles) or continuous depending on their thickness. A metallothermic reaction occurs in (Mg/NbOx)82 multilayer nanostructures at a temperature of 430 °C: niobium oxide decomposes and the released oxygen partly oxidizes the magnesium layers. That leads to the conductive magnesium metal layers breaking and to the sharp increase of the nanostructures’ resistance by more than two orders. Despite the metallothermic reaction, the layering of the (Mg/NbOx)82 nanostructures as a whole and the presence of unoxidized magnesium inclusions remain even after heating up to 450 °C. [ABSTRACT FROM AUTHOR]

In the present study, a multilayer, high-barrier, thin blown film based on a polybutylene adipate terephthalate (PBAT) blend with polyhydroxyalkanoate (PHA), and composed of four layers including a cellulose nanocrystal (CNC) barrier layer and an electrospun poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) hot-tack layer, was characterized in terms of the surface roughness, surface tension, migration, mechanical and peel performance, barrier properties, and disintegration rate. The results showed that the film exhibited a smooth surface. The overall migration tests showed that the material is suitable to be used as a food contact layer. The addition of the CNC interlayer had a significant effect on the mechanical properties of the system, drastically reducing the elongation at break and, thus, the flexibility of the material. The film containing CNCs and electrospun PHBV hot-tack interlayers exhibited firm but not strong adhesion. However, the multilayer was a good barrier to water vapor (2.4 ± 0.1 × 10−12 kg·m−2·s−1·Pa−1), and especially to oxygen (0.5 ± 0.3 × 10−15 m3·m−2·s−1·Pa−1), the permeance of which was reduced by up to 90% when the CNC layer was added. The multilayer system disintegrated completely in 60 days. All in all, the multilayer system developed resulted in a fully compostable structure with significant potential for use in high-barrier food packaging applications. [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]

Adding Al–5Ti–1B to the melt is a universal practice to refine the microstructure of aluminum alloys. However, its major problem is susceptibility to the appearance of element Zr. A novel insight toward Zr poisoning effect on grain refinement of Al–5Ti–1B as well as its solving method is proposed in this work. For an Al–Zr melt with the existence of solute Ti and TiB2, solutes Zr and Ti show almost the same effect on the kinetic behaviors of TiB2 or (Ti, Zr)B2. Solute Zr leads to the formation of Zr-contained multi-layers (ZCMLs) on the TiB2 surface in the form of (Ti, Zr)B2. Different from solute Ti, solute Zr shows no segregation tendency to the Al(L)/TiB2 interface and decreases the interfacial atomic ordering level. Zr poisoning effect is determined by the Zr mole fraction X Zr In in the interfacial monolayer between ZCMLs and Al melt. For a given Zr concentration, X Zr In and Zr poisoning effect decreases with Ti concentration of the melt. Zr poisoning effect can be vanished using hundreds of ppm of solute Ti within its allowed limit in most Al alloys while keeping the addition level of Al–5Ti–B unchanged. [ABSTRACT FROM AUTHOR]

A room-temperature photoluminescence (PL) study of amorphous Si/amorphous silicon oxynitride multilayer films prepared by plasma-enhanced chemical vapor deposition is reported. The PL peak position can be tuned from 800 nm to 660 nm by adjusting the oxygen/nitride ratio in the a-SiOxNy:H sublayer. The Fourier transform infrared (FTIR) absorption spectra indicate that the shift of the PL peak position is accompanied by an increase in the Si-O-Si absorption peak's intensity, which induces the structural disorder at the interface, resulting in an increase in band gap energy. The effects of size on the photoluminescence spectrum have been studied. As a result, it has been observed that the addition of oxygen atoms introduces a large number of localized states at the interface, causing a blue shift in the emission peak position. With an increase in oxygen atoms, the localized states tend to saturate, and the quantum phenomenon caused by the a-Si sublayer becomes more pronounced. It is found that, as the thickness of the a-Si sublayer decreases, the increase in the [O/N] ratio is more likely to cause an increase in disordered states, leading to a decrease in luminescence intensity. For a-Si/a-SiOxNy:H samples with thinner a-Si sublayers, an appropriate value of [O/N] is required to achieve luminescence enhancement. When the value of [O/N] is one, the enhanced luminescence is obtained. It is also suggested that the PL originates from the radiative recombination in the localized states' T3- level-related negatively charged silicon dangling bond in the band tail of the a-Si:H sublayer embedded in an a-Si/a-SiOxNy:H multilayer structure. [ABSTRACT FROM AUTHOR]

Realizing high efficiency of all Si-based light-emitting devices is currently one of interesting issues in order to develop monolithic opto-electronic integration on chips. Here, we report an electroluminescence device based on phosphorus (P)-doped silicon nanocrystals (Si NCs)/silicon carbide (SiC) multilayers by modulating carrier injection and recombination process. The p+-Si substrate is used instead of p-Si substrate for facilitating the hole injection into Si NCs. Additionally, the influences of annealing temperature on the device performance have been studied, and the optimized annealing temperature is achieved by balancing the crystallinity, defect state density, and recombination process. [ABSTRACT FROM AUTHOR]

This study investigates the active vibration control of multilayer Functionally Graded Carbon NanoTube Reinforced polymer Composite (FG‐CNTRC) plates and multilayer functionally graded graphene platelets reinforced polymer composite (FG‐GPLRC) plates covered with a piezoelectric layer (PZTG1195N) serve as both actuators and sensors. The plate's heart is supposed to be reinforced nonlinearly using both types of reinforcement. Active vibration control of plates under uniform load was achieved by utilizing a velocity feedback control algorithm with a specific gain value. The finite element method is employed to analyze both the static and dynamic behavior of a square plate discretized into 9‐node quadratic finite elements with 5 ° of freedom per node. The material properties are assumed to change across the thickness direction following a power law distribution, exhibiting various patterns: Uniform Distribution (UD), as well as Functionally Graded types X, O, and A (FG‐X, FG‐O, and FG‐A). The geometrical nonlinear equations are solved by the Newmark integration method. This work begins by validating the natural frequencies of a Functionally Graded (FG) composite plate reinforced with four different distributions of Nano‐filler and then aims to show the effect of the nonlinear distribution of nanofillers on the plate's stiffness. The Results obtained after the execution of a developed code highlight the significance of employing a nonlinear distribution of nanofillers to attenuate vibrations. Highlights: FG composite and sandwich plates reinforced with GPLs and CNTs.Effect of nonlinear nanofillers distribution of reinforcement on free and forced vibration.The ability of the nonlinear distribution of nanofillers to attenuate forced vibrations. [ABSTRACT FROM AUTHOR]

The authors propose a system of closely coupled‐complementary frequency‐selective surfaces (FSSs) based on the four‐arms star geometry with dual‐ and triple‐passbands responses for 5G applications. Four complementary structure configurations are presented, and depending on the chosen configuration, the structure can create two or three transmission bands in one or both polarisations of the electromagnetic waves. The designed FSSs are compact and have stable behaviour at different incident angles. The complementary FSS passes signals around 2.6 and 6.2 GHz, and a structural offset allows the transmission at a third frequency (4.2 GHz). To validate the proposed designs, four prototypes are fabricated and measured. Numerical and experimental characterisations are in good agreement. [ABSTRACT FROM AUTHOR]