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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]

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]

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]

Microwave Kinetic Inductance Detectors (MKIDs) combine significant advantages for photon detection like single photon counting, single pixel energy resolution, vanishing dark counts and µs time resolution with a simple design and the feasibility to scale up into the megapixel range. But high quality MKID fabrication remains challenging as established superconductors tend to either have intrinsic disadvantages, are challenging to deposit or require very low operating temperatures. As alternating stacks of thin Ti and TiN films have shown very impressive results for far-IR and sub-mm MKIDs, they promise significant improvements for UV, visible to near-IR MKIDs as well, especially as they are comparably easy to fabricate and control. In this paper, we present our ongoing project to adapt proximity coupled superconducting films for photon counting MKIDs. Some of the main advantages of Ti/TiN multilayers are their good control of critical temperature (Tc) and their great homogeneity of Tc even over large wafers, promising improved pixel yield especially for large arrays. We demonstrate the effect different temperatures during fabrication have on the detector performance and discuss excess phase noise observed caused by surface oxidization of exposed Si. Our first prototypes achieved photon energy resolving powers of up to 3.1 but turned out to be much too insensitive. As the work presented is still in progress, we also discuss further improvements planned for the near future. [ABSTRACT FROM AUTHOR]

Multi-layer commingle production is a common development technique to improve the overall oil recovery of multi-layer reservoirs. However, this technique is mainly used at low water cut stage. Research on this technique at high water cut stage is comparatively few. Therefore, in order to improve productivity and recovery of wells, feasibility analysis of commingle production of multi-layer reservoirs in the high water cut stage is analyzed. To achieve a good commingle production result, the production layers must be optimized and inter-layer interference must be analyzed and reduced as much as possible. Factors, such as permeability, porosity, viscosity, capillary pressure, gravity, pressure difference, and water cut difference, have impact on commingle production. But it is difficult to consider all these factors. Therefore, according to the geological reservoir characteristics of X Oilfield, a model is established to simulate commingle production process, and the results are compared and analyzed. The interference degree is characterized by seepage resistance. The commingle production effect is evaluated by dimensionless oil increase coefficient, production index, and production index interference coefficient. The results show that the larger the difference of permeability ratio and water cut between multi-layers, the more severe the interlayer interference; dimensionless oil increase coefficients are all positive, it means that commingle production can achieve good oil increase effect even in the high water cut stage; the recommended technical limits for commingle production are that: permeability ratio is less than 5; commingle production timing is that water cut of low permeability layer is higher than 80%. This technique has been applied to X Oilfield, and the oil recovery increased about 2.8%, which confirmed this method feasibility. [ABSTRACT FROM AUTHOR]

Magnetoelectric composite materials, which exhibit both ferroelectric and ferromagnetic properties simultaneously, have attracted considerable interest for their potential in various applications such as microelectronics, memory devices, and spintronics. In this study, we investigated the synthesis, structural, morphological, electrical, and magnetic properties of multiferroic CoFe2O4/0.65BiFeO3-0.35PbTiO3 (CFO/65BF-35PT) composite thin films. These films were prepared using a high ferroelectric, morphotropic phase boundary (MPB) composition, 65BF-35PT, combined with a high magnetostrictive compound, CFO. Multilayered CFO/65BF-35PT composite films were spin-coated onto fluorine-doped tin oxide (FTO)/glass substrates using the sol-gel method, with variation in the solution molarity to achieve different layer thicknesses. Structural analysis revealed a perovskite phase for 65BF-35PT and a spinal structure for CFO, with the presence of rhombohedral and tetragonal polymorphs confirming MPB composition. Scanning electron microscope images demonstrated uniform growth of 1 μm thick composite films. Ferroelectric hysteresis loops exhibited considerable leakage current at room temperature, increasing with higher CFO content, while current versus voltage plots revealed ohmic conduction at low applied fields and space charge limited current (SCLC) conduction at high fields in all composite films. The crossover field between ohmic and SCLC conduction decreased with increasing CFO content. Moreover, room-temperature magnetic hysteresis loops showed a decrease in saturation and coercive field with increasing CFO concentration, and the temperature-dependent magnetization response indicated a monotonic decrease, with magnetization vanishing around 800 K, confirming the magnetic order of CFO. Our findings demonstrate that stable ferroelectric and ferromagnetic phases can be achieved at low temperatures by depositing composite films containing CFO/MPB on a low-cost FTO substrate. [ABSTRACT FROM AUTHOR]

With help of ab-initio density functional theory calculation, DFT+U, and hybrid functional HSE06, we revisit the layer-dependent electronic structure and magnetic properties of pristine and 3d transition metal Cr doped MoS2 monolayer and multi-layers. Our results show that the dopant Cr atoms prefer to stay at nearest neighbor distances. In the multilayers, they prefer to remain in the outermost surface layers. Matching with the experimental band gap, the optimized U parameter we report is 4 eV. The band gap of the Cr-doped monolayer is indirect, confirming the experimental observation from photoluminescence experiments. The HSE06 calculation for Cr doped monolayer shows that the band gap of doped Cr MoS2 monolayer is indirect and no magnetism is observed. From the DFT studies, the band gap for the multilayers is indirect, and doping with Cr does not induce magnetic moments in MoS2 layers. The band gap is observed to decrease with the multilayer thickness. The strain induced by substitutional Cr doping at the Mo site transforms the band gap in monolayer MoS2 from direct to indirect; the defect states are produced within the band gap region close to the conduction band minimum. [ABSTRACT FROM AUTHOR]

Achieving effective manipulation of perpendicular exchange bias effect remains an intricate endeavor, yet it stands a significance for the evolution of ultra-high capacity and energy-efficient magnetic memory and logic devices. A persistent impediment to its practical applications is the reliance on external magnetic fields during the current-induced switching of exchange bias in perpendicularly magnetized structures. This study elucidates the achievement of a full electrical manipulation of the perpendicular exchange bias in the multilayers with an ultrathin antiferromagnetic layer. Owing to the anisotropic epitaxial strain in the 2-nm-thick IrMn3 layer, the considerable exchange bias effect is clearly achieved at room temperature. Concomitantly, a specific global uncompensated magnetization manifests in the IrMn3 layer, facilitating the switching of the irreversible portion of the uncompensated magnetization. Consequently, the perpendicular exchange bias can be manipulated by only applying pulsed current, notably independent of the presence of any external magnetic fields. Manipulating exchange bias is crucial for advancing spintronic devices. Here, the authors demonstrate full electrical switching of perpendicular exchange bias in multilayers featuring an antiferromagnetic layer with anisotropic epitaxial strain. [ABSTRACT FROM AUTHOR]

We present a detailed theoretical analysis of the magnetoresistance (MR) of Co/Cu magnetic metallic multilayers (MLs) and spin-valves (SVs) with spacer layer thickness ranging from 2.5 Å to 140 Å. The magnetoresistive properties of the systems under consideration are calculated using the Boltzmann equation. The MR exhibits a continuous monotonic decrease and a maximum triggered when Cu layer thickness is equal to 10 Å and its mean free path (MFP) exceeds 300 Å. An initial increase in the MR to achieve its maximum followed by a decrease is observed by varying the geometric roughness magnitude. The optimal MR is obtained at a Cu layer thickness equal to 20 Å for smooth interfaces. The MR also presents the same behaviour by modifying the top Co layer thickness, and the MR maximum is absent when the thickness of the bottom ferromagnetic (FM) layer has a value equal to or half that of the top FM layer. These magnetic behaviours can be explained by interfacial electronic scattering. The effects of characteristic and geometric parameters of the SV on the electrical conductivity of the spacer layer are also investigated. The results on [Co/Cu]10 MLs suggest a decrease in MR without any sign of oscillatory behaviour when the interlayer thickness increases. [ABSTRACT FROM AUTHOR]

The present work explores the shear and extensional rheology of immiscible multi-micro/nanolayered systems comprising low-density polyethylene (LDPE) paired with polystyrene (PS) and polycarbonate (PC) obtained from forced-assembly multilayer coextrusion. Firstly, miscible multilayer references based on LDPE/LLDPE layers were prepared with their miscibility characterized by shear and elongational measurements. Their strain hardening behaviors were found to be intricately linked to the number of layers and confinement. Secondly, for immiscible LDPE/PS and LDPE/PC multilayers with symmetric (50/50) and asymmetric (10/90) compositions, negative deviation of complex viscosities from neat polymers was highlighted because of the heightened confinement of LDPE chains by PS or PC and reduced entanglements at polymer–polymer interfaces. Intriguingly, LDPE/PC systems exhibited no strain hardening irrespective of layer configuration, while the geometric confinement imposed by PS layers facilitated interactions between single chains with long-chain branching (LCB), leading to strain hardening under specific conditions. Furthermore, the extensional viscosities were predicted using the Macosko model (C.W. Macosko et al. Journal of Rheology. 63 2019), accurately describing the behavior of 1024 layered films for both asymmetric (10/90) LDPE/PS and LDPE/PC systems, but not for 32 layers due to a limited number of interfaces. This study provides insights into quantifying interfacial tension properties in micro/nano-layered systems with high mismatched viscoelastic polymers, shedding light on their strain hardening properties in the presence of increased interfacial area. [ABSTRACT FROM AUTHOR]

Optical second harmonic generation (SHG) is a nonlinear optical effect widely used for nonlinear optical microscopy and laser frequency conversion. Closed-form analytical solution of the nonlinear optical responses is essential for evaluating materials whose optical properties are unknown a priori. A recent open-source code, ♯SHAARP.si, can provide such closed form solutions for crystals with arbitrary symmetries, orientations, and anisotropic properties at a single interface. However, optical components are often in the form of slabs, thin films on substrates, and multilayer heterostructures with multiple reflections of both the fundamental and up to ten different SHG waves at each interface, adding significant complexity. Many approximations have therefore been employed in the existing analytical approaches, such as slowly varying approximation, weak reflection of the nonlinear polarization, transparent medium, high crystallographic symmetry, Kleinman symmetry, easy crystal orientation along a high-symmetry direction, phase matching conditions and negligible interference among nonlinear waves, which may lead to large errors in the reported material properties. To avoid these approximations, we have developed an open-source package named Second Harmonic Analysis of Anisotropic Rotational Polarimetry in Multilayers (♯SHAARP.ml). The reliability and accuracy are established by experimentally benchmarking with both the SHG polarimetry and Maker fringes using standard and commonly used nonlinear optical materials as well as twisted 2-dimensional heterostructures. [ABSTRACT FROM AUTHOR]

Hardness of nanostructured metallic multilayers (NMMs) are often understood from their dependence on individual layer thickness (h), yet little is known about the impacts exerted by other microstructural factors. In this work, the effects of residual stress and interface coherency on the deformation mechanisms of Al/Ti NMMs with h = 2.5–52 nm were studied via experiments and molecular dynamics simulations. The residual stress was found to be tensile in Ti layers and compressive in Al layers in general, both of which tended to increase with decreasing h. Tensile stress of more than 2 GPa were measured in the Ti layers at h < 10 nm. Such high stress was related to the more coherent interfaces at small h, as confirmed by transmission electron microscopy analysis. Finally, molecular dynamics simulations showed that at h = 2.5 nm, the coherent interfaces were more effective barriers to dislocation initiation and transfer than the incoherent ones. [ABSTRACT FROM AUTHOR]

The slip systems and motion behavior of dislocations induced by nano-indentation technique in GaN-based LDs were investigated. Dislocations with burgers vector of b = 1/3 <11 2 ¯ 3> were introduced on either {11 2 ¯ 2} <11 2 ¯ 3>, or {1 1 ¯ 01} <11 2 ¯ 3> pyramidal slip systems in the upper p-GaN layer. Besides, {0001} <11 2 ¯ 0> basal slip system was also activated. The AlGaN/InGaN multi-layers in device can provide mismatch stresses to prevent dislocations from slipping through. It was observed that the density of dislocations induced by the indenter significantly decreased from the upper to the lower regions of the multi-layers. The a + c dislocations on pyramidal slip planes were mostly blocked by the strained layers. [ABSTRACT FROM AUTHOR]

The shear banding mechanisms of sputter-deposited nanoscale Cu/Ru multilayer with single-layer thickness of 0.8 nm and 1.5 nm, respectively, were investigated by nanoindentation. Shear bands can be observed in Cu/Ru multilayer only when the layer thickness is 1.5 nm. Deformed microstructure analysis showed that the plastic deformation behavior within the shear band of Cu1.5/Ru1.5 multilayer is primarily controlled by the dislocation dominated non-crystallographic rotation through the Cu/Ru interface without changing the crystallographic orientation. By synthetical analyzing of the indentation-induced deformed microstructures, a deformation mode transition from shear banding to opening crack is suggested as decreasing the layer thickness from 1.5 to 0.8 nm, mainly relating to the phase structure of Ru layer. Moreover, the excellent toughness of Cu/Ru multilayers also could be obtained by regulating the influences of phase structure on the shear band formation. [ABSTRACT FROM AUTHOR]

Organic solar cell (OSC) devices suffer from low power conversion efficiency (PCE) due to deep trap states that absorb photogenerated charges, act as recombination centers, and reduce charge collection. To further improve the PCE, an optimized hole transport layer (HTL) must be engineered for efficient hole transport and reduced deep trap states. A hybrid HTL consisting of organic and inorganic materials was formed using a combination of CuO nanoparticles (NPs) having an average size of 50 nm and poly(3-hexylthiophene) (P3HT). The hybrid HTL was used in the fabrication and characterization of an inverted OSC device structure. In consequence, the incorporation of CuO-NPs into the P3HT resulted in an increase of 8.66% in photocurrent density. Additionally, the PCE increased from 3.77 to 4.22% while the open circuit voltage (Voc) was maintained. The higher hole mobility obtained for the optimum device using the charge extraction by increasing voltage (CELIV) measurement was 8.47 × 10− 4 cm2 V− 1 s− 1. This highlights the potential of designing novel organic solar cells with inorganic nanoparticles, offering enhanced performance and efficiency. [ABSTRACT FROM AUTHOR]

The effect on the magnetic properties of multilayer films is investigated by changing the roughness variation due to the thickness of the non-magnetic layer film. The increase in roughness due to the thickness of the nonmagnetic layer affects the ease with which the magnetic moments of the two layers can be reversed, which is reflected as the magnitude of the demagnetizing field in the hysteresis loop. We have investigated the interface structure and magnetic properties of [Co/Cu]2 multilayers. Anomalous hysteresis "steps" were observed during the demagnetization process, and the reverse magnetic field became larger with the thickness of the nonmagnetic layer. Time-of-flight polarized neutron reflectometry and atomic force microscope are used as structural probes to explore the interface roughness and surface roughness in [Co/Cu]2 multilayers, respectively. The law of increasing surface roughness with thickness is verified. It will help to achieve material modification and artificial adjustment of the demagnetization process through a relatively easy preparation method for the development of complex devices. Moreover, the preparation of the hundred nanometer thickness films by sputtering technology is advantageous, which can be used in large quantities for industrial production. [ABSTRACT FROM AUTHOR]

According to the previous studies of sialolithiasis reported so far, this study is aimed to identify the biological components of sialolith, which show different ultrastructures and chemical compositions from other stones, cholelith and urolith. Twenty-two specimens obtained from 20 patients were examined histologically, and analyzed with micro-CT, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM). All sialoliths (n = 22) observed in this study showed a central nidus, which was filled with organoid matrix admixed with exosome vesicles, loose calcium apatite crystals, and many bacteria. The micro-CT and SEM observation clearly defined a single or multiple central nidus(es) encircled by highly calcified compact zone. The circular compact zone showed a band-like calcification, about 1–3 mm in thickness, and usually located between the central nidus and the peripheral multilayer zone. But some sialoliths (n = 5) showed severe erosion of compact zone by expanding multilayered zone depending on the level of calcification and inflammation in sialolith. By observing TEM images, many exosome vesicles and degraded cytoplasmic organelles were found in the central nidus, and some epithelial cells were also found in the calcified matrix of peripheral multilayer zone. Particularly, EDS analysis indicated the highest Ca/P ratio in the intermediate compact zone (1.77), and followed by the central nidus area (1.39) and the peripheral multilayer zone (0.87). Taken together, these data suggest that the central nidus containing many inflammatory exosomes and degraded cytoplasmic organelles has a potential to induce a band-like calcification of compact zone, and followed by the additional multilayer deposition of exfoliated salivary epithelial cells as well as salivary materials. Thereby, the calcium apatite-based sialolith is gradually growing in its volume size, and eventually obstructs the salivary flow and provides a site for the bacterial infection. [ABSTRACT FROM AUTHOR]

The tropical carpenter bee, Xylocopa latipes, has metallic-reflecting, iridescent wings. The wing reflectance spectra for TE- and TM-polarized light depend on the angle of light incidence in a way characteristic for dielectric multilayers. Anatomy indicates the presence of melanin multilayers in the wing's chitinous matrix. A simple optical model of melanin multilayers explains the angle dependence of the wing reflectance spectra. The wing reflections that occur upon oblique illumination exhibit colourful and strongly polarized light patterns, which may mediate intraspecific signaling and mutual recognition by conspecifics. [ABSTRACT FROM AUTHOR]

Al-rich waste pharmaceutical blisters (WPBs) have a multi-layer structure that contains aluminum and polymer-based fractions. Although the aluminum mass in WPBs is less than typical aluminum packaging products such as beverage cans, establishing a feasible recycling procedure is possible by separating the fractions to recover both metal and plastic. Hydrometallurgical methods are mostly preferred for the separation of aluminum and plastic in multi-layered structures. This work reports the characterization of Al-rich WPBs and the separation behavior of aluminum and plastic layers. The effects of hydrochloric acid, acetic acid, formic acid, sulfuric acid, ethanol, acetone, and organic solvent (benzene–ethanol–water) on the separation behavior of layers were studied at different temperatures. Furthermore, the recycling yield of the aluminum fraction was experimentally assessed. [ABSTRACT FROM AUTHOR]

A comparative study of the processes of metal-stimulated formation of silicon nanocrystals in SiOx–Sm structures was carried out. Samples with identical oxide matrix stoichiometry and Sm impurity content were formed using two methods: layer-by-layer deposition and coevaporation of SiO and Sm. Studies of PL and IR absorption spectra found that the admixture of samarium in samples of both types accelerates the thermally stimulated decomposition of samarium-doped SiOx films into Si and SiO2 and reduces the transition temperature of silicon nanoparticles from an amorphous state to a crystalline state. However, in (SiOx/Sm)10 multilayers, this effect is more pronounced than in single-layer films obtained using the co-evaporation method. Studying the Raman spectra of (SiOx/Sm)10 multilayers annealed at 750 °C determined that the relative volume fraction of nanocrystals in the silicon phase of the sample is ~ 38%. No line corresponding to the crystalline nc-Si was observed in the Raman spectra of samples deposited by co-evaporation and annealed under the same conditions. For these samples, a narrow line in the Raman spectrum corresponding to crystalline nc-Si appears only after annealing at 970 °C. In this case, the relative fraction of Si nanocrystals in the silicon phase of the sample was ~ 17%, 2.2 times less than for a similar multilayer annealed at 750 °C. This also indicates that, in multilayer (SiOx/Sm)10 samples, the thermally stimulated decomposition of SiOx, as well as the formation and crystallization of silicon nanoparticles, occurs at lower temperatures than in similar samples obtained by coevaporation. A possible mechanism for lowering the crystallization temperature of nc-Si in (SiOx/Sm)10 multilayers is discussed. [ABSTRACT FROM AUTHOR]

Biomaterial science has contributed tremendously to developing nanoscale materials for delivering biologically active compounds, enhancing protein stability, and enabling its therapeutic use. This paper presents a process of formation of polyelectrolyte multilayer (PEM) prepared by sequential adsorption of positively charged polydiallyldimethylammonium chloride (PDADMAC) and negatively charged heparin sodium salt (HP), from low polyelectrolyte concentration, on a solid substrate. PEM was further applied as a platform for the adsorption of a brain-derived growth factor (BDNF), which is a protein capable of regulating neuronal cell development. The multilayers containing BDNF were thoroughly characterized by electrokinetic (streaming potential measurements, SPM) and optical (optical waveguide lightmode spectroscopy, OWLS) techniques. It was found that BDNF was significantly adsorbed onto polyelectrolyte multilayers terminated by HP under physiological conditions. We further explore the effect of established PEMs in vitro on the neuroblastoma SH-SY5Y cell line. An enzyme-linked immunosorbent assay (ELISA) confirmed that BDNF was released from multilayers, and the use of the PEMs intensified its cellular uptake. Compared to the control, PEMs with adsorbed BDNF significantly reduced cell viability and mitochondrial membrane polarization to as low as 72% and 58%, respectively. HPLC analysis showed that both PDADMAC-terminated and HP-terminated multilayers have antioxidative properties as they almost by half decreased lipid peroxidation in SH-SY5Y cells. Finally, enhanced formation of spheroid-like, 3D structures was observed by light microscopy. We offer a well-characterized PEM with antioxidant properties acting as a BDNF carrier, stabilizing BDNF and making it more accessible to cells in an inhomogeneous, dynamic, and transient in vitro environment. Described multilayers can be utilized in future biomedical applications, such as boosting the effect of treatment by selective anticancer as adjuvant therapy, and in biomedical research for future development of more precise neurodegenerative disease models, as they enhance cellular 3D structure formation. [ABSTRACT FROM AUTHOR]

In honeycomb multilayers with staggered AB-sublattice potentials, we predict gapless edge states localized to either of the odd and the even layers for the AA ′ stacking order in which the sublattice-pseudospin polarizations of adjacent layers are antiparallel. Gaps in the projected layer-pseudospin spectrum suppress interlayer hopping between odd and even layers. The layer-valley Chern number corresponding to the edge states was obtained by decomposing the occupied state into two layer-pseudospin sectors by using a projected layer-pseudospin operator. For the AB ′ stacking, the sublattice-pseudospin polarizations of adjacent layers are antiparallel, but the layer-pseudospin spectrum gap closes at the interface of the topologically different states, leading to gapped edge states. For the AA and AB stackings where the sublattice-pseudospin polarizations of the adjacent layers are parallel, the gapless edge states corresponding to quantum valley Hall states are evenly distributed across the layers. [ABSTRACT FROM AUTHOR]

In twisted two-dimensional (2D) magnets, the stacking dependence of the magnetic exchange interaction can lead to regions of ferromagnetic and antiferromagnetic interlayer order, separated by non-collinear, skyrmion-like spin textures. Recent experimental searches for these textures have focused on CrI3, known to exhibit either ferromagnetic or antiferromagnetic interlayer order, depending on layer stacking. However, the very strong uniaxial anisotropy of CrI3 disfavors smooth non-collinear phases in twisted bilayers. Here, we report the experimental observation of three distinct magnetic phases—one ferromagnetic and two antiferromagnetic—in exfoliated CrBr3 multilayers, and reveal that the uniaxial anisotropy is significantly smaller than in CrI3. These results are obtained by magnetoconductance measurements on CrBr3 tunnel barriers and Raman spectroscopy, in conjunction with density functional theory calculations, which enable us to identify the stackings responsible for the different interlayer magnetic couplings. The detection of all locally stable magnetic states predicted to exist in CrBr3 and the excellent agreement found between theory and experiments, provide complete information on the stacking-dependent interlayer exchange energy and establish twisted bilayer CrBr3 as an ideal system to deterministically create non-collinear magnetic phases. Van der Waals materials often exhibit different metastable structures, with the constituent layers shifted by small, atomic scale distances. If the material is magnetic, the resulting different layer stackings can cause drastic changes in magnetic ordering. Here, Yao et al. observe all three locally stable magnetic orderings predicted to occur in CrBr3 multilayers, two antiferromagnetic and one ferromagnetic. [ABSTRACT FROM AUTHOR]

Fast energy release, which is a fundamental property of reactive multilayer systems, can be used in a wide field of applications. For most applications, a self-propagating reaction and adhesion between the multilayers and substrate are necessary. In this work, a distinct approach for achieving self-propagating reactions and adhesion between deposited Ni/Al reactive multilayers and silicon substrate is demonstrated. The silicon surface consists of random structures, referred to as silicon grass, which were created by deep reactive ion etching. Using the etching process, structure units of heights between 8 and 13 µm and density between 0.5 and 3.5 structures per µm2 were formed. Ni and Al layers were alternatingly deposited in the stoichiometric ratio of 1:1 using sputtering, to achieve a total thickness of 5 µm. The analysis of the reaction and phase transformation was done with high-speed camera, high-speed pyrometer, and X-ray diffractometer. Cross-sectional analysis showed that the multilayers grew only on top of the silicon grass in the form of inversed cones, which enabled adhesion between the silicon grass and the reacted multilayers. A self-propagating reaction on silicon grass was achieved, due to the thermally isolating air pockets present around these multilayer cones. The velocity and temperature of the reaction varied according to the structure morphology. The reaction parameters decreased with increasing height and decreasing density of the structures. To analyze the exact influence of the morphology, further investigations are needed. [ABSTRACT FROM AUTHOR]

Ion-exchange membranes (IEMs) have found potential applications in diverse areas, such as environment related issues and addressing energy. Due to their increasing importance, several studies have been made on the preparation, characterization, modification, and applications of IEMs. This paper first discusses IEMs, their use as new separation materials, and the methods to characterize them. Subsequent sections review IEM-based ion separation techniques, such as diffusion dialysis, Donnan dialysis, and particularly electrodialysis (ED). Importantly, the section on ED reviews concentration polarization (CP), which is especially relevant to the recent trends of research. More specifically, a discussion on monovalent ion permselective membranes and the methods to create them has been made in the paper. Layer-by-layer (LBL) adsorption of polyelectrolyte multilayers (PEMs) gives rise to remarkable monovalent to multivalent cation and anion selectivities > 1000 and > 100, respectively. However, such high selectivities are accompanied by lower current efficiencies (∼ 50%) and lower recoveries of the ions. Additionally, the PEMs assembled through LBL deposition method may start delaminating under an applied potential after a certain period of time. The later part of the paper suggests creating selective PEMs with a net charge matching the native charge of IEMs to reduce CP in ED. Suggestions to increase current efficiencies, percentage recoveries of ions of interest, and the possible ways to increase the stability of PEMs deposited on IEMs have also been discussed in the paper. [ABSTRACT FROM AUTHOR]

In multilayers of magnetic thin films with perpendicular anisotropy, domain walls can take on hybrid configurations in the vertical direction which minimize the domain wall energy, with Néel walls in the top or bottom layers and Bloch walls in some central layers. These types of textures are theoretically predicted, but their observation has remained challenging until recently, with only a few techniques capable of realizing a three dimensional characterization of their magnetization distribution. Here we perform a field dependent X-ray resonant magnetic scattering measurements on magnetic multilayers exploiting circular dichroism contrast to investigate such structures. Using a combination of micromagnetic and X-ray resonant magnetic scattering simulations along with our experimental results, we characterize the three-dimensional magnetic texture of domain walls, notably the thickness resolved characterization of the size and position of the Bloch part in hybrid walls. We also take a step in advancing the resonant scattering methodology by using measurements performed off the multilayer Bragg angle in order to calibrate the effective absorption of the X-rays, and permitting a quantitative evaluation of the out of plane (z) structure of our samples. Beyond hybrid domain walls, this approach can be used to characterize other periodic chiral structures such as skyrmions, antiskyrmions or even magnetic bobbers or hopfions, in both static and dynamic experiments. [ABSTRACT FROM AUTHOR]

Reactive multilayer systems consisting of alternating nanoscale Al and Ni layers are applicable in joining, various pyrotechnic applications and thermal batteries. Since diffusion based high-temperature synthesis occurs without the presence of air, efforts have focused on investigating the understanding of the fundamental reaction processes and characteristics. The aim of this study is to expose the reactive multilayers to extrinsic induced tensile stress so that the self-propagating synthesis can proceed under these conditions. Further, the properties during and after the reaction will be investigated. Multilayers deposited by sputtering on Kapton® substrates with different bilayer– and total thicknesses as well as commercial Nanofoils® with thicknesses of 40 µm and 60 µm were used as samples. The investigations focused on the propagation velocity measured with a high-speed camera, the temperature regime determined with a high-speed pyrometer, and the formed phases after the synthesis examined via X-ray diffraction. The gained results of this study reveal important insights for the application of the reactive Al/Ni multilayer system in terms of stability or reliability related to propagation front velocity, maximum temperature and formed phases under induced external tensile stresses. [ABSTRACT FROM AUTHOR]

Skyrmions and skyrmioniums are topologically non-trivial spin textures found in chiral magnetic systems. Understanding the dynamics of these particle-like excitations is crucial for leveraging their diverse functionalities in spintronic devices. This study investigates the dynamics and evolution of chiral spin textures in [Pt/Co]3/Ru/[Co/Pt]3 multilayers with ferromagnetic interlayer exchange coupling. By precisely controlling the excitation and relaxation processes through combined magnetic field and electric current manipulation, reversible conversion between skyrmions and skyrmioniums is achieved. Additionally, we observe the topological conversion from a skyrmionium to a skyrmion, characterized by the sudden emergence of the skyrmion Hall effect. The experimental realization of reversible conversion between distinct magnetic topological spin textures represents a significant development that promises to expedite the advancement of the next generation of spintronic devices. Skyrmionium, like the more well-known magnetic skyrmion, is a topological spin texture. It is characterized by ring shaped magnetic texture, where both inside and outside the magnetization is the same, yielding a topological charge of zero. Here, Yang et al demonstrate reversible control of skyrmioniums, switching between skyrmions and skyrmionium using electric currents. [ABSTRACT FROM AUTHOR]

Titanium dioxide (TiO2) and zinc oxide (ZnO) multilayer thin films were deposited on p-type silicon substrate using a sol–gel-based dip coating technique. The morphological and structural properties of multilayers were investigated prior to the study of electrical properties. Field emission scanning electron microscopy (FESEM) studies showed films with uniform distributions of grains. The presence of crystalline phases of TiO2 and ZnO has been observed from x-ray diffraction (XRD) studies. XRD and Raman peaks confirmed the deposition of multilayers of TiO2 and ZnO thin films. The oxide charge density (Qox) was found to be a maximum of 2.88 × 1012 cm−2 for TiO2-TiO2-ZnO-TiO2 multilayer thin film and the corresponding interface trap density (Dit) was calculated as 1.73 × 1012 eV−1 cm−2. The resistive switching performance of multilayer thin films has been significantly improved in comparison to the individual ZnO and TiO2 thin film. TiO2-ZnO-TiO2-TiO2 multilayer structure has shown better memory window with an on/off ratio of 1.45 × 104. [ABSTRACT FROM AUTHOR]

Diamond-like carbon (DLC) coatings have gained wide attraction, due to ultra-low coefficient of friction, high resistance to wear, excellent mechanical properties, and inert to chemical substance, especially in the automobile industry in the last decade. However, a lot of research is still carried out to improve the adhesion properties of DLC coatings to metallic substrate to prevent debonding caused mostly by high internal compressive stress and the difference in thermal expansivity between the metallic substrate and the DLC coatings. Consequently, to improve the adhesion of DLC coatings on metallic substrate, the use of interlayers (Si, SiH and Cr, CrN, Ti and TiN) and metallic (Mo, Ti, Cr, and W) and non-metallic (Si, N, and F) doping elements has been put to use. The interlayers form a transition layer between the metallic substrate and the DLC coating, thereby reducing the thermal expansivity between the metallic substrate and the DLC coatings. On the other hand, the metallic and non-metallic doping elements help in reducing the internal compressive stress in the DLC coatings. The present review article focuses mainly on the deposition techniques, characterisation techniques, and improvement of the adhesion properties of DLC coatings on metallic substrates. It showcases Cr-based interlayers and W/WC dopants as an efficient way to improve adhesion properties of DLC coatings for tribological and tribo-corrosion application in the automobile industry. [ABSTRACT FROM AUTHOR]

A new ensemble framework for an interpretable model called linear iterative feature embedding (LIFE) has been developed to achieve high prediction accuracy, easy interpretation, and efficient computation simultaneously. The LIFE algorithm is able to fit a wide single-hidden-layer neural network (NN) accurately with three steps: defining the subsets of a dataset by the linear projections of neural nodes, creating the features from multiple narrow single-hidden-layer NNs trained on the different subsets of the data, combining the features with a linear model. The theoretical rationale behind LIFE is also provided by the connection to the loss ambiguity decomposition of stack ensemble methods. Both simulation and empirical experiments confirm that LIFE consistently outperforms directly trained single-hidden-layer NNs and also outperforms many other benchmark models, including multilayers feed forward neural network (FFNN), Xgboost, and random forest (RF) in many experiments. As a wide single-hidden-layer NN, LIFE is intrinsically interpretable. Meanwhile, both variable importance and global main and interaction effects can be easily created and visualized. In addition, the parallel nature of the base learner building makes LIFE computationally efficient by leveraging parallel computing. [ABSTRACT FROM AUTHOR]

Chern insulators are two-dimensional magnetic topological materials that conduct electricity along their edges via the one-dimensional chiral modes. The number of these modes is a topological invariant called the first Chern number C that defines the quantized Hall conductance as Sxy = Ce2/h. Increasing C is pivotal for the realization of low-power-consumption topological electronics, but there has been no clear-cut solution to this problem so far, with the majority of existing Chern insulators showing C = 1. Here, by using state-of-the-art theoretical methods, we propose an efficient approach for the realization of the high-C state in MnBi2Te4/hBN van der Waals multilayer heterostructures. We show that a stack of n MnBi2Te4 films with C = 1 intercalated by hBN monolayers gives rise to a high Chern number state with C = n, characterized by n chiral edge modes. This state can be achieved both under the external magnetic field and without it, both cases leading to the quantized Hall conductance Sxy = Ce2/h. Our results, therefore, pave the way to practical high-C quantized Hall systems. [ABSTRACT FROM AUTHOR]

Thermal spray coatings are material systems with unique structures and properties that have enabled the growth and evolution of key modern technologies (i.e., gas turbines, structurally integrated components, etc.). The inherent nature of these sprayed coatings, such as their distinctive thermal and mechanical properties, has been a driving force for maintaining industrial interest. Despite these benefits and proven success in several fields, the adoption of thermal spray technology in new applications (i.e., clean energy conversion, semiconductor thermally sprayed materials, biomedical applications, etc.) at times, however, has been hindered. One possible cause could be the difficulty in concurrently maintaining coating design considerations while overcoming the complexities of the coatings and their fabrication. For instance, a coating designer must consider inherent property anisotropy, in-flight decomposition of molten material (i.e., loss of stoichiometry), and occasionally the formation of amorphous materials during deposition. It is surmisable for these challenges to increase the risk of adoption of thermal spray technology in new fields. Nevertheless, industries other than those already mentioned have benefited from taking on the risk of implementing thermal spray coatings in their infrastructure. Benefits can be quantified, for example, based on reduced manufacturing cost or enhanced component performance. In this overview paper, a historical presentation of the technological development of thermal spray coatings in several of these industries is presented. Additionally, emerging industries that have not yet attained this level of thermal spray maturation will also be discussed. Finally, where applicable, the utility and benefits of multilayer functional thermal spray coating designs will be demonstrated. [ABSTRACT FROM AUTHOR]

We report on the magnetic properties of antiferromagnetic NiO(001) thin films in epitaxially grown NiO/MgO(dMgO)/Cr/MgO(001) system for different thicknesses of MgO, dMgO. Results of X-ray Magnetic Linear Dichroism show that together with an increase of dMgO, rotation of NiO spins from in-plane towards out-of-plane direction occurs. Furthermore, we investigated how the proximity of Fe modifies the magnetic state of NiO in Fe/NiO/MgO(dMgO)/Cr/MgO(001). We proved the existence of a multidomain state in NiO as a result of competition between the ferromagnet/antiferromagnet exchange coupling and strain exerted on the NiO by the MgO buffer layer. [ABSTRACT FROM AUTHOR]

A bi-layers stack consisting of a semiconductor thin film of a varied thickness and a very thin Pd layer (SiC/Pd/c-Si).was deposited onto c-Si by e-beam evaporation at room temperature. The multi-layers structure was subjected to a thermal annealing process at near eutectic temperature of the Si – Pd phase. It is noticed, through top view SEM and cross-section STEM analyses, that the sandwiched Pd metal layer dewets from the interface with the c-Si substrate in well dispersed nanoparticles and it diffuses inward onto the top few monolayers of the substrate; at times it permeates shallowly through the SiC semiconductor top layer. The size distribution of the nanoparticles was found to be closely linked to the thickness of the top semiconductor layer. On the other hand, the top SiC layer was found to form islands protruding above the surface, when the film was very thin. When thicker, the semiconductor SiC layer retained its integrity and remained unaffected. An optical model of the resulting metal-dielectric mixed layer is proposed. [ABSTRACT FROM AUTHOR]

This study aims to provide insight to assist in decision-making in wire arc additive manufacturing based on the prediction of bead geometry, which is affected by the behavior of the melt pool. This requires the identification of welding techniques that can minimize the material transfer rate, minimize the effects caused in the lower layers, and reduce the volume of the molten pool material. It was also found there exists a minimum deposition volume such that the beads remain stable. Therefore, in this study, the behavior of the weld beads was verified as a function of the volume of metal deposited over the welded length by systematically varying the mean current and the pulse frequency in GMAW-P. In addition, the prediction of weld bead geometry decreases the possibility of error, avoiding material waste. Thus, the influences of each welding parameter (voltage, current, and welding speed) on the dimensional characteristics of the beads (width and reinforcement) were analyzed. The analysis results allowed formulation of the relationships among the bead features and the welding parameters. Additionally, it was verified that the deposition rate is directly affected by the stick-out and inversely proportional to the arc voltage. The modeling of the weld bead geometry as a function of the welding parameters will enhance the quality of automated welding, allowing early simulation and achieving an efficient process. The modeling of the weld bead geometry using the linear regression technique will allow manipulation of the welding process variables based on the necessary bead characteristics. [ABSTRACT FROM AUTHOR]

The phase composition of periodic Mo/Si multilayers with different thicknesses of silicon and molybdenum layers, and bilayer films with the combination of Mo–on–Si and Si–on–Mo with varying thicknesses of the upper layers (Mo or Si) were investigated. X-ray diffraction and high-resolution transmission electron microscopy were used for the investigation of phases and microstructure of periodic multilayer. Core-levels and valence-bands X-ray photoelectron spectroscopy was performed for the study of electronic structure and phase composition of surface and interfaces in bilayer films. Although the intermetallic silicide phases (Mo5Si3, Mo3Si and MoSi2) in multilayer and bilayer systems evolved similar, differences were observed in specific phases compared to bilayer systems in the Mo–on–Si and Si–on–Mo sequences. The amorphous silicon layer in periodic multilayers was highly disordered as compared to the amorphous layer of silicon in bilayer films. This was originated to formation of specific silicide phases in the periodic multilayers and bilayers systems. [ABSTRACT FROM AUTHOR]

The effect of the top Ag electrode on local piezoelectric and the ferroelectric response of PVDF thin films in PVDF/Au/Si and Ag/PVDF/Au/Si multilayers is probed using dual AC resonance tracking piezo force microscopy (DART-PFM). The 4 wt% PVDF thin films are prepared on Au/Si using a spin coater and the top electrode Ag is deposited with the DC magnetron sputtering method. The structural and microstructural characteristics are analyzed using a Raman spectrometer, grazing incidence X-ray diffraction, scanning electron microscopy with electron dispersive spectroscopy, and atomic force microscopy. The local piezoelectric and ferroelectric characteristics are found to be dependent upon the presence or absence of the top Ag electrode. Both the device structures display typical bi-stable ferroelectric and piezoelectric switching. The resultant non-uniform electric field due to the absence of a top electrode shows ferroelectric switching at an applied voltages ≥ ± 20 V compared to the low-voltage (down to ± 5 V) switching on Ag/PVDF/Au junctions. Furthermore, a higher d33 coefficient recorded in Ag/PVDF/Au is discussed with uniform electric field distribution in the devices. Our study reveals a clear dependency of local piezoelectric and ferroelectric characteristics upon the top electrode and its local domain switching phenomena. [ABSTRACT FROM AUTHOR]

Two-dimensional layered gallium monochalcogenide (GaX, where X = S, Se, Te) semiconductors possess great potential for use in optoelectronic and photonic applications, owing to their direct band edge. In this work, the structural and optical properties of full-series multilayer GaTe1−xSex for x = 0 to x = 1 are examined. The experimental results show that the whole series of GaTe1−xSex layers may contain one hexagonal (H) phase from GaTe to GaSe, whereas the monoclinic (M) phase predominates at 0 ≤ x ≤ 0.4. For x ≥ 0.5, the H-phase dominates the GaTe1−xSex series. The micro-photoluminescence (μPL) results indicate that the photon emission energy of M-phase GaTe1−xSex increases as the Se content increases from 1.652 eV (M-GaTe) to 1.779 eV (M-GaTe0.6Se0.4), whereas that of H-phase GaTe1−xSex decreases from 1.998 eV (H-GaSe) to 1.588 eV (H-GaTe) in the red to near-infrared (NIR) region. Micro-time-resolved photoluminescence (TRPL) and area-fluorescence lifetime mapping (AFLM) of the few-layer GaTe1−xSex series indicates that the decay lifetime of the band-edge emission of the M phase is faster than that of the H phase in the mixed alloys of layered GaTe1−xSex (0 ≤ x ≤ 0.4). On the other hand, for H-phase GaTe1−xSex, the decay lifetime of the band-edge emission also increases as the Se content increases, owing to the surface effect. The dark resistivity of GaTe1−xSex for 0.5 ≤ x ≤ 1 (i.e., predominantly H phase) is greater than that of the other instance of majority M-phase GaTe1−xSex for 0 ≤ x ≤ 0.4, owing to the larger bandgaps. The predominantly H phase GaTe1−xSex (0.5 ≤ x ≤ 1) also shows a greater photoconductive response under visible-light illumination because of the greater contribution from surface states. The superior light-emission and photodetection capability of the GaTe1−xSex multilayers (0 ≤ x ≤ 1) means that they can be used for future optoelectronic devices. [ABSTRACT FROM AUTHOR]

This work present structural, morphological, magnetic, and electrical properties of GaSb/Mn multilayer deposited via DC magnetron sputtering at room temperature and at 423 K. The samples are characterized by forming layers of 3, 6 and 12 periods of the GaSb/Mn structure. Through XRD patterns, it was possible to stablish the formation of GaSb, Mn3Ga, and Mn2Sb2 phases. FTIR measurements present an optical interference associated with periodicity and the homogenous thickness of the layers. HR-SEM shows the multilayer architecture with columnar microstructure in the formation of layers with grain nucleation on the surface. A ferromagnetic-like behavior was observed in the multilayers at room temperature related to the domains and interlayers interaction. Additionally, the hysteresis curves present shifts attributed to the effect of exchange bias coupling. I-V curves show RESET-SET states of the multilayer system with bipolar resistive behavior, which can be modified by external magnetic fields. The resistive switching evidenced corresponds to the conductive mechanism based on the capacitive conductance and the formation of conductive filaments in multilayer structure. [ABSTRACT FROM AUTHOR]

Repeated and alternate treatment of a nickel surface with Na2PtCl6, CoCl2, and NaBH4 solutions with the general formula [n(Co(OH)2–mPt(0)]k (n and m denote the number of Successive Ionic layers Deposition (SILD) cycles in the preparation of Co(OH)2 and Pt(0), respectively, and k is the number of their repetitions] leads to the formation of multilayer nanocomposites consisting of Co(OH)2 nanosheets and Pt(0) nanoparticles. Their studying by TEM, SEM, XPS, and X-ray diffraction methods showed that it is possible to change morphological characteristics of both nanosheets and nanoparticles, and also of the arrays which they form, by changing the synthesis program, i.e., for example, the n and m values. The most significant differences in such characteristics are observed for samples obtained at n and m values preset in the range of 1–5. The study of the electrocatalytic behavior of such samples in the reaction of hydrogen evolution during the electrolysis of water in the alkaline region showed that the overvoltage values in the series of such samples are largely determined by the synthesis conditions, and their analyzing in the series of samples obtained according to various algorithms allows us to choose the conditions that provide the lowest overvoltage values. [ABSTRACT FROM AUTHOR]

We evaluated the cytotoxicity effect of polyelectrolyte–quercetin (PMQ)-coated iron oxide nanoparticles (Fe2O3) on human ovarian carcinoma cell line (A2780). The γ-Fe2O3@shell (PMQ) was obtained by synthesizing magnetic nanoparticles (MNPs) by chemical co-precipitation and covering it through layer-by-layer (LbL) technique with two different systems of polyelectrolytes: (i) cationic polyallylamine hydrochloride (PAH) and anionic polystyrene sulfonate (PSS) as a synthetic system, and (ii) cationic chitosan (CHI) and anionic carboxymethylcellulose (CMC) as a biopolymer (natural) system. Before using the layer-by-layer technique, quercetin with a negative charge was added to the cationic polyelectrolyte (PAH or CHI) solution, forming a positively charged complex. The nanoparticle size, morphology, and structural, optical, and magnetic properties were analyzed by DLS, TEM, XRD, FTIR, and vibrating sample magnetometer, respectively. Otherwise, the experimental results of TGA and ζ-potential suggest that the layer-by-layer technique is a feasible way to encapsulate quercetin with high efficiency: 64.7% in the PSS/PAH (synthetic polyelectrolytes) and 87.7% in the CMC/CHI (natural polyelectrolytes). The MNPs@PSS/PAH and MNPs@CMC/CHI systems showed no cytotoxicity; however, when quercetin was loaded in the system, we observed a statistically significant reduction in the viability of the human ovarian carcinoma cell line (A2780), though their cytotoxicity was less efficient compared with the high cytotoxicity showed with the quercetin alone. Our results indicated that the reduction in cell viability depends on the number of layers of polyelectrolytes. These systems can potentially be drug carriers for targeted cancer chemotherapy. [ABSTRACT FROM AUTHOR]

The magnetic properties of nanoobjects of nonmagnetic substances based on silicon and transition metal (iron) are considered. It is found that a system of -FeSi nanorods with a mean height of 6.6 nm and lengths from 50 to 200 nm is formed by deposition of iron with 5.22 monolayers in ultrahigh vacuum on a vicinal silicon surface Si(111)-4 followed by annealing at a temperature of C. Soft ferromagnetic loops with a coercive force from 90 to 180 Oe, which persist up to a temperature of 300 K, are observed in nanorods. It is found that easy magnetization axis is perpendicular to the nanorods, while the hard magnetization axis is parallel to them. This type of nanoobjects is promising for developing spintronic devices within the planar silicon technology. [ABSTRACT FROM AUTHOR]

Binary and ternary multilayers comprising paramagnetic and ferromagnetic materials filter out a specific neutron wavelength from the reflected broad spectrum. The effect of the grazing angle, the magnetization of the ferromagnetic layers, and the scattering length density of the ferromagnetic layers for both structures are numerically studied. The best performance of the proposed filter, such as the broadest neutron bandgap of 0.46 Å and the smallest bandwidth of the transmitted beam of 0.0016 Å, was achieved using the binary structure at magnetization of 40 kOe. These findings hold potential in the nuclear fields, including neutron waveguides and filters. [ABSTRACT FROM AUTHOR]

Chiral magnets are known to possess interesting electromagnetic properties that result from the coupling of electrons with nontrivial magnetic phases, such as particle-like magnetic spin textures termed skyrmions. So far, it is unclear how the local and global chirality of magnetic spin textures contributes to the electromagnetic transport responses that have so far been observed. In this work, we focus on unraveling the contributions in the field-dependent longitudinal resistivity response that arises from magnetic spin textures in a centrosymmetric Fe/Gd multilayer that exhibits an array of magnetic phases ranging from stripe, mixed stripe-skyrmion, skyrmion lattice, and disordered skyrmion. Using a combination of transport measurements and micromagnetic simulations, we demonstrate a domain wall chirality reconfiguration occurs as the domain morphology transitions from disordered stripe to skyrmion lattice phase under applied fields that is responsible for the interesting transport responses noted in the field-dependent longitudinal resistivity. Chiral magnets are known to exhibit interesting electromagnetic properties that result from the coupling of electrons with nontrivial magnetic spin textures. Here, the authors demonstrate the interesting responses observed in the field-dependent longitudinal resistivity of a centrosymmetric magnet arises from domain morphology transitions. [ABSTRACT FROM AUTHOR]

To investigate magnetic anisotropy in Si/Ni multilayers, ferromagnetic resonance (FMR) and magnetization studies are carried out by preparing a series of samples of the form [Si(10 Å)/Ni(tNiÅ)]20, where tNi and 20 denote the Ni layer thickness and number of bilayers, respectively. The samples are prepared using a DC magnetron sputtering system by fixing the Si layer thickness at 10 Å and by varying the Ni layerthickness from 10 to 100 Å. The surface morphology study confirms that the multilayers were deposited smoothly over the substrates. The variation of the surface roughness with tNi attains a maximum for tNi = 50 Å. The structural study shows that the average crystallite size increases with as tNi increases. The magnetic anisotropy exhibited by the samples has been systematically studied through static and dynamic processes. The effective magnetization obtained from the MH loops and FMR spectra increases with increasing tNi and approaches towards the bulk value of Ni. Static and dynamic magnetization processes yeilds the values of surface anisotropy constant (Ks) and volume anisotropy constant (Kv) to be positive and negative, respectively. Through FMR studies, it is found that the rougher surfaces/interfaces lead to the multiple resonances peaks, higher asymmetry ratio, minimum value of spectroscopic splitting factor g and higher surface anisotropy. [ABSTRACT FROM AUTHOR]

Three-dimensional spin textures emerge as promising quasi-particles for encoding information in future spintronic devices. The third dimension provides more malleability regarding their properties and more flexibility for potential applications. However, the stabilization and characterization of such quasi-particles in easily implementable systems remain a work in progress. Here we observe a three-dimensional magnetic texture that sits in the interior of magnetic thin films aperiodic multilayers and possesses a characteristic ellipsoidal shape. Interestingly, these objects that we call skyrmionic cocoons can coexist with more standard tubular skyrmions going through all the multilayer as evidenced by the existence of two very different contrasts in room temperature magnetic force microscopy. The presence of these novel skyrmionic textures as well as the understanding of their layer resolved chiral and topological properties have been investigated by micromagnetic simulations. Finally, we show that the skyrmionic cocoons can be electrically detected using magneto-transport measurements. Three dimensional topological spin textures, such as hopfions and skyrmion tubes, have seen a surge of interest for their potential technological applications. They offer greater flexibility than their two dimensional counterparts, but have been hampered by the limited material platforms. Here, Grelier et al. look at aperiodic multilayers, and observe a three dimensional skyrmionic cocoon. [ABSTRACT FROM AUTHOR]

Challenges in the understanding of three-dimensional (3D) brain networks by simultaneously recording both surface and intracortical areas of brain signals remain due to the difficulties of constructing mechanical design and spatial limitations of the implanted sites. Here, we present a foldable and flexible 3D neural prosthetic that facilitates the 3D mapping of complex neural circuits with high spatiotemporal dynamics from the intracortical to cortical region. This device is the tool to map the 3D neural transmission through sophisticatedly designed four flexible penetrating shanks and surface electrode arrays in one integrated system. We demonstrate the potential possibilities of identifying correlations of neural activities from the intracortical area to cortical regions through continuous monitoring of electrophysiological signals. We also exploited the structural properties of the device to record synchronized signals of single spikes evoked by unidirectional total whisker stimulation. This platform offers opportunities to clarify unpredictable 3D neural pathways and provides a next-generation neural interface. [ABSTRACT FROM AUTHOR]

This paper discusses the use of reactive multi-layers for selective assembly of ICs (Integrated Circuits) in an LTCC (Low Temperature Co-fired Ceramics) based SiP (System-in-Package). To understand the requirements for the use of self-propagating reactive multilayers in die bonding, CFD (Computational Fluid Dynamics) simulations have been carried out to simulate the die bonding process of a silicon chip onto a ceramic LTCC substrate. Reactive foils of 40 and 80 µm thicknesses and a simulated reaction propagation speed of 1 m/s were studied and used to melt a solder preform underneath a silicon chip. The results of the CFD simulations were analysed, particularly with respect to temperature and liquid fraction contours, as well as time–temperature histories obtained from temperature probes which were included in the model, such as to approximate the real behaviour of Pt-100 temperature probes, when a real bonding process is being tracked. The CFD method, in this instance realised with ANSYS Fluent software, can track the melting and solidification of the solder as well as model the influence of latent heat, which is crucial to ascertaining the true evolution of the bonding process. [ABSTRACT FROM AUTHOR]