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Despite numerous limitations, graphene characterization using scanning tunneling microscopy is an important aspect of graphene research. In the present study, an ambient, large effective field of view scanning tunneling microscope (A‐LEF‐STM) is used as a more practical extension of a standard STM for analyzing chemical vapor deposited (CVD)‐graphene: A rigid sample stage, which allows the tip to be relocated to any point over an area of 3.5 × 3.5 mm, is attached to the latter. This simple enhancement allows rough patches spanning hundreds of nanometers on any sample to be easily circumnavigated, almost always without damaging the tip. Ripples and multi‐layer regions including those with twisted bi‐layers, in a graphene sheet grown on a copper foil using CVD, are located using the augmented manoeuvrability, and imaged in high‐definition from micron to angström scales. Insights relating to the resolution with which surfaces of varying roughness can be imaged are developed using simulations and a careful analysis of the scanning process. The enhanced field of view is also utilized to verify the extent of graphene coverage over the entire sample area. The acquired images of single and multi‐layer depositions are carefully interpreted. The applicability of this end‐to‐end characterization process for other samples is also discussed. Overall, this study demonstrates the potential benefits of the A‐LEF‐STM as an eminent characterization tool, complementary to a Raman spectrometer, for CVD‐graphene and other two‐dimensional materials. [ABSTRACT FROM AUTHOR]

The two-dimensional van der Waals (2D vdW) Janus materials have different atomic species on both sides to ensure their structural asymmetry and inherent out・of~plane polarizations. A novel 2D vdW Janus material, GeS, was found to develop ferroelectrie tunnel junctions (FTJs) with low energy consumption and high response speed. Based on our first-principles calculations, it is found that the Janus GeS bilayers own three stacking modes, and their lateral sliding and vertical displacement can both modulate the electron transport in GeS-bilay er-based tunnel junc tions. In addition, the FTJ based on GeGe-co nt acting GeS bilayer exhibits the highest on/ofl ratio. Our study expands the concept of sliding ferroelectricity to a new class of 2D vdW Janus mat erials and reveals the possible resis tance switching mechanism of these mat erials in real devices. FuYt hermore, it provides theo retie al guidance for the design of low-energy-consumption and fast-switching nano devices based on 2D vdW Janus materials. [ABSTRACT FROM AUTHOR]

• Relativistic DFT calculations have been performed for bi layers on the Mo(112) surface. • Bi atoms tend to occupy adsorption sites in Mo(112) surface furrows. • For a complete Bi monolayer, the most favored is the centered c(2 × 1) structure. • No Bi-induced surface states were found along Γ – X, corresponding to the direction along furrows. • In contrast, along Γ – y the SOC-split surface band moves upwards with increasing Bi coverage and twice crosses E F. Relativistic DFT calculations performed for Bi layers adsorbed on the Mo(112) surface have shown that Bi atoms tend to occupy adsorption sites in furrows and, at a half-monolayer coverage, form a rectangular p(2 × 1) structure. For a complete Bi monolayer, the most preferred structure is the centered c(2 × 1) structure, with one half of Bi adatoms in on-row sites. No Bi-induced surface states have been indicated along Γ – X, corresponding to the direction along furrows, which can explain only minor changes in the band structure and density of states in vicinity of E F with increasing Bi coverage. On the contrary, changes in the band structure along Γ – Y turn out to be very significant. Specifically, the SOC-splitting band, associated with surface states generated by the Bi adlayer, moves upward and twice crosses E F thus becoming a valence band. This feature may be important in the search for new layered structures for nano and spin-electronics. Band structures along Γ – Y for Bi p(2 × 1) (a), c(2 × 1) (b), and Sb p(2 × 1) (c) layers on Mo(112). The states located predomoinantly in Bi layers are marked by red-white circles. Blue lines an circles in (a) indicate the states located at Mo surface rows. [Display omitted] [ABSTRACT FROM AUTHOR]

Miniaturized in-plane π-type thermoelectric devices composed of p-type Mg2Sn0.8Ge0.2 and n-type Bi layers were prepared by microfabrication techniques. Structural effects on thermoelectric device performance need to be evaluated and optimized to improve device performance and operation. In this study, a rational analysis of the correction of the open-circuit output voltages, output powers, and output power densities by using effective temperature differences was performed, and the effects of device geometries (e.g., the number of π junctions and the cross-sectional area ratio between p- and n-type layers) were determined by comparing different types of in-plane π-type thermoelectric devices. The results revealed that it is crucial to consider the heat transfer loss caused by thermal contact effects in the device and to optimize the structural geometries of the device. Proper structural trends and the effects of the number of p–n pairs on the device performance were observed, which indicated the reasonable device operation of microfabricated in-plane π-type thermoelectric devices. [ABSTRACT FROM AUTHOR]

Complex morphology is observed in the GaAs:Bi cap layer of Ga(As,Bi) films grown on GaAs(001) substrates by low-temperature (LT) molecular beam epitaxy (MBE). The microstructure is dominated by the presence of V-shaped domains in the LT-GaAs cap layer and by the (unintentional) inhomogeneous incorporation of Bi from the underlying Ga(As,Bi) layer growth. Aberration-corrected scanning transmission electron microscopy techniques enabled two types of domain to be identified: (i) twinned domains and (ii) Bi-rich atomically ordered domains with triple periodicity. The observed microstructure is discussed in the context of LT-MBE growth in combination with the presence of a small amount of Bi, which seemingly alters adatom diffusivity. Surface processes and (surface) kinetic factors play a key role in the resultant morphology and explain the appearance of both types of domains. [ABSTRACT FROM AUTHOR]

Using first principles calculations based on density functional theory (DFT), we probe various possible stacking arrangements of bilayer aluminene and intercalate six transition metal (TM) atoms (Ti, Cr, Mn, Fe, Co, and Ni) in unique bilayer aluminene systems. Further, we calculate valence charge density and electron localization function to ascertain the nature of bonding present in both the pristine and TM-intercalated composite systems. Intercalation of Cr, Mn, and Fe is found to result in the magnetic ground state. For Ti, Co, and Ni-intercalated systems, the starting trigonal symmetry has changed to a tetragonal symmetry. Co and Ni intercalated systems exhibit much higher (negative) formation energies compared to the other composite systems. In addition, nesting of the Fermi surface has been probed for the Co and Ni intercalated systems and observations indicate the possibility of the presence of charge density wave in the systems. A dispersion-corrected DFT study suggests that the van der Waals interaction is not likely to play a crucial role in determining the properties of both the pristine and TM-intercalated systems. [ABSTRACT FROM AUTHOR]

We report the influence of reactive oxygen (O 2) and argon (Ar) plasma based ITO:Zr bi-layers for silicon heterojunction (SHJ) solar cells. The purpose of reactive O 2 sputtered ITO:Zr was to improve the Hall mobility and work function while the Ar based ITO:Zr films play an important role to maintain good electrical characteristics. The thickness of reactive O 2 based ITO:Zr films was fixed at 15 nm while Ar based films was varied from 65 to 125 nm, respectively. ITO:Zr bi-layers with the thickness of 15/105 nm deposited by O 2 and Ar plasma, respectively, showed lowest resistivity of 2.358 × 10−4 Ω cm and high Hall mobility of 39.3 cm2/V · s. All ITO:Zr bi-layers showed an average transmittance of above 80% in the visible wavelength (380–800 nm) region. Work function of ITO:Zr bi-layers was calculated from the X-ray photoelectron spectroscopic (XPS) data. The ITO:Zr work function was enhanced from 5.3 eV to 5.16 eV with the variation of ITO:Zr bi-layers from 15/65 to 15/125 nm, respectively. Front barrier height in SHJ solar cells can be modified by using TCO films with high work function. The SHJ solar cells were fabricated by employing the ITO:Zr bi-layer as front anti-reflection coating. The SHJ solar cells fabricated on ITO:Zr bi-layer with the thickness of 15/105 nm showed the best photo-voltage parameters as; V oc = 739 mV, J sc = 39.12 mA/cm2, FF = 75.97%, η = 21.96%. Image 1 • Reactive O 2 and Ar plasma based ITO:Zr bi-layers with high work function are presented for SHJ solar cells. • Role of ITO:Zr bi-layers was to improve the Hall mobility, work function and to maintain good electrical characteristics. • ITO:Zr work function was improved from 5.3 eV to 5.16 eV with variation of ITO:Zr bi-layers from 15/65 to 15/125 nm. • SHJ solar cells fabricated on ITO:Zr bi-layers with thickness of (15/105) nm showed maximum efficiency of 21.96%. • High work function based ITO:Zr bi-layers are proposed for future high efficiency SHJ solar cells. [ABSTRACT FROM AUTHOR]

The present endeavor is to develop a highly-intelligent catalyst prototype which is able to autonomously adapt to the environment and provide an in-situ triple-shift catalytic function. By searching strategies from the nature, this objective is gained by developing a self-adaptive polymer reactor which held Venus flytrap-inspired catalytic bi-layers capable of reverse thermo-responsive properties. The first layer was fabricated with a negatively-thermo-responsive imprinted polymer and embedded metal nanoparticles which were responsible for catalytic reduction. In contrast, the second layer was made of a positively-thermo-responsive polymer containing acidic groups, which were capable of catalytic hydrolysis. This reactor presented individually one single catalytic process at relatively low temperatures and high temperatures because one of the simple layers validated. This reactor presented nevertheless the tandem catalytic ability due to the simultaneous work of the two layers at modest temperatures. With increasing temperatures, the catalytic bi-layers of this reactor would function in a sequential way (i.e., one simple layer, both layers and then another simple layer) and as a result led to the single-tandem-single triple-shift catalytic ability. The protocol of this reactor shares a prospect with developing manipulatable catalytic paradigms. [ABSTRACT FROM AUTHOR]

We have measured the relative orientation of rotated graphene bi-layers (RGBs) deposited by chemical vapor deposition and found that there are spontaneously occurring preferred orientations. Measurements were performed using selected area electron diffraction patterns on various regions of the RGBs. These orientations minimize the complexity of the lattice defined by the set of all possible Burgers vectors. By using a precise definition of singularity, we have been able to show that all non-singular preferred orientations are special in the sense that their angular distance Δ θ to the closest singular orientation also complies with the definition of singularity. Our results show that these special interfaces, named secondary singular interfaces, have simpler displacement fields compared to other non-singular RGBs, implying that interfacial dislocations have fewer Burgers vectors to choose from. Since all observed orientations were found to be either singular or secondary singular, we found evidence that RGBs starting out with rotation angles far from singular orientations re-orient themselves into a nearby secondary singular state in order to simplify their strain fields. Secondary singular orientations also account for the spontaneous formation of high Σ interfaces, although the lack of a precise definition of singularity caused them to remain unnoticed. [ABSTRACT FROM AUTHOR]

Abstract In this paper, we report results on the processing of cadmium zinc sulfide (Cd x Zn 1-x S) ternary compound starting from the deposition of cadmium sulfide (CdS)/zinc sulfide (ZnS) bi-layers buffer configuration and a subsequent thermal annealing for its application to thin film solar cells. The impact of different CdS/ZnS bi-layers buffer configurations as effective alternative to the single CdS buffer layer, as well as the physical and chemical properties of the equivalent Cd x Zn 1-x S ternary compound are presented and discussed. Results on physical properties optimization of Cd x Zn 1-x S ternary compound for future applications to thin film solar cells are presented. Highlights • Synthesis of cadmium zinc sulfide compound starting from bilayers deposition • A varied range of ternary composition can be obtained in a more controlled way. • The impact of different layer thickness on physical properties is studied. • Zinc sulfide thickness lower than 20 nm allows optimal physical properties. [ABSTRACT FROM AUTHOR]

The influence of thickness of silver-magnesium fluoride bi-layers on the sensitivity of SPR based fiber optic sensor has been experimentally examined. The sensitivity is enhanced with increasing magnesium fluoride layer thickness up to 30 nm and decreases at values exceeding 30 nm. The optimum thickness of magnesium fluoride layer was determined to be 30 nm. A sensor fabricated from bi-layers of 40 nm thick silver and 30 nm thick magnesium fluoride demonstrated favorable sensing behavior. [ABSTRACT FROM AUTHOR]

We explore a strategy to counteract aging issues in TiO2/aluminium-doped ZnO bi-layers used in hybrid solar cells photo-anodes, mainly related to Zn diffusion in the TiO2 matrix. Different Ti4+ and Zn2+ local structures within the anatase grains and along the film thickness were found as a function of post-deposition annealing treatments in the range between 200 °C and 500 °C by synchrotron radiation extended x-ray absorption fine structure analyses. In particular, in the 500 °C-treated sample, diffusion of zinc species along the TiO2 grain-boundaries has been observed with aging (3 years). In contrast, a mild thermal budget at 200 °C favours a proper atomic arrangement of the zinc-containing anatase lattice which reduces Zn diffusion, thus guaranteeing a good stability with aging. [ABSTRACT FROM AUTHOR]

Oral drug delivery is the most preferred and convenient option as the oral route provides maximum active surface area among all drug delivery system for administration of various drugs. In present work, Bilayer tablet of Acebrophylline (Sustain Release) & Montelukast Sodium (Immediate Release) were prepared by direct compression method. All trials of Acebrophylline & Montelukast Sodium and were subjected to precompression, post compression & in vitro drug release study. Bilayer tablet were prepared with passed trials of Acebrophylline & Montelukast sodium (i.e. FP-02) compared with ACEBRO-M (Marketed Product) for its pot compression parameters && in vitro drug release study. [ABSTRACT FROM AUTHOR]

Earlier [1, 2, 3], exact analytical solutions were obtained for three configurations of composed bi‐layers with semi‐infinite interface cracks: (i) the bilayer composed of two isotropic layers of equal thicknesses; (ii) an orthotropic layer with the central semi‐infinite crack; (iii) an isotropic layer on isotropic half‐plane of a different material (may be considered as a bilayer, the thickness of one of its layers tending to infinity). In all cases the second Dundur's parameter were supposed to be equal to zero. Here by using a scaling technique all three solutions have been extended to cover wider range of elastic and geometric parameters (elastic constants and thicknesses). In particular, a 2‐D problem of a bilayer composed by dissimilar anisotropic layers partly separated by semi‐infinite crack arbitrary loaded at infinity is considered. The principle axes of elasticity tensor for both layers are supposed to coincide with the geometrical axes. The problem involves 10 constants: four elastic constants for each layer and two thicknesses of the layers. By choosing the proper scales for length and for elastic moduli, the number of dimensionless constants is reduced to 8. By using a scaling technique exact analytical solutions are obtained for two subclasses of the problem with four conditions imposed on the parameters for each case, so that four out of eight parameters remain arbitrary. Similarly a solution is obtained for 2‐D problem of a layer on a half‐plane partly separated by semi‐infinite crack arbitrary loaded at infinity. For all considered cases two modes of stress intensity factors are found in terms of four integral characteristics of the external loads. [ABSTRACT FROM AUTHOR]

Solid-state dewetting (SSD) of the immiscible Ag/Ni bi-layers was studied. After annealing at 400 °C for 1 min, the Ag film was dewetted on the Ni film, and this is the first observation about the SSD of one metal film on another metal film. The easier dewetting of Ag than Ni was attributed to its lower melting point, faster grain boundary self-diffusion and poor wettability between them. At 500 °C, the void formation in the bottom Ni layer was highlighted and compared to Ni single layer: many voids in the former while no visible voids in the latter, indicating that the presence of Ag accelerated the SSD of Ni. It was attributed to the vertical stress gradient in the bottom Ni film of Ag/Ni bi-layers, which accelerated the Ni diffusion and formation of the voids in the underlying Ni film around and below the Ag particles. Besides, voids were more easily formed below the Ag particles than between them due to the large lattice mismatch at the Ag/Ni interface and the possible formation of Ag-Ni alloys. The destabilization of the Ag on the Ni film contributes to the understanding of dewetting kinetics, which is beneficial to realize the controllable nanofabrication. [Display omitted] • Solid-state dewetting of Ag film on Ni film after annealing at 400 °C for 1 min. • Voids are formed in Ni film of Ag/Ni bi-layers but absent in pure Ni film at 500 °C. • The weakened stability is due to the vertical stress gradient in the bottom Ni film. • Compressive stress at the Ni/SiO 2 interface and tensile stress at the Ag/Ni interface. • The possibility of void formation is higher below the Ag particles than between them. [ABSTRACT FROM AUTHOR]

We report on the mechanism of magnetization reversal in epitaxial Co/Fe bi-layers grown by molecular beam epitaxy on MgO(001) substrates. For Co films thicker than 5 nm, the crystal structure is hexagonal. The Fe layer follows an epitaxial relation relative to the MgO substrate of (001)[100]Fe//(001)[110]MgO. When deposited on a cubic Fe layer, the Co layer follows a bi-crystal epitaxial relation of (1120)[0001]Co//(001)<100>Fe as previously reported [Popova et al., Appl. Phys. Lett. 81, 1035 (2002); Wang et al., J. Appl. Phys. 101, 09D103 (2007)]. The magnetization reversal in-plane follows a cubic fourfold symmetry, which coincides with that of the underlying bcc Fe layer. In this study, we find that the area of each Co crystal domain spans 200-1500 nm2 and that these two domains are approximately evenly distributed. The micromagnetic reversal mechanism is a combination of coherent rotational processes and domain wall displacement. These magnetic domains are sized tens of μm and separated by predominately 90° or occasionally 180° domain walls along the Fe<110> and Fe<100> directions, respectively. The cubic anisotropy of the bi-crystalline Co layer is explained by exchange-coupling between hcp grains with perpendicular crystallographic orientation, each having in-plane uniaxial magnetic anisotropy along its respective [0001] direction. [ABSTRACT FROM AUTHOR]

Laser powder bed fusion manufactured (LPBF-ed) porous Ti6Al4V materials have attracted much attention in the biomedical industry due to their functional properties. In this study, mono- and bi-layer LPBF-ed surfaces were prepared to better understand the dynamics of pore formation and the impact of one layer on the next. The powder spreading direction was regarded as the direction here, and then LPBF-ed surfaces could be defined as x- and y- scanned ones. As for LPBF-ed monolayers, the y-scanned surface was rougher than the x-scanned surface, in good agreement with the surface profile of the powder layer extracted from the numerical work. The finding indicates that the morphology of LPBF-ed layers is affected by the relationship between the powder spreading direction and the laser scanning direction. Besides, surfaces scanned with varying laser numbers were used to analyze the effect of the remelting phenomenon, which confirmed that additional laser scans prone to reshaping the pore distribution. The wettability was further studied to investigate their biocompatibility initially. No obvious changes were observed between the CAs of the x- and y-scanned surfaces, whereas the remelting accelerated the surface stabilization of LPBF-ed monolayers. LPBF-ed bilayers were much rougher and more hydrophilic compared to monolayers, and the same result could be verified on xy- and yx-scanned surfaces. The study contributes to better control pores and even performance within LPBF-ed samples by investigating the surface morphology and wettability of LPBF-ed layers. [Display omitted] [ABSTRACT FROM AUTHOR]

Warping of layered wood-based panels is still a challenging problem in the development of thin engineered wood products. Wood as an anisotropic and hydrophilic material tends to change its volume and mechanical properties with changing moisture content. Besides the wood components, also the mechanical properties of certain adhesives are sensitive to moisture changes. A moisture load onto the adhered wood is resulting in different stress and strain states between the adherends. It is expected that adhesives with different moisture-related properties participate differently to this interaction. To observe an adhesive-related warping, thin spruce/HDF (Picea abies and high-density fibreboard) bi-layers with identical material geometries were manufactured under laboratory conditions, using different wood adhesive systems, which are currently used in furniture and flooring industry [polyurethane (PUR), emulsion polymer isocyanate (EPI), polyvinyl acetate (PVAc), urea formaldehyde (UF) and ultra-low emitting formaldehyde amino adhesive (ULEF)]. The bi-layers were exposed to certain relative humidity conditions, and the resulting deformation was measured with a high-precision laser distance detector. Moisture-dependent warping of the bi-layers was obtained in relation to the used adhesive systems. As a result of the study, it can be shown that initial warping after panel manufacturing strongly depends on the adhesive curing characteristics and, especially, on the amount of water that is released into the wood adherend. For the post-setting panel warping, a differentiation into two adhesive groups became visible: rigid and flexible adhesives. Rigid adhesives (UF and ULEF) showed a higher degree of warping compared to the group of flexible adhesives (PUR, EPI and PVAc). [ABSTRACT FROM AUTHOR]

MgZnO/ZnO bilayers (Mg concentration of ∼30%) have been grown and subsequently annealed at different temperatures in the range of 600-900 °C with the specific interest of studying the effect of inter-diffusion of Mg on the photoluminescence (PL) properties of the bilayers. The influence of Mg diffusion and material homogenization is evaluated through absorption, PL, and secondary ion mass spectrometry (SIMS) measurements. No appreciable change in the spectral positions is seen either in PL or absorption up to an annealing temperature of 700 °C, which is also supported by SIMS. However at higher annealing temperatures, diffusion of Mg into the ZnO layer is clearly evident in SIMS profile, which results in the red-shift (blue-shift) of spectral positions of MgZnO (ZnO) layer, respectively. Finally, for the sample annealed at 900 °C, the two layers are completely merged providing a single peak at ∼3.60 eV in PL/absorption corresponding to a completely homogenized MgZnO layer. Spectroscopic results are corroborated by the numerical simulations based on a simple theoretical model, which correlates the observed PL spectra of the heterostructures with the experimental Mg diffusion profiles across the heterointerface, as measured by SIMS. [ABSTRACT FROM AUTHOR]

Highlights • Transparent heat mirrors based on dielectric/gold bi-layers were investigated. • The chosen dielectrics were ten metals oxides. • Performance was evaluated in terms of visible transmittance and infrared reflectance. • Also, performance was evaluated in terms of integrated solar quantities. • Tow oxides (WO 3 and HfO 2) yielded the best performance. Abstract Thin films of noble metals, such as gold, have high visible transparency and infrared reflectance. The former is due to the presence of surface plasmons, and the latter is due to the large density of free electrons. Gold thin films have a transmittance peak at 520 nm, which is closely matched to the maximum emission of solar radiation. These properties have been utilized in several applications, including energy-saving transparent heat mirrors that consist of a bi-layer of a thin gold film over-coated with a dielectric layer. These coatings transmit light and reflect heat. For such an application, the transmittance of the thin gold film needs to be enhanced; this is achieved by the dielectric layer that functions as an antireflective coating. In this work, the dielectrics were metal oxides that are transparent in the visible range. The selection criteria based on the band gap, and refractive index were first imposed to identify potential metal oxides. This resulted in the choice of ten metal oxides (CeO 2 , HfO 2 , MoO 3 , Nb 2 O 5 , NiO, SnO 2 , Ta 2 O 5 , TiO 2 , WO 3 , and ZrO 2). The bi-layer performance was then optimized theoretically. The gold-metal oxide layers were subsequently fabricated, and their optical spectra were measured over the ultraviolet–visible-near infrared ranges. The performance of the heat mirrors was assessed in terms of their visible and solar transmittance and reflectance. A figure of merit was defined to evaluate the suitability of the oxides. The optical properties suggest that tungsten oxide (WO 3) is the best oxide; however, hafnium oxide (HfO 2) has the best performance for solar energy applications. [ABSTRACT FROM AUTHOR]

We have investigated optically induced ultrafast magnetization dynamics of a series of Fe55Pt45/Ni80Fe20 exchange spring bi-layers with varying Ni80Fe20 thickness. Rich spin-wave spectra are observed; whose frequency shows a strong dependence on the Ni80Fe20 layer thickness. Micromagnetic simulations based on a simplified magnetic microstructure were able to reproduce the experimental data qualitatively. The spin twist structure introduced in the Ni80Fe20 layer gives rise to new modes in the composite system as opposed to the bare Ni80Fe20 films. [ABSTRACT FROM AUTHOR]

Cu wires are coated by porous/dense Ni bi-layers as current collectors through electroless plating and hydrogen bubble dynamic template electrodepostion methods. The unique coaxial composite current collectors can be beneficial from the high electrical/thermal conductivity of metal Cu core and high corrosion resistance of dense metal Ni coating as well as porous Ni substrate for growth of active materials. Furthermore, the metal wire current collectors have excellent flexibility and mechanical strength. Highly flexible solid-state fiber supercapacitors are then fabricated by binder-free integrated electrodes of hierarchical MnCo 2 O 4 nanothorns grown on porous/dense Ni bi-layers coated Cu wires. The fiber supercapacitors reach capacitance of 20.6 mF cm −1 (54.8 mF cm −2 ) and energy density of 4.8 μWh cm −1 (12.8 μWh cm −2 ) at a power density of 32.25 μW cm −1 (110 μW cm −2 ). Moreover, the twist fiber supercapacitors show good rate capability and cycling stability. The outstanding performances of the fiber supercapacitors might be attributed to the hierarchically nanothorns MnCo 2 O 4 active materials and the unique porous/dense Ni coated Cu wire current collectors. Our results can provide a novel strategy to design flexible nanostructure fiber supercapacitors for energy storage applications in future wearable electronics. [ABSTRACT FROM AUTHOR]

The magnetic and thermal relaxation of exchange coupling, H[sub ex] in (NiFe/CoFe)/PtMn and NiFe/NiMn bi-layers has been studied as a function of temperature between 25 °C to 250 °C and magnetic field between 0 to 1000 Oe applied antiparallel to the original exchange coupling direction. The blocking temperature was about 380 °C for (NiFe/CoFe)/PtMn, and 410 °C for NiFe/NiMn. It was found that the H[sub ex] of the bi-layers decreased gradually with increasing time, while the coercivities remained almost a constant. The H[sub ex], measured at a temperature of 250 °C and a reversal field of 1000 Oe, decreased from 205 Oe to 0 and then changed its sign. The relaxation time, defined as the time required for H[sub ex] to reach zero, is about 3.1 h and 8.7 h for (NiFe/CoFe)/PtMn and NiFe/NiMn, respectively. The relaxation process for the bi-layers could be understood as the superposition of two exponential decays with different rates associated with a distribution of energy barriers. Spin valve heads using NiFe/NiMn bi-layers could be expected more stable, than those using (NiFe/CoFe)/PtMn bi-layers at an elevated operating temperature. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Highlights • Application of extrapolation method for TEM-EDS quantitative analysis was studied in semiconductor production context. • The film density was measured by XSR. The applicability of thin foil criteria and the contribution of the secondary fluorescence were discussed. • The Cliff-Lorimer coefficient was calculated. • The Ni amount in Ag was measured by TEM-EDS (using the Cliff-Lorimer coefficient previously calculated). • The same sample was used as referring standards for Auger ERSF calculation. Abstract In fabrication of microelectronic devices two important steps are often recognized: i) all the processes performed on the wafer in order to build the active part of the devices and, ii) the assembly and packaging processes, typically performed on a chip, in order to fabricate interconnections between active part and exterior. The wafer back side is an active part of power devices and is normally coated with a stack of Ti-Ni-Au or Ti-Ni-Ag layers to ensure the best electrical contact with the frame on which the device is attached prior to the packaging. An important failure mechanism related to this particular process step is related to the diffusion of Ni to the surface of the stack that causes its oxidation on the back metal surface, inhibiting the correct connection to the metallic frame. Auger Electron Spectroscopy (AES) is a powerful analytical technique that can be used to detect this failure mechanism for its very high sensitivity in the characterization of surface layers. Unfortunately, its results are mainly qualitative. Quantitative extrapolations can be inaccurate using library Elemental Relative Sensitive Factor (ERSF) because they are mainly referred to a silicon substrate and could be not valid for a different matrix. A most accurate evaluation of the ERSF is based on the analysis, under identical experimental condition, of standard materials (with known concentration) that should be similar to the unknown sample and having the same matrix. However, the production of this kind of standard is not easy due to the mobility of Ni in Au and Ag. Another commonly used technique is the Energy Dispersive X-ray Spectrometry (EDS) which is less sensitive than the Auger and not sufficiently adequate for a quantitative analysis due to the limitation of the matrix correction methods. Recently, a new method to perform quantitative analysis by using Transmission Electron Microscopy (TEM) EDS was proposed, starting from bi-layers of pure elements. In this work we show how the use of TEM-EDS quantification of Ni in Ag could be a successful method for ERSF evaluation in order to overcome matrix effect in Auger quantification. For this purpose suitable foils of Ag/Al and Ni/Al were used. The validation of the method was performed on a sample with a tri-metal stack of Ti/Ni/Ag previously stimulated by means of a thermal budget to induce Ni migration on Ag surface. The quantitative analysis allowed us to use this characterized sample as AES standard for ERSF calculation. [ABSTRACT FROM AUTHOR]

Magnetization manipulation caused by spin–orbit torque is one of the central themes investigated in spintronics domain. The spin–orbit torque efficiencies can be manoeuvred by application of mechanical strain. In this direction, this study furthers the effort in understanding the evolution of spin–orbit torque efficiencies in mechanically strained ferromagnet (FM)/heavy metal(HM) (Ni 81 Fe 19 /Pt) bi-layer films on flexible kapton substrate, by the use of spin torque ferromagnetic resonance (ST-FMR) measurement technique. We report a tensile strain induced enhancement in damping-like and field-like spin–orbit torque efficiencies. The effective damping-like spin torque conductivity increased by 42% on the application of 0.312% tensile strain, which is encouraging from the magnetization switching application point of view. In order to investigate the driving factors behind the enhanced damping-like spin torque conductivity, ab-initio calculations were also carried out. Our findings provide insights into the workings of strain in FM/HM bi-layer stack and is a step forward in the implementation of flexible spintronics devices. • ST-FMR measurement of Py/Pt stack on strained flexible substrate • Strain induced enhancement in damping and field-like spin–orbit torque efficiencies • Significant role of interface in enhancement of spin–orbit torque efficiencies [ABSTRACT FROM AUTHOR]

Geometrical instability leading to cambering is recorded during co-sintering of zirconia dense/porous bi-layered planar structures. Sintering strain in the bi-layers rises mainly from mismatch between the different porosity volume fractions at the layers and their interface. In this paper, we analyze the model case of dense taped of 8 mol% Y 2 O 3 -stabilized ZrO 2 laminated on ca. 400 μ thick 3 mol% Y 2 O 3 doped zirconia porous tapes, with homogenous spherical porosity of 13 vol%, 46 vol%, and 54 vol%. Sintering stress during densification is evaluated from the shrinkage rates and viscoelastic behavior during sintering by thermo-mechanical analysis, using cyclic loading dilatometry. The camber development of the bi-layers is measured by in-situ optical dilatometry. In accordance with the model prediction, cambering can be controlled tuning the porosity while achieving a synergetic effect between densification and formation of open porosity at the bilayers. [ABSTRACT FROM AUTHOR]

Processed meat products have been increasingly consumed, a highlight being dried-cured coppa, commonly purchased sliced, making it more susceptible to bacterial deterioration and lipid oxidation. The aim of this work was to produce and apply bi-layers films based on gelatin (in both layers) with addition of nisin and/or Pitanga leaf hydroethanolic extract (PLHE) only in the food contact thinner layer, in order to evaluate their effect on the refrigerated storage of sliced dried-cured coppa. Dried-cured coppa slices covered with active films were vacuum-packaged and stored under refrigeration for 120 days. Every 30 days, samples were tested for moisture content, water activity, pH, color parameters, lipid oxidation by TBARS and peroxide index methods, and microbiological analysis. The different film formulations presented no influence on the water activity, pH and color parameters of sliced dried-cured coppa. However, they significantly affected moisture content, bacterial count and lipid oxidation. The addition of both active compounds – nisin and PLHE – in the food contact thinner layer was observed to have the most favorable effect. [Display omitted] • Gelatin films were incorporated with nisin/Pitanga leaf hydroethanolic extract (PLHE). • Bi-layers films were produced with Nisin/PHLE in a thin layer. • Active films contributed to storage conservation of sliced coppa under refrigeration. • The addition of active compounds into films can reduce additives in food composition. [ABSTRACT FROM AUTHOR]

We study the scattering of a long longitudinal radiating bulk strain solitary wave in the delaminated area of a two-layered elastic structure with soft ("imperfect") bonding between the layers within the scope of the coupled Boussinesq equations. The direct numerical modelling of this and similar problems is challenging and has natural limitations. We develop a semi-analytical approach, based on the use of several matched asymptotic multiple-scale expansions and averaging with respect to the fast space variable, leading to the coupled Ostrovsky equations in bonded regions and uncoupled Korteweg-de Vries equations in the delaminated region. We show that the semi-analytical approach agrees well with direct numerical simulations and use it to study the nonlinear dynamics and scattering of the radiating solitary wave in a wide range of bi-layers with delamination. The results indicate that radiating solitary waves could help us to control the integrity of layered structures with imperfect interfaces. [ABSTRACT FROM AUTHOR]

Cuprous halides (CuX with X = Cl, Br, I), intensely studied about four decades ago by experimentalists for excitons, are again drawing attention of researchers recently. Potential of cuprous halide systems for device applications has not yet been fully explored. We go beyond the one-particle picture to capture the two-particle physics (electron-hole interaction to form excitons). We have deployed the full tool kit of many-body perturbation technique, GW approximation + Bethe Salpeter equation, to unfurl the rich excitonic physics of the bulk as well as layers of CuX. The negative spin-orbit contribution at the valence band top in CuCl, compared to CuBr and CuI, is in good agreement with experiments. We note that CuX have exceptionally strong excitons, defying the linear fit (between the excitonic binding energy and band gap) encompassing many semiconductors. The mono- and bi- layers of cuprous halides are predicted to be rich in excitons, with exceptionally large binding energies and the resonance energies in UV/visible region. Hence this work projects CuX layers as good candidates for optoelectronic applications. With advancement of technology, we look forward to experimental realization of CuX layers and harnessing of their rich excitonic potential. [ABSTRACT FROM AUTHOR]

Theoretical analysis of surface plasmon resonance (SPR) based fiber optic sensor with bi layers of ITO-Pt is carried out. Sensitivity and figure of merit (FOM) of sensor increase with increase in Pt layer thickness for all thicknesses of ITO layers. Though, for a fixed thickness of Pt layer, sensitivity and FOM are reduced with increase in ITO layer thickness. 50 nm ITO–25 nm Pt based SPR sensor reveals maximum sensitivity and FOM. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Performances of binary and ternary combinations of BSTV, SubPc, C 60 in planar OPVC. • Use of BSTV/SubPc/C 60 three-layer structure allows improving cell efficiency of 11%. • Original branched sexithienylene vinylene oligomer-BSTV used as second electron donor. • EQE measurements show that both electron donors contribute to the current. Abstract In this study, organic photovoltaic cells based on planar heterojunctions using small-molecules were fabricated. Two cell configurations were used, planar heterojunctions based on a classical electron donor/electron acceptor couple and planar heterojunctions using three active layers, one donor, one acceptor and a central ambipolar layer. The donor is a thiophene derivative called BSTV, the acceptor is the fullerene while the ambipolar material is a phthalocyanine dye, the SubPc. After studying the performances of cells based on the couples SubPc/C 60 , BSTV/C 60 and BSTV/SubPc, we explore the dependence of the short circuit current and the external quantum efficiency on the SubPc interlayer thickness in cells with three active layers. By comparison with the optimum couple SubPc/C 60 the ternary structure BSTV/SubPc/C 60 exhibits higher short circuit current but smaller fill factor. Nevertheless, for an optimum interlayer thickness of 12.5 nm, the ternary structure allows an improvement of the cell efficiency of 11% by comparison with the highest result obtained with the best couple. As shown by optical measurements, long range Föster energy transfer from the larger band gap donor, BSTV, to the smaller band gap, SubPc, is possible. Therefore, the increase of Jsc is attributed to two-step exciton dissociation process. Excitons produced in the outer BSTV layer are transferred to the SubPc central layer and then dissociated at the interface. [ABSTRACT FROM AUTHOR]

Cell impurities are an emerging nucleating molecular barriers having the capability in disordering the metabolic chain reactions of proteolysis, glycolysis and lipolysis. Their massive effects induced by copolymer crystal growth in compaction with metal and mineral transients are extended as well as in damaging DNA and mRNA structure motif and other molecular assembly e.g. histones structure unites. Their polycrystalline packing modes, polydispersity and their tendency to surface and interface adhesion prompted us in structuring scaffold biomaterials enriched with biopeptides, layered by phospho-glycerides ester-forms. The interface tension of the formed map is flexible and dependent to the surface exposure and its collapse modes to the surrounding molecular ligands. Thus, the attempts in increasing surface exposure e.g. the viscoelastic of structured lipopeptides and types of formed network structures interplays an extra- conjugating biomolecules having a least cytotoxicity effects to cells constituents. Disulfides molecules are selected to be the key regulatory element in rejoining both lipidic and proteic moieties by disordering atoms status via chemical ionization using organic catalyst. The insertion of methionine based peptidic chain at the lateral surfaces of scaffold biomaterials enhances the electron-meta-static motions by raising a molecular disordering status at distinct regions of the map e.g. epimerization into a nonpolar side that helps the chemical conjunction of disulfide groups with the esterified phosphoglycerides mono-layers. These effects in turn are accomplished by the formation of meso-sphere nonpolar- vesicles. The oxidation of disulfide group would alter the ordering of initial molecules by raising a newly molecular disorders to the map with high polarity to surface regions. In the same time indicates a continuation in the crystallization growth factor via a low chemical lesions between the impurities and a supersaturation in the intra-atomic distances with maximum cross linking to the deformed ligand with scaffold biomaterials. [ABSTRACT FROM AUTHOR]

This study demonstrates two-stage cracking of an Inconel‑silver film system on a flexible Teflon substrate under uniaxial tension. In situ fragmentation experiments revealed that primary fracture of the brittle 30 nm Inconel overcoat induced brittle, secondary fracture of the normally ductile 150 nm silver base layer. Good correlation exists between the ratios of primary and secondary saturation crack spacing and individual layer thicknesses. Two-stage cracking was confirmed by cross-sectional analysis and explained by different steady state energy release rates of the individual layers. The results further illustrate how brittle layers are detrimental to the mechanical behaviour of polymer-supported thin film multilayer structures. [ABSTRACT FROM AUTHOR]

Tandem of photocathode (p-type semiconductor) and photoanode (n-type semiconductor) is a promising technique for photoelectrochemical (PEC) water overall splitting. However, the sluggish PEC property of the n-type semiconductor usually slow down the whole tandem system. n-silicon is a potential candidate for high-efficiency photoanode fabrication, but it is limited by the overlarded water oxidation reaction overpotential and the low stability. This work presents a CoO x and NiFe layered double hydroxide (LDH) composite bi-layer modified n-Si photoanode that exhibits excellent PEC performance. Experimental analysis and theoretical calculation results show that the CoO x -NiFe LDH bi-layer accelerates the bulk charge transfer as well as regulates the interfacial charge transfer by a synergistic effect. The prepared n-Si-CoO x -NiFe LDH photoanode exhibits a negative onset potential of 0.95 V (vs. RHE), a photocurrent of 12.2 mA cm−2 at 1.23 V (vs. RHE) and a saturated photocurrent of 41 mA m−2. In addition, the n-Si-CoO x -NiFe LDH photoanode can keep well stability for overall water splitting with nearly 100 % faradaic efficiency. This composite CoO x /NiFe LDH modification strategy provides a promising approach to improve the PEC performance of photoanodes. Develop of a CoO x -NiFe LDH bi-layers modified n-Si photoanode for water oxidation, the functionalized CoO x -NiFe LDH bi-layers improve PEC performance benefit from the synergistic effect between CoO x layer and NiFe LDH layer, the bi-layers can not only accelerate charge carriers transfer but also regulate OER kinetics. [Display omitted] • Cross-scale CoO x and NiFe LDH composite bi-layer modified n-Si photoanode was prepared. • A negative onset potential of 0.95 V (vs. RHE), and saturated photocurrent of 41 mA cm−2 was achieved. • Water oxidation overpotential was decreased synergistically by the CoO x and NiFe LDH composite bi-layer. • A built-in p-n junction field was formed between n-Si and atom-sized CoO x quantum layer. [ABSTRACT FROM AUTHOR]

Abstract: Studies on chemical bath deposited CdS bi-layers are reported. The deposition process consisted in depositing first a CdS layer at 75 °C for 10 min and then a second CdS film was deposited at 40 °C for 45 min to form the bi-layer. By depositing the second CdS film at a lower temperature we could increase the surface covering which allows us to have a better control of the kinetics of the bi-layer growth. In this work, four different structures were prepared and their optical properties studied. Prototype CdTe/CdS devices were developed using these samples. Results of the spectral response and the photovoltaic parameters of these four different structures of CdS/CdTe solar cells are presented and discussed. [Copyright &y& Elsevier]

Contact damage of a curved bi-layer system, consisting of a brittle zirconia coating (Y-TZP) on a compliant polymeric substrate from indentation by a hard tungsten carbide sphere is investigated. The specimens are loaded axially at their top surface. The failure evolution and critical loads to initiate radial cracking in curved zirconia/epoxy bi-layer specimens are compared to those of flat bi-layers with the same thickness. The onset of fracture is observed in situ using a video camera. Finite element modelling is used to evaluate the stress distribution in the zirconia coating, and to confirm experimental data. It is demonstrated that in all specimens, cone cracking occurs prior to radial cracking, with the latter being defined as the primary mode of failure. Increasing the curvature has little effect on the critical load to initiate radial cracking, but causes unstable crack propagation towards the extremities of the specimen resulting in catastrophic failure. The results of this study provide useful guidelines from the data trends, and for extending the system to tri-layers. [ABSTRACT FROM AUTHOR]

The interaction of 3-Hydroxyflavone with serum proteins (BSA and HSA) in lecithin lipidic bi-layers (PC) immobilized on silver nanoparticles (SNPs), was studied by fluorescence and Raman spectroscopy. BSA secondary structure was quantified with a deconvolution algorithm, showing a decrease in α-helix structure when lipids were added to the solution. The effect of temperature on the rate of the excited-state intra-molecular proton transfer and on the dual fluorescence emission of 3-HF in the HSA/PC/SNPs systems was discussed. Evaluation of the antioxidant activity of 3-HF in HSA/PC/SNPs systems was also studied. The antioxidant activity of 3-HF decreased in the presence of SNPs. The results are discussed with relevance to the secondary structure of proteins and of the 3-HF based nano-systems to a topical formulation useful in the oxidative stress process. [ABSTRACT FROM AUTHOR]

We study the scattering of a long longitudinal radiating bulk strain solitary wave in the delaminated area of a two-layered elastic structure with soft ("imperfect") bonding between the layers within the scope of the coupled Boussinesq equations. The direct numerical modelling of this and similar problems is challenging and has natural limitations. We develop a semi-analytical approach, based on the use of several matched asymptotic multiple-scale expansions and averaging with respect to the fast space variable, leading to the coupled Ostrovsky equations in bonded regions and uncoupled Korteweg-de Vries equations in the delaminated region. We show that the semi-analytical approach agrees well with direct numerical simulations and use it to study the nonlinear dynamics and scattering of the radiating solitary wave in a wide range of bi-layers with delamination. The results indicate that radiating solitary waves could help us to control the integrity of layered structures with imperfect interfaces. [ABSTRACT FROM AUTHOR]

Aluminum alloy 1050 strips are roll-bonded with interlayer AlO particles. The effect of rolling parameters on the bond strength, such as the content of AlO particles, plastic deformation, and rolling temperature are investigated by peel test. It is established that higher bond strength can be obtained by increasing the rolling temperature, reducing the thickness, and decreasing the alumina content. The peeling surface of samples versus alumina content is characterized by scanning electron microscopy. [ABSTRACT FROM AUTHOR]

This paper presents a study of the detectability of the level of adhesion at the Aluminum/Epoxy interface using the propagation of ultrasonic guided waves. The topic is relevant to the long-range ultrasonic inspection of structural adhesive bonding. The samples considered are epoxy-coated aluminum: samples were fabricated with partially or totally crosslinked epoxy groups and with different surface treatments of aluminum substrates. Experimentally measured dispersion curves and attenuation coefficients of a selected mode are used to quantitatively track changes at the epoxy-aluminum interface. The results show that modes could be very sensitive to the nature of the interface, that is to say to the level of adhesion, if properly selected. Numerical predictions via the Jones rheological model and their comparison with experimental results highlight three adhesion levels: weak, medium and high one. [ABSTRACT FROM AUTHOR]

We investigate the performance of monolithic copper-indium-gallium-selenide (CIGS)/perovskite tandem solar cells with two different CIGS bottom device absorbers: Cu(In,Ga)Se 2 or Cu(In,Ga)(S,Se) 2 and with three different hole-transporting layers (HTLs): NiO x + SAM, NiO x :Cu + SAM and SAM alone. NiO x (:Cu) is (2 wt% copper-doped) nickel oxide and SAM is the MeO-2PACz ([2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid) self-assembled monolayer. The CIGSe is fabricated by physical-vapor deposition (PVD), has a E g ∼ 1.06 e V, and a σ RMS,PVD ∼ 65 nm, while the CIGSSe is fabricated by rapid-thermal processing (RTP), has a E g ∼ 1.01 e V, and a σ RMS,RTP ∼ 120 nm. While the current certified, 24.2%-efficient, world-record monolithic CIGSe-perovskite tandem solar cell has previously been achieved with SAM as a stand-alone HTL, this work investigates whether SAM can yield similarly high efficiencies also on industrially compatible, very rough RTP CIGSSe absorbers. We find that the devices with SAM as stand-alone HTL suffer from severe FF and V oc losses and that NiO x :Cu is needed to act as a shunt-quenching layer below that SAM, ensuring conformal coverage of the rough bottom sub-cell surface. Within this work the highest-achieved (in-house measured) PCE s for the RTP and PVD CIGS-based tandems are 21.6% and 23.2% respectively, on a cell area of 1.08 cm2, both of which are obtained with NiO x :Cu + SAM as an HTL. • First >20%-efficient monolithic RTP CIGSSe-perovskite tandem on a cell area >1c m2. • RTP CIGSSe is industrially-compatible, but has a very high surface roughness >120 nm. • First integration of low-temperature sputtered NiO x :Cu in CIGSe-perovskite tandems. • NiO x :Cu acts as a shunt-quenching layer below a self-assembled monolayer (SAM). • NiO x :Cu + SAM enables 270 mV and 21.8% higher V oc and FF than the tandems with SAM. [ABSTRACT FROM AUTHOR]

Abstract: Electric light scattering from aqueous suspensions of positively charged ferric oxide particles is investigated in the presence of poly(sodium styrene sulfonate) and poly(allylamine hydrochloride) of different molecular weights, adsorbed sequentially on the particle surface at different ionic strengths. The adsorption is realized over a wide range of NaCl concentration (10−4 to 10−1 M) at pH 4.5 and the suspensions of coated particles are then rinsed to ionic strength of 10−4 M. Our measurements indicate that the amplitude of the electro-optical effect increases with increasing concentration of NaCl from 10−4 to 10−2 M due to the increased amount of polymers, adsorbing in more coiled conformation and on more highly charged particle surface. However, the electro-optical effect started to decrease at further increase of NaCl concentration, more expressively at higher field intensities and for bi-layers with first layer from polyelectrolyte of lower molecular weight. This is accompanied with a significant increase in the thickness of the deposited bi-layers after their rinsing to low ionic strength. We attribute both effects to partial desorption of polyelectrolyte complexes from the particle surface, which disturb the homogeneity of the bi-layer structure. The latter causes an increase in the amount of mechanically trapped water on the particle surface and the thickness of adsorbed bi-layers increases as well. As a result, an elasto-hydrodynamic effect, which favors perpendicular orientation with respect to the external electric field, becomes possible. [Copyright &y& Elsevier]

BiFeO3/BaTiO3 bi-layer thick films (~1 μm) were deposited on Pt/Ti/SiO2/(100) Si substrates with LaNiO3 buffer layers at 500 °C via a rf magnetron sputtering process. X-ray diffraction (XRD) analysis revealed that both BiFeO3 and BaTiO3 layers have a (00l) preferred orientation. The films showed a small remnant polarization (Pr ~ 7.8 μC/cm2) and a large saturated polarization (Ps ~ 65 μC/cm2), resulting in a slim polarization-electric field (P-E) hysteresis loop with improved energy storage characteristics (Wc = 71 J/cm3, h = 61%). The successful "slim-down" of the P-E loop from that of the pure BiFeO3 film can be attributed to the competing effects of space charges and the interlayer charge coupling on charge transport of the bi-layer film. The accompanying electrical properties of the bi-layer films were measured and the results confirmed their good quality. [ABSTRACT FROM AUTHOR]

Annular dark-field (ADF) imaging in a scanning transmission electron microscope (STEM) has been used to measure concentration profiles across thin Ga(As,Bi) layers grown by molecular beam epitaxy, from which the segregation lengths for bismuth surface segregation have been calculated. Performing this for layers grown at two different temperatures, the activation energies for Bi surface segregation have been determined for the lower (GaAsBi-on-GaAs) and for the upper (GaAs-on-GaAsBi) interface. The inequivalence observed is attributed to strain driving the larger Bi atoms preferably towards the free surface during growth. [ABSTRACT FROM AUTHOR]

Viscoelastic properties and sintering mechanisms of tape-casted gadolinium-doped ceria (CGO), yttrium-stabilized zirconia (YSZ), and scandium-yttrium-stabilized zirconia (ScYSZ) are characterized in order to investigate the reciprocal thermo-mechanical compatibility when arranged as a self-standing bi-layered electrolyte system. The combined use of thermo-mechanical analysis, optical dilatometry, and scanning electron microscopy ensures a systematic characterization of both the individual layers and CGO/YSZ and CGO/ScYSZ bi-layered laminates. The results of the co-firing process of the bi-layers are critical due to the mismatch of thermo-mechanical and sintering properties among the materials. Despite the better sinteractivity of ScYSZ, the self-standing CGO/ScYSZ bi-layer presents more challenges in terms of densification compared with the CGO/YSZ bi-layer. In particular, above 1200 °C, ScYSZ and CGO show residual porosity, and at higher sintering temperatures, above 1300 °C, full densification is completely inhibited by constrained sintering phenomena. [ABSTRACT FROM AUTHOR]

Ferromagnetic La0.7Sr0.3MnO3/La0.7Ca0.3MnO3 (LSMO/LCMO) bi-layers of submicron thickness were deposited by magnetron sputtering on SrTiO3 (STO) and Al2O3 (ALO) substrates and temperature dependence of their resistances were investigated. The samples grown on ALO substrates demonstrated lower metal-insulator transition temperatures and higher resistances. The maximum magnetoresistance (MR) of bi-layer grown on STO substrate reached --56% at 184.6 K and magnetic field of 1 T. At temperatures below 150 K a "switching" of MR from negative to positive values (+ 1.7% at 110 K) and a hysteretic behavior of the resistance at low magnetic fields were observed as well. [ABSTRACT FROM AUTHOR]

We have investigated the complex behaviour of boron (B) redistribution process via silicon thin bi-layers interface. It concerns the instantaneous kinetics of B transfer, trapping, clustering and segregation during the thermal B activation annealing. The used silicon bi-layers have been obtained by low pressure chemical vapor deposition (LPCVD) method at 480 °C, by using in-situ nitrogen-doped-silicon (NiDoS) layer and strongly B doped polycrystalline-silicon (P+) layer. To avoid long-range B redistributions, thermal annealing was carried out at relatively low-temperatures (600 °C and 700 °C) for various times ranging between 30 min and 2 h. To investigate the experimental secondary ion mass spectroscopy (SIMS) doping profiles, a redistribution model well adapted to the particular structure of two thin layers and to the effects of strong-concentrations has been established. The good adjustment of the simulated profiles with the experimental SIMS profiles allowed a fundamental understanding about the instantaneous physical phenomena giving and disturbing the complex B redistribution profiles-shoulders. The increasing kinetics of the B peak concentration near the bi-layers interface is well reproduced by the established model. [ABSTRACT FROM AUTHOR]

A simple analytical framework is developed to capture the characteristic features of the electric field–curvature response of piezoelectric bi-layers. For small deformations, the curvatures developed depend on the mismatch in the piezoelectric strengths and the mechanical stiffnesses in both the layers, and the relative thicknesses and the electric potentials applied across each of the layers. For large deformations, a bifurcation in curvature is generally observed at characteristic electric fields which depend strongly on the geometric asymmetry of the bi-layers. [ABSTRACT FROM AUTHOR]

Abstract: A possible route for the synthesis of Fe3O4, Fe, and Fe/Fe3O4 bi-layers with chemical vapor deposition by employing the same Fe3(CO)12 carbonyl precursor is presented. The comprehensive structural, chemical, and morphological investigation of the as-deposited thin single films and bi-layers is performed by X-ray diffraction, X-ray reflectivity, Raman spectroscopy, and time-of-flight secondary ion mass spectrometry depth profiling. We present the possibility of performing the deposition of pure metallic Fe and Fe3O4/γ-Fe2O3 by adjusting the deposition pressure from 10-3/-4 Pa to 1Pa, respectively. The integration of Fe3O4 thin films in a magnetic tunnel junction stack fully synthesized by in situ atomic layer and chemical vapor deposition processes is also presented, showing good stack stability and marginal interdiffusion. [Copyright &y& Elsevier]

Abstract: Epitaxial YBa2Cu3O7/La0.7Ca0.3MnO3 (YBCO/LCMO) bi-layers and La0.7Ca0.3MnO3/YBa2Cu3O7 (LCMO/YBCO) bi-layers were grown on (001)LaAlO3 by pulsed laser deposition, and their microstructures were compared by transmission electron microscopy investigation. In the YBCO(100 nm)/LCMO(150 nm) bi-layers, the LCMO layer consists of columnar grains of ~17 nm in diameter and contains mixed orientation domains of [100]c, [010]c and [001]c. The YBCO layer is totally c-axis oriented and the YBCO lattices are tilted −2.5° to +2.5° as they grew on the rough surfaces of LCMO columnar grains. For the LCMO(140 nm)/YBCO(140 nm) bi-layers, the LCMO/YBCO interface is sharp and flat. The initial 12-nm thickness of the YBCO layer is composed of c-axis oriented domains, and the upper part of YBCO layer is [100] oriented. The LCMO layer was predominantly [001]c oriented while [100]c-oriented domains were occasionally observed. [Copyright &y& Elsevier]