Near-field radiative heat transfer is investigated in composite media including nanoparticles. By modeling pair interactions only, the effective thermal conductivity due to near field radiation is calculated based on a thermal nodes model. We highlight the onset of a Near-Field percolation occurring much earlier than the mechanical percolation at critical volume fraction f=0.033. This 15 mechanism drastically increases the thermal conductivity even at low volume fractions. It also indicates a simple experimental protocol to prove Near-Field contact.
A range of percolation models of cluster systems of composites is discussed. In the models the parameters of the clusters of a substance and inner boundaries were obtained by the Monte Carlo method, and the possibility of affecting the properties of composite materials at the early stages of structure formation was studied.
The frequency dependence of the dielectric loss angle for a metal-insulator composite was shown previously to be an efficient method to experimentally determine the percolation threshold. The statistical properties of this angle are found here to be similar to those of the critical links (supporting the total current) near the percolation threshold close to dc and for very high frequencies. A further discussion is provided about the way to connect this angle to the critical links. The second aim of these studies is to connect the frequency dependence of this angle to the proportion of the cond…
We report the results of electrical resistivity measurements carried out on well-sintered La0.7Ca0.3MnO3 / Mn3O4 composite samples with almost constant composition of the magnetoresistive manganite phase (La0.7Ca0.3MnO3). A percolation threshold (fc) occurs when the La0.7Ca0.3MnO3 volume fraction is ~ 0.19. The dependence of the electrical resistivity as a function of La0.7Ca0.3MnO3 volume fraction (fLCMO) can be described by percolation-like phenomenological equations. Fitting the conducting regime (fLCMO > fc) by the percolation power law returns a critical exponent t value of 2.0 +/- 0.2 at…
Rare-earth-doped optical materials are important for light sources in optoelectronics, as well as for efficient optical amplification elements and other elements of photonics. On the basis of the previously developed method of anhydrous, low-temperature synthesis of Er/Yb oxides from their chlorides we fabricated proper nanoparticles with defined parameters and used them for the development of optically transparent, luminescent polymer nanocomposite with low optical scattering, suitable for direct, light-induced formation of photonic elements. Introduction of preformed gold nanoparticles in su…
Thin-film nanocomposites, consisting of silver nanoparticles embedded in a dielectric Teflon\textregistered AF matrix, were synthesized using vapor phase co-deposition. The electrical conductivity of these composites was measured in-situ as a function of film thickness at various metal concentrations. At low metal concentrations (<30%), dielectric behavior and very little change with film thickness was observed. At moderate to high silver loadings (30-80%) a large increase in electrical conductivity was observed as the films grew thicker. As the thickness increased further, the conductivity fl…
We observe the large enhancement in the dielectric response near the percolation threshold in a composite nanoparticle system consisting of metallic RuO$_2$ grains embedded into dielectric CaCu$_3$Ti$_4$O$_1$$_2$ (CCTO) matrix and annealed at 1100OC. To understand the nature of the dielectric response, we compare CCTO fabricated by two different techniques, solid state process (CCTO$_S$$_S$) and sol-gel process (CCTO$_S$$_G$) with the intrinsic dielectric constant in both cases found to be on the order of 10$^3$-10$^4$ at 10 kHz. For RuO$_2$/CCTO$_S$$_S$ and RuO$_2$/CCTO$_S$$_G$ composites and…
It is discussed that the classical effective medium theory for the elastic properties of random heterogeneous materials is not congruous with the effective medium theory for the electrical conductivity. In particular, when describing the elastic and electro-conductive properties of a strongly inhomogeneous two-phase composite material, the steep rise of effective parameters occurs at different concentrations. To achieve the logical concordance between the cross-property relations, a modification of the effective medium theory of the elastic properties is introduced. It is shown that the qualit…
While classical percolation is well understood, percolation effects in randomly packed or jammed structures are much less explored. Here we investigate both experimentally and theoretically the electrical percolation in a binary composite system of disordered spherocylinders, to identify the relation between structural (percolation) and functional properties of nanocomposites. Experimentally, we determine the percolation threshold $p_c$ and the conductivity critical exponent $t$ for composites of conducting (CrO$_2$) and insulating (Cr$_2$O$_3$) rodlike nanoparticles that are nominally geometr…
In the work, a modified effective medium theory is constructed for calculating the effective properties of thermoelectric composites with different values of percolation thresholds. It is shown that even at concentrations beyond the critical region, the threshold value is essential for determining the effective properties. Two fundamentally different cases of a set of local properties of the composite are considered. In one of these cases, the conductivity and thermal conductivity of one of the phases is simultaneously greater than the conductivity and thermal conductivity of the other phase. …
We explore the conductance of self-healing materials as a measure of the material integrity in the regime of the onset of the initial fatigue. Continuum effective-field modeling and lattice numerical simulations are reported. Our results illustrate the general features of the self-healing process: The onset of the material fatigue is delayed, by developing a plateau-like time-dependence of the material quality. We demonstrate that in this low-damage regime, the changes in the conductance and similar transport/response properties of the material can be used as measures of the material quality d…
In this report we present systematic magnetic studies of pure iron oxide nanoparticles and gold iron oxide nanocomposite with increasing Au particle size/content. For the magnetic studies of these samples we have measured: (1) zero field cooled (ZFC) and field cooled (FC) magnetization, (2) ac susceptibility, (3) magnetization vs field at various temperatures, (4) thermoremanant magnetization relaxation (TRM) and zero field cooled magnetization relaxation (ZFCM) at fixed temperature for various wait times tw for studying the aging effect, (5) magnetization memory effect and (6) exchange bias a…
We report on the effect of electric field on the photoluminescence, PL, from a composite consisting of a conjugated polymer mixed with zinc oxide nanoparticles. We have found that in the absence of electric field PL emission from the composite film has two maxima in the blue and green-yellow regions. Application of a voltage bias to planar gold electrodes suppresses the green-yellow emission and shifts the only PL emission maximum towards the blue region. Current-voltage characteristics of the polymer-nanoparticles composite exhibit the non-linear behavior typical of non-homogeneous polymer-in…
Numerical methods are developed to solve the problem of abnormal changes of current (conductivity) in polymer composite films which may be used as current, pressure or temperature sensors. General nonlinear model includes the heat equation, the nonlinear dependence of the resistivity of insulating composite intervals on temperature, taking into account the dehydrochlorination reaction, the appearance of conducting systems conjugated double bonds, and Ohm's law for full control circuit net. The property of thermal conductivity equation to smooth surges of source function allows to resolve the n…
Diffraction of slow neutrons by nanoparticle-polymer composite gratings has been observed. By carefully choosing grating parameters such as grating thickness and spacing, a three-port beam splitter operation for cold neutrons - splitting the incident neutron intensity equally into the plus-minus first and zeroth diffraction orders - was realized. As a possible application, a Zernike three-path interferometer is briefly discussed.
We present results of temperature dependent measurements of dynamics of micellar nanoparticle - polymer composites of fixed volume fraction and variable polymer chain grafting density. For nanoparticles with lower grafting density we observe dynamically arrested state at low temperatures corresponding to an attractive glass while at high temperature the same system shows relaxation typical of a repulsive glass. For higher grafting density, the low temperature dynamics resembles more of a gel which crosses over to a repulsive glass at high temperature. Possible reasons for such fascinating dyna…
We investigated thermal properties of the epoxy-based composites with a high loading fraction - up to f=45 vol.% - of the randomly oriented electrically conductive graphene fillers and electrically insulating boron nitride fillers. It was found that both types of the composites revealed a distinctive thermal percolation threshold at the loading fraction f>20 vol.%. The graphene loading required for achieving the thermal percolation was substantially higher than the loading for the electrical percolation. Graphene fillers outperformed boron nitride fillers in the thermal conductivity enhancemen…
Polymer nanoparticle composites (PNC) with ultra high loading of nanoparticles (> 50%) have been shown to exhibit markedly improved strength, stiffness, and toughness simultaneously compared to the neat systems of their components. Recent experimental studies on the effect of polymer fill fraction in these highly loaded PNCs reveal that even at low polymer fill fractions, hardness and modulus increase significantly. In this work, we aim to understand the origin of these performance enhancements by examining the dynamics of both polymer and nanoparticles (NP) under tensile deformation. We perfo…
A cell dynamics method for domain separation of diblock copolymers (DBCPs) interacting with nanoparticles (NPs) whose diffusion coefficients depend on chain configuration is proposed for self-assembly of DBCP/NP composites. Increasing NP concentration slows down domain separation, but matching NP diffusion lengths and lamellar size of DBCPs reduces this effect. The model also explains features of different nanocomposites, such as morphological transitions induced by NPs, the coexistence of lamellar and hexagonal patterns in a single sample and peaked NP density profiles across the parallel dom…
Here, we show that the conductivity of conductor-insulator composites in which electrons can tunnel from each conducting particle to all others may display both percolation and tunneling (i.e. hopping) regimes depending on few characteristics of the composite. Specifically, we find that the relevant parameters that give rise to one regime or the other are $D/ξ$ (where $D$ is the size of the conducting particles and $ξ$ is the tunneling length) and the specific composite microstructure. For large values of $D/ξ$, percolation arises when the composite microstructure can be modeled as a regular l…
The in-plane anisotropy (IPA) of mechanical properties existed in plate products is often undesired since it limits the industrial application and increases the difficulty of material processing. It is thus one of the important factors which requires strict control during the manufacture of high-performance aluminum alloy plates. The anisotropic behavior of TiB2/2024Al composite rolling sheet under different heat treatment is studied in this article. T4 heat treated specimen shows good isotropy of yield strength and its texture components are significantly weakened compared with traditional Al…
Scaling theory, duality symmetry, and numerical simulations of a random network model are used to study the magnetoresistance of a metal/insulator/perfect conductor composite with a disordered columnar microstructure. The phase diagram is found to have a critical line which separates regions of saturating and non-saturating magnetoresistance. The percolation problem which describes this line is a generalization of anisotropic percolation. We locate the percolation threshold and determine the t = s = 1.30 +- 0.02, nu = 4/3 +- 0.02, which are the same as in two-constituent 2D isotropic percolati…
In our previous publication (Ref. 1) we have shown that the data for the normalized diffusion coefficient of the polymers, $D_p/D_{p0}$, falls on a master curve when plotted as a function of $h/λ_d$, where $h$ is the mean interparticle distance and $λ_d$ is a dynamic length scale. In the present note we show that also the normalized diffusion coefficient of the nanoparticles, $D_N/D_{N0}$, collapses on a master curve when plotted as a function of $h/R_h$, where $R_h$ is the hydrodynamic radius of the nanoparticles.
We investigate the near-field heat transfer between a semi-infinite medium and a nanoparticle made of composite materials. We show that, in the effective medium approximation, the heat transfer can be greatly enhanced by considering composite media, being maximal at the percolation transition. Specifically, for titanium inclusions embedded in a polystyrene sphere, this enhancement can be up to thirty times larger than in the case of the corresponding homogeneous titanium sphere. We demonstrate that our findings are robust against material losses, to changes in the shape of inclusions and mater…
Diffraction experiments with holographic gratings recorded in SiO$_2$ nanoparticle-polymer composites have been carried out with slow neutrons. The influence of parameters such as nanoparticle concentration, grating thickness and grating spacing on the neutron-optical properties of such materials has been tested. Decay of the grating structure along the sample depth due to disturbance of the recording process becomes an issue at grating thicknesses of about 100 microns and larger. This limits the achievable diffraction efficiency for neutrons. As a solution to this problem, the Pendellösung in…
We report a breakthrough in the search for versatile diffractive elements for cold neutrons. Nanoparticles are spatially arranged by holographical means in a photopolymer. These grating structures show remarkably efficient diffraction of cold neutrons up to about 50% for effective thicknesses of only 200 micron. They open up a profound perspective for next generation neutron-optical devices with the capability to tune or modulate the neutron diffraction efficiency.
We propose the concept of autonomous self-damaging in "smart" composite materials, controlled by activation of added nanosize "damaging" capsules. Percolation-type modeling approach earlier applied to the related concept of self-healing materials, is used to investigate the behavior of the initial material's fatigue. We aim at achieving a relatively sharp drop in the material's integrity after some initial limited fatigue develops in the course of the sample's usage. Our theoretical study considers a two-dimensional lattice model and involves Monte Carlo simulations of the connectivity and con…
The author reports an experimental study of electrical and thermal transport in reduced graphene oxide (RGO)/polystyrene (PS) composites. The electrical conductivity ($σ$) of RGO/PS composites with different RGO concentrations at room temperature shows a percolation behavior with the percolation threshold of ~ 0.25 vol.%. Their temperature-dependent electrical conductivity follows Efros-Shklovskii (ES) variable range hopping (VRH) conduction in the temperature range of 30 to 300 K. The thermal conductivity ($κ$) of composites is enhanced by ~ 90 % as the concentration is increased from 0 to 10…
Correlations between electrical and thermal conduction in polymer composites are blurred due to the complex contribution of charge and heat carriers at the nanoscale junctions of filler particles. Conflicting reports on the lack or existence of thermal percolation in polymer composites have made it the subject of great controversy for decades. Here, we develop a generalized percolation framework that describes both electrical and thermal conductivity within a remarkably wide range of filler-to-matrix conductivity ratios (Y_f/Y_m), covering 20 orders of magnitude. Our unified theory provides a …
We fabricated Pb(Zr0.52Ti0.48)O3-NiFe2O4 composite films consisting of randomly dispersed NiFe2O4 nanoparticles in the Pb(Zr0.52Ti0.48)O3 matrix. The structural analysis revealed that the crystal axes of the NiFe2O4 nanoparticles are aligned with those of the ferroelectric matrix. The composite has good ferroelectric and magnetic properties. We measured the transverse and longitudinal components of the magnetoelectric voltage coefficient, which supports the postulate that the magnetoelectric effect comes from direct stress coupling between magnetostrictive NiFe2O4 and piezoelectric Pb(Zr0.52Ti…
There is a strong interest to attach nanoparticles non-covalently to one-dimensional systems like boron nitride nanotubes to form composites. The combination of those materials might be used for catalysis, in solar cells, or for water splitting. Additionally, the fundamental aspect of charge transfer between the components can be studied in such systems. We report on the synthesis and characterization of nanocomposites based on semiconductor nanoparticles attached directly and non-covalently to boron nitride nanotubes. Boron nitride nanotubes were simply integrated into the colloidal synthesis…
We use molecular dynamics simulations to study a semidilute, unentangled polymer solution containing well dispersed, weakly attractive nanoparticles (NP) of size ($σ_N$) smaller than the polymer radius of gyration $R_g$. We find that if $σ_N$ is larger than the monomer size the polymers swell, while smaller NPs cause chain contraction. The diffusion coefficient of polymer chains ($D_p$) and NPs ($D_N$) decreases if the volume fraction $ϕ_N$ is increased. The decrease of $D_p$ can be well described in terms of a confinement parameter, while $D_N$ shows a more complex dependence on $σ_N$, which …
Embedding silicon nanoparticles in an intermetallic matrix is a promising strategy to produce remarkable bulk anode materials for lithium-ion (Li-ion) batteries with low potential, high electrochemical capacity and good cycling stability. These composite materials can be synthetized at a large scale using mechanical milling. However, for Si-Ni3Sn4 composites, milling also induces a chemical reaction between the two components leading to the formation of free Sn and NiSi2, which is detrimental to the performance of the electrode. To prevent this reaction, a modification of the surface chemistry…
It is shown that a two-component percolation model can explain an experimentally observed behavior, namely that a network built up by a mixture of sintered nanocrystalline semiconducting n- and p-grains can exhibit selective behavior, i.e. respond with a resistance increase when exposed to a reducing gas A and with a resistance decrease in response to another reducing gas B. To this end, a simple model is developed based on realistic assumptions about the reactions on the grain surfaces. The resistance is calculated by random walk simulations with nn-, pp- and np-bonds between the grains and t…
Structure of amorphous nangranular composite (Co$_{86}$Nb$_{12}$Ta$_2$)$_x$(SiO$_2$)$_{1-x}$ films was studied by means of grazing-incidence small-angle X-ray scattering as a function of atomic concentration $x$ of the metal fraction in vicinity of the percolation threshold. It has been established that the average size of magnetic nanoparticles increases with $x$ and this increment exhibit the anisotropic character. It was found that in a whole concentration range the particles are elongated along the growth direction perpendicular to the film plane. For the lowest concentration $x=0.193$ clu…
In this work, a theoretical study of phase equilibrium in mixtures of a calamitic nematic liquid crystal and hard spherical nanoparticles is presented. A mean-field thermodynamic model is used, where the interactions are considered to be proportional to the number of contacts, which in turn are proportional to the areas and area fractions of each component. It is shown that, as the radius of the particle is increased, the effect of the particles on the isotropic-nematic transition is less pronounced, and that for large radius the miscibility increases as the particle radius increases.
A modified cathodic arc technique has been used to deposit carbon nitride thin films directly on n+ Si substrates. Transmission Electron Microscopy showed that clusters of fullerene-like nanoparticles are embedded in the deposited material. Field emission in vacuum from as-grown films starts at an electric field strength of 3.8 V/micron. When the films were etched in an HF:NH4F solution for ten minutes, the threshold field decreased to 2.6 V/micron. The role of the carbon nanoparticles in the field emission process and the influence of the chemical etching treatment are discussed.
Silver nanoparticles embedded in a dielectric matrix are investigated for their potential as broadband-absorbing optical sensor materials. This contribution focuses on the electrical properties of silver nanoparticles at various morphological stages. The electrical current through thin films, consisting of silver nanoparticles, was characterized as a function of film thickness. Three distinct conductivity zones were observed. Two relatively flat zones ("dielectric" for very thin films and "metallic" for films thicker than 300 - 400 Å) are separated by a sharp transition zone where percolation …
Multiwalled carbon nanotubes (MWCNTs) are decorated with Pt nanoparticles by a "layer-by-layer" approach using poly (sodium 4-styrene sulfonate) (PSS) and poly (diallyl dimethylammonium chloride) (PDDA). Transmission electron microscopy (TEM) images and Energy Dispersive X-Ray (EDX) analysis of the samples confirm Pt deposition on surfaces of CNTs. Dispersibility and dispersion stability of MWCNTs in the solvents are enhanced when MWCNTs are coated with Pt nanoparticles. Mg AZ91 composites reinforced with MWCNTs are then produced by a melt stirring process. Compression tests of the composites …
We report the magnetic properties of magnetic nano-composite, consisting of different quantity of NiFe2O4 nanoparticles in polymer matrix. The nanoparticles exhibited a typical magnetization blocking, which is sensitive on the variation of magnetic field, mode of zero field cooled/field cooled experiments and particle quantity in the matrix. The samples with lower particle quantity showed an upturn of magnetization down to 5 K, whereas the blocking of magnetization dominates at lower temperatures as the particle quantity increases in the polymer. We examine such magnetic behaviour in terms of …
Using magnetron sputtering, we produced a series of Co/CoO-MgO nanoparticles on Si(100) substrates. High-resolution transmission electron microscopy (HRTEM) image shows that small isolated Co-clusters (core) covered with CoO (shells) with a size of a few nm embedded in a MgO matrix. Resistivity as a function of Co atomic ratio exhibits a distinct percolation threshold with a sharp decrease around 69% Co content. Across the threshold, the resistivity drops about 7 orders of magnitude. For a sample at this percolation critical threshold, we have observed a giant exchange bias field HE=2460 Oe at…
We study the self-healing process of materials with embedded "glue"-carrying cells, in the regime of the onset of the initial fatigue. Three-dimensional numerical simulations within the percolation-model approach are reported. The main numerical challenge taken up in the present work, has been to extend the calculation of the conductance to three-dimensional lattices. Our results confirm the general features of the process: The onset of the material fatigue is delayed, by developing a plateau-like time-dependence of the material quality. We demonstrate that in this low-damage regime, the chang…
Complex permittivity studies on glassy poly(vinyl alcohol)/poly(vinyl pyrrolidone) (1/1) at proper pressure-temperature condition, provide the activation volume and energy values for both dc conductivity and \b{eta}-relaxation. The temperature dependence of the activation volume, which signatures volume-fluctuations accompanying a dynamic process, maximizes at temperature near the glass transition temperature of neat polyvinyl alcohol. The phenomenon is interpreted by a local softening of polyvinyl alcohol domains, while the blend remains in its glassy state. The scenario is also supported by …
The focus in this paper is an analysis of existing state of the arts directed toward the development of the next generation of vibration damping systems. The research work concentrates on an investigation related to nanoparticles/fibres/tubes-reinforced materials and coatings dynamic characterization and modeling of the fundamental phenomena that control relationships between structure and damping/mechanical properties of the materials. We simulated composite materials using finite element and mesh free methods, using a hollow shell representation of the individual nanotube/fiber. Results of t…
Conducting polymers have wide technological applications in sensors, actuators, electric and optical devices, solar cells etc. To improve their operational performance, mechanical, thermal, electrical and optical properties, such polymers are doped with carbon allotrope nanofillers. Functionality of the novel nanocomposite polymers may be stipulated by size characteristics of nanoparticles and the polymer, different physical effects like charge transfer in such objects etc. We characterize and analyze structure, elastic, electric properties and of novel polymer nanocomposites, isotactic polypr…
We present a numerical study on geometric percolation in liquid dispersions of hard slender colloidal particles subjected to an external orienting field. In the formulation and liquid-state processing of nanocomposite materials, the alignment of particles by external fields such as electric, magnetic or flow fields is practically inevitable, and often works against the emergence of large nanoparticle networks. Using continuum percolation theory in conjunction with Onsager theory, we investigate how the interplay between externally induced alignment and the spontaneous symmetry breaking of the …
This work discusses optical singularities and electrical conductivity behavior in a thin electrooptical cell filled with composites including multi-walled carbon nanotubes (MWCNTs) and nematic liquid crystal (LC). The MWCNTs with high aspect ratio $L/d\approx 300\div1000$ and nematic LC 5CB (4-pentyl-4-0-cyanobiphenyl) were used. The composites were prepared by introduction of MWCNTs ($0.0001\div0.1$ % wt) into LC solvent with subsequent sonication. The increase of MWCNT concentration (between $0.005\div0.05$ % wt) resulted in self-organization of MWCNTs and formation of micron-sized aggregate…
The attachment of semiconducting nanoparticles to carbon nanotubes is one of the most challenging subjects in nanotechnology. Successful high coverage attachment and control over the charge transfer mechanism and photo-current generation opens a wide field of new applications such as highly effective solar cells and fibre-enhanced polymers. In this work we study the charge transfer in individual double-wall carbon nanotubes highly covered with uniform ZnO nanoparticles. The synthetic colloidal procedure was chosen to avoid long-chained ligands at the nanoparticle-nanotube interface. The result…
Poly(ethylene imine) functionalized carbon nanotube thin films, prepared using the vacuum filtration method, were decorated with Au nanoparticles by in situ reduction of HAuCl4 under mild conditions. These Au nanoparticles were subsequently employed for the growth of GaAs nanowires (NWs) by the vapor-liquid-solid process in a gas source molecular beam epitaxy system. The process resulted in the dense growth of GaAs NWs across the entire surface of the single-walled nanotube (SWNT) films. The NWs, which were orientated in a variety of angles with respect to the SWNT films, ranged in diameter be…
In this article, we study the Faraday effect in a binary composite consisting of a dielectric matrix with metallic inclusions. We first use the replica trick together with a variational method in order to compute the effective permittivity tensor (in the quasi-static limit) of this composite in a static magnetic field. In order to find the scaling exponents near the percolation threshold, we use a high contrast or low frequency expansion combined with scaling. The result of the two methods are in agreement and predict that near the percolation threshold (and below, that is in the dielectric re…
Exchange biased composites of ferromagnetic single-domain Ni nanoparticles embedded within large grains of MnO have been prepared by reduction of Ni$_x$Mn$_{1-x}$O$_4$ phases in flowing hydrogen. The Ni precipitates are 15-30 nm in extent, and the majority are completely encased within the MnO matrix. The manner in which the Ni nanoparticles are spontaneously formed imparts a high ferromagnetic- antiferromagnetic interface/volume ratio, which results in substantial exchange bias effects. Exchange bias fields of up to 100 Oe are observed, in cases where the starting Ni content $x$ in the precur…
Nanocrystalline bulk materials are desirable for many applications as they combine mechanical strength and specific electronic transport properties. Our bottom up approach starts with tailored nanoparticles. Compaction and thermal treatment are crucial, but usually the final stage sintering is accompanied by rapid grain growth which spoils nanocristallinity. For electrically conducting nanoparticles, field activated sintering techniques overcome this problem. Small grain sizes have been maintained in spite of consolidation. Nevertheless, the underlying principles, which are of high practical i…
We report on the synthesis and characterization of the epoxy-based composites with the few-layer graphene fillers, which are capable of the duel functional applications. It was found that composites with the certain types of few-layer graphene fillers reveal an efficient total electromagnetic interference shielding, SE~45 dB, in the important X-band frequency range, f=8.2 GHz - 12.4 GHz, while simultaneously providing the high thermal conductivity, K = 8 W/mK, which is a factor of x35 larger than that of the base matrix material. The efficiency of the dual functional application depends on the…
The self consistent effective medium approximation (SEMA) is used to study three-dimensional random conducting composites under the influence of a strong magnetic field {\bf B}, in the case where all constituents exhibit isotropic response. Asymptotic analysis is used to obtain almost closed form results for the strong field magnetoresistance and Hall resistance in various types of two- and three-constituent isotropic mixtures for the entire range of compositions. Numerical solutions of the SEMA equations are also obtained, in some cases, and compared with those results. In two-constituent fre…
