The ubiquitous power-law frequency dependence observed for the ac conductivity in highly disordered semiconductors has a number of competing explanations. We review these mechanisms and discuss their relation to a simple Langevin theory for conductivity in confined regions. The theory is used to interpret recent measurements of the ...

The exact frequency dependence of the ac hopping conductivity of a one-dimensional chain with random interruptions is obtained. The real and imaginary parts of the ac conductivity are shown to vanish quadratically and linearly, respectively, with frequency at the static limit. Critical behavior ...

The ac conduction in ZnO nanorods has been investigated in the frequency range of 100 Hz-1 MHz and at various temperatures between 303 and 543 K. An agreement between experimental and theoretical results suggests that the ac conduction in ZnO nanorods can be successfully explained by Correlated Barrier ...

The present work reports the temperature and frequency dependence of a.c. conductivity in glassy Se{70}Te{30-x}Zn{x} (x = 0, 2, 4 and 6) alloys in the temperature range 300-500 K and frequency range 1 kHz. An agreement between experimental and theoretical results suggests that the a.c. conductivity behaviour of the ...

Ion conduction in noncrystals (glasses, polymers, etc) has a number of properties in common. In fact, from a purely phenomenological point of view, these properties are even more widely observed: ion conduction behaves much like electronic conduction in disordered materials (e.g., amorphous semiconductors). These universalities are ...

We present dc and ac conductivity measurements performed on boron carbide which is a disordered refractory semiconductor. The dc measurements have been performed as a function of temperature over 12 orders of magnitude of conductivity while the ac ones cover 6 orders of magnitude of frequency. We were able to ...

This paper presents a model to describe alternating current (AC) conductivity of DNA sequences, in which DNA is considered as a one-dimensional (1D) disordered system, and electrons transport via hopping between localized states. It finds that AC conductivity in DNA sequences increases as the ...

The ac conduction in ZnO nanotubes has been investigated in the frequency range 100 Hz-1 MHz and at temperatures between 303 and 543 K. An agreement between experimental and theoretical results suggests that the electron transport in ZnO nanotubes can be successfully explained by Correlated Barrier Hopping model. PL spectrum gives the ...

The electrical properties of alizarin doped anthraquinone were investigated using a complex impedance spectroscopy technique. Dielectric study revealed a phase transition from the semiconducting to the conducting state at 53�C. The dielectric relaxation was found to be of non-Debye type. Evidence of temperature-dependent electrical relaxation phenomena as well as a positive ...

Ionic conductivity for the chitosan-NH4CF3SO3 system was conducted over a wide range of frequency and at temperatures between 298 and 313 K. Dielectric data were analyzed using complex permittivity ?* and complex electrical modulus M* for the sample with the highest ionic conductivity at various temperatures. The temperature-dependent ...

Mn1.85Co0.3Ni0.85O4 thin films with single cubic spinel phase and compact surface were prepared by chemical solution deposition method on Al2O3 substrates. Temperature dependent ac impedance spectroscopy was employed to analyze the contributions of grain boundary (GB) and grain to the conduction mechanism. The major characteristics ...

The ac conductivity and dielectric properties of glassy system SexTe79 - xGe21, with x = 11, 14, 17 at.%, has been studied at temperatures 300 to 450 K and over a wide range of frequencies (50 Hz to 500 kHz). Experimental results indicate that the ac conductivity and the dielectric constants depend on temperature, ...

The A.C. conductivity and dielectric properties of Bi2Cu0.1V0.9O5.35 thin films were studied as a function of frequency and temperature. The A.C. conductivity of Bi2Cu0.1V0.9O5.35 film increases with frequency. The low frequency region corresponds to the D.C. conductivity where the inter-well ...

The highly (00l)-oriented 5 mol % Mn doped Pb0.5Sr0.5TiO3 films with remarkable ferroelectric properties (2Pr=27.1 ?C/cm2 and 2Ec=55.5 kV/cm) were fabricated on LaNiO3 coated silicon substrates by chemical solution deposition. The ac conductivity and the dielectric response of the films at various temperatures were studied. Hopping ...

The ac electrical parameters of thermally evaporated zinc phthalocyanine, ZnPc, semiconducting thin films was measured in the temperature range of 180 390 K and frequency between 0.1 and 20 kHz. Aluminum electrode contacts were utilized to sandwich the organic ZnPc semiconducting films. Capacitance and loss tangent decreased rapidly with frequency at high temperatures, but at ...

Polyaniline is chemically synthesised and doped with camphor sulphonic acid. FTIR studies carried out on these samples indicate that the aromatic rings are retained after polymerisation. The percentage of crystallinity for polyaniline doped with camphor sulphonic acid has been estimated from the X-ray diffraction studies and is around 56% with respect to polyaniline emeraldine base. The change in ...

Temperature and frequency dependence of a.c. conductivity have been studied in glassy Se{70}Te{30-x}Sb{x} (2 ? x ? 10). An agreement between experimental and theoretical results suggests that the a.c. conductivity behaviour of Se-Te-Sb system can be successfully explained by correlated barrier ...

Dielectric constant and ac conductivity of highly c-axis oriented LiNbO3 thin film grown by pulsed laser deposition were studied in a metal-insulator-metal configuration over a wide temperature (200 to 450 K) and frequency (100 Hz to 1 MHz) range. The preferred oriented Al (1%) doped ZnO film with electrical conductivity 1.1�103 ?-1 ...

Layered graphite oxide is used as host material for the synthesis of conducting polymer intercalated nanocomposites. Powder X-ray diffraction, Fourier transform infrared, and UV-VIS absorption spectra indicate the formation of polyaniline within the interlamellar spaces of graphite oxide. The red shift of UV-VIS absorption associated with graphite oxide is found. The direct ...

The temperature and frequency dependences of the dielectric functions and ac conductivities ({sigma}{sub ac}) of several boron carbide compositions in the single phase region (9--20 at %C) have been investigated. The low temperature ({lt}25 K) responses are found to be characteristic of phonon-assisted hopping ...

The temperature and frequency dependences of the dielectric functions and ac conductivities ({sigma}{sub ac}) of several boron carbide compositions in the single phase region (9--20 at. % C) have been investigated. The low temperature (<25 K) responses are found to be characteristic of phonon-assisted hopping ...

The temperature and frequency dependences of the dielectric functions and ac conductivities (?ac) of several boron carbide compositions in the single phase region (9-20 at %C) have been investigated. The low temperature (<25 K) responses are found to be characteristic of phonon-assisted hopping transport. ...

The transmission electron microscopy images of in situ prepared multiwall carbon nanotubes (MWNTs) and polyaniline (PANI) composites show that nanotubes are well dispersed in aqueous medium, and the nanofibers of PANI facilitate intertube transport. Although low temperature transport indicates variable range hopping (VRH) mechanism, the dc and ac ...

The AC electrical conductivity of (Ag2O)x (Bi2O3)30 (B2O3)60?x (TeO2)10 glass (x=0, 2, 4, 5, 10, 15 and 20) were measured at different temperatures and frequencies. The results obtained indicated that glasses containing silver<5 mol% have values nearly approximately equal to AC electrical conductivity. A slight ...

... Title : Hopping Conduction from Multiple Scattering Theory and Continuous Time Random Walk to the Coherent Medium Approximation,. ...

The dielectric functions of several boron carbides with composition spanning the single-phase region (9-19 at. % C) have been measured over a broad range of frequencies (102-1015 Hz), making it possible to evaluate the various polarization contributions to the dielectric response. The high-frequency (electronic) contributions to the real part of the dielectric constants (?') are sizable (?'?~=7), ...

Sb2Te3 single crystals have been grown by Travelling Heater Method. EDAX was carried out for confirmation of constituent elements. By the measurements of Dielectric constant (k) and dielectric loss (tan?), we are able to understand various polarization mechanism in the grown crystals such as space charge polarization, orientational polarization of dipoles and atomic polarization of lattice. ...

Differential scanning calorimetry (DSC) was used to identify the phase transitions of polyvinyl alcohol (PVA) doped with europium chloride (EuCl3) and terbium chloride (TbCl3). The dielectric constant and the loss tangent behavior of the investigated samples were studied as a function of temperature in the frequency range 1 100 kHz. The detailed analysis of the results showed that dielectric ...

The ac conductivity measurements have been carried out for the activated Ba/SrO cathode with additional 5% Ni powder for every 100 h acceleration life time at the temperature around 1125 K. The ac conductivity was studied as a function of temperature in the range 300 1200 K after conversion and activation of the ...

A study of the effect of polyaniline doping (with HCl) on the DC and AC conductivity of polyaniline is reported. Additional ESR studies are reported. It is concluded that the charge tansfer in pristine and doped polyaniline occurs through one-dimensional variable large hopping, that the charge transport is dominated by polarons. The ...

The AC electrical conductivity and dielectric relaxation of Ge30Sb10S60 chalcogenide glasses thin films in the frequency range 100Hz-100kHz and in the temperature span 290-450K are reported for the first time. The DC conductivity and thermoelectric power of such system are also measured. From the DC data, a presence of a wide range of ...

Measurements of the electrical DC and AC conductivities were performed on three Fe-phosphate compounds in the temperature range ~210K<=T<=~450K. The Fe-phosphates are semiconducting with activation energy of DC conductivity ?DC of EA~0.35-0.45eV. For ?-Fe2PO4O, the AC conductivity ...

The dc and ac electrical transport property of polyvinyl alcohol-multiwall carbon nanotubes composites has been investigated within a temperature range 77<=T<=300 K and in the frequency range 20 Hz-1 MHz in presence as well as in absence of a transverse magnetic field up to 1 T. The dc conductivity follows variable range hopping ...

TlInS2 single crystals were grown by using Bridgman-Stockbauer technique. Measurements of DC conductivity were carried out in parallel (?//) and perpendicular (??) directions to the c-axis over a temperature range from 303 to 463 K. The anisotropic behaviour of the electrical conductivity was also detected. AC ...

Multilayer films containing polypyrrole mixed with palmitic acid were built up using a technique based on Langmuir-Blodgett deposition followed by two solid state reactions. The resulting films exhibited a room temperature, in-plane dc conductivity of 20 S 0022-3727/31/13/002/img10 and a conductivity in the out-of-plane direction seven orders of magnitude ...

In spite of a metallic C60 molecular ground state, electrical conductivity measurements performed on single crystals of ferromagnetic TDAE- C60 fail to show evidence of metallic behavior. Instead, the material appears to be an insultor exhibiting conductivity of the form ?\\(?,T\\) = ?dc\\(T\\)+?ac\\(?\\). Phonon-assisted activated ...

Relaxation and conduction mechanisms under small ac fields of laser ablated ZrTiO4 thin films were analyzed in the light of impedance and modulus spectroscopy. The overall dielectric properties were mainly dominated by a Maxwell-Wagner type of relaxation with grains and the grain boundary two distinct parts of the circuit. Each of these parts was found to ...

Impedance spectroscopy has been used to study the effect of kaolinite grain sizes on the AC electrical properties of kaolinite/polystyrene composites under different temperatures and applied frequencies. Impedance measurements were performed on prepared composites containing 20% kaolinite mineral of grain sizes 63, 106, 212, and 300 ?m in addition to neat polystyrene. The ...

Thin Bis-(dimethylglyoximato)nickel(II) [Ni(DMG)2] films of amorphous and crystalline structures were prepared by vacuum deposition on Si (P) substrates. The films were characterised by X-ray fluorescence and X-ray diffraction. The constructed Al/Ni(DMG)2/Si(P) metal-insulator-semiconductor devices were characterised by the measurement of the gate-voltage dependence of their capacitance and ...

... I Capacitive Behavior in Conducting Polymers: AC Impedance and Quartz Crystal Microbalance Studies by ... AC Impedance Analysis - ...

The electrical properties of alizarin, a ?-conjugated organic semiconductor, were investigated by the complex impedance spectroscopy technique. A transition from semiconducting to conducting state has been observed and the transition temperature shifts to higher side with the increment in frequency. The dielectric relaxation was found to be of non-Debye type (polydispersive). ...

Substitution of an electron donor such as phosphorus for a carbon or boron atom in [ital p]-type semiconducting boron carbides is expected to reduce the hole concentration. Phosphorus-doped boron carbide samples have been prepared by hot isostatic pressing with homogeneous dopant levels of up to one phosphorus atom per ten unit cells. Raman spectroscopy and x-ray diffraction confirm the presence ...

The ac electrical properties of several Y-Al-Si oxynitride glasses were measured as a function of temperature at 20/sup 0/ to 625/sup 0/C in the frequency range 50 to 10/sup 5/Hz. The low-field dc conductivity was also determined. Dispersions in the dielectric constant associated with the peaks in the tan delta curves were observed in all cases. The peaks ...

The ac electrical properties of evaporated cadmium telluride thin films sandwiched between ohmic aluminum electrodes have been investigated for temperatures of approximately 200 - 400 K over the frequency range 102 - 2 multiplied by 104 Hz. The ac conductivity (sigma) ((omega) ) was found to follow a (sigma) ((omega) ) varies direct as ...

... TITLE: High-Frequency Hopping Conductivity of Two-Dimensional Electronic System in GaAs/AlGaAs Heterostructures [Acoustical Method] ...

The dielectric constant and the dielectric loss of thin films of metal-free phthalocyanine dispersed in polycarbonate using ohmic gold electrodes are investigated in the frequency range 20-105 Hz and within the temperature range 300-388 K. The frequency dependence of the impedance spectra plotted in the complex plane shows semicircles. The Cole-Cole diagrams have been used to determine the ...

Nanocrystalline indium oxide samples with various sizes of nanocrystals are synthesized by the sol-gel method. The minimal and maximal average sizes of nanocrystals are 7-8 and 18-20 nm, respectively. An analysis of conductivity measured at dc and ac signals in a wide temperature range (T = 50-300 K) shows that the transport of charge carriers at high ...

We discuss results of ac impedance spectroscopy and dc I-V measurements applied to microbial biofilms and demonstrate that the biofilms of Geobacter sulfurreducens that grow on the anodes of microbial fuel cells are electronically conductive, with conductivities comparable to conjugated polymers. To investigate the components ...

Single phase perovskite Ba(Sr1/3Nb2/3)O3 ceramics was prepared using the columbite precursor method. X-ray diffraction (XRD) technique is used to verify the single phase formation. It stabilizes in hexagonal phase with lattice constants a=12.1243 � and c=15.3747 �. Impedance analysis shows distributed relaxation time. Single semicircular arc observed in complex impedance plot confirms that ...

Humidity sensing characteristics of NiO/Al2O3 nanocomposites, prepared by sol-gel method, are studied by impedance spectroscopy. Modeling of the obtained impedance spectra with an appropriate equivalent circuit enables us to separate the electrical responses of the tightly bound chemisorbed water molecules on the grain surfaces and the loosely associated physisorbed water layers. Dependence of the ...

The cobalt cadmium ferrite has an n-type conductivity. As the Cd addition (x) increases, the hopping rate increases and so the conductivity increases up to x=0.5. A sudden decrease in the hopping rate occurs above x=0.5 due to the decrease of Co2+ ions on octahedral sites. Above x=0.7, the ...

The effects of the molar mass of polymethylmethacrylate (PMMA) on electrical, structural and morphological properties of conductive polyaniline-polymethylmethacrylate blends have been studied. We have plasticized the PMMA matrix by using dioctyl phthalate (DioPh). Three different molar masses of PMMA, 15 000, 120 000 and 350 000 g mol-1, have been used. The x-ray diffraction ...

Successful incorporation of vanadium dopant within the giant dielectric material CaCu 3Ti 4O12 (CCTO) through a conventional solid-state sintering process is achieved and its influence on the dielectric as well as electrical properties as a function of temperature and frequency is reported here. Proper crystalline phase formation together with dopant induced lattice constant shrinkage was ...

Successful incorporation of vanadium dopant within the giant dielectric material CaCu 3Ti 4O12 (CCTO) through a conventional solid-state sintering process is achieved and its influence on the dielectric as well as electrical properties as a function of temperature and frequency is reported here. Proper crystalline phase formation together with dopant induced lattice constant shrinkage was ...

Electronic transport in a-C films has been the subject of considerable debate. In this study, combined stress relaxation and electrical transport studies were used to identify the transport mechanism in a-C films prepared by pulsed-laser deposition. The stress relaxation was modeled by a first-order kinetic reaction involving transformation of 4-fold ...

Thin chalcogenide films of Bi30 Se(70-x) Tex (x=35, 40, and 45 at%), with a thickness of about 200 nm, have been prepared by the thermal evaporation technique. The physical properties that have been studied are: the density (d), the heat of atomisation (Hs), the average coordination number (Z), and the number of lone pair bonds. The AC conductivity ...

The electrical and dielectric properties of CuFe1?xCrxO2 (0 <= x <= 1) powders, doped with 3% of Mg and prepared by solid-state reaction, were studied by broadband dielectric spectroscopy in the temperature range from ?100 to 150 �C. The frequency-dependent electrical and dielectric data have been discussed in the framework of a power law conductivity and complex ...

We investigate the origin of the optical ac and dc conductivity anisotropies observed in the low temperature orthorhombic phase of lightly doped, untwinned La2 ? xSrxNiO4 single crystals. We show that these anisotropies can be naturally ascribed to the emergence of two odd parity, rotational-symmetry-broken, localized impurity acceptor states, one deeper ...

We investigate the origin of the optical ac and dc conductivity anisotropies observed in the low temperature orthorhombic phase of lightly doped, untwinned La(2 - x)Sr(x)NiO(4) single crystals. We show that these anisotropies can be naturally ascribed to the emergence of two odd parity, rotational-symmetry-broken, localized impurity acceptor states, one ...

The frequency and temperature dependences of the magnetic susceptibility and the ac electrical conductivity in magnetoelectric K3FeII3CrIII2F15 were investigated. The zero-field-cooled-field-heated magnetic susceptibility reveals phase transitions at 14.2 and 36.6 K. The phase below 36.6 K is ferromagnetic. At temperatures below 200 K, the ...

In this paper, we have studied the temperature and frequency dependence behavior of ac conductivity in the glassy system Se80?xTe20Snx (0<=x<=10). All the measurements have been carried out in the frequency range 1�500 kHz and in the temperature range from room temperature to the glass transition temperature Tg. The density of defect states has ...

We present a quantitative analysis of ac electrical conductivity and dielectric constant measurements that were performed on boron carbide samples. This material is crystalline but disordered on the atomic scale because of the existence of a large stoichiometry range from B{sub 9}C to B{sub 4}C. The polaronic character of the hopping ...

In recent times antiferroelectric thin-film material compositions have been identified as one of the most significant thin films for development of devices such as high charge storage, charge couplers/decouplers, and high strain microelectromechanical systems. Thus, understanding the dielectric and electrical properties under an ac signal drive in these antiferroelectric ...

Electrical transport properties of nanocrystalline zinc ferrite were investigated in the temperature range 77?T?300 K, applying magnetic field upto 1 T in the frequency range 20 Hz 1 MHz. The DC conductivity follows a simple hopping type charge transport. The DC magnetoresistivity of the samples is negative, which has been explained by using tunnelling ...

... A crossover from ES to Mott regime is expected when, either the Coulomb interaction is screened, or the hopping energy exceeds the width of the ...

Three issues concerning phonon-assisted hopping in molecularly doped polymers are considered. The first issue is whether Arrhenius jump rates in the vicinity of room temperature arise from single- phonon or small-polaronic hopping. It is concluded that Ar...

Perovskite Ba0.6Sr0.4TiO3 sol�gel thin films with different thicknesses are fabricated as MFM configuration to study the effect of the film thickness on the dielectric relaxation phenomenon and the ionic transport mechanism. The frequency dependent impedance, electric modulus, permittivity and AC conductivity have been investigated in this context. Z* ...

The anisotropy of the dynamic properties of interlayer water molecules along the a and b axes of vanadium pentoxide hydrate, orthorhombic V2O5.nH2O, was studied using quasielastic neutron scattering (QENS) in relation to the anisotropy of the ac conductivity. The QENS spectra were analyzed using a stretched exponential function and a Lorentzian function. ...

The ac conductivity and dielectric relaxation properties of silver selenomolybdate glasses, Y% AgI-(1-Y)%{MAg2O-F0.4SeO3-0.6MoO3} with varying dopant salt concentration, Y=20-80% have been investigated as a function of frequency and temperature. The dc conductivity is found to increase by more than two orders of magnitude with ...

(Pb0.97Sr0.03)(Zr0.05Ti0.95)O3 nanocrystalline powder was prepared by a solution based chemical method. Preliminary x-ray diffractogram analysis of some aspects of crystal structure showed that a single-phase compound was formed exhibiting a tetragonal system. Impedance spectroscopy study showed the presence of both bulk and grain boundary effects in the material, which is also evident from the ...

The double perovskite oxide holmium copper zirconate, Ho2CuZrO6 (HCZ), was synthesized by a solid-state reaction technique. The crystal structure of HCZ shows a monoclinic phase. The dielectric relaxation of HCZ was investigated in the frequency range 44 Hz�1 MHz and in the temperature range 40�360 �C by using impedance spectroscopy. The complex impedance data were analysed by the ...

Low-temperature dielectric measurements on FeTiMO6 (M = Ta,Nb,Sb) rutile-type oxides at frequencies from 0.1 Hz to 10 MHz revealed anomalous dielectric relaxations with frequency dispersion. Unlike the high-temperature relaxor response of these materials, the low-temperature relaxations are polaronic in nature. The relationship between frequency and temperature of dielectric loss peak follows ...

Indium tin oxide (ITO) substrates have been functionalized by several substituted calix[n]arene (n = 5 or 9) derivatives using spin coating to fabricate organic diode devices. The effect of rim size and side substituents has been investigated by UV-visible absorption spectrophotometry. The energy band gaps of these calixarene derivative thin films have been found in the 1.166-1.450 eV range. The ...

Careful consideration of the hopping conductivity in 'one-dimensional' disordered compounds reveals that there is a low-temperature region in which the conductivity is given by ln sigma approximately = minus (T(0)/T) to the 1/2 power. Further empirical ev...

... Accession Number : AD0606014. Title : THE LANGEVIN EQUATION AND THE AC CONDUCTIVITY OF NON-MAXWELLIAN PLASMAS,. ...

Impedance measurements have been made in the frequency range 10 Hz-50 kHz and temperature range from 25 to 55 �C on poly(ethylene oxide) doped with iodine. The iodine concentration ranged from 0% up to 10% by weight. Impedance, dielectric constant, dielectric loss, AC conductivity and activation energy showed frequency and temperature dependence. It was ...

We use experimental results of low signal impedance spectroscopy to investigate the conduction mechanism in organic semiconductor, zinc phthalocyanine (ZnPc). The first 10 nm, of a total of 150 nm thermally deposited ZnPc, was doped with molybdenum oxide (MoO3) by co-evaporation to obtain a 20% doping concentration. The ac electrical parameters were ...

We consider diffusive systems with static disorder, such as Lorentz gases, lattice percolation, ants in a labyrinth, termite problems, random resistor networks, etc. In the case of diluted randomness we can apply the methods of kinetic theory to obtain systematic expansions of dc and ac transport properties in powers of the impurity concentration c. The method is applied to a ...

We have performed a detailed study of the electrical conduction process in CuO thin films deposited by the sol�gel dip coating technique in a temperature range 280�420 K. The electrical conduction is analyzed within the framework of various hopping conduction models. Multiphonon hopping ...

Here, we report the synthesis of polyaniline-zirconium nanocomposite by chemical oxidative polymerization of aniline. Structural, thermal, and morphological properties of the samples are characterized by XRD, FTIR, TGA, SEM, and UV-Vis spectroscopy. Crystalline behavior of the nanocomposite has been obtained due to the presence of zirconium nanoparticles in polyaniline. FTIR analysis reveals the ...

Conductivity relaxation and charge transport mechanisms in polypyrrole (PPy) nanofibers synthesized using a micellar polymerization technique with varying surfactant concentration has been investigated by dielectric relaxation spectroscopy. TEM micrographs depict that the increasing surfactant concentration leads to the reduction of the nanofiber diameter. X-ray diffraction ...

We discuss memory effects in the conductance of hopping insulators due to slow rearrangements of many-electron clusters leading to formation of polarons close to the electron hopping sites. An abrupt change in the gate voltage and corresponding shift of the chemical potential change populations of the hopping ...

Glass system of the composition (Na2B4O7)100-x (V2O5)x, with x=0, 5, 7.5, 10, 12.5, 15 and 20 mol% has been prepared by conventional melt-quenching technique. The optical absorption and A.c conductivity have been measured. The optical absorption reveals that the electronic transition is indirect. The exponential dependence of the absorption coefficient ...

Films with different compositions of polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC) blends have been prepared using the casting method. Differential scanning calorimetery (DSC), thermogravimetric analysis (TGA) and dielectric spectroscopy of all compositions have been investigated. It was found that PVA and CMC are compatible in the studied range of composition. With increasing CMC ...

Cubic pyrochlore Bi1.5Zn1.0Nb1.5O7 thin films were deposited by pulsed laser ablation on Pt(200)/SiO2/Si at 500, 550, 600, and 650 �C. The thin films with (222) preferred orientation were found to grow at 650 �C with better crystallinity which was established by the lowest full-width half maxima of ~0.38. The dielectric response of the thin films grown at 650 �C have been characterized ...

A brief review is provided of the considerations leading to the concept of electrical resistivity, thermal conductivity, and Seebeck coefficient. The mode of electrical conductivity in metallic oxides characterized by 'hopping' processes is discussed sche...

Electrical properties of polyethylene terephthalate (PET), irradiated with gamma rays, have been investigated. The PET films were irradiated with high gamma dose levels in the range from 100 to 2000 kGy. The changes in the DC (?DC) and the ac (?ac) conductivities, with the dose, have been performed. The effect of gamma irradiation on ...

At operating temperatures, heterogeneous catalysts behave like lossy dielectrics. The technique of impedance spectroscopy has been used in conjunction with other AC methods to differentiate between different loss processes. At low frequencies and high temperatures, thermally activated hopping of relatively free charges is dominant, whilst at higher ...

... briefly described. It concerned the phase studies of the precipitation of iron oxides in boron oxides. Descriptors : (*GLASS ...

The transport properties of Nd-doped perovskite materials (La0.7?xNdx)Sr0.3Mn0.7Cr0.3O3 (x?0.30) were investigated using impedance spectroscopy techniques over a wide range of temperatures and frequencies. AC conductance analyses indicate that the conduction mechanism is strongly dependent on temperature and frequency. The DC ...

In this investigation, the effect of Zr substitution at the Ti site of the CaCu3Ti4O12 on the electrical properties has been studied. Samples with composition x = 0.00, 0.10 and 0.30 have been synthesized by the solid state ceramic route in the system CaCu3Ti4-xZrxO12. Powder x-ray diffraction data showed the formation of a single phase solid solution. The structure remains cubic similar to an ...

We measured resistivity in the range of 30-390 K on four semi-insulating low-temperature grown molecular-beam epitaxy GaAs samples. The growth temperature range was from 215 �C to 315 �C. Arrhenius fittings with T-1 and hopping fitting with T-1/4 do not permit us the definition of the temperature ranges controlled by band and hopping ...

The influence of $gamma$ irradiation on arsenic- or antimony-doped germanium was investigated in the temperature range 2--4$sup 0$K by measuring the electrical properties. The results were analyzed using the hopping conduction theories of Miller and Abrahams, and of Shlovskii and Efros. It was concluded that the modern theories describe only ...

Weakly compensated germanium was irradiated with gamma rays, reactor neutrons, and 4 MeV electrons. Irradiation reduced the resistivity and gave rise to hopping conduction with a variable activation energy at temperatures T or approx. =200 /sup 0/K restored the initial properties. Inhomogeneity of the doping played an important role in the appearance of ...

The response to small amplitude AC signals of nanometer-sized carbon films with nitrogen added in the gas is analyzed in a wide frequency range. Measurements have also been developed at temperatures between 300 and 600 K. Domains of sp3-coordinated carbon embedded into a connective tissue have been evidenced in SEM micrograph and confirmed by photocurrent yield measurements. ...

The influence of the microstructural characteristics on the dielectric and electrical properties has been investigated for Nd{sup 3+} doped lanthanum modified lead zirconate titanate ferroelectric ceramics, obtained by the conventional solid-state reaction method, by taking into account different sintering conditions. The grain growth mechanism has been investigated and a cubic-type grain growth ...

The influence of the microstructural characteristics on the dielectric and electrical properties has been investigated for Nd3+ doped lanthanum modified lead zirconate titanate ferroelectric ceramics, obtained by the conventional solid-state reaction method, by taking into account different sintering conditions. The grain growth mechanism has been investigated and a cubic-type grain growth law was ...

Measurements of bulk conductivity and dielectric relaxation processes by ac methods including complex-plane impedance analyses have been carried out on insulating {\\mathrm {Nd}}_{1-x}{\\mathrm {Pb}}_x{\\mathrm {MnO_3}}~(0.10 \\leq x \\leq 0.25) , together with measurements of four-probe dc conductivity and magnetic susceptibility, so ...

DNA is a one-dimensional nanowire in nature, and it may not be used in nanodevices due to its low conductivity. In order to improve the conducting property of DNA, divalent Ni2+ are incorporated into the base pairs of DNA at pH>=8.5 and nickel DNA (Ni-DNA) is formed. Conducting scanning probe microscopy (SPM) analysis reveals that ...

Single crystals of Si-doped yttrium iron garnet (YIG: Si) have been irradiated with 6 GeV 208Pb ions at 80 K and 300 K. The amorphization cross section, for a mean electronic stopping power of 35 MeV ?m-1, was determined from the 300 K 57Fe M�ssbauer spectra. When going from the crystalline to the amorphous phase, the 300 K dc conductivity was found to decrease versus ...

We observe variable-range hopping conduction in thermal admittance spectroscopy and develop a method to evaluate the signal under this condition. As a relevant example of demonstration we employ Cu(In,Ga)(Se,S)2 thin-film solar cells and show that the fundamental N1 signal, which has been discussed for more than a decade in terms of minority carrier traps, ...

Nanometric nickel copper ferrites Ni1-xCuxFe2O4, 0?x?0.45 were prepared by the citrate precursor method. X-ray diffraction measurements confirm the formation of single phase cubic spinel structure. The lattice parameter (a) is increased with increasing Cu2+ ion substitution. The crystallite size was calculated from XRD data and compared with that obtained from TEM micrographs. A significant ...

Multiwall carbon nanotube (MWNT)/polypyrrole (PPy) fibrils were fabricated by template-free in situ electrochemical deposition of PPy over MWNTs, and characterized by electron microscopy and electrical measurements. Scanning and transmission electron microscopy studies reveal that PPy coating on the surface of nanotube is quite uniform throughout the length, with the possibility of forming unique ...

Systematic studies on the {ital R}Ba{sub 2}Cu{sub 3{minus}{ital x}}{ital M}{sub {ital x}}O{sub 7} ({ital R}=Sm, Dy; {ital M}=Fe, Ni, Zn) system were carried out in order to determine the effect of the rare-earth ionic size and magnetic moment on the {ital T}{sub {ital c}} suppression rate. The phases were characterized by powder x-ray diffraction (XRD), resistivity, and ac ...

Samples of AgPO3 were prepared from analar oxides (BDH) using standard sintering ceramic technique. The effect of UV Nd:YAG pulsed laser irradiation with wavelength of 355 nm on the transport properties of the prepared glassy samples AgPO3 was studied. The frequency and temperature dependences of the A.C. conductivity and dielectric properties were ...

Seebeck-coefficient, dc conductivity, ac conductivity from 10kHz to 1 GHz and dielectric constant measurements have been made on hot-pressed samples of boron carbide B/sub 1-x/C/sub x/ in the compositional range 0.13< x <0.2, between room temperature and 4.2 K. The dielectric constant measurements, performed over five orders of ...

Seebeck-coefficient, dc conductivity, ac conductivity from 10kHz to 1 GHz and dielectric constant measurements have been made on hot-pressed samples of boron carbide B1-xCx in the compositional range 0.13

... including such extremes as hopping and liquid-like diffusion ... furnished keywords include: Solid electrolytes; batteries; ionic conductivity; conduction ...

Polycrystalline ferrites with general formula Co0.5CdxFe2.5-xO4 (0.0?x?0.5) were prepared by sol gel method. The dielectric properties ??, ??, loss tangent tan ? and ac conductivity ?ac have been studied as a function of frequency, temperature and composition. The experimental results indicate that ??, ??, tan ? and ...

Ammonium zinc chloride (AZC) crystals doped with different strontium concentrations have been grown by the slow evaporation technique. Detailed temperature (300-450 K) and frequency (400-105 Hz) study of the dielectric constant (\\varepsilon), loss factor (\\tan?) and the ac conductivity (?ac) of the grown crystals has been carried ...

The new mono-nuclear 4-5 and ball-type homo-dinuclear 6 phthalocyanines have been synthesized from the corresponding phthalodinitrile derivative 3. The synthesized compounds have been characterized by elemental analysis, UV-vis, IR,(1)H-NMR and MALDI-TOF-mass spectroscopies. The redox behaviours of the complexes were identified by cyclic voltammetry and square wave voltammetry. The temperature ...

In situ polymerization of aniline was carried out in the presence of molybdenum trioxide to synthesize polyaniline/molybdenum trioxide composites (PANI/MoO3) by chemical oxidation method. The composites have been synthesized with various compositions (10, 20, 30, 40 and 50 wt%) of MoO3 in PANI. The surface morphology of these composites was studied with scanning electron micrograph (SEM). The ...

Pb0.5Sr0.5TiO3 (PST50) fine ceramic powders have been prepared by mechanosynthesis and mixed oxides methods. The dielectric, impedance, electric modulus, and ac conductivity have been carried out over a wide range of frequency and temperature i.e. 100 Hz 1 MHz and 100 650 K, respectively. PST50 shows low dielectric constant, very low dielectric loss, and ...

... The theory of AC conductivity for a weakly ionized gas is reviewed ... expression for the conductivity of a weakly ionized mixture of gases is formulated ...

The electrical conductivity of monocrystalline triphylite, Li(Fe2+,Mn2+)PO4, with the orthorhombic olivine-type structure was measured parallel (?) to the [010] direction and ? [001] (space group Pnma), between �400 and �700 K. Electrical measurements on triphylite are of technological interest because LiFePO4 is a promising electrode material for rechargeable Li ...

Ferrite nanoparticles of basic composition Ni0.7Mg0.3Fe2-xAlxO4 (0.0<=x<=0.5) were prepared through citrate gel method and characterized using XRD, TEM and dielectric spectroscopy techniques. The dielectric properties were studied as a function of frequency (42 Hz-5 MHz) at room temperature. The average particle size has been found between 8-17 nm. The dispersion in dielectric properties and ...

The complex permittivity of FeCl(3)/AOT/CCl(4) microemulsions in the 1-10(5) Hz frequency range has been measured by the conventional AC complex impedance technique. Measurements as a function of the volume fraction of the dispersed phase (FeCl(3)+AOT) and temperature at fixed salt-to-AOT molar ratio (R, R = 0.5) show that the entrapment of FeCl(3) clusters significantly ...

... Accession Number : ADD854901. Title : Inductance Effect in the AC Impedance of Conducting Polypyrrole Films. Descriptive Note : Journal article,. ...

Complex impedance analysis of a new rare earth-based ceramic oxide, LaLiMo2O8, prepared by a standard solid-state reaction technique has been carried out. Material formation under the reported conditions has been confirmed by X- ray diffraction studies. A preliminary structural analysis indicates the crystal structure to be orthorhombic. Electrical properties of the material sample have been ...

In this study, 4,4',4''-[benzene-1,3,5-tryltris(oxy)]tri-9,10,16,17,23,24-hexa(hexylthio)phthalocyaninatocobalt(II) has been synthesized from 4-[3,5-bis(3,4-dicyanophenoxy)phenoxy]phthalonitrile and 4,5-bishexylthiophthalonitrile with CoCl2.6H2O in ethylene glycol at 170-180�C for 6 hours. The effects of substrate temperature (during coating of the films) on the electrical characteristics were ...

BaMnO3 nanorods were synthesized at 200 �C and atmospheric pressure using the composite-hydroxide mediated method. X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy were used to investigate the structure, size, morphology, phase purity and elemental composition of BaMnO3 nanorods. Electrical characterization of BaMnO3 pellet was performed at 300�400 K and ...

National University Jeju, South Korea indigo@ncl.cheju.ac.kr Hanan Lutfiyya Department of Computer Science-hop clustering does not support nodes outside the k- hop range. As join, leave and move may frequently occur leave the current PDP only if it finds a new PDP that is nearer than the current PDP. Figure 4 shows how

A series of W-type hexaferrite samples with composition Ba1?yLayZn0.5Mg0.5CoFe16O27; 0?y?0.07 were prepared using the solid state reaction to investigate their magnetic properties, AC and DC electrical conductivity and thermoelectric power as a function of composition and temperature. The X-ray diffraction was studied to identify the formation of the ...

For the heterostructure n-GaAs/AlxGa1-xAs with a sheet density n=2�1011cm-2 and mobility ??2�106 cm2/Vs with integer and fractional quantum Hall effects (IQHE and FQHE, respectively) we demonstrate the wide applicability of acoustic methods for determining the general conduction parameters of a two-dimensional electron gas. We also examine the mechanisms of low-temperature ...

The present work is to produce thin film semiconductor thermistors which can be directly fabricated on radiation absorbers to act as ultra low-mass, highly sensitive cryogenic phonon sensors for detecting single nuclear radiation interaction invents. The specific application envisioned for these devices is in the search for galactic Dark Matter, which is proposed to exist in the form of weakly ...

This thesis reports on three separate investigations in solid state physics. The first is electron paramagnetic resonance in the spin glass Ag:Mn. EPR measurements were performed at two resonance frequencies, concentrating on temperatures above the glass transition temperature. The measured linewidth appears to diverge at T/sub g/ for low resonance frequencies. These results will be compared with ...

The dielectric response of hard (Fe-doped) and soft (Nb-doped) rhombohedral Pb(Zr0.58Ti0.42)1-xMexO3 (Me=Fe or Nb) ceramics was studied at subswitching conditions over a wide range of temperatures (50-450 �C) and frequencies (10 mHz to 10 kHz). The results show qualitative differences in the behavior of the acceptor- and donor-doped samples. Hard materials exhibit a steep increase in the complex ...

Dc and ac conductivity studies were made on a-CuInTe2 thin films deposited onto substrates held at liquid nitrogen temperatures. The dc results may be understood in terms of three modes of current paths, viz., hopping of carriers near the valence band tail, near an acceptor induced defect state and near the Fermi level at appropriate ...

In several cycloalkanes, ionization of the solvent or photoexcitation of a solute radical cation results in the formation of rapidly hopping solvent holes. Here we report the temperature dependence of scavenging rate constants and conductivity signals (220 to 350 K) for the solvent holes in liquid cyclohexane, methylcyclohexane, and Decalins. Our results ...

Hip-hop culture's force as part of globalization in the fields of economics, popular aesthetics, and identity politics has been well documented. However, its articulation to educational practices has received less attention. This article draws upon fieldwork conducted in 1999 and 2002 in a youth correctional facility to analyze how state institutional ...

The temperature and frequency dependences of the dielectric functions and ac conductivities ((sigma)(sub ac)) of several boron carbide compositions in the single phase region (9--20 at. % C) have been investigated. The low temperature (

...to be connected to the public utility (AC) power line, the radio frequency voltage that is conducted back onto the AC power line on any frequency or frequencies...operation and which do not operate from the AC power lines or contain provisions for...

...to be connected to the public utility (AC) power line, the radio frequency voltage that is conducted back onto the AC power line on any frequency or frequencies...to be connected to the public utility (AC) power line, the radio frequency...

Four glasses of (V2O5)0.3-(P2O5)0.6-(MO)0.1 where MO=(TeO2, GeO2, Bi2O3 or P2O5) were prepared by melting the appropriate amounts of V2O5, MO and (NH4)2HPO4 in an open crucible. The structures of the virgin and annealed glasses (at 673 K for 24 h) were studied using density, FT-IR, X-ray diffraction (XRD), electron spin resonance (ESR) and scanning electron microscope (SEM). The electrical ...

We have fabricated suspended, doubly clamped, carbon nanotube (NT) transistors to investigate the low temperature coupling between mechanical vibration of the NT and single electron effects. At low temperatures of 0.3K to 4.2K, the NT behaves as a quantum dot. The NT quantum dot displays Coulomb oscillations in the conductance by sweeping a gate voltage. Mechanical vibrations ...

The authors consider diffusive systems with static disorder, such as Lorentz gases, lattice percolation, ants in a labyrinth, termite problems, random resistor networks, etc. In the case of diluted randomness the authors can apply the methods of kinetic theory to obtain systematic expansions of dc and ac transport properties in powers of the impurity concentration c. The ...

The ac electrical conductivity and dielectric relaxation properties of nanocrystalline 20 mol% Ho doped ceria (Ce0.8Ho0.2O2??) prepared by citrate auto ignition method, were studied in the temperature range 300-550 �C. The conductivity behaviour showed the absence of any precipitation of Ho inside the grains, even though it has the ...

High temperature bismuth layered piezoelectric and ferroelectric ceramics of CaBi{sub 4}Ti{sub 4}O{sub 15} (CBT) have been prepared using the solid state route. The formation of single phase material with orthorhombic structure was verified from x-ray diffraction and Raman spectroscopy. The orthorhombic distortion present in the CBT ceramic sintered at 1200 deg. C was found to be maximum. A sharp ...

... SAMPLE AND AN AC MAGNETIC FIELD ... FREQUENCY, WHERE IMPEDANCE HERE IS ... THE RECONSTRUCTION METHOD ARE PRESENTED ...

... in Scheme -LI, has good ionic conductivity above the ... assumed to be ion hopping from Lewis base site ... Earlier work on redox active ions in solution ...

... Abstract : The conductivity of gas free thin films of a-germanium was measured as a function of temperature and of film thickness. ...

... themselves are complex in structure, and most likely consist of an inner ferrimagnetic core surrounded by an anti-ferromagnetic grape-fruit skin. ...

May 16, 2001 ... In doped semiconductor thermistors, electricity is conducted by thermally activated charge carriers that hop between localized impurity ...

... Scanning Tunneling Microscopy using a voltage biased tip. ... stepwise hopping conduction of electrons through sites ... threshold for one electron, Vc=e ...

... temperatures. First, the activation energy (,zý 2 meV) can be due to the thermally activated hopping conductivity. In dependence ...

Experimental results of transport in emeraldine form of polyaniline are reported for the first time in the thesis. Possible models of different transport mechanisms are proposed and examined. Polyaniline family has been proven to be an interesting system in that it provides a means of systematically studying the electronic structure of polymers as a function of both the number of electrons and the ...

Manganitelike double perovskite Sr2TiMnO6 (STMO) ceramics fabricated from the powders synthesized via the solid-state reaction route, exhibited dielectric constants as high as ~105 in the low frequency range (100 Hz-10 kHz) at room temperature. The Maxwell-Wagner type of relaxation mechanism was found to be more appropriate to rationalize such high dielectric constant values akin to that observed ...

We present a new approach to study the conductivity of granular metals in a hopping conductivity regime. It is shown that in a bicomponent mixture of metallic spheres embedded in an insulator matrix the current-carrying routes are a sparse network of grains with given correlations between grain separations and grain sizes. The type of ...

Measurements of the electric field dependence of the conductivity have been made on the transition-metal oxide Ni0.6Mn2.4O4. It is found that the conductivity is a linear function of field to fields of 3 � 105 V/cm after corrections for thermal response are made. The observed effect cannot be explained in terms of current theory of field-dependent ...

... From the latter, the coil impedance and the ... FIELDS, HALL EFFECT, ELECTRICAL IMPEDANCE, COILS, VOLTAGE, CONDUCTIVITY ...

The phthalodinitrile derivative 3 was prepared by the reaction of 1,4-dithioerythritol 1 and 4-nitrophthalonitrile 2 in dry DMF as the solvent in the presence of K(2)CO(3) as the base by the method of nucleophilic substitution of an activated nitro group in an aromatic ring. The template reaction of compound 3 with the corresponding metal salts gave the novel binuclear MPcs of ball-type (M = Zn 4, ...

...approved two optional air conditioning test simulation procedures, AC1 and AC2, for the 2001...desires to conduct an alternative SC03 test simulation other than AC1 and AC2, or the AC1 and AC2 simulations for the 2004 and subsequent model...

Films of PVA/PVP blend (50/50) filled with different concentrations of NiCl2 were prepared by casting method. The prepared films were investigated by different techniques. XRD scans demonstrated that the peak intensity at 2??20� decreased and the band width increased with increase in the concentrations of NiCl2 content, which implied decrease in the degree of crystallization and hence causes ...

We observe variable-range hopping conduction in thermal admittance spectroscopy and develop a method to evaluate the signal under this condition. As a relevant example of demonstration we employ Cu(In,Ga)(Se,S)2 thin-film solar cells and show that the fundamental N1 signal, which has been discussed for more than a decade in terms of minority carrier traps, ...

Recently the change in temperature dependence of conductivity observed in polythiophene field-effect transistors has been attributed to field-induced metal-insulator transition. Under a high source-drain voltage, the conductivity becomes independent from temperature and depends exponentially on the inverse of the square root of electric field. In this ...

The x-ray absorption near edge structures of amorphous ZnO (a-ZnO) films were examined. The near-edge structure, which reflects the virtual electron hopping interactions in the photoabsorption final states, increased in intensity compared to crystalline ZnO. Theoretical path-by-path analyses revealed that this reflects the extinction of the multiple ...

Nanocomposites of polyaniline with some rare earth chlorides like neodymium chloride, europium chloride, and dysprosium chloride were synthesized by chemical oxidative polymerization of aniline. Morphological, structural, thermal, optical, magnetic, and electrical properties of the samples were characterized by scanning electron microscope, x-ray diffractometer, Fourier transform infrared ...

The ac and dc conductivities of single-crystal and polycrystalline NaCl were measured as a function of both temperature and particle size. The ac conductivity results for single-crystal NaCl agreed well with the literature. In the intrinsic range, however...

Measurements of the electrical conductivity and of the complex permittivity of water-sodium bis(2-ethylhexyl) sulfosuccinate (AOT)-n-heptane microemulsions are reported. The experimental results are rationalized in terms of a hopping mechanism of AOT anions within clusters of reversed micelles. The dependence of the hopping rate and of ...

The crystal structure, cation distribution and exchange interactions in the Co2.25Fe0.75O2BO3 ludwigite have been explored through X-ray diffraction, electrical resistivity, ac-susceptibility and Mossbauer effect measurements. The crystal data have shown that iron atoms occupy the most symmetric crystallographic sites Fe4 and Fe2. The complex magnetic behavior with two ...

The paper reports on the effect of Al substitution on the structural and electrical properties of bulk ferrite series of basic composition MnFe2?2xAl2xO4 (0.0?x?0.5) synthesized using solid state reaction method. XRD analysis confirms that all the samples exhibit single phase cubic spinel structure excluding presence of any secondary phase. The dielectric constant shows a normal behaviour with ...

We explore various properties of classical one-dimensional Wigner solids in the presence of weak disorder at T=0 in the context of a recently discovered Anderson transition of plasma modes in a random potential system. The extent to which the Wigner lattice is really a �crystal� rather than an amorphous solid is discussed for two types of disorder. The probability density of particle ...

The interplay between the crystalline and magnetic structures of a 4% Cr-doped Bi(0.37)Ca(0.63)Mn(0.96)Cr(0.04)O(2.99) has been investigated by alternating current (ac) magnetic susceptibility, electrical resistivity, and neutron diffraction measurements. The compound crystallizes into a monoclinic P2(1)/m symmetry. A Jahn-Teller distortion occurs at 280 K. The thermal ...

Polycrystalline LaFe1?xNixO3 (x = 0.0, 0.1, 0.3 and 0.5) oxides are prepared by a solid-state reaction method. In order to explore the delocalization effects of disorder induced by Ni substitution, dependence of the ac electrical properties of the synthesized composition is investigated in a wide temperature (77�300 K) and frequency (1�10 MHz) range by impedance ...

Polycrystalline sample of NaCa2Nb5O15 was prepared by a high-temperature solid-state reaction technique. Preliminary X-ray structural analysis exhibits the orthorhombic crystal structure of the compound at room temperature. Detailed dielectric studies of NaCa2Nb5O15 over a wide range of temperature (31-500�C) and frequency (102-106 Hz) did not show any dielectric anomaly (or ferroelectric phase ...

The time, voltage, and temperature dependencies of transient polarization currents are reported for two types of varistors (i.e., ZnO and a SiC composite). The current transients exhibit a power-law time response to a step change in voltage (i.e., {ital I}{approx}{ital I}{sub 0}/{ital t}{sup {ital m}}, where {ital m} is slightly less than unity) that persists over a time scale exceeding 10{sup ...

In order to apply widely the superconductivity technology to electric power equipments, the development and evaluation on the AC superconducting cables have been conducted in the Central Research Institute of Electric Power Industry. The superconducting c...

This paper discusses the physics of ac losses in type-II superconductors and in multifilamentary superconducting-normal composite conductors. As an introduction, the ac eddy-current losses in a homogeneous normal conducting cylindrical specimen subjected ...

This lecture discusses the physics of ac losses in type-II superconductors and in multifilamentary superconducting-normal composite conductors. As an introduction, the ac eddy-current losses in a homogeneous normal conducting cylindrical specimen subjecte...

The phenomena of electrical conductivity and diffusion in plasmas is analyzed. Expressions are derived for the DC and AC conductivity of anisotropic plasma, as well as of an anisotropic magnetoplasma, using the macroscopic equations pertinent to the cold ...

Control on the conductivity behaviors has been achieved in nanoparticles of NiFe2O4, synthesized by the hydrothermal route at a fixed temperature of 225 �C by varying the pH of the starting solution. Particles synthesized at pH 7 and 8 behave as n-type semiconductors, while those synthesized at pH 9 and above behave as p-type semiconductors. The observed ...

LiF-V2O5-P2O5 glasses mixed with different concentrations of Ag2O (ranging from 0 to 1.5 mol%) were prepared. The DSC studies of these glasses indicated that the glass forming ability is the highest for the glass doped with 0.6 mol% of Ag2O. D.C. conductivity and dielectric properties over a range of temperature and also optical absorption, ESR, IR and magnetic susceptibility ...

The preparation of vanadate glasses containing barium oxide and their electrical properties in the temperature range of 80-500 K have been reported in this article. Analysis of the electrical properties has been made in the light of different hopping models. The multiphonon assisted hopping model of small polarons in the nonadiabatic regime, proposed by D. ...

The temperature dependent Hall effect and resistivity measurements of Si ?-doped GaAs are performed in a temperature range of 25-300 K. The temperature dependence of carrier concentration shows a characteristic minimum at about 200 K, which indicates a transition from the conduction band conduction to the impurity band conduction. The ...

This paper reports on a local electrochemical impedance spectroscopy (LEIS) technique for mapping the ac impedance distribution, as a function of frequency, of an electrode. In LEIS, as in traditional ac impedance methods, a sinusoidal voltage perturbation between the working and reference electrode is maintained by driving an ac ...

A calculation is done to determine the range of temperature for hopping conduction (with a Log sigma equivalent Tsup(-1/2) law) and the average metallic grain size in granular metals. It is shown that the correlation between the separation of nearest neig...

The electronic specific heat and the dc conductivity of the uncompensated Si:P are calculated via a previously developed theory for impurity band in semiconductors. The theory is investigated further in order to take into account the effect of correlation...

We discuss a small polaron hopping model, in order to explain the intense temperature (T) dependence of the electrical conductivity (?) observed at high temperatures along the DNA molecules. The model takes into account the one-dimensional character of the system as well as the presence of disorder in the DNA double helix. Theoretical considerations based ...

The frequency dependent electrical conductivity below 1 MHz was studied on wet-spun, macroscopically oriented, calf thymus DNA bulk samples. Temperature dependence of the quasistatic electrical conductivity measured perpendicular to the long DNA axis is discussed within the framework of activated variable range hopping mechanism. It is ...

In this paper, the direct current and alternating current (ac) electrical transport properties of doped and undoped regioregular poly[3-(4-alkoxyphenyl)-thiophenes], where the alkoxy groups are O-(CH2)n-1CH3 with n=1,4,6, and 8, have been investigated. The films have been synthesized by an experimental procedure based on the oxidation of 3-(4-alkoxylphenyl)-thiophenes with ...

We present a scaling theory for charge transport in disordered molecular semiconductors that extends percolation theory by including bonds with conductances close to the percolating one in the random-resistor network representing charge hopping. A general and compact expression is given for the charge mobility for Miller-Abrahams and Marcus ...

We have studied the insulator-to-metal transition in Mo-C films by tuning the thickness from 2.6 to 20 A. The temperature dependence of the conductivity evolves from hopping transport, for the thin insulating films, to a ln{ital T} dependence for the thicker metallic films. In the insulating regime we find a variable range Mott hopping ...

Three high polymers, Mylar^circler , Ultem^circler, and Kapton^circler, were irradiated to total doses of 1, 5, and 9.5 gigarad using 1-MeV electrons. The glass transition temperatures ({rm T }_{rm g}) of the materials before and after irradiation were measured using an AC electrical dissipation factor technique. From the {rm T}_{rm g} data, it was found that the electron ...

Measurements of the quasistatic and frequency dependent electric conductivity below 1MHz were carried out on wet-spun, macroscopically oriented, calf thymus DNA bulk samples, thus effectively extending previous radio frequency data down to quasistatic time scales. The frequency dependence of the electrical conductivity in the frequency range of ...

Silicon carbide (SiC) materials are prime candidates for high temperature heat exchangers for next generation nuclear reactors due to their refractory nature and high thermal conductivity at elevated temperatures. This research has focused on demonstrating the potential of liquid silicon infiltration (LSI) for making SiC to achieve this goal. The major advantage of this method ...

An extensive survey of the experimental literature on ac conductivity and on the dielectric dispersion in glasses is reported. Research is focused on the region where sigma = A(omega to the s power), s approximately equal to 1. The various materials seem ...

First, it is shown how an expression for the ac conductivity of an ionically conducting material derived by Almond and West and co-workers from an earlier universal dielectric response equation of Jonscher may be related to and subsumed under a response f...

Results are given for the permeability, conductivity, and dielectric constant of a multifilament superconductor, treated as an anisotropic state of matter. The calculations are made for the limiting cases of strong and weak ac magnetic fields compared with the field required for complete penetration of the filaments. General expressions are given ...

It is shown that the basic integral for computing the a-c conductivity of a weakly ionized mixture of gases is reducible to tabulated functions if the collision frequency of electrons and gas molecules is representable by a finite series as a function of velocity. (C.E.S.)

... Accession Number : ADD250533. Title : AC Conduction Through MIM Sandwich Samples of Evaporated Thin Films of V2O5 and V2O5/B2O3. ...

The electrical conductivity, optical and thermal properties of newly synthesized N-[5-methyl-1,3,4-tiyodiazole-2-yl] ditiyocarbamate compound have been investigated. In order to find an explanation for the conduction mechanism, different conduction models were tested. The best fit of the experimental conductivity ...

Crossover from Mott variable-range-hopping conductivity to the Coulomb-gap Efros-Shklovskii (ES) variable-range-hopping conductivity has been observed in amorphous indium oxide films. The hopping exponent x~=0.56 in the activated Coulomb-gap regime is greater than the x=0.50 value predicted by ...

Workers engaged in a wide range of investigations of charge transport in non-metallic solids came together at a meeting of the Institute of Physics Dielectric Group, held in London on 2 April 2008. Topics included both ionic and electronic conduction, investigations of the fundamental mechanisms of charge transport, percolation, modelling the conduction ...