Materials Literature
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Magnetic properties of stoichiometric and off-stoichiometric NbFe 2 intermetallic compounds have been studied. It has been revealed that the stoichiometric NbFe 2 shows strongly enhanced Pauli paramagnetic properties. The temperature dependence of its susceptibility in a weak external field shows a maximum as observed…
We present a simple phenomenological model for glasses which fits both the thermal conductivity \ensuremath{\kappa} and the specific heat C up to roughly 100 K. This includes the plateau in \ensuremath{\kappa} as well as the maximum in C/${T}^{3}$ which occur between 3--10 K. In addition to conventional tunneling syst…
In poly(3-methylthiophene), P3MT, charge is stored in spinless bipolarons at all but the most dilute doping levels. From the combination of magnetic and electrochemical measurements, we find definitive evidence of the reversed spin-charge relation expected for bipolarons with ${N}_{s}$/${N}_{\mathrm{ch}{<10}^{\math…
The pressure effect on the magnetic transition temperatures of Mn 3 GaC, Mn 3 ZnC and Mn 3 SnC were measured under pressures up to 13 kbar. The pressure derivatives of the transition temperatures are obtained to be d T t /d P =-3.5 K/kbar and d T C /d P =0.4 K/kbar for Mn 3 GaC, d T t /d P =-0.9 K/kbar and T C /d P =0…
Smetic and nematic liquid-crystal materials can be homogeneously aligned by buffed thin films of appropriate polymers. We propose that the buffing process orients the polymer’s molecular chains in a manner similar to cold drawing of bulk polymer samples. Experimental verification of this theory is obtained by measurin…
An asymptotic method for analysing steady corona discharges is described. Formulae are obtained for curves of current versus voltage for the discharge between coaxial concentric and accentric cylinders.
The electronic energy levels of polyaniline (PANi) thin films have been investigated using UV/VIS/NIR spectroscopy and X-ray photo-electron spectroscopy. The experimental results have been compared with the latest theoretical band structure calculations for the polyemeraldine salt form of PANi, and also the various st…
Molecular structure-preparation condition relationships are reported for electrochemically prepared polypyrrole-toluene sulphonate electrically conducting films. Polypyrrole films have been prepared from aqueous solutions employing a range of anodic potentials (0.5-1.6 V versus SCE) and at several temperatures. Consis…
Absolute total scattering cross sections have been measured for electron scattering from krypton in the energy range 0.175-20 eV. The measurements have been performed with a linear time of flight electron transmission spectrometer. Comparisons are made with the results of a number of other experiments and theoretical…
The thermal conductivity of the amorphous alloy Fe 40 Ni 40 P 14 B 6 is investigated with the aim to separate out the lattice contribution and to compare it with that of amorphous dielectrics. The problems of the influence of the radiative transfer of heat between the sample and its environment, which causes errors in…
Conjugated polymers such as polyacetylene form a group of model semiconductors in which the 'one-dimensional' character of the polymer strongly modifies the behaviour of charges added to the chains from that usually observed in three-dimensionally bonded semiconductors. First, the polymer chain can undergo local reorg…
The authors review the results of extensive studies that have been reported by the author and by other workers on the preparation and properties of the conjugated polymer poly(p-phenylenevinylene) (PPV). The use of the sulphonium polyelectrolyte precursor-route synthesis gives considerable flexibility for materials pr…
Potassium-smectites with various layer-charge densities and layer-charge locations were subjected to as many as 100 wetting and drying cycles, thereby producing randomly interstratified illite/smectite that contained illite layers stable against exchange by 0.1 N SrCl 2 or 1 N NaCl. The percentage of illite layers for…
The explicit forms of the density-density correlation function H( Delta x,z 1 ,z 2 ) for the transverse separation Delta x approximately W 2 , where W is the interface thickness, are obtained in the two-dimensional solid-on-solid model in two different asymptotic cases of a finite system in a vanishing external field.…
The Madelung constant-essentially the Coulomb energy density of a crystal-is usually calculated via Ewald error function expansions or, for the simpler cubic structures, by the 'cosech' series of modern vintage. By considering generalised functional equations for multidimensional zeta functions, the authors provide ex…
Assuming that deformation is caused solely by dislocation glide and mechanical twinning, with negligible strain rate sensitivity, the plastic behavior of crystals is described by a polyhedron in stress space, the single‐crystal yield surface (SCYS). Each facet of the SCYS represents the yielding condition on one slip…
We propose a simple density-functional theory for the isotropic-nematic transition of a system of hard ellipsoids which yields results in fair agreement with the computer simulation studies and which reduces exactly to Onsager's theory in the limit of infinitely dilute systems of infinitely long ellipsoids. When the f…
We report 77-K electroluminescence from an irradiated carbon-rich silicon diode that has an internal quantum efficiency more than 103 times higher than that of band-to-band recombination in an unirradiated, but otherwise identical diode. This is achieved by creating optically active Cs-SiI-Cs complexes with room-tempe…
Hydrogenated amorphous carbon (a-C:H) films, deposited onto negatively biased substrates in a 13.56-MHz hydrocarbon glow discharge system, have been investigated by mass spectroscopic thermal effusion measurements. Depending on the bias voltage UB as the most important deposition parameter, hydrocarbons and/or H2 mole…
Abstract The effect of stretching condition on stress‐induced crystallization of amorphous polyethylene terephthalate (PET) film has been studied. Cast PET film was stretched at 85°C with stretching rates ranging from 100% per minute to 600% per minute for various stretching ratios. The stretched film samples were ann…