Materials Literature
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The thermal properties of bulk copper are investigated by performing ab initio DFT and DFPT calculations and using the quasiharmonic approximation for the free energy. Using both the LDA and the GGA for the exchange-correlation potential, we compute the temperature dependence of the lattice constant, coefficient of th…
We present results of a numerical mean field treatment of interacting spins and carriers in doped diluted magnetic semiconductors, which takes into account the positional disorder present in these alloy systems. Disorder is found to enhance the ferromagnetic transition temperature significantly for metallic densities…
We have studied the evolution of the magnetic, electronic, and structural properties of annealed epilayers of Ga1−xMnxAs grown by low temperature molecular beam epitaxy. Annealing at the optimal temperature of 250 °C for less than 2 h significantly enhances the conductivity and ferromagnetism, but continuing the annea…
In order to utilize the unique properties of carbon nanotubes in microelectronic devices, it is necessary to develop a technology which enables high yield, uniform, and preferential growth of perfectly aligned nanotubes. We demonstrate such a technology by using plasma-enhanced chemical-vapor deposition (PECVD) of car…
Ultrananocrystalline diamond (UNCD) films with up to 0.2% total nitrogen content were synthesized by a microwave plasma-enhanced chemical-vapor-deposition method using a CH4(1%)/Ar gas mixture and 1%–20% nitrogen gas added. The electrical conductivity of the nitrogen-doped UNCD films increases by five orders of magnit…
Sputter deposition of ZnO on Si specimens with surface metallization of copper was performed using a radio frequency sputter deposition technique using various deposition temperatures and ratio of O2/Ar. Copper metallization was carried out using an ion beam sputter deposition technique at different temperatures. Spec…
A series of new compounds has been synthesized by insertion of alkali or alkaline earth-metals in chalcopyrite, CuFeS2. Their crystal structures vary from layered arrangements of tetrahedra in a trigonal (LiCuFeS2, NaCuFeS2) or a tetragonal symmetry (KCuFeS2, CsCuFeS2), to three-dimensional cubic framework (Ba6Cu12Fe1…
The reduction of MoCl5 with metallic tin in diethyl ether provides a rapid and convenient entry to [MoCl4(OEt2)2] This compound can be transformed easily and in high yields into a variety of other useful synthons. The loss of ether in the solid state affords a new and reactive form of MoCl4. Treatment with THF, PMe3 o…
Polypropylene staple fibres were mixed with cotton in different proportions for producing ring-spun yarns and the yarns so produced were converted into both woven and knitted fabrics. Various fabric properties including low-stress mechanical properties and hand values were determined on Kawabata fabric evaluation syst…
The low-frequency internal friction and elastic modulus have been measured as functions of temperature at different strain amplitudes in wrought Al–Mg–Si (6082) alloys after quenching and after ageing. The damping spectrum exhibits a relaxation peak located at about 420 K in over-aged specimens. This damping peak. wit…
A structural relationship between the μ-Al4Mn phase and the Λ-Al4Mn phase, which are approximants of icosahedral and decagonal quasicrystals respectively, was studied from the viewpoint of the modulated structure. The difference between these phases is basically understood by the difference in the ordered arrangements…
Magnetisation and magnetostriction are macroscopic manifestations of a complex magnetic domain structure that is modified by applied mechanic and magnetic loads. In the multiscale model used in this paper this domain structure is statistically described by a set of internal variables that are defined in each grain. Th…
In order to design an optimal planar inductor, this paper carries out several axisymmetrical magnetic field simulations fully taking the magnetic hysteretic properties of ferromagnetic core materials as well as open boundary condition into account. Finite element method is applied to evaluating the magnetic fields, re…
Abstract The chemical, textural and structural transformations of Al 13 -intercalated montmorillonite, resulting from the depolymerization of the interlamellar Al 13 polycations by Na salicylate solutions, were studied. Nitrogen gas adsorption shows a dramatic decrease in specific surface area from 493 to 39 m2g –1 ,…
Diammine cobalt(II) chloride, Co(N(H, D)3)2Cl2 was prepared by decomposition of the corresponding hexaammines at 120 °C in dynamical vacuum. Crystal structures and magnetic properties of these materials were characterised by X-ray and neutron powder diffraction, and heat capacity measurements. At ambient temperatures…
Abstract Polyolefins are under evaluation for a variety of applications with increasingly stringent requirements, including long‐term exposure outdoors. While the range of physical properties and appearance has been extended by the development of new resins, additives are required to help maintain those properties upo…
Abstract Large and well-formed crystals of strontium chlorapatite [Sr5Cl(PO4)3] were grown for the first time from a sodium chloride flux. The obtained crystals were colorless and transparent. The crystal growth of Sr5Cl(PO4)3 was conducted by heating a mixture of solute and flux at 1100 °C for 10 h, and then cooling…
The process of the developed plastic deformation is studied when defects density is so high that collective effects play key role. On the basis of conception of rearrangable potential relief, the field theory of the superplastic-state type of the Lüders band is stated. At stress more than a critical threshold, the dis…
An extension of a full-constraints Taylor model is presented which captures substructural dislocation features, e.g. cell boundaries and cell-block boundaries. This allows coupling the anisotropy due to slip processes, texture and substructure. The extended Taylor model is used to study the dislocation sheets during r…
The reflection spectra of porous gallium phosphide samples are investigated in the far infrared region of wave numbers (10–700 cm −1 ). In addition of the longitudinal and transverse optical phonon modes corresponding to the bulk material, additional vibrational modes are detected. Their number and spectral position a…