Materials Literature
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Modeling the conductive channel as a series of ferromagnetic (FM) domain with resistivity of ${\ensuremath{\rho}}_{\mathrm{FM}}$ and paramagnetic (PM) region with resistivity of ${\ensuremath{\rho}}_{\mathrm{PM}},$ we propose a phenomenological equation for resistivity as $\ensuremath{\rho}=[1\ensuremath{-}f(T,H)]{\en…
The spontaneous generation of voltage has been observed during the first-order magnetic-Martensitic phase transition process in ${\mathrm{Gd}}_{5}{(\mathrm{S}\mathrm{i}}_{x}{\mathrm{Ge}}_{4\ensuremath{-}x})$ alloys regardless of whether the transformation is triggered by temperature or magnetic field. Based on various…
In a diffusion-controlled interaction, the Kirkendall plane, as marked by inert particles placed at the original contact surface of a reaction couple, need not be unique. Multiple planes can develop, and sometimes the Kirkendall plane does not exist at all. A phenomenological approach is introduced to rationalize the…
Nearest- and higher-neighbor distances as well as bond length distributions (static and thermal) of the ${\mathrm{In}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{As}$ $(0<~x<~1)$ semiconductor alloys have been obtained from high-real-space resolution atomic pair distribution functions. Using this structural info…
Aligned carbon nanotubes (CNTs) with diameters of 50–100 nm, synthesized by plasma-assisted hot filament chemical vapor deposition, were employed for hydrogen adsorption experiments in their as-prepared and pretreated states. Quadruple mass spectroscopy and thermogravimetric analysis show a hydrogen storage capacity o…
Giant dielectric permittivity was observed in La-modified PbTiO (3) (PLT) with A-site vacancy. The observed values of PLT with A-site vacancy are 1 order of magnitude larger than those of relaxor ferroelectrics. The giant relative dielectric permittivity, coupled with a low dielectric loss (tandelta approximately 0.03…
We study optically single self-assembled quantum dots embedded within the wide quantum well of a mixed type quantum structure. We compare the steady state and pulsed photoluminescence spectra of these dots to those of previously studied "regular" dots. We unambiguously identify experimentally emission from various dis…
We report first-principles all-electron density-functional-based studies of the electronic structure, magnetic ordering, and anisotropy for the V15 molecular magnet. From these calculations, we determine a Heisenberg Hamiltonian with five antiferromagnetic and one ferromagnetic exchange couplings. We perform direct di…
We use ab initio total-energy calculations to predict the existence of polarons in semiconducting carbon nanotubes (CNTs). We find that the CNTs' band edge energies vary linearly and the elastic energy increases quadratically with both radial and with axial distortions, leading to the spontaneous formation of polarons…
A new efficient numerical algorithm for interacting fermion systems is proposed and examined in detail. The ground state is expressed approximately by a linear combination of numerically chosen basis states in a truncated Hilbert space. Two procedures lead to a better approximation. The first is a numerical renormaliz…
In the Brazil nut problem (BNP), hard spheres with larger diameters rise to the top. There are various explanations (percolation, reorganization, convection), but a broad understanding or control of this effect is by no means achieved. A theory is presented for the crossover from BNP to the reverse Brazil nut problem…
The low-lying electronic transitions in a peroxy radical, ≡Si–O–O•, a fundamental radiation induced point defect in silicon dioxide, have been investigated by means of ab initio multiconfiguration perturbation theory calculations, CASPT2, and cluster models. The accuracy of the computed transition energies and intensi…
The dynamical behavior of a thin film of ice Ih deposited on MgO(001) surface has been investigated both experimentally and theoretically. Incoherent neutron quasielastic scattering experiments, using uniform MgO powders, show that a quasiliquid water layer of monolayer thickness exists at T=265 K. The translational m…
In this work we introduce two models to understand the anomalous composition dependence of viscosity of binary mixtures. Both models consist of a mixture of two molecular species (A and B) with the same diameter and mass but varying solute–solvent Lennard-Jones interaction. In model I, the two different species are st…
The behavior of the various relaxation modes in poly(ε-caprolactone) (PCL), is studied by Broad Band Dielectric Spectroscopy in the frequency range from 3×10−3 to 1.8×109 Hz and from 133 to 313 K. The experimental trace of the dielectric loss as a function of the angular frequency, ε″(ω), is analyzed by best fitting a…
The catalytic reaction between adsorbed oxygen atoms and CO molecules on Pt(111) was investigated by scanning tunneling microscopy and modeled by Monte Carlo simulations. Experiments were performed by dosing preadsorbed Oad layers with CO between 237 and 274 K. Two stages were observed during dosing with CO, an initia…
The mononuclear gadolinium mixed-ligand complex [Gd(CF3CO2)3(phen)2(H2O)] has been prepared and structurally characterized by X-ray crystallography. Two complex molecules are doubly bridged by H bonds between carboxylate and aqua ligands with a Gd−Gd separation of 7.16(1) Å. Magnetic susceptibility and EPR measurement…
Isolation of the free bicyclic tetraamine, [3(5)]adamanzane.H(2)O (1,5,9,13-tetraazabicyclo[7.7.3]nonadecane.H(2)O), is reported along with the synthesis and characterization of a copper(II) complex of the smaller macrocycle [(2.3)(2).2(1)]adamanzane (1,5,9,12-tetraazabicyclo[7.5.2]hexadecane) and of three cobalt(II),…
Surface bound chitosan−sialodendrimers with a high degree of substitution were successfully prepared using a doubly convergent approach. Poly(amidoamine) (PAMAM) dendrimers ( G = 1−5) having a 1,4-diaminobutane core were amidated to N -carboxyethylchitosan methyl ester under conditions that prevented cross-linking. Th…
The first photosensitive liquid crystalline (LC) dendrimer with terminal cinnamoyl groups was synthesized. A new approach to the synthesis of photochromic carbosilane LC dendrimers was elaborated. The method consists of synthesis of dendrimer with terminal hydroxyl groups and then coupling of 4-methoxycinnamoyl chlori…