Materials Literature
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Erbium surface segregation is observed during growth of Er-doped Si by molecular beam epitaxy on Si(100) at 600 °C. Once a critical Er surface areal density of 2×1014 Er/cm2 is reached, enhanced Er trapping is observed, possibly due to the formation of silicide precipitates. Er segregation on Si(100) is fully avoided…
Silicon samples were implanted with 20 keV He at various temperatures. The damage and the size of the He bubbles created during the implantation were measured with Raman spectroscopy and transmission electron microscopy. Room temperature implantation with 2.5×1017 He atoms/ cm2 produced an amorphized layer with a high…
The magnetic properties of icosahedral Mg 42 RE 8 Zn 50 (RE identical to Gd, Tb, Dy, Ho or Er) quasi-crystals have been investigated. These quasi-crystalline phases have a face-centred icosahedral lattice with a highly ordered Frank-Rasper-type structure as identified by electron diffraction and X-ray diffraction. The…
We report on the structure and composition of codeposited thin Ag and Cu films on a Ru(0001) substrate. All three metals are immiscible in their bulk forms, however, monolayer films of Ag and Cu are observed to alloy on Ru(0001). In the dilute Cu case, preferential formation of the alloy is found. With increasing Cu c…
The magnetoresistance of epitaxial Nd0.7Sr0.3MnOδ thin films has been studied. A giant magnetoresistance, with more than 4 orders of magnitude change in resistance (−ΔR/RH≳106%), was obtained at ∼60 K and a magnetic field of 8 T. This giant magnetoresistance (GMR) ratio is about one order of magnitude larger than the…
${}^{30}\mathrm{Si}$ diffusion was measured in quartz along c axis in the $\ensuremath{\beta}$-phase field, at $T\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1400$-- $1600\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ by Rutherford backscattering spectrometry and the ${}^{30}\mathrm{Si}(p,\ensuremath{\gamma})^{3…
The role of externally-controlled chemical reactions in the selection of patterns in phase-separating mixtures is presented. Linearized theory and computer simulation show that the initial long-wavelength instability characteristic of spinodal decomposition is suppressed by chemical reactions, which restrict domain gr…
Electroluminescence is obtained from nearly monodisperse CdSe nanocrystallites (quantum dots) incorporated into thin films (1000 Å) of polyvinylcarbazole (PVK) and an oxadiazole derivative (t-Bu-PBD) and sandwiched between ITO and Al electrodes. The electroluminescence and photoluminescence spectra (bandwidths ≤40 nm)…
A numerical study is presented of the motion of two-dimensional, doubly periodic, dilute and concentrated emulsions of liquid drops with constant surface tension, subject to a simple shear flow. The numerical method is based on a boundary integral formulation that employs a Green's function for doubly periodic Stokes…
The Jones matrix is obtained for a film with a photoinduced anisotopy. The anisotropy of the film is considered to be caused by photoinduced anisotropic grains. On the basis of the Jones matrix we study Weigert's hologram of linearly polarized plane waves.
A simple preparation of Cd(17)S(4)(SCH(2)CH(2)OH)(26) clusters in aqueous solution leads to the formation of colorless blocky crystals. X-ray structure determinations revealed a superlattice framework built up of covalently linked clusters. This superlattice is best described as two enlarged and interlaced diamond or…
A new tight-binding total energy method, which has been shown to accurately predict ground state properties of transition and noble metals, is applied to Manganese, the element with the most complex ground state structure among the $d$ metals. We show that the tight-binding method correctly predicts the ground state s…
We study the early-stages of ordering in $Cu_3 Au$ using a model Hamiltonian derived from the effective medium theory of cohesion in metals: an approach providing a microscopic description of interatomic interactions in alloys. Our simulations show a crossover from a nucleated growth regime to a region where the order…
Exciton effects on soliton and bipolaron lattice states are investigated using an electron-lattice Peierls model with long-range Coulomb interactions. The Hartree-Fock (HF) approximation and the single-excitation configuration-interaction (single-CI) method are used to obtain optical absorption spectra. We discuss the…
Abstract We have shown liquid crystals to be members of the more general class of helicoidal bianisotropic mediums (HBMs) and have discussed physical realizations of HBMs as liquid crystals, cross-linked polymer networks and solid thin films. Solutions of the time-harmonic Maxwell postulates for axial propagation in a…
Abstract A novel polymer processing technique known as elastic strain pulverization (ESP) involves the simultaneous effects of high pressure and shear deformation to pulverize polymers. Homopolymers and blends of commercially important postconsumer plastics, including high‐density and low‐density polyethylene (HDPE, L…
Transmission electron microscopy has been used to characterize the large solvent‐stabilized palladium clusters with uniform size distribution that are formed in homogeneous Pd II ‐catalyzed oxidations in dimethyl sulfoxide.
On the basis of the available high-resolution structures of mandelate racemase (MR) from Pseudomonas putida [Landro, J. A., Gerlt, J. A., Kozarich, J. W., Koo, C. W., Shah, V. J., Kenyon, G. L., Neidhart, D. J., Fujita, J., & Petsko, G. A. (1994) Biochemistry 33, 635-643], Lys 166 and His 297 are positioned appropriat…
In the high-resolution X-ray structure of mandelate racemase (MR) with the competitive inhibitor (S)-atrolactate bound in the active site [Landro, J. A., Gerlt, J. A., Kozarich, J. W., Koo, C. W., Shah, V. J., Kenyon, G. L., Neidhart, D. J., Fujita, J., & Petsko, G. A. (1994) Biochemistry 33, 635-643], the carboxylic…
Structural features of the heavier and lighter homologues of tellurium are embodied in the two partial structures of Cs3Te22: crown-shaped Te8 rings, which are stabilized in the coordination sphere of a cesium cation (shown on the right), are similar to analogous S8 and Se8 rings, whereas the layer anions [Te4Te] may…