Materials Literature
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We have resolved single-exponential relaxation dynamics of the 2-, 3-, and 4-electron-hole pair states in nearly monodisperse cadmium selenide quantum dots with radii ranging from 1 to 4 nanometers. Comparison of the discrete relaxation constants measured for different multiple-pair states indicates that the carrier d…
Ferromagnetism in manganese compound semiconductors not only opens prospects for tailoring magnetic and spin-related phenomena in semiconductors with a precision specific to III-V compounds but also addresses a question about the origin of the magnetic interactions that lead to a Curie temperature (T(C)) as high as 11…
The formation and crystal structure of a novel rare-earth compound series, R 3 Co 29 M 4 B 10 , have been investigated by electron microscopy, x-ray diffraction and Rietveld refinement. R 3 Co 29 M 4 B 10 can form for R = La, Ce, Pr, Nd, Sm, Gd, Ho, Tb, Er, Tm, Dy, Lu and M = Si, Al, Ge, and are isostructral with Nd 3…
The effects of range and geometry of a simple attractive square-well on the phase diagram of hard ellipsoids and hard spherocylinders is systematically studied using a simple van der Waals type theory. The orientational single particle distribution function is approximated using the Onsager trial function. The quantit…
This paper describes the growth of single crystals of Cr 4+ -doped Y 3 Ga 5 O 12 (YGG) and Y 3 Al 5 O 12 (YAG). Control of melt composition and post-growth annealing yields material that contains optimal concentrations of Cr 4+ ions in distorted tetrahedral sites normally occupied by Ga 3+ ions in YGG and Al 3+ ions i…
A tunnel junction based on the half-metallic oxide CrO 2 uses a native oxide barrier layer and a cobalt top electrode. The I : V characteristic is fitted to the Simmons model with = 0.76 eV and t = 2.0 nm. The magnetoresistance is positive with R / R = 1.0% at 77 K.
Samples with nominal compositions La 1.2 (Sr 1- x Ca x ) 1.8 Mn 2 O 7 ( x = 0.00, 0.25, 0.50, 0.65, 0.80 and 1.00) have been prepared and characterized by x-ray diffraction (XRD) and ac susceptibility techniques. Drastic changes in the XRD pattern and in the ac susceptibility versus temperature behaviour at x = 0.65 i…
Boron-doped diamond-like carbon (DLC) was prepared using an inductive radio-frequency Ar + C 2 H 2 + B 2 H 6 plasma-immersion ion-processing (PIIP) technique. The novel results show that B incorporation reduces the stress and that low-energy Ar-ion impingement suppresses the increase of the amount of hydrogen in the B…
Understanding the evolution of surface morphology or surface texture of molecular crystals by dissolution/etching may be useful in determining the dissolution mechanisms at the molecular level. In this study, partial dissolution tests were conducted on the (010) face of acetaminophen single crystals with selected solv…
Nuclear magnetic resonance (NMR) spectra have been used to investigate the spinodal phase separation of sodium borosilicate glasses in the early stage, in which the phase separation is induced by rapidly quenching as opposed to heat treatment at a constant temperature. The experimental results show that the spinodal p…
Sequencing of siloxane units was studied in the copolymer chain formed by anionic polymerization of 2,2,4,4-tetramethyl-6,6-diphenylcyclotrisiloxane. The study involved three polymerization systems: lithium silanolate in THF, potassium silanolate complexed with 18-crown-6 in toluene, and tetramethylammonium silanolate…
We report electronic, magnetic and transport properties of (Fe 1- x V x ) 3 Al alloys with x = 0 - 0.38 and analyse the results on the basis of the measured electronic specific-heat coefficient, the Debye temperature and the magnetic stiffness constant. As the V composition increases, the electrical resistivity increa…
Small-angle X-ray scattering profiles for an amylose fragment (maltoheptaose) in aqueous solution were observed and compared with the theoretical profiles calculated for an ensemble of chain conformations generated by molecular dynamics simulations and Monte Carlo simulations. The Monte Carlo results based on the disa…
The synthesis and characterization of cofacial bisporphyrins juxtaposed by xanthene-bridged pillars are presented. The one-pot preparation of the xanthene dialdehyde avoids the lengthy bridge synthesis accompanying other cofacial porphyrin systems, thus allowing for the facile preparation of homobimetallic zinc (10),…
Thin films were grown by vacuum co-evaporation of CsI and PbI 2 compounds from two independent crucibles. X-ray diffraction spectroscopy revealed formation of CsPbI 3 and Cs 4 PbI 6 nanoaggregates in the thin film samples and gave an estimate of their volume percentage as well. It provided also the grain size estimate…
Rubber materials for high-voltage outdoor applications have been studied. They were prepared as mixtures of silicone polymer with different concentrations of powdered aluminium trihydrate as a filler. The dielectric properties, *( ) = ´-i ´´, were measured at different temperatures using a low-frequency dielectric spe…
We present Monte Carlo simulations of surface induced disordering in a model of a binary alloy on a bcc lattice which undergoes a first order bulk transition from the ordered DO3 phase to the disordered A2 phase. The data are analyzed in terms of an effective interface Hamiltonian for a system with several order param…
We present recent Monte Carlo results on surfaces of bcc-structured binary alloys which undergo an order-disorder phase transformation in the bulk. In particular, we discuss surface order and surface induced disorder at the bulk transition between the ordered (DO3) phase and the disordered (A2) phase. An intricate int…
Raman spectroscopy of radiation-damaged natural zircon samples shows increased line broadening and shifts of phonon frequencies with increasing radiation dose. Stretching and bending frequencies of SiO 4 tetrahedra soften dramatically with increasing radiation damage. The frequency shifts can be used to determine the…
The magnetization distributions in a series of ternary intermetallic compounds based on the composition Co 2 YZ where Y is Ti, Mn or Fe and Z a subgroup-B element have been determined from polarized neutron diffraction measurements. Comparison of the magnetic structure factors with model calculations shows that the ma…