Materials Literature
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Large single crystals of the chiral ferrimagnet [{Cr(CN)6}{Mn(S)-pnH(H2O)}](H2O) can be recovered from the reaction between K3[Cr(CN)6], Mn(ClO4)2, and (S)-1,2-diaminopropane dihydrochloride (see picture). Magnetic measurements of the complex show that MnII and CrIII ions interact ferrimagnetically, with a magnetic tr…
Electron spins in a semiconductor quantum well couple to an electric field {\it via} spin-orbit interaction. We show that the standard spin-orbit coupling mechanisms can provide extraordinary efficient electron spin manipulation by an in-plane ac electric field.
We report on the fabrication and electrical characterization of field-effect transistors at the surface of tetracene single crystals. We find that the mobility of these transistors reaches the room-temperature value of $0.4 \ cm^2/Vs$. The non-monotonous temperature dependence of the mobility, its weak gate voltage de…
We extend the phase-field approach to model the solidification of faceted materials. Our approach consists of using an approximate gamma plot with rounded cusps that can approach arbitrarily closely the true gamma plot with sharp cusps that correspond to faceted orientations. The phase-field equations are solved in th…
We have studied the phase diagram of ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ for $0.5<~x<~0.9$ using neutron powder diffraction and magnetization measurements. At 300 K all samples are paramagnetic and single phase with crystallographic symmetry Pnma. As the temperature is reduced a…
The phonon-dispersion relations and elastic constants for ferromagnetic ${\mathrm{Ni}}_{2}\mathrm{MnGa}$ in the cubic and tetragonally distorted Heusler structures are computed using density-functional and density-functional-perturbation theory within the spin-polarized generalized-gradient approximation. For $0.9<…
The surface stress and the contact potential differences of elastically deformed faces of Al, Cu, Au, Ni, and Ti crystals are calculated within the modified stabilized jellium model using the self-consistent Kohn-Sham method. The obtained values of the surface stress are in agreement with the results of the available…
The quantum size oscillations of the energetic properties and the elongation force of the gold slabs and wires, isolated and in a contact with electrodes, are calculated in a free-electron model. A simple relation between the Fermi energy and the square-potential-well depth is used and tested for low-dimensional syste…
We report on the 29Si nuclear spin decoherence time at room temperature for a pure (99.99999%, 7N) and carrier-less (p-type, doping level of 10^15cm-3) silicon in which 29Si nuclei are naturally abundant (4.7%). Despite the experimental difficulties coming from the extremely long spin-lattice relaxation time T1 (of th…
Accurate ab initio full-potential augmented plane wave (FLAPW) electronic calculations within density functional theory in both local density and generalized gradient approximations have been performed for ${\mathrm{Mn}}_{x}{\mathrm{Ge}}_{1\ensuremath{-}x}$ and ${\mathrm{Mn}}_{x}{\mathrm{Si}}_{1\ensuremath{-}x}$ order…
The evolution of the optical phonon spectra of colloidal core/shell CdSe/ZnS quantum dots with an increase of the shell thickness from 0.5 to 3.4 monolayers has been studied by resonant Raman spectroscopy. The results obtained suggest that the ZnS shell changes its structure from amorphous to partly crystalline as the…
The galvanic replacement reaction between Ag nanoparticles and an aqueous HAuCl 4 solution has recently been demonstrated as a simple and convenient route to metal nanostructures with hollow interiors and highly crystalline walls (see, for example, Sun, Y.; Mayers, B. T.; Xia, Y. Nano Lett. 2002, 2, 481. Sun, Y.; Xia,…
A glowing response: Novel fluoride-selective sensors, utilizing fluoride-induced lactonization to highly fluorescent coumarin derivatives, are reported. The incorporation of this sensory system into a conjugated polymer amplifies the fluorescence response which can be detected visually, see scheme; TIPS=triisopropylsi…
We discuss dissipative particle dynamics as a thermostat to molecular dynamics, and highlight some of its virtues: (i) universal applicability irrespective of the interatomic potential; (ii) correct and unscreened reproduction of hydrodynamic correlations; (iii) stabilization of the numerical integration of the equati…
Different kinds of hemicellulose-based hydrogels have been made by radical polymerization using hydrosoluble hemicellulose from spruce chips with a number-average molecular weight and polydispersity of 2400 and 1.5 respectively. 80% of the hemicellulose was galactoglucomannan and the remainder mainly 4- O -methylglucu…
A review of our work with spectral fitting of CP/MAS 13 CNMR spectra recorded on isolated cellulose I, on a mixtures of cellulose I and xylan and, on kraft pulps is given. The conceptual model for cellulose I used by us is presented. References demonstrating the validity of the spectral fitting model is given. Results…
The self-assembly behavior of a series of fluorinated cellulose ester copolymers with different F-substituents and with varying cellulose propionate (CP) molecular weight, and that of several xylan-rich hetero-polysaccharides and their derivatives, were examined in relation to their critical micelle concentration (CMC…
Silicon nanoparticles have been fabricated in both oxide and nitride matrices by using plasma-enhanced chemical vapour deposition, for which a low substrate temperature down to 50 °C turns out to be most favourable. High-rate deposition onto such a cold substrate results in the formation of nanoscaled silicon particle…
Layer-by-layer (LBL) films of chitosan alternated with an azopolymer, PS119, have been used for optical storage and fabrication of surface-relief gratings. The optical properties stem from the trans-cis-trans isomerization cycles undergone by the azochromophore, with a kinetics for writing the birefringence pattern th…
Oat spelts contain high amounts of xylan whereas the lignin content is comparatively low. Accordingly this raw material is an interesting candidate for the isolation of xylan. The variation in chemical composition of oat spelts from different sources was investigated. Xylans were isolated by alkaline extraction under…