Materials Literature
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Nanoscale superlattices with uniaxial ferromagnetic layers antiferromagnetically coupled through non-magnetic spacers are recently used as components of magnetoresistive and recording devices. In the last years intensive experimental investigations of these artificial antiferromagnets have revealed a large variety of…
Highly luminescent and monodisperse CdS nanocrystals (see Figure) have been synthesized using a two‐phase approach. The synthesis of CdS nanocrystals at the liquid–liquid interface was easy, safe, and highly reproducible, and the reaction conditions were mild and controllable.
Extracting the P: Two novel amorphous allotropes of elemental phosphorus that consist of polymeric chains (see example depicted) were obtained in a pure form by extraction from their copper iodide adducts with an aqueous solution of potassium cyanide. 31P NMR spectra and high-resolution TEM images suggest that the str…
We reanalyze the condition for metallic ferromagnetism in the framework of the tight-binding approximation and investigate the consequences of the inter-site Coulomb interactions using the Hartree-Fock approximation. We first consider a non-degenerate $s$ band and we show that the inter-site interactions modify the oc…
The spin dynamics of a canted antiferromagnet with a quadratic spin-wave dispersion near $\vq =0$ is shown to possess a unique signature. When the anisotropy gap is negligible, the spin-wave stiffness $\dsw (\vq, B) = (ω_{\vq}-B)/q^2$ depends on whether the limit of zero field or zero wavevector is taken first. Conseq…
Post mortem analysis of fracture surfaces of ductile and brittle materials on the microm-mm and the nm scales, respectively, reveal self-affine cracks with anomalous scaling exponent zeta approximately 0.8 in three dimensions and zeta approximately 0.65 in two dimensions. Attempts to use elasticity theory to explain t…
Critical hysteresis in ferromagnets is investigated through a N-component spin model with random anisotropies, more prevalent experimentally than the random fields used in most theoretical studies. Metastability, and the tensorial nature of anisotropy, dictate its physics. Generically, random-field Ising criticality o…
In this paper one can find a detailed description of the research performed by author during his stay at IMEC (Belgium). It deals with the experimental verification of the highly coherent electron spin transport across ferromagnetic metal / semiconductor interface at low and room temperatures.
Recently, it was reported that crystals of the organic material dithiophene-tetrathiafulvalene (DT-TTF) have a high field-effect charge carrier mobility of 1.4 cm(2)/(V x s). These crystals were formed by a simple drop-casting method, making this material interesting to investigate for possible applications in low-cos…
Amorphous calcium carbonate is produced as spherical particles (see Figure) via in‐situ generation of CO 2 by hydrolysis of dialkyl carbonates in aqueous solution of CaCl 2 at room temperature. This method of synthesis (precipitation) allows detailed studies of the particle formation process. Temperature‐dependent res…
A nanocomposite of polypyrrole/carbon nanotubes prepared by in situ chemical polymerization shows improved conductivity of the polypyrrole as compared with its pure form. Its application as a chemical sensor, made using a simple spin‐casting technique, shows a drastically increased sensitivity. The Figure shows a fiel…
ZnO nanoparticles dispersed in a semiconducting polymer form the active layer of a solar cell (see Figure) that is able to convert up to 40 % of the incident photons at 500 nm into electrical current and has a power conversion efficiency of about 1.5 % in sunlight. Manufactured at low temperature using environmentally…
We show the anisotropic selective growth of gold tips onto semiconductor (cadmium selenide) nanorods and tetrapods by a simple reaction. The size of the gold tips can be controlled by the concentration of the starting materials. The new nanostructures display modified optical properties caused by the strong coupling b…
A reversible ordered state induced by the combined action of above band-gap light and temperature in a-Si1−xGex layers with 0⩽x<0.38 is reported. The experimental conditions for the observation of this effect are described, as well as the main phenomenological aspects. The illumination of these layers with abov…
We report the self-assembly and characterization of amorphous SiOx nanospheres with diameters 210–240 nm. The preparation method was based on hydrolysation-induced self-assembly with Na2SiO3 as the silica precursor and polyacrylamide gels as the template. Ultraviolet and blue–green photoluminescence were observed at r…
We report a Raman spectroscopy study of B12As2 under hydrostatic pressure up to 15 GPa. Mode Grüneisen parameters were determined for the B12As2 phonon modes. Phonon modes attributed to the As–As chain have a weak pressure dependence (0.6–1.9 cm−1 GPa−1) relative to inter- and intra-icosahedral vibrations (3.4–6.6 cm−…
We studied ferroelectric ordering in a triphenylene derivative embedded with electric dipoles [2,3,6,7,10,11-hexakis (4-octyloxy-benzoyloxy) triphenylene (HOBPT)] in a crystalline state. Experimental results indicate that the ferroelectricity in HOBPT is caused by an ordered orientation of $\mathrm{C}\mathrm{O}$ dipo…
The aim of this paper is to present a new experimental procedure to evaluate yarn characteristics, in real time, using capacitive sensors with a width below 8 mm (commercial equipments use 8 mm sensors). The new approach allows a direct measurement in 1 mm range (increasing resolution eight times). Using software modu…
Methyl methacrylate/1,2-divinylbenzene (MMA/DVB) in an opaque emulsion were successfully grafted onto the surface of polymeric substrate under the irradiation of UV light with benzophenone (BP) as a photoinitiator that was previously coated on the substrate surface. Monomer conversion, grafting efficiency, and graftin…
A solute atmosphere forms around a dislocation at temperatures where the diffusion of solute atoms is comparable to or faster than the dislocation motion. The dynamic interactions between diffusive solutes and moving dislocations were studied using a phase-field model which takes into account both the chemical interac…