Materials Literature
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A Raman spectroscopic study of the high-frequency optical phonons in single crystals of the multiferroic system $R{\mathrm{Mn}}_{2}{\mathrm{O}}_{5}$ ($R=\mathrm{Bi}$, Eu, Dy) was performed. All studied materials show anomalous phonon shifts, below a new characteristic temperature for these materials, ${T}^{*}\ensurema…
A hydrotalcite-like film has been successfully deposited on an Al-bearing glass substrate based on an interface reaction between an Al layer and a zinc aqueous solution. The film selectively grew on the Al surface but not on the glass surface. The film on Al was composed of layered nanosheets of a hydrotalcite-like co…
Uniaxially anisotropic chiral media are quite easy to be realized artificially, where the chirality appears only in one direction. In this report, we investigate the refractive properties of a plane wave incident from free space to such uniaxially chiral media. We show that different negative phase or group refraction…
We study the current and temperature dependences of the microwave voltage emission of spin-valve nanopillars subjected to an in-plane magnetic field and a perpendicular-to-plane current. Despite the complex multilayer geometry, clear microwave emission is shown to be possible and spectral lines as narrow as 3.8 MHz (a…
We present a detailed study of the magnetic structure and spin waves in the Fe jarosite compound ${\rm KFe_3(SO_4)_2(OH)_6}$ for the most general Hamiltonian involving one- and two-spin interactions which are allowed by symmetry. We compare the calculated spin-wave spectrum with the recent neutron scattering data of M…
A 2D temperature-dependent effective potential is calculated for the interacting longitudinal and transverse $L-$phonons of $β$ zirconium in the frozen-phonon model. The effective potentials obtained for different temperatures are used for the numerical solution of a set of stochastic differential equations with a the…
X-ray photoelectron diffraction is used to directly probe the intracell polar atomic distortion and tetragonality associated with ferroelectricity in ultrathin epitaxial $\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}$ films. Our measurements, combined with ab initio calculations, unambiguously demonstrate noncentrosymmetry i…
We present the first results of directional point-contact measurements in Mg_{1-x}Mn_{x}B_2 single crystals, with x up to 0.015 and bulk T_c down to 13.3 K. The order parameters Delta_{sigma} and Delta_{pi} were obtained by fitting the conductance curves with the two-band Blonder-Tinkham-Klapwijk (BTK) model. Both Del…
This review covers the results obtained in carbon nanotube synthesis by chemical vapor deposition. Parameters such as catalysts, supports, carbon precursors, reaction time, temperature and gas flow rates that are used in the production of carbon nanotubes are discussed throughout the text. Purification of the synthesi…
A wide set of cooling scans and subsequent melting behavior of isotactic polypropylene (i-PP) were investigated using differential scanning calorimetry and nanocalorimetry at very high cooling rate. The latter technique offers, indeed, the distinctive possibility to perform heat capacity measurements at rates of more…
Modern compound prediction methods can efficiently screen large numbers of crystal structure phases and direct the experimental search for new materials. One of the most challenging problems in alloy theory is the identification of stable phases with a never seen prototype; such predictions do not always follow ration…
Besides a drastic reduction in saturation magnetization of disordered Sr2FeMoO6 compared to highly ordered samples, magnetizations as a function of the temperature for different disordered samples may also show qualitatively different behaviors. We investigate the origin of such diversity by performing spatially resol…
We measure the conductance of amine-terminated molecules by breaking Au point contacts in a molecular solution at room temperature. We find that the variability of the observed conductance for the diamine molecule-Au junctions is much less than the variability for diisonitrile and dithiol-Au junctions. This narrow dis…
The electronic properties of bulk fcc americium and the (111) surface have been investigated with the full-potential linearized augmented plane wave (FP-LAPW) method as implemented in the WIEN2K suite of programs. The study is carried out for the anti-ferromagnetic ground state of Am at different levels of theory: (1)…
Chirality from blood: Serum albumins form strong complexes with CuII–phthalocyanines, leading to protein conjugates. These hybrid catalysts promote enantioselective Diels–Alder reactions, such as that of azachalcones 1 with cyclopentadiene (2) to give products 3 with 85–98 % ee.
We investigated methanol adsorption and dissociation on bridge-bonded oxygen vacancies of the TiO2(110)-(1x1) surface using in situ scanning tunneling microscopy. We provide the first direct evidence that methanol dissociates on oxygen vacancies via O-H bond scission rather than C-O scission. For CH3OH coverages lower…
In an attempt to develop lithium borohydrides as reversible hydrogen storage materials with high hydrogen storage capacities, the feasibility of reducing the dehydrogenation temperature of the lithium borohydride and moderating rehydrogenation conditions was explored. The lithium borohydride was modified by ball milli…
The crystallization kinetics and resulting morphology of polyethylene (PE) in the presence of single wall carbon nanotubes (SWNT) are investigated in isotropic and aligned composites. A hot coagulation method was developed to incorporate SWNT loadings as high as 30 wt % with uniform distribution. Thermal analysis inte…
Interaction of silver surface with atomic oxygen has been studied at low oxygen pressures (10 15 – 10 17 atoms.cm −2 s −1 ) and in a wide temperature range from 373 to 673 K. The only product of surface oxidation observed at these conditions was silver (I) oxide Ag 2 O. Parabolic rate law was normally observed under s…
Hydrocarbon polymers that are exposed to atomic oxygen in low Earth orbit are slowly oxidized which results in recession of their surface. Atomic oxygen protective coatings have been developed which are both durable to atomic oxygen and effective in protecting underlying polymers. However, scratches, pin window defect…