Materials Literature
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Low-field tunneling magnetoresistance was observed in films of half-metallic CrO2 that were grown by high-pressure thermal decomposition of CrO3. High-temperature annealing treatments modified the intergrain barriers of the as-grown films through surface decomposition of CrO2 into insulating Cr2O3, which led to a thre…
We show that Bayesian inference, like that used in statistical mechanics, can guide the systematic construction of Fourier dark-field methods for localizing periodicity in near-field (e.g. scanning-tunneling and electron-phase-contrast) images. For crystals in an aperiodic field, the Fourier coefficient Ze^{i phi} com…
We investigate the cooling rate of a gas of inelastically interacting particles. When we assume velocity dependent coefficients of restitution the material cools down slower than with constant restitution. This behavior might have large influence to clustering and structure formation processes.
The synthesis of polypropylene (PP) oligomer—clay intercalation compounds was studied by using three kinds of PP oligomers and organophylic clay. PP oligomers were two types of maleic-anhydride-modified PP oligomers containing different amount of maleic anhydride groups and one type of hydroxy modified PP oligomer. Or…
Lattice relaxations, surface phonon spectra, surface energies, and work functions are calculated for Rh(100) and Rh(110) surfaces using density-functional theory and the full-potential linearized augmented plane wave method. Both, the local-density approximation and the generalized gradient approximation to the exchan…
We present a comment on a recent letter by B. Edwards, N.W. Ashcroft, Nature 388 (1997) 652, in which the dielectric instabilty of the phase III of the solid molecular hydrogen system is suggested on the basis of electrostatics.
In this note microgels with and without excluded volume interactions are considered. Based on earlier exact computations on Gaussian mircogels, which are formed by self-crosslinking (with $M$ crosslinks) of polymer chains with chain length $N$ Flory type approximations are used to get first insight to their behavior i…
The elpasolite compound lead magnesium tellurate undergoes a structural phase transition at about 194 K. This phase transition has been characterized by calorimetry, by dielectric permittivity measurements and by Raman spectroscopy. The main features of the Raman spectra, collected between 35 K and room temperature, a…
We study a model for the nematic--to--smectic- $A$ (NA) transition in aerogel, and find that even arbitrarily weak quenched disorder (i.e., low aerogel density) destroys translational (smectic) order. Ignoring elastic anharmonicities, but keeping anharmonic couplings to disorder, leads to the prediction that there is…
Novel field emission devices with electron path lengths an order of magnitude less than the elastic mean free path of electrons in air have been fabricated and tested at atmospheric pressure. The nanoscale-tip field emission system consisted of multiple emitter tips of radii about 1 nm within an extractor aperture of…
Crystallographic orientations between thin-sputtered Cu film and β-Ta adhesion layer have been studied using high resolution electron microscopy and electron diffraction. Tetragonal β-Ta deposited on SiO2 has a strong texture with its closest packed plane (002) parallel to the film surface. On (002) β-Ta, the growth o…
The surface structure of nonstoichiometric ${\mathrm{CeO}}_{2}(111)$ has been studied by scanning tunneling microscopy (STM). By using extremely small tunneling currents it was possible to obtain the first ever reported atomically resolved images of this oxide. STM imaging was possible at a sample bias voltage between…
The scaling properties of the cluster size distribution of a system of diffusing clusters is studied in terms of a simple kinetic mean field model. It is shown that a one parameter family of mathematically valid scaling solutions exists. Despite this, the kinetics reaches a unique scaling solution independent of initi…
We evaluate the electronic self-energy Sigma(E) at an Al(111) surface using the GW space-time method. This self-energy automatically includes the image potential V_{im} not present in any local-density approximation for exchange and correlation. We solve the energy-dependent quasiparticle equations to obtain surface s…
The magnetic properties of [Ti(OH2)6]3+ within CsTi(SO4)2⋅12H2O and doped into a range of isostructural diamagnetic lattices, has been reinvestigated using electron paramagnetic resonance (EPR) and magnetic susceptibility measurements. Whereas previous attempts to rationalise the variation of the magnetic susceptibili…
Simulations on a Lennard-Jones computer glass are performed to study effects arising from defects in glasses at low temperatures. The numerical analysis reveals that already a low concentration of defects may dramatically change the low temperature properties by giving rise to extrinsic double-well potentials (DWP’s).…
Slow structural relaxations can complicate the interpretation of thermodynamic measurements on glass-forming liquids. Here we demonstrate using model calculations that structural recovery can lead to an apparent frequency-dependent heat capacity in ac calorimetry experiments. The model is shown to describe the complex…
Molecular dynamics simulations are described for liquid crystal molecules composed of two Gay-Berne particles connected by an eight-site Lennard-Jones alkyl chain. Calculations have been carried out for 512 molecules in the NVE and NPT ensembles for simulation times of up to 6.4 ns. The system exhibits the sequence of…
Atomic-force pictures reveal a heterogeneous microstructure at the surface of glassy layers which should be similar to one of the many equivalent microstructures a liquid is running through. These microstructures are described with the aid of a kinetic model of reversible aggregation which goes back to formulations as…
The electronic structure of two series of small titanium oxide clusters, TiOy (y = 1−3) and (TiO2)n (n = 1−4), is studied using anion photoelectron spectroscopy. Vibrationally resolved spectra are obtained for TiO− and TiO2−. Six low-lying electronic states for TiO are observed with five of these excited states result…