Materials Literature
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We report scanning tunneling microscope images of isolated oxygen atoms adsorbed on the GaAs(110) surface. The images display a dramatic voltage dependence, which arises from the energy dependence of the local state density, and provides a signature of an adsorbed electronegative atoms. At low oxygen coverages, a long…
Using molecular-dynamics calculations, we show that at 80 K, ice Ih undergoes a transition to a high-density amorphous (hda) form at about 13 kbar. At higher pressures, the calculated oxygen atom radial distribution function shows strong resemblance to that of ice VIII. The most characteristic feature of hda ice, name…
The formation of metal-containing amorphous hydrogenated carbon films (a-C:H) in a reactive sputtering process is reported. The layers were prepared at room temperature using various metals of different concentrations. According to tribological measurements the layers exhibit small friction values and an extremely low…
High-intensity femtosecond laser pulses are used to induce non- equilibrium electron heating in gold metal. The thermal relaxation of the electronic distribution is studied through pump and continuum probe measurements of transient reflectivity. Measurements are performed for different heating-pulse fluences and probe…
The systems Ba(PO3)2-BaF2/ZnF2-AlF3 and Zn(PO3)2-ZnF2-AlF3 are investigated in order to find the glass-forming regions and structure-property relationships. 19F and 31P nuclear magnetic resonance of the glassy material are measured using a breadline spectrometer. The second moments of the measured line shapes and the…
The crystal structures of [NH3(CH2)5NH3]CdCl4 are determined by X-ray diffraction at 293 K (phase I) and 353 K (phase II) in order to obtain a structural description of the second-order phase transition occurring at 337 K. This continuous transition is mainly of order-disorder type and can be associated to the reorien…
The far-infrared spectrum of MnFe2O4 reveals two prominent bands v1 and v2 and two weak bands v3 and v4 in the range 600 to 200 cm−1. The high frequency band (v1) and the low frequency band (v2) are assigned to tetrahedral and octahedral metal complexes, respectively. The spectra of the mixed Mn1–xMgxFe2O4, with x ran…
We examine the effects that strong electron-phonon coupling has on the electronic density of states and the phonon spectrum of the mixed valent phase. We examine the dependence of the polaronic properties on the position of the f level relative to the Fermi level.
The magnetic susceptibilities of five trinuclear pseudoplanar bibridged copper(II) chloride species have been measured from approximately 5 to 300 K. The compounds all show antiferromagnetic intratrimer and generally weaker ferromagnetic intertrimer spin coupling. These compounds show systematic deviations from the su…
The domain structure of cast NdFeB magnets has been observed using the Kerr effect, both at room temperature and at temperatures up to the Curie point. The domain structure is typical of strongly uniaxial materials, and no substantial changes in domain size or domain structure are found up to the Curie point. The valu…
The magnetic phase transition in the (NiAs-type) system Mn0.5Te0.5−xSbx was investigated by electrical resistivity and x-ray powder diffraction techniques. Crystallographically, the lattice parameter (a) was found to decrease smoothly with x, while (c) behaved in a steplike manner with the changeover taking place at 0…
A well-known model for the rate of heterogeneous nucleation and growth of a second-phase precipitate in a solid matrix has successfully been applied to electromigration rate studies in metallic thin-film interconnects. The application of these rate equations is based on the analogy between the nucleation and growth of…
We have prepared thin (50–1500 Å) polycrystalline films of Cr by vacuum (10−8 Torr) evaporation methods using the deposition rate on Corning glass 7059 and its temperature as experimental parameters. Electrical resistivity (ρ) of these films has been studied in situ as a function of temperature (T), film thickness (t)…
Evidence is presented showing that the radiative decay of localized surface-plasmon modes from metal particulates on aluminum-alumina-gold tunnel junctions is due to these modes being driven off resonance by the fields of the gold electrode. The metal particulates are formed on top of an insulating spacer set above th…
Thin films of vanadium dioxide exhibit a thermally induced semiconductor-to-metal phase transition near 67 degrees C. In most deposition conditions, the transition is accompanied by large changes in optical properties at infrared wavelengths, but with only slight visible contrast. Recently, reactive evaporation at hig…
Using Preisach’s model, general expressions for hysteretic energy losses are derived. These expressions are valid for arbitrary (not necessarily periodic) variations of magnetic field. Moreover, these expressions are given in terms of Preisach’s function as well as in terms of experimentally measured ‘‘first-order tra…
Energy spectral properties in one-dimensional quasi-crystalline and incommensurate systems are studied numerically. It is known that the critical state, which is intermediate between the localized and the extended ones, occurs in these models. We find that those critical states are well characterized in common by the…
We have examined the effect of growth temperature and growth interruption time on molecular-beam-epitaxial growth of GaAs, Al0.3Ga0.7As, and InxGa1−xAs on GaAs substrates and In0.53Ga0.47As and In0.52Al0.48As on InP substrates using dynamical reflection high-energy electron diffraction as an in situ probe. We have stu…
Pronounced Fano-like resonant effects are observed in the photoemission spectra of the localized U 5f and O?p ndash---U?f,6d--- bonding bands of ${\mathrm{UO}}_{2}$ when photon energies near the U 5${d}_{3/2}$,5/2 thresholds (105 and 97.1 eV, respectively) are employed. The constant-final-state spectra are well descri…
Alternate layers of Co and Cu of individual layer thicknesses from 1.5 to 8.0 nm and total thickness of about 100 layers and of Co bilayers separated by Cu have been electroplated from an electrolyte having a low concentration of Cu and a high concentration of Co atoms. The properties of the resulting structures have…