Materials Literature
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We have used a novel, high-pressure high-temperature scanning tunneling microscope, which is set up as a flow reactor, to determine simultaneously the surface structure and the reactivity of a Pt(110) model catalyst at semirealistic reaction conditions for CO oxidation. By controlled switching from a CO-rich to an O2-…
The low electron energy loss and complex dielectric functions of an arbitrary grain boundary and its proximity in ZnO thin films have been studied by using the spatially resolved electron energy loss spectroscopy. The critical point parameters have been determined by fitting the dielectric functions simultaneously wit…
The structure and electronic bonding in the spinel SiAlON (Si6−zAlzOzN8−z, z=1) derived from the cubic c-Si3N4 are studied by a first-principles density functional method. Al prefers the octahedral site of the spinel lattice. The small energy difference between the four possible structural configurations indicates tha…
The behavior of a diverse range of soils from Trinidad with respect to strongly fixed dynamics was studied. Fixed contents and additional ammonium fixation capacity (AAF) varied among the soils; the former increasing with clay content and ammonium fixation capacity (AFC) while the latter was related more to the soil's…
An electron-paramagnetic-resonance (EPR) study of molecular-beam-epitaxy-grown Mn-doped GaAs is presented. The resolved fine structure in insulating ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ allows us to evaluate the crystal-field parameters of the spin Hamiltonian. The exchange narrowing of the s…
We investigated conduction through an artificial grain-boundary junction made in La0.67Ba0.33MnO3 thin films, deposited on a 36.7° SrTiO3 bicrystal substrate using a laser ablation technique. The grain boundary exhibits substantial magnetoresistance at low temperatures and also shows nonlinear I–V characteristics. Ana…
Starting from a microscopic description of the exchange interaction in Ga(1-x)Mn(x)As, we derive an effective Mn-Mn interaction. Because of the strong spin-orbit coupling in the valence band, this effective interaction is highly anisotropic and has a spatial structure somewhat similar to dipolar interactions. The corr…
Recent applications of organic low-k dielectrics in microelectronics have stimulated many investigations of metal diffusion in polymers. Here we report results from radiotracer measurements of110mAg diffusion in trimethylcyclohexane polycarbonate. Serial sectioning was carried out with 190 eV krypton ions in and oppos…
Elementary reactions in atomic layer deposition of zirconia using zirconium tetrachloride and water are investigated using the density functional theory. The atomistic mechanisms of the two deposition half cycles on the Zr–OH and Zr–Cl surface sites are investigated. Both half reactions proceed through the formation o…
The aim of the present work is an atomic scale characterization of the ${\mathrm{SrTiO}}_{3}/{\mathrm{La}}_{2/3}{\mathrm{Sr}}_{1/3}{\mathrm{MnO}}_{3}$ interface involved in ${\mathrm{C}\mathrm{o}/\mathrm{S}\mathrm{r}\mathrm{T}\mathrm{i}\mathrm{O}}_{3}/{\mathrm{La}}_{2/3}{\mathrm{Sr}}_{1/3}{\mathrm{MnO}}_{3}$ tunnel ju…
Zero- and finite-temperature (T) first-principles calculations versus composition (c) show that magnetochemical effects lead to Invar anomalies in Fe-(Ni, Co, Pt) alloys. Chemical short- or long-range order and negative interatomic exchange interaction of electrons in antibonding majority-spin states force the face-ce…
The nucleation, growth, and coalescence of Cu2O islands due to oxidation of Cu(001) films were visualized by in situ ultrahigh-vacuum transmission electron microscopy. We have previously demonstrated that the nucleation and initial growth of copper oxides is dominated by oxygen surface diffusion. These surface models…
The photoluminescence observed in ABO3 type perovskite in their highly structural disordered state can be explained by a model in which is assumed a distribution of electronic states localized within the energy band gap coupled to lattice local vibrational states. The model fits very well the experimental results and…
Epitaxial Na0.5K0.5NbO3 (NKN) thin films have been grown on LaAlO3 substrates by rf magnetron sputtering of a stoichiometric, high-density, ceramic target. X-ray diffraction analysis showed c-axis oriented cube-on-cube growth. Micrometer size interdigital capacitor (IDC) structures were defined on the surface of the N…
The crystal structure, near-infrared spectrum and electrochemistry of a quinoidal triply-linked porphyrin dimer are compared with those of its singly-linked precursor; fusing the two porphyrins planarizes the pi-system and reduces the optical HOMO-LUMO gap while increasing the gap between the first oxidation and reduc…
We have grown high-crystallinity ZnO thin films on lattice-matched ScAlMgO4 substrates by pulsed-laser deposition with doping donor (Ga) and acceptor (N) simultaneously. Alternating ablation of ceramics with concentrated Ga addition and highly pure single crystal targets yielded in a controlled Ga concentration (CGa)…
BACKGROUND: The largest open reading frame in the Saccharomyces genome encodes midasin (MDN1p, YLR106p), an AAA ATPase of 560 kDa that is essential for cell viability. Orthologs of midasin have been identified in the genome projects for Drosophila, Arabidopsis, and Schizosaccharomyces pombe. RESULTS: Midasin is presen…
Highly ordered arrays of nanosized GaAs-based dots were successfully prepared on GaAs (001) substrates by molecular-beam epitaxy using selected area growth. Selected area growth employed alumina nanochannel array (NCA) templates formed by anodic oxidation, bonded to the GaAs substrates. Homogeneous GaAs dots, as well…
Field electron emission behavior of individual multiwalled carbon nanotubes (MWNTs), that are elements of a vertically aligned array grown on a Si wafer, were analyzed with a scanning anode field emission microscope. The electron emission of each MWNT followed the conventional Fowler–Nordheim field emission mechanism…
The temperature and thickness dependence of permittivity of (Ba,Sr)TiO3 has been investigated. The films were deposited by liquid-source metalorganic chemical vapor deposition onto Pt/SiO2/Si, with thicknesses ranging from 15 to 580 nm. The dielectric response was measured from 100 to 520 K. As film thickness decrease…