Materials Literature
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A theory of the anisotropic superexchange and low-energy spin excitations in a Mott insulator with ${t}_{2g}$ orbital degeneracy is presented. We observe that the spin-orbit coupling induces frustrating Ising-like anisotropy terms in the spin Hamiltonian, which invalidate noninteracting spin-wave theory. The frustrati…
The novel complex trans-Cu(hfac)2(TTF-py)2 (hfac = hexafluoroacetylacetonate; TTF-py = 4-(2-tetrathiafulvalenyl-ethenyl)pyridine) in which the paramagnetic transition metal and the organic donor are covalently linked through a conjugated bridge is synthesized and characterized aiming at a new approach for the occurren…
We present an analysis of the vibrational dynamics of metal vicinal surfaces using the embedded atom method to describe the interaction potential and both a real space Green's function method and a slab method to calculate the phonons. We report two main general characteristics : a global shift of the surface vibratio…
We study the recently discovered 117-Kelvin superconducting system C60/CHBr3 of the field-effect transistor and propose a possibility that the intercalation molecule CHBr3 plays a role of an electric capacitor in the C60 fullerene superconductor, which contrasts rather with an expectation that the intercalation molecu…
We consider the competition between superconducting, charge ordered, and metallic phases in layered molecular crystals with the $\ensuremath{\theta}$ and ${\ensuremath{\beta}}^{\ensuremath{'}\ensuremath{'}}$ structures. Applying slave-boson theory to the relevant extended Hubbard model, we show that the superconductiv…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTOcta(aminophenyl)silsesquioxane as a Nanoconstruction SiteRyo Tamaki, Yasuyuki Tanaka, Michael Z. Asuncion, Jiwon Choi, and Richard M. LaineView Author Information Department of Materials Science and Engineering Macromolecular Science and Engineering Center University…
Hydrotalcite-like anionic clays (HTs; or layered double hydroxides, LDHs) can be used as precursors to mixed oxides, but their catalytic potential reaches much further. This review demonstrates that HTs can be successfully applied in a broad spectrum of organic reactions, with advantages such as improved activity, sel…
During the last few decades, concerns have grown on the negative effects that diesel particulate matter has on health. Because of this, particulate emissions were subjected to restrictions and various emission-reduction technologies were developed. It is ironic that some of these technologies led to reductions in the…
Abstract Surface‐enhanced Raman scattering (SERS) of xanthopterin adsorbed on colloidal silver was measured and the Raman spectrum calculated by the density functional theory method was also obtained. Xanthopterin can be detected down to 5 × 10 −9 M and the enhancement of the scattering intensity is at least 10 5 ‐fol…
At present, band pass filtered, very high-gain photomultiplier tube (PMT) imaging sensors are employed to detect and image hot, UV emitting objects within the solar blind UV spectral region for wavelengths < 289 nm, either within or through the earth's atmosphere. In this paper we will reviews and summarize the str…
Nanoparticles of silver and nickel were grown in thermally evaporated fatty acid (stearic acid) films by immersion of the film sequentially in solutions containing Ag+ ions and Ni2+ ions. Attractive electrostatic interaction between the metal cations and the carboxylate ions in the fatty acid film leads to entrapment…
In magnetic fields applied parallel to the anisotropy axis, the relaxation of the magnetization of Mn(12)-acetate measured for different sweep rates collapses onto a single scaled curve. The form of the scaling implies that the dominant symmetry-breaking process responsible for tunneling is a locally varying second-or…
Electromigration tests at temperatures between 340 and 400 °C and current densities between 1.0 and 3.0 MA/cm2 have been performed to determine the temperature dependence of the critical length effect in 0.5-μm-wide Cu/oxide dual-damascene interconnects with 0.1 μm silicon nitride (SiNx) passivation. A focused-ion-bea…
We have analyzed cascades of secondary electrons in diamond and amorphous carbon generated by the thermalization of a single Auger electron. The elastic electron mean free path was calculated as a function of impact energy in the muffin-tin potential approximation. The inelastic scattering cross section and the energy…
We use scanning gate microscopy to precisely locate the gating response in field-effect transistors (FETs) made from semiconducting single-wall carbon nanotubes. A dramatic increase in transport current occurs when the device is electrostatically doped with holes near the positively biased electrode. We ascribe this b…
The Raman spectra of a new type of graphite whiskers have been measured in the range of $150--7800{\mathrm{cm}}^{\ensuremath{-}1}.$ The intensity of the overtone $(2D)$ located at $\ensuremath{\sim}2700{\mathrm{cm}}^{\ensuremath{-}1}$ is found to be about 10 times stronger than that of the C-C stretching mode (G) at $…
Abstract Melt‐crystallized, low molecular weight poly( L ‐lactic acid) (PLLA) consisting of α crystals was uniaxially drawn by solid‐state extrusion at an extrusion temperature ( T ext ) of 130–170 °C. A series of extrusion‐drawn samples were prepared at an optimum T ext value of 170 °C, slightly below the melting tem…
The crystal structure and the magnetic properties of the W1-xNbxO3-d, (x<0.03) system have been investigated. In contrast to the orthorhombic diamagnetic WO3, the material with x=0.01 is paramagnetic down to 5 K. Introducing of 2.5 at. % of Nb into WO3 leads to a tetragonal structure and to a weak itinerant ferromagne…
The present study summerizes magnetic and Mossbauer measurements on ceramic Li2MO3 M= Mn, Ru and Ir and the mixed Li2(Mn1-xRux)O3 materials, which show many of the features reflecting to antiferromagnetic ordering or to existence of paramagnetic states. Li2IrO3 and Li2RuO3 are paramagnetic down to 5 K. Li2(Mn1-xRux)O3…
We have investigated the thermoelasticity of body-centered cubic (bcc) tantalum from first principles by using the linearized augmented plane wave (LAPW) and mixed--basis pseudopotential methods for pressures up to 400 GPa and temperatures up to 10000 K. Electronic excitation contributions to the free energy were incl…