Materials Literature
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Reversibly photoswitchable proton transfer processes can occur between a three‐state molecular switch based on spiropyran (SP) and the “salt form” of polyaniline (see Figure), both in solution and in the solid state. As a result, the electrical conductivity of the thin‐film of SP‐doped polyaniline can be photoregulate…
Abstract Single‐walled carbon nanotubes (SWNTs) were modified with polyethylene (PE) prepared by in situ Ziegler–Natta polymerization. Because of the catalyst pretreated on the surface of the SWNTs, the ethylene was expected to polymerize there. Scanning electron microscopy images and solubility measurements showed th…
Resistivity, dc magnetization, ac susceptibility, and heat-capacity measurements were carried out for polycrystalline ${\mathrm{Pr}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{CoO}}_{3}$ $(0<~x<~0.55).$ Insulating, metallic, and metal-insulator transition (MIT) regions appear successively with increasing x. The…
$\mathrm{Ln}\mathrm{CuO}\mathrm{Ch}$ $(Ln=\mathrm{lanthanide},Ch=\mathrm{chalcogen})$ layered oxychalcogenides are wide-gap $p$-type semiconductors composed of alternately stacked ${(Ln}_{2}{\mathrm{O}}_{2}{)}^{2+}$ oxide layers and $({\mathrm{Cu}}_{2}{\mathrm{Ch}}_{2}{)}^{2\ensuremath{-}}$ chalcogenide layers. Energy…
We have made a detailed temperature-dependent photoemission study of ${\mathrm{VO}}_{2}/{\mathrm{TiO}}_{2}(001)$ thin films, which show a metal-insulator transition at \ensuremath{\sim}300 K. Clean surfaces were obtained by annealing the films in an oxygen atmosphere. Spectral weight transfer between the coherent and…
Ultra‐thin t ‐Se nanoribbons are produced simply and conveniently via a vapor–liquid–solid (VLS) mechanism. The nanoribbons are highly crystalline and grow preferentially along the c ‐axis, with an average thickness of 15 nm (see Figure) and lengths up to several hundreds of micrometers. The intermediates in the forma…
The temperature dependence of thermal conductivity, $\ensuremath{\kappa}(T),$ and magnetic susceptibility, $\ensuremath{\chi}(T),$ have been measured on single crystals of $L{\mathrm{CoO}}_{3}$ $(L=\mathrm{La},$ Pr, Nd) grown by the floating-zone method. The susceptibility measurement shows a progressive stabilization…
Raman spectroscopy on carbon nanotubes (CNT) yields a rich variety of information owing to the close interplay between electronic and vibrational properties. In this paper, we review the properties of double wall carbon nanotubes (DWCNTs). In particular, it is shown that SWCNT encapsulating C$_{60}$, so-called peapods…
The distribution of the transport current in a superconducting filament aligned parallel to the flat surface of a semi-infinite bulk magnet is studied theoretically. An integral equation governing the current distribution in the Meissner state of the filament is derived and solved numerically for various filament-magn…
We show that spin-polarized dc current passing through a small magnetic element induces two-state, random telegraph switching of the magnetization via the spin-momentum transfer effect. The resistances of the states differ by up to 50% of the change due to complete magnetization reversal. Fluctuations are seen for a w…
We study theoretically the temporal evolution and the spatial structure of the interface between two polymer melts involving three different species (A, A* and B). The first melt is composed of two different polymer species A and A* which are fairly indifferent to one another (Flory parameter chi_AA* ~ 0). The second…
Point-contact measurements on the carbon-substituted Mg(B$_{1-x}$C$_x$)$_2$ filament/powder samples directly reveal a retention of the two superconducting energy gaps in the whole doping range from $x = 0$ to $x \approx 0.1$. The large gap on the $σ$-band is decreased in an essentially linear fashion with increasing t…
A carbon nanotube film (see Figure) can be used as a strain sensor at the macroscale, due to the dependence of the electrical properties of single‐walled carbon nanotubes on mechanical deformation at the nanoscale.
We show the differences in the stability of 3d-5d (NiPt and CuAu) and 3d-4d (NiPd and CuAg) alloys arise mainly due to relativistic corrections. The magnetic properties of disordered NiPd and NiPt alloys also differ due to these corrections which lead to increase in the separation between s-d bands of 5d elements in t…
Electrostatic energy (Madelung energy) is a major constituent of the cohesive energy of ionic crystals. Several physicochemical properties of these materials depend on the response of their electrostatic energy to a variety of applied thermal, electrical and mechanical stresses. In the present study, a method has been…
Neutral and charged phosphorus clusters of a wide size range have been produced by pulsed laser ablation (PLA) in vacuum at 532, 337, and 193 nm ablating wavelengths and investigated by time-of-flight mass spectrometry. The neutral P_n clusters are even-numbered with local abundance maxima at n = 10 and 14, while the…
LixMn2O4 is an important cathode material for the Li ion battery. During battery charging, the stoichiometry x varies continuously from 1 to zero and on discharging it varies from zero to one. The cubic lattice constant a of LixMn2O4 depends on the value of x and the variation of a with x has important consequences fo…
Photocurrents in nanotube p-n junctions are calculated using a non-equilibrium Green function quantum transport formalism. The short-circuit photocurrent displays band-to-band transitions and photon-assisted tunneling, and has multiple sharp peaks in the infrared, visible, and ultraviolet ranges. The operation of such…
Femtosecond transient absorption measurements were carried out to investigate the scavenging effect, at low concentration, of the radiosensitizing molecule 5-bromo-2‘-deoxyuridine (BrdU) on presolvation states of the hydrated electron. Hydrated electrons were generated by two photon absorption of bulk water at 267 nm,…
X-ray studies on degummed B. mori silk fibers and on hydrogels prepared under a variety of conditions reveal moderately small angle reflections. These reflections are often highly oriented and are correlated to silk II lattice reflections. A superstructure can explain these features. Silk fibroin hydrogels were monito…