Materials Literature
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The thermal decomposition and crystallisation behaviour of boron containing siliconoxycarbide (SiCO) ceramics were studied. The samples were prepared by pyrolysis of SiO 2 /B 2 O 3 filled poly(dimethylsiloxanes) at 1300°C and subsequent annealing at T > 1300°C. TEM and XRD investigations show the formation of β‐SiC…
A tunable metamaterial based on conducting coils loaded by an electronic circuit containing a varicap diode has been demonstrated. The agility exceeds one octave inside the 100–500 MHz range. Permeability levels are significantly increased when the loop is loaded by a proper magnetic material. A model gives a good des…
We report electrical transport measurements of individual carbon nanotubes grown catalytically in a nanoporous anodic aluminum oxide template by thermal chemical vapor deposition of acetylene. The four-terminal resistance at room temperature scales linearly with the nanotube length indicating diffusive nature of trans…
Material selection in real‐world problems normally entails considering several, usually conflicting, design criteria/objectives. Thus, a designer has to strike a balance between these objectives to find the best compromise solution for the particular application. A novel design support tool, the exchange constant char…
Abstract Wood was sampled from 22 locations in 3 Pinus radiata trees and characterized by solid-state 13 C NMR spectroscopy. Values of a cellulose crystallinity index were confined to the range 0.486 to 0.541 despite inclusion of earlywood and latewood, compression wood and opposite wood, juvenile wood and mature wood…
Orbital ordering (OO) in the layered perovskite La0.5Sr1.5MnO4 has been investigated using the enhanced sensitivity of soft x-ray resonant diffraction at the Mn L edges. The energy dependence of an OO diffraction peak over the L(2,3) edges is compared to ligand-field calculations allowing a distinction between the inf…
Single-crystal ZnWO 4 nanorods can direct the self-aggregation of the amorphous nanoparticulates and promote the crystallization and transformation process of the amorphous nanoparticulates derived from a simple supersaturation precipitation reaction in a nanorod/amorphous nanoparticle coexisting system under refluxin…
The surface sol−gel method has been demonstrated to be an effective method for the modification of silica mesopore surfaces and the tuning of mesopore diameters. This layer-by-layer approach allows the control of mesopore diameters with monolayer precision. Ultrasmall gold nanoparticles were successfully prepared on s…
We have probed the local thermoelectric power of semiconductor nanostructures with the use of ultrahigh-vacuum scanning thermoelectric microscopy. When applied to a p-n junction, this method reveals that the thermoelectric power changes its sign abruptly within 2 nanometers across the junction. Because thermoelectric…
A paramagnetic muonium (Mu) state with an extremely small hyperfine parameter was observed for the first time in single-crystalline GaN below 25 K. It has a highly anisotropic hyperfine structure with axial symmetry along the [0001] direction, suggesting that it is located either at a nitrogen-antibonding or a bond-ce…
We demonstrate that the spin-polarized electron current can interact with a microwave electric field in a resonant manner. The spin-orbit interaction gives rise to an effective magnetic field proportional to the electric current. In the presence of both dc and ac electric field components, electron spin resonance occu…
Since Br adsorption on Au(100) displays an incommensurate ordered phase, a lattice-gas treatment of the adlayer configurations is not reliable. We therefore use density functional theory slab calculations to determine the parameters necessary for the construction of an off-lattice model. We compute and analyze the tot…
The temperature dependence of the Hall coefficient of a series of ferromagnetic Ga(1-x)Mn(x)As samples is measured in the temperature range 80K < T < 500K. We model the Hall coefficient assuming a magnetic susceptibility given by the Curie-Weiss law, a spontaneous Hall coefficient proportional to rho_xx^2(T), and incl…
The capability of the density functional broken symmetry approach for the calculation of various EPR parameters of exchange coupled metal clusters is demonstrated by studying the experimentally well-investigated [Mn(III)Mn(IV)(mu-O)(2)(mu-OAc)DTNE](2+) complex. Geometry optimizations of the complex in its broken symme…
We present a first principle computation of vertical stripes in $La_{15/8}Sr_{1/8}CuO_4$ within the LDA+U method. We find that Cu centered stripes are unstable toward O centered stripes. The metallic core of the stripe is quite wide and shows reduced magnetic moments with suppressed antiferromagnetic (AF) interactions…
We report a pulsed EPR study of the phase relaxation of electron spins bound to phosphorus donors in isotopically purified 29^Si and natural abundance Si single crystals measured at 8 K.
A class of materials known as ``ferroelectric metals'' was discussed theoretically by Anderson and Blount in 1965 [Phys. Rev. Lett. 14, 217 (1965)], but to date no examples of this class have been reported. Here we present measurements of the elastic moduli of Cd2Re2O7 through the 200 K cubic-to-tetragonal phase trans…
The ability to follow Moore's Law has been the basis of the tremendous success of the semiconductor industry in the past decades. To date, the greatest challenge for device scaling is the required replacement of silicon dioxide-based gate oxides by high-k oxides in transistors. Around 2010 high-k oxides are required t…
In the present paper we investigate the restriction conditions for three kinds of cavity resonators ({\it i.e.}, the rectangular, cylindrical, spherical resonators). It is shown that the layer of materials with negative optical refractive indices can act as a phase compensator/conjugator, and thus by combining such a…
We present measurements of electrical resistivity, thermal conductivity, and thermopower of polycrystalline Sr-doped LaCoO3 with composition La0.95Sr0.05CoO3. Our data show that the investigated compound exhibits a very respectable room-temperature thermoelectric figure of merit value of 0.18. Our results not only sho…