Materials Literature
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We report a multicomponent theory for the coexistence of charge ordering (CO), and antiferromagnetic (AFM) and ferromagnetic (FM) spin ordering. This kind of state is invoked for manganites by Moreo et al., Science 283, 2034 (1999) and observed in recent experiments. We show that doping an AFM or CO state always gener…
The tuning properties of epitaxial Ba0.5Sr0.5TiO3 (BST) thin films were investigated by a scanning microwave microscope (SMM) and an LCR meter. Although the BST films on LaAlO3 and MgO substrates showed similar tuning behavior when measured by the LCR meter at 1 MHz, remarkably different tuning properties were observe…
The thermal stability of faceted self-assembled PbSe quantum dots during annealing is investigated. With increasing annealing time, the dot density is found to decrease rapidly with a simultaneous increase of the average island volumes. In addition, a shape transition from pyramidal islands to truncated pyramids is ob…
Epitaxial SrBi2Nb2O9 thin films have been grown on (110) SrTiO3 substrates by pulsed laser deposition. Four-circle x-ray diffraction and transmission electron microscopy reveal nearly phase pure epitaxial films with the c axis of the films at 45° with respect to the substrate normal. Electrical characterization is pre…
We present a theoretical analysis of quasicrystals (QCs) as potential thermoelectric materials. We consider a self-similar density of states model and extend the framework introduced in [G. D. Mahan and J. O. Sofo, Proc. Natl. Acad. Sci. U.S.A. 93, 7436 (1996)] to systems exhibiting correlated features in their electr…
New inelastic x-ray scattering experiments have been performed on liquid lithium in a wide wave vector range. With respect to the previous measurements, the instrumental resolution, improved up to 1. 5 meV, allows one to accurately investigate the dynamical processes determining the observed shape of the dynamic struc…
The high frequency dynamics of low-density (LDA) and high-density (HDA) amorphous ice and of cubic ice ( ${I}_{\mathrm{c}}$) has been measured by inelastic x-ray scattering in the $1--15{\mathrm{nm}}^{\ensuremath{-}1}$ momentum transfer ( $Q$) range. Sharp phononlike excitations are observed, and the longitudinal acou…
The FexCo1−xS2 system is predicted, on the basis of density functional calculations, to be a half metal for a wide concentration range. Unlike most known half metals, the half metalicity in this system is expected to be very stable with respect to crystallographic disorder and other types of defects.
We report the observation of a photorefractivelike nonlinearity responsible for the formation of giant relief modulations in amorphous semiconductor glasses. The photoinduced softening of the matrix, formation of defects with enhanced polarizability, and their drift under the optical field gradient force is believed t…
We report an atomistic simulation study of laser-induced graphitization on the diamond (111) surface. Our simulation results show that the diamond to graphite transition occurs along different pathways depending on the length of the laser pulse being used. Under nanosecond or longer laser pulses, graphitization propag…
A large magnetic entropy change has been observed in an intermetallic compound LaFe10.6Si2.4. The maximum −ΔSM≈3.2 J/kg K was found at its Curie temperature, ∼242 K, upon a 2 T magnetic field change. Although the entropy change is slightly smaller than that of pure Gd metal, such Fe-rich compounds still appear to be v…
The theory of the depinning transition of elastic manifolds in random media provides a framework for the statistical dynamics of dislocation systems at yield. We consider the case of a single flexible dislocation gliding through a random stress field generated by a distribution of immobile dislocations threading throu…
A Maxwell–Wagner series capacitor model is proposed to explain anomalous dielectric properties of ferroelectric superlattices. The results of the model show that a superlattice consisting of normal ferroelectric layers separated by low-resistivity interfacial regions can account for most experimental results reported…
Magnetic properties and magnetic-field-induced strains (MFIS) have been investigated for off-stoichiometric Ni–Mn–Al Heusler alloys with an ordered L21 structure. A clear martensitic transformation in Ni53Mn25Al22 alloy was revealed below the Curie temperature. In the polycrystalline specimen, an irreversible relative…
We have developed a simple, fast, and flexible technique to measure optical scattering spectra of individual metallic nanoparticles. The particles are placed in an evanescent field produced by total internal reflection of light from a halogen lamp in a glass prism. The light scattered by individual particles is collec…
Suspended single-wall carbon nanotubes are used as substrates for deposition of various metals by evaporation. Deposition of many types of metals normally forms discrete particles on nanotubes due to a weak interaction between the metals and nanotubes. However, continuous nanowires of virtually any metal are obtained…
Abstract The U. S. Navy has a long-standing history of ship design using metals. With the improvements in weapon systems, it is becoming increasingly critical to design ship structures not only to satisfy the structural loading but also to exhibit additional multifunctional properties. This is becoming evident with st…
A new azobenzene-containing gelator for low-molar-mass liquid crystals (LCs) was synthesized. It can effectively gel nematic LCs such as E7 through the formation of a hydrogen-bonded network. Moreover, an intriguing self-assembly process was observed. When thin films of the E7/gelator mixture, cast on CaF 2 crystal wi…
Impregnation of polymers with supercritical CO 2 appears to be a promising technique in the area of polymer processing. The main aim of this paper is to measure the diffusion coefficients of a solute (a dyestuff) permeating a poly(ethylene terephthalate) (PET) film in a supercritical impregnating system at different w…
The early kinetic events of protein folding are an important part of the folding pathway, yet our understanding towards the process is limited. Information from the study of these early events can allow us to distinguish between the various models that have been proposed to describe the folding of a protein in real ti…