Materials Literature
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A spectroscopic study of the optical nonlinearity of PbSe colloidal solutions was performed with the Z-scan technique at wavelength intervals of 1200–1350 and 1540–1750nm. While nonlinear absorption remains below the detection threshold, the third order nonlinear refractive index n2 shows clear resonances, somewhat bl…
Abstract The structural, optical, and electronic properties of a series of lithium rare earth polyphosphates [LiLn(PO 3 ) 4 ] [Ln = La ( 1 ), Eu ( 2 ), Gd ( 3 )] have been investigated by means of single‐crystal X‐ray diffraction, elemental analyses, and spectroscopic measurements, as well as calculations of energy‐ba…
Electroluminescence (EL) and electrical properties of nanocrystalline porous silicon (PS) diodes have been sufficiently improved by introducing high pressure water vapor annealing into the active PS layer. The EL emission is significantly enhanced without affecting the operating voltage. In addition, the fabricated de…
We present a systematic investigation of the magnetoreflectance $R(\ensuremath{\omega},B)$ of highly oriented pyrolytic graphite in magnetic field $B$ up to $18\phantom{\rule{0.3em}{0ex}}\mathrm{T}$. From these measurements, we report the determination of lifetimes $\ensuremath{\tau}$ associated with the lowest Landau…
Abstract Reversible addition–fragmentation chain transfer (RAFT) mediated radical polymerizations of allyl methacrylate and undecenyl methacrylate, compounds containing two types of vinyl groups with different reactivities, were investigated to provide hyperbranched polymers. The RAFT agent benzyl dithiobenzoate was d…
Dielectric spectroscopy was used in this study to examine CaCu3Ti4O12 polycrystalline samples. The analysis involved systems presenting low non-Ohmic properties, and the grain’s internal domain was evaluated separately from the contribution of barrier-layer capacitances associated with Schottky-type barriers in this t…
Nanoporous poly(4-fluorostyrene) templates on gold-coated silicon/silicon oxide substrates were prepared by the electric field alignment of poly(4-fluorostyrene)-b-poly(d,l-lactide) block copolymer thin films followed by mild degradation of the polylactide phase using dilute aqueous base. Electrochemical deposition of…
Highly ordered transparent self-supporting films of layered double hydroxides (LDHs) with a size of the order of cm2 have been obtained by a simple method; the chemical composition of both the layers and interlayers can be readily tuned, as demonstrated by the preparation of [ZnAl-NO3] LDH, [NiAl-NO3] LDH and [Tb(EDTA…
We report ab initio density functional theory calculations of generalized planar fault energies of fcc Cu–xAl (x=0, 5.0, and 8.3at.%) alloys. We investigate the effects of substitutional solute Al on the unstable intrinsic γus and twin γut stacking fault energies (SFEs). Our results reveal an increased tendency of Cu–…
A lipid-encapsulated perfluorocarbon nanoparticle molecular imaging contrast agent that utilizes a paramagnetic chemical exchange saturation transfer (PARACEST) chelate is presented. PARACEST agents are ideally suited for molecular imaging applications because one can switch the contrast on and off at will simply by a…
We study the relaxation of a spin density injected into a two-dimensional electron system with generic spin-orbit interactions. Our model includes the Rashba as well as linear and cubic Dresselhaus terms. We explicitly derive a general spin-charge coupled diffusion equation. Spin diffusion is characterized by just two…
Two-photon excitation is gaining rapidly in interest and significance in spectroscopy and microscopy. Here we introduce a new approach that suggests versatile optical labels suitable for both one- and two-photon excitation and also two-photon-excited ultrasensitive, nondestructive chemical probing. The underlying spec…
We use an "equation-free", coarse-grained computational approach to accelerate molecular dynamics-based computations of demixing (segregation) of dissimilar particles subject to an upward gas flow (gas-fluidized beds). We explore the coarse-grained dynamics of these phenomena in gently fluidized beds of solid mixtures…
Electromechanical hysteresis loop measurements in piezoresponse force microscopy (PFM) [piezoresponse force spectroscopy (PFS)] have emerged as a powerful technique for probing ferroelectric switching behavior on the nanoscale. Interpretation of PFS data requires the relationship between the domain parameters and PFM…
Ferroelectric BiFeO3 thin films were grown on Pt∕TiO2∕SiO2∕Si substrates by pulsed-laser deposition. From the x-ray diffraction analysis, the BiFeO3 thin films consist of perovskite single phase, and the crystal structure shows the tetragonal structure with a space group P4mm. The BiFeO3 thin films show enhanced elect…
In this study, a piezoelectric composite is fabricated from a Ba0.67Sr0.33TiO3 (BST) composition and air, and measured at room temperature (24°C) where the BST is in its paraelectric centric phase. The charge separation mechanism is flexoelectricity, driven by the strain gradient introduced by the pyramidal boundary s…
Fully epitaxial, exchange-biased magnetic tunnel junctions (MTJs) were fabricated with a Co-based full-Heusler alloy Co2MnSi (CMS) thin film as a lower electrode, a MgO tunnel barrier, and a Co50Fe50 upper electrode. The microfabricated CMS∕MgO∕Co50Fe50 MTJs exhibited relatively high tunnel magnetoresistance ratios of…
Using Coulomb correlation parameters appropriate for $\ensuremath{\pi}$-conjugated polymers (PCPs), and a nearest neighbor hopping integral that is arrived at by fitting the energy spectra of three zigzag semiconducting single-walled carbon nanotubes (S-SWCNTs), we are able to determine quantitatively the exciton ener…
We consider quasistatic fiber bundle models with interactions. Classical load sharing rules are considered, i.e. local, global or decaying as a power-law of distance. All fibers are identically elastic, initially intact, and break at a random threshold picked from a quenched disorder (q.d.) distribution. We are intere…
Key manifestations of the glassy and liquid states, such as viscous flow and structural relaxation, occur spatial and temporal heterogeneously, within highly localized rare events, termed shear transformation zones. Characterization of these basic entities with respect to thermal activation and mechanical response is…