Materials Literature
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From systematic ab initio calculations of the alloy system Mg_{1-x}Al_{x}B_2, we find a strong tendency for the formation of a superstructure characterized by Al-rich layers. We also present a simple model, based on calculated energies and an estimate of the configurational entropy, which suggests that the alloy has t…
Antisite disordering in ${\mathrm{Sr}}_{2}{\mathrm{FeMoO}}_{6}$ double perovskites (containing Mo atoms at Fe positions, and vice versa) has recently been shown to have a dramatic influence in their magnetic and magnetotransport properties. In the present paper, two polycrystalline ${\mathrm{Sr}}_{2}{\mathrm{FeMoO}}_{…
In this work, a question is tackled concerning the formation of a superconducting condensate in an earlier proposed model of "elastic jelly", in which phonons of the ion system play the part of initiating ones. It was shown that in distinction from the BCS theory, the momenta of forming electron pairs are different fr…
We show that backflow, the coupling between the order parameter and the velocity fields, has a significant effect on the motion of defects in nematic liquid crystals. In particular, the defect speed can depend strongly on the topological strength in two dimensions and on the sense of rotation of the director about the…
Massively cross-linked and property-tunable membranes have been fabricated by free radical polymerization of self-assembled, block copolymer vesicles − polymersomes. Similar efforts with cross-linkable lipids would appear frustrated in the past due to at least two factors: limited reactivity and membrane fragility und…
We have grown epitaxial NdNiO3 films on Si(100) substrate under ambient oxygen pressure using a pulsed-laser deposition method. The integration of NdNiO3 with Si(100) was accomplished by lattice-matching epitaxy of MgO and SrTiO3 and domain matching epitaxy of TiN on Si(100). During domain matching epitaxy, four latti…
A bubble translating through a continuous liquid (i.e. Newtonian) phase moves as a sphere when inertial and viscous forces are small relative to capillary forces. Spherical bubbles with stress-free interfaces do not retain wakes at their trailing ends as inertial forces become important (increasing Reynolds number). T…
Abstract Two types of novel functionalized N ‐[4‐(4′‐hydroxyphenyloxycarbonyl)phenyl]maleimide and N ‐(4‐{[2‐(3‐thienyl)acetyl]oxyphenyl}oxycarbonylphenyl)maleimide (MIThi) were synthesized starting from 4‐maleimido benzoic acid. Photoinduced radical homopolymerization of MIThi and its copolymerization with styrene we…
Abstract Poly( o ‐aminophenethyl alcohol) and its copolymers containing the aniline unit were synthesized in aqueous hydrochloric acid medium by chemical oxidative polymerization. The chemical composition of these novel polymers was determined spectroscopically, and their viscosities were measured. These polymers exhi…
Mn(hfac)2 and Cu(hfac)2 form 1:1 complexes with 5-(4-[N-tert-butyl-N-aminoxyl]phenyl)pyrimidine that exhibit strong metal-nitroxide exchange; spin polarization models do not explain the antiferromagnetic exchange behavior between spin sites in these complexes.
In ferroelectric thin films, a decrease of the permittivity is observed obeying a logarithmic time dependence. In the literature, a similar effect has been reported for ferroelectric single crystals and ceramics, which is referred to as ferroelectric aging, and different models have been proposed to explain this pheno…
Abstract In this paper, we present a macroscopic numerical model that is capable of capturing the interaction between the double‐diffusive convective field and a localized fluid flow on account of solutal undercooling during non‐equilibrium solidification of binary alloys. The model is essentially based on a fixed‐gri…
The optical properties of single zinc oxide (ZnO) nanocrystallites were investigated at room temperature by extending the optical near-field technique to the UV region. Using a UV fiber probe with a subwavelength aperture, we performed spatially- and spectrally-resolved photoluminescence (PL) imaging of individual ZnO…
Carbon nanotubes films have been prepared by low-velocity spraying of carbon nanosized particles on heated Si substrate. Studies reveal that by properly choosing the deposition temperature, well-aligned carbon nanotubes are self-assembled from the particles without a catalyst. Raman scattering and reflection high-ener…
In this letter, a method is presented to perform current versus voltage measurements on carbon nanotubes using the tip of a scanning force microscope as an electrode that can be positioned along the molecule. This method allows current versus voltage measurements to be carried out at any spot along a nanotube. By usin…
The domain structure in a ferroelectric with well-defined crystallography and negligible ferroelastic distortion (<0.002%) is reported. In contrast to prototypical ferroelectrics in which long-range elastic strain dictates the domain structure, in SrBi2Nb2O9 the elastic term is insignificant, allowing dipole-dipole in…
Ultrathin films (&lt;30 nm) of Pr0.7Sr0.3MnO3 on LaAlO3 have been studied using transmission electron microscopy (TEM). It was shown that the films are highly uniform and defect-free, and that they are coherently strained to the smaller lattice parameter of the substrate, resulting in a tetragonal expansion perpen…
Abstract The ring‐opening polymerization of ϵ‐caprolactone (ϵ‐CL) catalyzed by iodine (I 2 ) was studied. The formation of a charge‐transfer complex (CTC) among triiodide, I , and ϵ‐CL was confirmed with ultraviolet–visible spectroscopy. The monomer ϵ‐CL was polymerized in bulk using I 2 as a catalyst to form the poly…
Ge island formation on ultrathin SiO2 films enabled us to fabricate multilayer structures of Ge dots ∼6–7 nm in diameter and with an extremely high dot density of 2×1012 cm−2. Each dot had a boundary with the SiO2 film and a Si spacer layer. The multilayer structures exhibited photoluminescence (PL) with a maximum in…
Abstract Structural changes during tensile deformation in semicrystalline polymers are studied by the analysis of both small‐ and wide‐angle X‐ray scattering data from polyamide‐6 fibers. The strain in the lamellar spacing is about the same as or higher than the fiber strain, suggesting that fiber elongation occurs by…