Materials Literature
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Nanocompatible chemistry which utilizes a novel nontoxic phosphino amino acid as a reducing agent has resulted in the development of therapeutically useful gold nanoparticles under biologically benign media. Stabilization of gold nanoparticles by the edible gum arabic matrix has provided an effective pathway toward in…
The $\ensuremath{\pi}$-electronic excitations are studied for the AA- and AB-stacked bilayer graphites within the linear self-consistent-field approach. They are strongly affected by the stacking sequence, the interlayer atomic interactions, the interlayer Coulomb interactions, and the magnitude of the transferred mom…
A rheological law based on the concept of cooperatively sheared flow zones is presented, in which the effective thermodynamic state variable controlling flow is identified to be the isoconfigurational shear modulus of the liquid. The law captures Newtonian as well as non-Newtonian viscosity data for glass-forming meta…
We theoretically study the magnetoresistance of single wall carbon nanotubes (SWCNTs) in the ballistic transport regime, using a standard tight-binding approach. The main attention is directed to spin-polarized electrical transport in the presence of either axial or perpendicular magnetic field. The method takes into…
The intrinsic anomalous Hall effect in ferromagnets depends on subtle spin-orbit-induced effects in the electronic structure, and recent ab-initio studies found that it was necessary to sample the Brillouin zone at millions of k-points to converge the calculation. We present an efficient first-principles approach for…
We studied the persistent photoconductivity (PPC) effect in AlGaN/AlN/GaN heterostructures with two different Al-compositions (x=0.15 and x=0.25). The two-dimensional electron gas formed at the AlN/GaN heterointerface was characterized by Shubnikov-de Haas and Hall measurements. Using optical illumination, we were abl…
We report systematic studies of structural, microstructural and transport properties of (Hg_0.80 Sb_0.2-x Pb_x)Ba_2 Ca_2 Cu_3O_8+δ(where x = 0.0, 0.05, 0.1, 0.15, 0.2) compounds. Bulk polycrystalline samples have been prepared by two-step solid-state reaction route at ambient pressure. It has been observed that simult…
The realization of semiconductors that are ferromagnetic above room temperature will potentially lead to a new generation of spintronic devices with revolutionary electrical and optical properties. Transition temperatures in doped ZnO are high but, particularly for Mn doping, the reported moments have been small. We s…
Vanadium oxide aerogels were used as a precursor for preparing nanotextured VO 2 [B] by low-temperature heat treatment under vacuum. The VO 2 [B] material retains the fibrous morphology and high surface area of the aerogel. Evolution of the VO 2 [B] phase, as studied by FTIR and X-ray diffraction, indicates that the l…
We report a study in which Point contact Andreev reflection (PCAR) spectroscopy using superconducting Nb tip has been carried out on NdNi5, a ferromagnet with a Curie temperature of TC~7.7K. The measurements were carried out over a temperature range of 2-9K which spans across the ferromagnetic transition temperature.…
Neutron scattering techniques have been used to study the relaxor ferroelectric 0.68PbMg1/3Nb2/3O3-0.32PbTiO3 denoted in this paper as 0.68PMN-0.32PT. On cooling, these relaxor ferroelectrics have a long-range ordered ferroelectric phase and the composition is close to that at which the ferroelectric structure changes…
The fracture resistance of structures is optimised using the level-set method. Fracture resistance is assumed to be related to the elastic energy released by a crack propagating in a normal direction from parts of the boundary which are in tension, and is calculated using the virtual crack extension technique. The sha…
T.W. Noh and his group (Kim et al.: PRL, 2005) have recently published a seminal experimental study of very thin ferroelectric (FE) BaTiO3 capacitors. They found an evidence that all their samples, including the thinnest one (d=5 nm), are multi-domain (MD). Under a high enough external field, the MD state goes over in…
The low-temperature magnetic structure of \HG has been studied by high-resolution powder neutron diffraction. Long-range incommensurate magnetic order sets in at T$_N\sim$22K with propagation vector \textbf{k}=(0,0,$\sim$0.18). On cooling below T$_N$, the propagation vector increases and saturates at the commensurate…
By the formation of ZnO and Pt nanocomposites, it is found that the bandgap emission can be greatly enhanced, while the defect emission is suppressed to the noise level. The photoluminescence intensity ratio between the bandgap and defect emission can be improved by up to 10 3 times. The underlying mechanism behind en…
The body of research on (III,Mn)V diluted magnetic semiconductors (DMSs) initiated during the 1990s has concentrated on three major fronts: (i) the microscopic origins and fundamental physics of the ferromagnetism that occurs in these systems, (ii) the materials science of growth and defects, and (iii) the development…
We report a study of self-assembled beta-pleated sheets in B. mori silk fibroin films using thermal analysis and infrared spectroscopy. B. mori silk fibroin may stand as an exemplar of fibrous proteins containing crystalline beta-sheets. Materials were prepared from concentrated solutions (2−5 wt % fibroin in water) a…
The laser cladding process inherently includes multiscale, highly nonlinear, and non-equilibrium transport phenomena due to nonuniform and rapid heat flow caused by the laser and the material interaction. In this work, a process model of solidification micro-structure evolution for the laser cladding process has been…
Polypropylene-filled alkali-extracted steam-exploded Acacia mangium fiber (AEF–PP) composites are immersed in water at room temperature for three months. All composites, including those with maleated polypropylene (MAPP) are found to absorb water considerably. The results of tensile properties indicate that the proper…
A giant softening by $30\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ of the 490 and $620\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ Jahn-Teller and breathing optical phonon modes is observed in Raman spectroscopy below the Curie temperature of single crystalline $\mathrm{La}\mathrm{Mn}{\…