Materials Literature
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Electric transport of a zigzag graphene nanoribbon through a steplike potential and a barrier potential is investigated by using the recursive Green's function method. In the case of the steplike potential, we demonstrate numerically that scattering processes obey a selection rule for the band indices when the number…
This work explores, from a theoretical viewpoint, the aluminum incorporation into silicate chains with dreierketten conformation relevant in the cementitious calcium-silicate-hydrate (C-S-H) gel and in other minerals, such as wollastonite and hillebrandite. To this end, we have investigated by means of ab initio calcu…
Stroboscopic wavepacket basis sets [P. Bokes, F. Corsetti, R. W. Godby, Phys. Rev. Lett. 101, 046402 (2008)] are specifically tailored for a description of time-dependent processes in extended systems like non-periodic geometries of various contacts consisting of solids and molecules. The explanation of the constructi…
Bulk superconductivity was discovered in BaRh2P2 (Tc = 1.0 K) and BaIr2P2 (Tc = 2.1 K), which are isostructural to (Ba,K)Fe2As2, indicative of the appearance of superconductivity over a wide variety of layered transition metal pnictides. The electronic specific heat coefficient gamma in the normal state, 9.75 and 6.86…
We present evidence of direct electron tunneling across intrinsic insulating regions in sub-micrometer wide bridges of the phase separated ferromagnet (La,Pr,Ca)MnO$_3$. Upon cooling below the Curie temperature, a predominantly ferromagnetic supercooled state persists where tunneling across the intrinsic tunnel barrie…
We report the preparation, characterization, and magnetic properties of highly crystalline colloidal Fe-doped indium oxide nanoparticles. The nanoparticles have been prepared in high yields by simple one-pot thermal decomposition of indium and iron precursors in hexadecylamine and can be easily dispersed in solvents l…
4-(4-cyanobenzylideneamino)antipyrine (CBAP) has been synthesized and characterized by elemental analysis, FT-IR, UV-VIS and X-ray single crystal diffraction techniques. Crystallographic study reveals that the compound adopts trans configuration about the Schiff base imine double bond. The substituted p-cyanophenyl ri…
The catalytic activity toward H2 dissociation of several Au nanoparticles of different shape, supported on stoichiometric and reduced TiO2 surfaces, has been investigated by means of periodic DF calculations. Gold nanoparticles become positively charged when supported on stoichiometric TiO2 and negatively charged when…
Multilayers of hydrogenated ultrathin (3 nm) amorphous a-Si and a-Ge layers prepared by sputtering have been studied by atomic force microscopy (AFM) and transmission electron microscopy (TEM) to check the influence of annealing on their structural stability. The annealed multilayers exhibit surface and bulk degradati…
Au/Co/Au nanopillars fabricated by colloidal lithography of continuous trilayers exhibit and enhanced coercive field and the appearance of an exchange bias field with respect to the continuous layers. This is attributed to the lateral oxidation of the Co interlayer that appears upon disc fabrication. The dependence of…
Basement membranes have many features that greatly influence vascular endothelial cell function, including a complex three-dimensional topography. As a first step in the design and development of vascular prosthetics, we undertook a thorough characterization of the topographic features of endothelial vascular basement…
We report ac electrical transport in La0.7Sr0.3CoO3 and La1-xSrxMnO3 (x = 0.18- 0.5) as a function of temperature and frequency in H = 0 and 60 mT. Both resistive (R) and reactive (X) components of impedance (Z = R+jX) were measured. It is shown that a smooth decrease of the resistance around the Curie temperautre in…
Electromagnetic properties of doped perovskites depend sensitively on the doping level. Both the superconducting transition temperature of Bi2Sr2Ca(Pr)Cu2O8+d compounds and the magnetic and electronic transport properties of La(Sr)Co(Fe)O3 perovskites change dramatically with the doping level. Apart from doping, oxyge…
Using a systematic search algorithm we identify several types of point defects in the boron fullerene with 80 atoms. All these point defect leave the cage structure intact. In addition the cage structure is also very stable with respect to elastic deformations and addition or removal of atoms.
The structure and the magnetic properties of an InGaAs/Fe3Si superlattice in a cylindrical geometry are investigated by electron microscopy techniques, x-ray diffraction and magnetometry. To form a radial superlattice, a pseudomorphic InGaAs/Fe3As bilayer has been released from its substrate self-forming into a rolled…
Thermal stability of hydrogenated amorphous Si/Ge multilayers has been investigated by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Small-Angle X-Ray Diffraction (SAXRD) techniques. Amorphous H-Si/Ge multilayers were prepared by RF sputtering with 1.5 and 6 ml/min H2 flow-rate. It is…
The overall quality of multilayer thin films prepared by electrodeposition is strongly influenced by the surface and interface roughness which increases with the layer number. For that very reason the reliable analysis of the first few layers can be necessary. However, in depth profiling methods based on sputtering te…
Carbon-supported Fe@Pt core-shell nanoparticle (NP) catalysts with Fe cores in different crystal states have been successfully synthesized by a sequential reduction process. Unexpectedly, in contrast to its crystallized counterpart, iron in the amorphous state exerts a distinct and powerful ability as the core for the…
We present a detailed infrared study of the insulator-to-metal transition (IMT) in vanadium dioxide $({\text{VO}}_{2})$ thin films. Conventional infrared spectroscopy was employed to investigate the IMT in the far field. Scanning near-field infrared microscopy directly revealed the percolative IMT with increasing temp…
Tissue engineering of fibrous tissues of the musculoskeletal system represents a considerable challenge because of the complex architecture and mechanical properties of the component structures. Natural healing processes in these dense tissues are limited as a result of the mechanically challenging environment of the…