Materials Literature
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In a first approximation, known as the adiabatic process, the direction of the spin polarization of currents is parallel to the local magnetization vector in a domain wall. Thus the spatial variation of the direction of the spin current inside the domain wall results in an adiabatical spin transfer torque on the magne…
We present adaptive finite element simulations of dendritic and eutectic solidification in binary and ternary alloys. The computations are based on a recently formulated phase-field model that is especially appropriate for modelling non-isothermal solidification in multicomponent multiphase systems. In this approach,…
Gamma - Iron Oxide prepared by sol -gel process was used to produce nanocomposites with polyaniline of varying aniline concentrations. TEM shows the presence of chain like structure for lower polyaniline concentration. The room temperature hysteresis curves show finite coercivity of 160 Oe for all the composites while…
We consider the optical properties of a single magnetic impurity in a self-assembled quantum dot. We show that using the resonant pumping one can address and manipulate selectively individual spin states of a magnetic impurity. The mechanisms of resonant optical polarization of a single impurity in a quantum dot invol…
We investigated the optical properties of epitaxial n-type ZnO films grown on lattice-matched ScAlMgO4 substrates. As the Ga doping concentration increased up to 6×1020cm−3, the absorption edge showed a systematic blueshift, consistent with the Burstein–Moss effect. A bright near-band-edge photoluminescence (PL) could…
Fluctuations in the fluorescence from macroscopic ensembles of colloidal semiconductor quantum dots have the spectral form of 1∕f noise. The measured power spectral density reflects the fluorescence intermittency of individual dots with power-law distributions of “on” and “off” times, and can thus serve as a simple me…
RbOs 2 O 6 , the third superconducting pyrochlore oxide (known so far), has been synthesized by encapsulation and by high pressure techniques. Suitable post chemical treatment of the as-prepared sample allowed us to eliminate the impurity phases. Bulk superconductivity with T c = 6.4 K was observed in magnetization an…
Silicon is a leading candidate material for spin-based devices, and two-dimensional electron gases (2DEGs) formed in silicon heterostructures have been proposed for both spin transport and quantum dot quantum computing applications. The key parameter for these applications is the spin relaxation time. Here we apply th…
We report neutron diffraction data on single crystal ${\mathrm{PrO}}_{2}$ which reveal a cooperative Jahn-Teller distortion at ${T}_{\mathrm{D}}=120\ifmmode\pm\else\textpm\fi{}2\phantom{\rule{0.2em}{0ex}}\mathrm{K}$. Below this temperature an internal distortion of the oxygen sublattice causes the unit cell of the cry…
Formation of colloids based on polyelectrolyte complexes (PECs) was mainly studied with synthetic polyelectrolytes. In this study, we describe the elaboration of positively charged PEC particles at a submicrometer level obtained by the complexation between two charged polysaccharides, chitosan as polycation and dextra…
The low-energy part of the vibration spectrum in KNbO$_3$ was studied by cold neutron inelastic scattering in the cubic phase. In addition to acoustic phonons, we observe strong diffuse scattering, which consists of two components. The first one is quasi-static and has a temperature-independent intensity. The second c…
We report initial NMR studies of gas dynamics in a particle bed fluidized by laser-polarized xenon (129Xe) gas. We have made preliminary measurements of two important characteristics: gas exchange between the bubble and emulsion phases; and the gas velocity distribution in the bed. We used T2* contrast to differentiat…
A general spin symmetry argument is proposed for spin currents in semiconductors. In particular, due to the symmetry with respect to spin polarization of the helicity eigenstates of the Luttinger Hamiltonian for a hole-doped semiconductor, the spin polarized flux from a single helicity eigenstate induced by an externa…
In this work we present measurements of permeability, effective porosity and tortuosity on a variety of rock samples using NMR/MRI of thermal and laser-polarized gas. Permeability and effective porosity are measured simultaneously using MRI to monitor the inflow of laser-polarized xenon into the rock core. Tortuosity…
Using a first-principles-based approach, we determine the ferroelectric pattern in PbZr$_{0.5}$Ti$_{0.5}$O$_3$ ultrathin film. It is found that vortex stripes are formed in the system and they are responsible for the 180$^\circ$ domains observed. When a local external field is exerted, the vortex stripe transforms int…
Mechanical properties of polyelectrolyte multilayer films were studied by nanoindentation using the atomic force microscope (AFM). Force-distance measurements using colloidal probe tips were systematically obtained for supported films of poly(L-lysine) and hyaluronan that are suited to bio-application. Both native and…
The structural evolution and crystallization dynamics of poly( l -lactide) (PLLA) during isothermal cold-crystallization process are studied by infrared (IR) spectroscopy and two-dimensional correlation analysis. In the C O stretching region, the band shift to a higher wavenumber taking place during the crystallizatio…
Thermal decomposition of the molecular single-source precursor (PPh 3 ) 2 CuIn(SEt) 4 in the presence of hexanethiol in dioctylphthalate forms colloidal CuInS 2 at 200 °C. The colloidal solution displays size-dependent quantum confinement behavior in the absorption and photoluminescence spectra. The average size of th…
Preface. List of Contributors. Polymer Brushes: On the Way to Tailor-Made Surfaces (Jurgen Ruhe). 1 Growth of Polymer Molecules at Surfaces: Introductory Remarks. 2 Coatings: First Principles to High-Tech Applications. 3 Surface-Coating Techniques. 4 Surface-Attached Polymers. 5 Polymer Brushes: General Features. 6 Th…
We report on the use of dopamine (DA) as a robust molecular anchor to link functional molecules to the iron oxide shell of magnetic nanoparticles. Using nitrilotriacetic acid (NTA) as the functional molecule, we created a system with an M/Fe2O3-DA-NTA (M = Co or SmCo5.2) nanostructure, which possesses high stability a…