Magnetic Field. (magnetic + field)

Distribution by Scientific Domains


Selected Abstracts


Silicon transport under rotating and combined magnetic fields in liquid phase diffusion growth of SiGe

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 4 2010
N. Armour
Abstract The effect of applied rotating and combined (rotating and static) magnetic fields on silicon transport during the liquid phase diffusion growth of SiGe was experimentally studied. 72-hour growth periods produced some single crystal sections. Single and polycrystalline sections of the processed samples were examined for silicon composition. Results show that the application of a rotating magnetic field enhances silicon transport in the melt. It also has a slight positive effect on flattening the initial growth interface. For comparison, growth experiments were also conducted under combined (rotating and static) magnetic fields. The processed samples revealed that the addition of static field altered the thermal characteristics of the system significantly and led to a complete melt back of the germanium seed. Silicon transport in the melt was also enhanced under combined fields compared with experiments with no magnetic field. ( 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


The low-energy electronic properties of graphene ribbons in spatially modulated magnetic fields

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 12 2008
J. Y. Wu
Abstract The low energy magnetoelectronic structures for a nanographene ribbon under modulated magnetic fields are investigated through the Peierls tight-binding model. They are dominated by the field strength, period, phase, the ribbon width, and edge structure. The modulated magnetic field could add state degeneracy, modify energy dispersions, alter subband spacings, affect carrier-density distributions, create additional band-edge states, and extend the partial flat bands. The main features of energy bands are directly reflected in density of states, such as the position, the height, the structure, and the number of the prominent peaks. These results are compared with a zigzag ribbon under a uniform magnetic field. ( 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Spin orientation of excitons, trions and tetraons in charge tunable InP quantum dots

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2009
Yasuaki Masumoto
Abstract In the longitudinal magnetic field, photoluminescence (PL) polarization in InP quantum dots (QDs) dramatically changed depending on the number of doped electrons. Under linearly polarized excitation, PL polarizes resonantly at two magnetic fields where bright and dark excitons anticross each other in neutral QDs. On the other hand, PL polarization monotonously increases with the increase of longitudinal magnetic field in one- and two-electron doped QDs, where thermal spin orientation of a photoexcited hole determines the PL polarization of a trion and a tetraon. At low temperatures, however, the electron-hole exchange interaction reduces the thermal spin orientation of holes. In two-electron doped QDs, the anisotropic electron-hole exchange interaction gives small structure in the magnetic-field-dependent circular polarization at the low field region. Time-resolved circular polarization clearly shows the dynamical spin polarization process in charged QDs in the longitudinal magnetic field. ( 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Linear polarization in small radio sources

ASTRONOMISCHE NACHRICHTEN, Issue 5-6 2006
A. Rossetti
Abstract Polarimetric observations at 5 and 8.4 GHz have been performed for 3 CSS quasars. These observations are part of a programme aimed at studying the polarization characteristics of the core regions, jets, and lobes in such objects and at possibly finding of jet-cloud interactions in CSSs. The behaviour of the fractional polarization and of the observed polarization angle as a function of ,2 provides information on the density distribution of the ISM embedding the radio source, on its clumpiness and on the ordered and random components of the interstellar magnetic field. ( 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Gamma-convergence of gradient flows with applications to Ginzburg-Landau

COMMUNICATIONS ON PURE & APPLIED MATHEMATICS, Issue 12 2004
Etienne Sandier
We present a method to prove convergence of gradient flows of families of energies that ,-converge to a limiting energy. It provides lower-bound criteria to obtain the convergence that correspond to a sort of C1 -order ,-convergence of functionals. We then apply this method to establish the limiting dynamical law of a finite number of vortices for the heat flow of the Ginzburg-Landau energy in dimension 2, retrieving in a different way the existing results for the case without magnetic field and obtaining new results for the case with magnetic field. 2004 Wiley Periodicals, Inc. [source]