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Rotating Magnetic Field (rotating + magnetic_field)
Selected AbstractsCrystal growth by the travelling heater method using tapered crucibles and applied rotating magnetic fieldCRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2010J. Roszmann Abstract Crystal growth experiments were carried out by the Travelling Heater Method using tapered growth ampoules with and without the application of a rotating magnetic field. The objective was to enhance its commercial potential by reducing the size of required seed crystals and increasing the growth rate. To this end, a number of GaSb crystals were grown using either 25 mm diameter straight, or 10 mm to 25 mm tapered growth ampoules. Growth rates of 2 mm/day and 5 mm/day were employed. The effect of rotating magnetic fields of several strengths and frequencies was examined. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Silicon transport under rotating and combined magnetic fields in liquid phase diffusion growth of SiGeCRYSTAL RESEARCH AND TECHNOLOGY, Issue 4 2010N. 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] New Developments in Vertical Gradient Freeze Growth,ADVANCED ENGINEERING MATERIALS, Issue 7 2004O. Pätzold The Vertical Gradient Freeze (VGF) technique is an important method for growing high quality compound semiconductors such as GaAs. Results obtained with a novel VGF set-up developed for the growth under influence of a rotating magnetic field (RMF) and under vapour pressure control are presented in this paper. The RMF is shown to be a powerful tool to affect the heat and mass transport within the melt in a definite way. In GaAs:Si growth, RMF induced flow results in a decreased curvature of a nominally concave-shaped interface, i.e., it contributes to an axial heat transfer at the solid-liquid interface. The axial dopant segregation of Ga in Ge is found to be improved under continuous RMF action due to better mixing of the melt. The set-up also allowed to determine the influence of carbon and the arsenic vapour pressure on the dopant incorporation and crystal quality. [source] Influence of transverse rotating magnetic field on enhancement of solid dissolution processAICHE JOURNAL, Issue 6 2010Rakoczy Abstract The main objective of this work is to study the effect of transverse rotating magnetic field (TRMF) on the enhancement of solid dissolution process in the novel type reactor (TRMFR). The application of magnetically driven fluidization (MDF with homogeneous and heterogeneous systems) on mass transfer process is presented. A study of the effect of ferromagnetic particles content on solid,liquid mass transfer has been made. The experimental investigations are provided for the explanation of the influence on the dissolution process of a solid body to surrounding its dilute solution in a novel type reactor with the ferromagnetic particles suspended. The mass transfer coefficient is calculated from a kinetic equation and correlated in the relationship including standard and magnetic dimensionless numbers. The overall enhancements due to TRMF and MDF were compared. Unique correlating relations were obtained to generalize the experimental database. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Quantum chemistry investigation of electronic structure and NMR spectral characteristics for fluorides of dialkylamidosulfoxylic acids and related compoundsMAGNETIC RESONANCE IN CHEMISTRY, Issue 9 2009A. B. Rozhenko Abstract The parent (H2NSF) and N,N -dialkyl-substituted fluorides of amidosulfoxylic acid (R2NSF, RMe or R2NMorph) as well as the related compounds XSF (XCH3, OH, F, SiH3, PH2, SH, Cl) have been investigated with quantum chemical calculations at the ab initio (MP2) level of approximation. The geometries, electronic structures, molecular orbital (MO) energies and NMR chemical shift values have been calculated to evaluate the role and extent of the polarization and delocalization effects in forming of the high-field fluorine NMR resonances within the series of interest. The ,F magnitudes for all investigated fluorides of amidosulfoxylic acid as well as the ,N value calculated for Me2NSF are in the good agreement with the 19F and 14N NMR chemical shift values measured experimentally. For the parent compounds, H2NSF and H2NSO2F, the orientation of principal axes of the magnetic shielding tensors and the corresponding principal ,ii values along these axes have been qualitatively interpreted basing on the analysis of the MO interactions in the presence of the rotating magnetic field. Copyright © 2009 John Wiley & Sons, Ltd. [source] Spin-decoherence effects on the pumped spin-dependent transport through a quantum dotPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 6 2009Hui Pan Abstract We theoretically study the spin-decoherence effects on the pumped spin-polarized current through a quantum dot subject to a rotating magnetic field and coupled to two ferromagnetic electrodes. The dependence of the current on the magnetic moment orientation angle of the two leads is greatly influenced by the spin pump and the spin decoherence. The spin pump destroys the normal spin-valve effects, and the spin decoherence makes the current exhibiting a quite complicated angle dependence. These distinct transport behaviors can be used as electrical schemes for detection of electron spin resonance and spin decoherence. Moreover, the current is closely related to the magnetic Rabi frequency and the detuning, in which the spin decoherence also plays an important role, and thus the pumped spin-polarized current can be used as a sensitive tool to measure these pumping parameters. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||