868 research outputs found
On a Taylor Weak Statement for Finite Element Computations in Gas Dynamics
The Taylor Weak Statement has been developed as a potential unified approach for approximate computation of fluid flows. It is verified to contain a variety of numerical dissipative methods developed for advection problems by specific identification of its expansion parameters. Generalized Fourier modal analysis has been completed in one space dimension for both semi-and fully-discrete approximations, from which the flux limiter method is herein developed and evaluated for finite element computations. Its application to 1- and 2-dimensional scalar models is investigated for continuous and discontinuous initial value problems, and its use for the Euler equation system of gas dynamics in 1- and 2-dimensional cases is demonstrated
Spin-orbit torques from interfacial spin-orbit coupling for various interfaces
We use a perturbative approach to study the effects of interfacial spin-orbit
coupling in magnetic multilayers by treating the two-dimensional Rashba model
in a fully three-dimensional description of electron transport near an
interface. This formalism provides a compact analytic expression for
current-induced spin-orbit torques in terms of unperturbed scattering
coefficients, allowing computation of spin-orbit torques for various contexts,
by simply substituting scattering coefficients into the formulas. It applies to
calculations of spin-orbit torques for magnetic bilayers with bulk magnetism,
those with interface magnetism, a normal metal/ferromagnetic insulator
junction, and a topological insulator/ferromagnet junction. It predicts a
dampinglike component of spin-orbit torque that is distinct from any intrinsic
contribution or those that arise from particular spin relaxation mechanisms. We
discuss the effects of proximity-induced magnetism and insertion of an
additional layer and provide formulas for in-plane current, which is induced by
a perpendicular bias, anisotropic magnetoresistance, and spin memory loss in
the same formalism.Comment: 24 pages, 9 figure
Prediction of Giant Spin Motive Force due to Rashba Spin-Orbit Coupling
Magnetization dynamics in a ferromagnet can induce a spin-dependent electric
field through spin motive force. Spin current generated by the spin-dependent
electric field can in turn modify the magnetization dynamics through
spin-transfer torque. While this feedback effect is usually weak and thus
ignored, we predict that in Rashba spin-orbit coupling systems with large
Rashba parameter , the coupling generates the spin-dependent
electric field [\pm(\alpha_{\rm R}m_e/e\hbar) (\vhat{z}\times \partial
\vec{m}/\partial t)], which can be large enough to modify the magnetization
dynamics significantly. This effect should be relevant for device applications
based on ultrathin magnetic layers with strong Rashba spin-orbit coupling.Comment: 4+ pages, 2 figure
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