Searched for:
(1 - 20 of 46)

Pages

document
Skarsvag, H. (author), Bauer, G.E.W. (author), Brataas, A. (author)
We study the dynamics of spin valves consisting of two layers of magnetic insulators separated by a normal metal in the macrospin model. A current through the spacer generates a spin Hall current that can actuate the magnetization via the spin-transfer torque. We derive expressions for the effective Gilbert damping and the critical currents for...
journal article 2014
document
Qaiumzadeh, A. (author), Bauer, G.E.W. (author), Brataas, A. (author)
We investigate the nonresonant all-optical switching of magnetization. We treat the inverse Faraday effect (IFE) theoretically in terms of the spin-selective optical Stark effect for linearly or circularly polarized light. In the dilute magnetic semiconductors (Ga,Mn)As, strong laser pulses below the band gap induce effective magnetic fields of...
journal article 2013
document
Brataas, A. (author), Tserkovnyak, Y. (author), Bauer, G.E.W. (author)
The magnetization dynamics of ferromagnets is often formulated in terms of the Landau-Lifshitz-Gilbert (LLG) equation. The reactive part of this equation describes the response of the magnetization in terms of effective fields, whereas the dissipative part is parametrized by the Gilbert damping tensor. We formulate a scattering theory for the...
journal article 2011
document
Bandopadyay, S. (author), Brataas, A. (author), Bauer, G.E.W. (author)
The miniaturization of magnetic read heads and random access memory elements makes them vulnerable to thermal fluctuations. We demonstrate how current-induced spin-transfer torques can be used to suppress the effects of thermal fluctuations. This enhances the fidelity of perpendicular magnetic spin valves. The simplest realization is a dc to...
journal article 2011
document
Morten, J.P. (author), Brataas, A. (author), Bauer, G.E.W. (author), Belzig, W. (author), Tserkovnyak, Y. (author)
The injection of pure spin current into superconductors by the dynamics of ferromagnetic contact is studied theoretically. Taking into account the suppression of the order parameter at the interfaces (inverse proximity effect) and the energy-dependence of spin-flip scattering, we determine the temperature-dependent ferromagnetic resonance...
journal article 2010
document
Starikov, A.A. (author), Kelly, P.J. (author), Brataas, A. (author), Tserkovnyak, Y. (author), Bauer, G.E.W. (author)
Using a formulation of first-principles scattering theory that includes disorder and spin-orbit coupling on an equal footing, we calculate the resistivity ?, spin-flip diffusion length lsf, and Gilbert damping parameter ? for Ni1-xFex substitutional alloys as a function of x. For the technologically important Ni80Fe20 alloy, Permalloy, we...
journal article 2010
document
Bauer, G.E.W. (author), Bretzel, S. (author), Brataas, A. (author), Tserkovnyak, Y. (author)
We present the linear-response matrix for a sliding domain wall in a rotatable magnetic nanowire, which is driven out of equilibrium by temperature and voltage bias, mechanical torque, and magnetic field. An expression for heat-current-induced domain-wall motion is derived. Application of Onsager’s reciprocity relation leads to a unified...
journal article 2010
document
Bretzel, S. (author), Bauer, G.E.W. (author), Tserkovnyak, Y. (author), Brataas, A. (author)
The Barnett effect refers to the magnetization induced by rotation of a demagnetized ferromagnet. We describe the location and stability of stationary states in rotating nanostructures using the Landau–Lifshitz–Gilbert equation. The conditions for an experimental observation of the Barnett effect in different materials and sample geometries are...
journal article 2009
document
Foros, J. (author), Brataas, A. (author), Bauer, G.E.W. (author), Tserkovnyak, Y. (author)
The interplay between current and magnetization fluctuations and dissipation in layered-ferromagnetic-normal-metal nanostructures is investigated. We use scattering theory and magnetoelectronic circuit theory to calculate charge and spin-current fluctuations. Via the spin-transfer torque, spin-current noise causes a significant enhancement of...
journal article 2009
document
Xiao, J. (author), Bauer, G.E.W. (author), Maekawa, S. (author), Brataas, A. (author)
Spin pumping by a moving magnetization gives rise to an electric voltage over a spin valve. Thermal fluctuations of the magnetization manifest themselves as increased thermal voltage noise with absorption lines at the ferromagnetic resonance frequency and/or zero frequency. The effect depends on the magnetization configuration and can be of the...
journal article 2009
document
Foros, J. (author), Brataas, A. (author), Tserkovnyak, Y. (author), Bauer, G.E.W. (author)
In the presence of spatial variation in the magnetization direction, electric current noise causes a fluctuating spin-transfer torque that increases the fluctuations of the ferromagnetic order parameter. By the fluctuationdissipation theorem, the fluctuations at thermal equilibrium are related to the viscous magnetization damping, which in...
journal article 2008
document
Brataas, A. (author), Tserkovnyak, Y. (author), Bauer, G.E.W. (author)
The magnetization dynamics of a single domain ferromagnet in contact with a thermal bath is studied by scattering theory.We recover the Landau-Liftshitz-Gilbert equation and express the effective fields and Gilbert damping tensor in terms of the scattering matrix. Dissipation of magnetic energy equals energy current pumped out of the system by...
journal article 2008
document
Xiao, J. (author), Bauer, G.E.W. (author), Brataas, A. (author)
We study the bias-dependent spin-transfer torque in magnetic tunnel junctions in the Stoner model by scattering theory. We show that the in-plane (Slonczewski type) torque vanishes and subsequently reverses its direction when the bias voltage becomes larger or the barrier wider than material and device-dependent critical values. We are able to...
journal article 2008
document
Xiao, J. (author), Bauer, G.E.W. (author), Brataas, A. (author)
We study theoretically the charge transport pumped by magnetization dynamics through epitaxial FIF and FNIF magnetic tunnel junctions (F, ferromagnet; I, insulator; N, normal metal). We predict a small but measurable dc pumping voltage under ferromagnetic resonance conditions for collinear magnetization configurations, which may change sign as a...
journal article 2008
document
Kovalev, A.A. (author), Bauer, G.E.W. (author), Brataas, A. (author)
journal article 2007
document
Foros, J. (author), Brataas, A. (author), Bauer, G.E.W. (author), Tserkovnyak, Y. (author)
journal article 2007
document
Wang, X. (author), Bauer, G.E.W. (author), Van Wees, B.J. (author), Brataas, A. (author), Tserkovnyak, Y. (author)
A ferromagnet can resonantly absorb rf radiation to sustain a steady precession of the magnetization around an internal or applied magnetic field. We show that, under these ferromagnetic resonance conditions, a dc voltage is generated at a normal-metal electric contact to a ferromagnet with spin-flip scattering. The spin dynamics in the...
journal article 2006
document
Tserkovnyak, Y. (author), Skadsem, H.J. (author), Brataas, A. (author), Bauer, G.E.W. (author)
Current-driven magnetization dynamics in ferromagnetic metals is studied in a self-consistent adiabatic local-density approximation in the presence of spin-conserving and spin-dephasing impurity scattering. Based on a quantum kinetic equation, we derive Gilbert damping and spin-transfer torques entering the Landau-Lifshitz equation to linear...
journal article 2006
document
Kovalev, A.A. (author), Bauer, G.E.W. (author), Brataas, A. (author)
journal article 2006
document
Brataas, A. (author), Tserkovnyak, Y. (author), Bauer, G.E.W. (author)
journal article 2006
Searched for:
(1 - 20 of 46)

Pages