Large-amplitude coherent spin waves exited by spin-polarized current in nanoscale spin valves
| Autor: | N. L. Gorn, Jack C. Sankey, Daniel C. Ralph, Dmitry Berkov, Robert A. Buhrman, Ilya Krivorotov, N. C. Emley |
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| Jazyk: | angličtina |
| Rok vydání: | 2007 |
| Předmět: |
Physics
Condensed Matter - Materials Science Condensed matter physics Spin polarization Condensed Matter - Mesoscale and Nanoscale Physics Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences Biasing Condensed Matter Physics Nanomagnet Electronic Optical and Magnetic Materials Amplitude Spin wave Excited state Mesoscale and Nanoscale Physics (cond-mat.mes-hall) Spin Hall effect Spin-½ |
| Popis: | We present spectral measurements of spin-wave excitations driven by direct spinpolarized current in the free layer of nanoscale Ir20Mn80/Ni80Fe20/Cu/Ni80Fe20 spin valves. The measurements reveal that large-amplitude coherent spin wave modes are excited over a wide range of bias current. The frequency of these excitations exhibits a series of jumps as a function of current due to transitions between different localized nonlinear spin wave modes of the Ni80Fe20 nanomagnet. We find that micromagnetic simulations employing the Landau-Lifshitz-Gilbert equation of motion augmented by the Slonczewski spin torque term (LLGS) accurately describe the frequency of the current-driven excitations including the mode transition behavior. However LLGS simulations give qualitatively incorrect predictions for the amplitude of excited spin waves as a function of current. 24 pages, 4 figures, submitted to Physical Review B; in the 1st revised version some references were corrected |
| Databáze: | OpenAIRE |
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