Dresden 2009 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
MA: Fachverband Magnetismus
MA 2: Spin-Dynamics / Spin-Torque I
MA 2.7: Vortrag
Montag, 23. März 2009, 12:30–12:45, HSZ 04
Oersted field influence on three-magnon-scattering processes in nanopoint contact spin-valves — •F. Ciubotaru1, H. Schultheiss1, A.A. Serga1, X. Janssens2, M. van Kampen2, L. Lagae2, B. Leven1, A.N. Slavin3, and B. Hillebrands1 — 1FB Physik and Forschungszentrum OPTIMAS, TU Kaiserslautern, Germany — 2IMEC, Leuven, Belgium — 3Oakland University, Rochester, MI, USA
Using Brillouin light scattering microscopy we have investigated the spin-wave emission from a point contact spin-valve structure driven by a combined microwave and dc current. The spin waves irradiated into a free Py layer by an 80 nm point contact were studied for several applied microwave frequencies and powers with and without influence of dc current We report on observation of several nonlinear effects, namely the generation of higher harmonics (2f, 3f) as well as spin-wave modes with a half-integer factor (0.5f, 1.5 f) relative to the driving microwave frequency f. These modes are associated with three-magnon-scattering processes. The appearance of the 0.5f mode presents a clear threshold behavior as a function of the applied microwave power. Moreover, the threshold shows a strong nonlinear dependence on the dc current. The threshold power was calculated within three-magnon-scattering theory taking into account the influence of the Oersted field created by the dc current. The theoretical and experimental results agree and show that the threshold properties of 0.5 mode are controlled by the Oersted field. Support from EC-MRTN SPINSWITCH (MRTN-CT-2006-035327) is gratefully acknowledged.