Berlin 2008 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 19: Spin Dynamics / Spin Torque I
MA 19.5: Vortrag
Mittwoch, 27. Februar 2008, 15:00–15:15, EB 301
Investigation of spin-wave radiation and current controlled three-magnon-scattering in spin-torque nanocontact devices — •Helmut Schultheiß1, Xavier Janssens2, Sven Cornelissen2, Maarten van Kampen2, Sebastian Hermsdörfer1, Britta Leven1, Andrei N. Slavin3, Liesbet Lagae2, and Burkard Hillebrands1 — 1Fachbereich Physik and FSP MINAS, TU Kaiserslautern, 67663 Kaiserslautern, Germany — 2IMEC, Kapeldreef 75, Leuven, Belgium — 3Oakland University, Rochester, Michigan, USA
The magnetization dynamics of spin torque oscillators are of large interest for the fundamental understanding of the interaction between a spin polarized current and a magnetic thin film. Here we report on Brillouin light scattering microscopy investigations of the magnetization dynamics in spin-torque nanocontacts under the influence of an applied ac and dc current. The spin-wave radiation patterns are studied for several applied microwave frequencies. Strong nonlinear effects are observed and discussed within the framework of three-magnon-scattering. Intriguing is the shift of the power threshold for these nonlinear processes when a dc current is applied. Depending on the dc current direction the threshold and efficiency of the three-magnon-scattering can be strongly enhanced or reduced. This is a clear evidence that the internal damping due to magnon scattering can be tuned by a dc current. Support by the DFG within the SPP 1133 and by the EC-MRTN SPINSWITCH (MRTN-CT-2006-035327) and EC-Dynamax (IST-033749) is acknowledged. MvK acknowledges the IWT Flanders for financial support.