Berlin 2012 – scientific programme
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MA: Fachverband Magnetismus
MA 34: Magnetization / Demagnetization Dynamics III
MA 34.10: Talk
Wednesday, March 28, 2012, 17:30–17:45, H 1012
Precessional dynamics and damping in Co/Cu/Py spin valves — •Ruslan Salikhov1, Radu Abrudan1, Frank Brüssing1, Stefan Buschhorn1, Melanie Ewerlin1, Durga Mishra1, Florin Radu2, Ilgiz A. Garifullin3, and Hartmut Zabel1 — 1Ruhr-Universität Bochum, Germany — 2Helmholtz-Zentrum Berlin, Germany — 3Zavoisky Physical-Technical Institute, Kazan, Russia
We have studied Co/Cu/Py (where Py = Ni81Fe19) spin valve systems with different thicknesses of Cu-spacer layers (25 and 40 nm) using the Time-Resolved X-ray Resonant Magnetic Scattering at the synchrotron radiation facility BESSY II of the HZB. This method enables the detection of the free precessional decay of the magnetization of ferromagnetic (F) films in response to a field pulse excitation [St. Buschhorn, et. al., J. Phys. D 44, 165001 (2011)]. We have found that the magnetic precessional decay time of Fe magnetic moments in Py layers decreases when changing the mutual orientation of the magnetization direction of Py and Co layers from parallel (P) to antiparallel (AP). Taking into account all possible mechanisms which can cause the observed effect in our samples where the exchange interaction between F-layers is negligible, we suppose that the increase of damping for AP orientation of magnetizations is associated with the spin-pumping-induced damping effect. The observed orientational dependence of the damping of free F-layer in the spin valves due to spin pumping was predicted theoretically by Kim and Chappert [J.-V. Kim, C. Chappert, JMMM 286, 56 (2005)] and until now there was no experimental evidence for this effect in the literature.