Precessional dynamics and damping in Co/Cu/Py spin valves

We have studied the precessional dynamics of Co/Cu/Py (where Py = Ni81Fe19) trilayers by time-resolved x-ray resonant magnetic scattering at the synchrotron radiation facility BESSY II. 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 to antiparallel. The observed changes of the decay time can be associated with the spin pumping induced damping effect. (C) 2011 American Institute of Physics. [doi:10.1063/1.3633115]