Invited Paper MI+NC-TuA10
Magnetization Damping in Magnetic Multilayers

Tuesday, October 21, 2008, 4:40 pm, Room 206

For the application of magnetic multilayers in spintronic devices the magnetization relaxation is of great importance. Of particular practical interest are multilayers which include an exchange biased ferromagnet, i.e. a ferromagnet/antiferromagnet bilayer system for which the hysteresis loop of the ferromagnet can be shifted along the field axis. In comparison to bulk properties the magnetization relaxation in thin magnetic films can be enhanced for example by spin-pumping and two-magnon scattering due to local inhomogeneities. We investigated the magnetization relaxation in metallic ferromagnet/antiferromagnet based multilayer systems, using broadband ferromagnetic resonance measurements. By inserting a thin non-magnetic spacer layer, we find that spin-pumping contributes significantly to the damping in these multilayers, even for structures with no shift of the hysteresis loop. However, in exchange biased systems we observe a strong additional contribution to the magnetization relaxation.