Regensburg 2007 – scientific programme
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MA: Fachverband Magnetismus
MA 19: Spin-Dynamics/Switching I
MA 19.9: Talk
Wednesday, March 28, 2007, 17:15–17:30, H23
Magnetic damping in all-optical pump-probe experiments — •J. Walowski1, G. Müller1, M. Djordjevic Kaufmann1, M. Münzenberg1, and M. Kläui2 — 1IV. Phys. Inst., Universität Göttingen, Germany — 2Fachbereich Physik, Universität Konstanz, Germany
Magnetization dynamics of ferromagnetic films (FM) was studied with the help of an amplified 80 fs Ti:Sapphire laser system. The sample located in an external magnetic field Hext is demagnetized by an intensive pump laser pulse (>40 mJ/cm2). The magnetization relaxation is traced with a probe beam up to 1 ns after excitation.
The magnetic damping constant is investigated in the case of emission of spin currents on FM/NM interfaces (non-local damping) and spin scattering on nonmagnetic (NM) dopants.
For the non-local damping wedge shaped samples with Ni and Py are investigated for various spin sinks (Cu, Pd, Dy). It is found that the damping increases up to three times at thicknesses <10 nm of the FM layer.
In the case of spin scattering permalloy samples alloyed with low concentration of Dy and Pd were studied. The results show that the damping parameter depends on the alloy material and its percentage.
The nature of the different dissipation processes is further investigated.
Research is supported by DFG SPP 1133.