Berlin 2005 – wissenschaftliches Programm
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MA: Magnetismus
MA 8: Spindynamik I
MA 8.11: Vortrag
Freitag, 4. März 2005, 17:45–18:00, TU H1028
Time resolved magnetization dynamics of ultrathin Fe(001) films: Spin-pumping and two-magnon scattering — •Georg Woltersdorf1,2, Matthias Buess1, Christian Back1, and Bret Heinrich2 — 1Universität Regensburg, Universitätsstraße 31, 93040 Regensburg Germany — 2Simon Fraser University 8888 University Drive V5A 1S6 Burnaby BC Canada
The time resolved magnetic response of ultrathin epitaxial Fe(001) grown on GaAs(001) and covered by Au, Pd, and Cr capping layers was investigated by time and spatially resolved Kerr effect measurements. The multilayer structures were prepared by Molecular Beam Epitaxy on GaAs(001) substrates. The magnetization was excited by an in-plane magnetic field pulse while the wavelength of the excitation (resonant mode) was roughly 2 µm. Each of the three capping layer represents a unique case of spin dynamics. Au cap layers resulted in the Fe bulk Gilbert damping. Pd cap layers caused an additional Gilbert damping due to spin-pump/spin-sink effects. Cr cap layers lead to a strong extrinsic damping which can be described by two-magnon scattering. The strength of the extrinsic damping can be controlled by shifting the spin manifold with respect to the excited k-vector using an external bias field.