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MA: Magnetismus

MA 33: Spin-Dynamics, Magnetization Reversal III

MA 33.3: Vortrag

Donnerstag, 30. März 2006, 15:45–16:00, HSZ 403

Probing the Electron and Spin Dynamics of 3d-transition Elements in Real-Time — •Bernd Heitkamp, L. Heyne, H. A. Dürr, and W. Eberhardt — BESSY, Berlin, Germany

We report on pump-probe experiments investigating the physical properties of 3d transition elements. An intensive fs laser pump pulse is used to heat the electron system, which triggers a fast quenching of the magnetic moments. Observing the energy distribution of the hot electron and spin subsystem on a fs time scale after excitation gives a deep insight into the interplay of electron relaxation, spin-orbit coupling and spin-lattice relaxation. Time-resolution of the experiment is given by a fs-laser system. The photoelectron emission microscope (PEEM) allows to investigate structures with a spatial resolution well below one micrometer. Measuring the time-of-flight of the emitted photoelectrons by means of a delayline detector determines the energy resolution. In addition sensitivity to the photoelectron spin is given by SPLEED-detector. Experiments on Nickel and Cobalt show a demagnetization below one picosend while the electron subsystem is still not thermalized. Both the demagnetization and the relaxation are strongly affected by the dielectric response of the nanoscale structures.