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SYET: Dynamics of electron transfer processes at surfaces

SYET 1: Dynamics of electron transfer processes at surfaces

SYET 1.2: Hauptvortrag

Donnerstag, 30. März 2006, 10:30–11:00, HSZ 04

Spin-dependent dynamics of electrons at ferromagnetic surfaces — •Martin Weinelt^1,2, Anke B. Schmidt^1,3, Martin Pickel⁴, and Markus Donath⁴ — ¹Max-Born-Institut, Max-Born-Straße 2A, 12489 Berlin, Germany — ²Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany — ³Universität Erlangen, Lehrstuhl für Festkörperphysik, Staudtstr. 7, 91058 Erlangen, Germany — ⁴Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany

Recent experiments demonstrated that significant demagnetization of ferromagnetic thin films upon laser excitation can be achieved within a few hundred femtoseconds. Which microscopic processes lead to the loss of magnetization remains, however, controversial.

Our approach is to find possible decay channels for demagnetization processes by studying the electron dynamics in a ferromagnet spin dependently. We combined ultrafast time-resolved spectroscopy with spin-resolved electron detection. Despite the loss of about four orders of magnitude in count rate due to the spin-selective detector, our experiment allows for a time-, energy, and angle-resolved analysis of majority- and minority-electron dynamics.

We could demonstrate that image-potential states in front of ultrathin ferromagnetic films provide a simple model system for a detailed investigation of spin-dependent scattering processes at surfaces.

[1] A.B. Schmidt, M. Pickel, M. Wiemhöfer, M. Donath, and M. Weinelt, Phys. Rev. Lett. 95, 107402 (2005).