Berlin 2005 – wissenschaftliches Programm
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O: Oberflächenphysik
O 25: Zeitaufgelöste Spektroskopie II
O 25.3: Vortrag
Samstag, 5. März 2005, 15:30–15:45, TU EB420
Spin-dependent electron dynamics in front of an ultrathin iron film — •Anke Schmidt1, Martin Pickel2, Martin Wiemhöfer2, Markus Donath2, and Martin Weinelt3 — 1Lehrstuhl für Festkörperphysik, Staudtstraße 7, 91058 Erlangen — 2Physikalisches Institut, Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster — 3Max-Born-Institut, Max-Born-Straße 2A, 12489 Berlin
Ultrafast demagnetisation of ferromagnetic thin films upon laser excitation is a phenomenon not yet fully understood. It is still controversial which processes lead to the loss of total magnetic moment. Two-photon photoemission (2PPE) provides a powerful tool for the investigation of electron dynamics and the identification of scattering processes at surfaces [1].
We have studied the energetics and dynamics of exchange-split image-potential states on ultrathin iron films on Cu(100) with time-, energy-, and spin-resolved bichromatic 2PPE. We are able to observe the exchange splitting of the first and the second image-potential state directly. In time- and spin-resolved measurements, spin-dependent lifetimes were found. A linewidth analysis of the energy-resolved 2PPE-spectra shows spin-dependent dephasing, which indicates a spin-dependent elastic scattering process.
[1] K. Boger, M. Weinelt and Th. Fauster, Phys. Rev. Lett. 92, 126803 (2004)