Berlin 2015 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 35: Magnetization / Demagnetization Dynamics II
MA 35.14: Vortrag
Mittwoch, 18. März 2015, 18:30–18:45, EB 301
Monitoring of spin-polarized hot carrier currents by time-resolved magneto-induced SHG in metallic multi-layers — Alexandr Alekhin1, Nikita Ilin1, Damian Bürstel2, Detlef Diesing2, Tim O. Wehling3, Ivan Rungger4, Maria Stamenova4, Stefano Sanvito4, Vladimir Roddatis5, Uwe Bovensiepen6, and •Alexey Melnikov1 — 1Fritz-Haber-Institut der MPG, Abt. Phys. Chemie — 2Universität Duisburg-Essen, Institut für Phys. Chemie — 3Universität Bremen, Theor. Phys. Institut — 4Trinity College Dublin, School of Physics and CRANN — 5Universität Göttingen, Institut für Materialphysik — 6Universität Duisburg-Essen, Fakultät für Physik
In metals, spin dynamics is non-local and determined by the transport of spin-polarized hot carriers (HC). We monitor resulting ultrafast variations of the magnetization in ferro- and the appearance of transient magnetization in paramagnetic layers by time-resolved MOKE. To get deeper insight in complex dynamics of the excited state, we complement MOKE by magneto-induced second harmonic generation (mSHG) which is sensitive to electron and magnetization dynamics at interfaces. In addition, it contains terms proportional (i.e. giving a direct access) to electric and spin currents in the bulk of metallic layers. Analyzing the response of Au/Fe/MgO(001) and Fe/Au/Fe/MgO(001) structures with varying layer thicknesses, we observe contributions from both charge/particle and spin components of HC currents within 300 fs after the excitation. The underlying mechanisms and related details of mSHG diagnostics are discussed. DFG (ME 3570/1, Sfb 616) and EU 7-th framework program (CRONOS) are acknowledged.