Dresden 2014 – scientific programme
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MA: Fachverband Magnetismus
MA 22: Magnetization Dynamics I
MA 22.10: Talk
Wednesday, April 2, 2014, 12:00–12:15, HSZ 401
Spin transfer in Au/Fe/MgO(001) structures by optically excited hot carrier transport — •Alexandr Alekhin1, Damian Bürstel2, Tim O. Wehling3, Detlef Diesing2, Ivan Rungger4, Maria Stamenova4, Stefano Sanvito4, Uwe Bovensiepen5, 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 Duisburg-Essen, Fakultät für Physik
Spin transfer induced by ultrashort laser pulses is of great importance in light of recent advances in spintronics and attempts to control magnetization on femtosecond (fs) time scales. Using 14 fs laser pulses in pump-probe experiments performed on the epitaxial Au/Fe/MgO(001) structures, we pump the Fe film to excite and inject spin-polarized hot carriers (HC) into the Au layer and probe the Au side of the samples to monitor transient bulk spin polarization (SP) by the magneto-optical Kerr effect (MOKE) and transient SP at the Au surface by the magneto-induced second harmonic generation (mSHG). Analyze of the transient MOKE and mSHG signals as functions of Au thickness let us study evolution of the HC packet and the spin current pulse and evaluate that the velocity of the ballistic fraction of the HC packet equals to 1.19 nm/fs which is close to the ballistic velocity of minority electrons in Au. Varying Fe thickness, we demonstrate the possibility to manipulate the ballistic fraction of the HC packet. DFG (ME 3570/1, Sfb 616) and EU 7-th framework program (CRONOS) are acknowledged.