Regensburg 2013 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 12: Focus Session: Terahertz Spintronics

MA 12.4: Topical Talk

Dienstag, 12. März 2013, 11:00–11:30, H10

Ultrafast spin dynamics induced by laser-generated spin currents in metallic multilayers probed by non-linear magneto-optics — •Alexey Melnikov — Fritz-Haber-Institut der MPG, Abt. Phys. Chemie, Faradayweg 4-6, 14195 Berlin

The ultrafast spin dynamics (SD) induced by a transport of spin-polarized carriers is a hot topic motivated by the fundamental interest in magnetic excitations and applications like spintronics and data storage. To understand underlying elementary processes typically occurring on femtosecond time scales, we have developed a time-of-flight-like approach that probes the SD induced by hot carriers (HC) and demonstrated a spin polarized HC transport through an epitaxial Au/Fe/MgO(001) structure. Optical second harmonic generated at the Au surface monitors the transient surface HC density and spin polarization. Using a back pump-front probe configuration, we establish that HC induced in Fe by the pump laser pulse can form a nearly ballistic spin current (SC) in the Au layer which works as spin-selective HC retarder/attenuator. First experiments on the SD induced by femtosecond SC pulses in Fe/Au/Fe/MgO(001) structures demonstrate the spin transfer between the two Fe layers and the Au spacer serving as a spin sink. We discuss the key role of spin-dependent interface scattering of HC in the excited SD and consider the extension of our experimental approach to the investigation of spin transfer torque effects induced by femtosecond SC pulses. Financial support by the DFG through ME 3570/1-1 is acknowledged.