Regensburg 2010 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 14: Spin Dynamics / Spin Torque I

MA 14.8: Vortrag

Mittwoch, 24. März 2010, 11:30–11:45, H10

Theoretical investigation of ultrafast laser-induced magnetization dynamics in small quantum mechanical systems — •Daria Popova, Andreas Bringer, and Stefan Blügel — Institut für Festkörperforschung & Institute for Advanced Simulation, Forschungszentrum Jülich, 52425 Jülich, Germany

Ultrafast optical control of the magnetic state of a medium is presently a subject of intense research. It is of importance for the development of novel concepts for high-speed magnetic recording and information processing. A series of experiments has revealed direct optical control on magnetization via inverse Faraday effect [1]. In these experiments femtosecond circularly polarized high-intensity laser pulses are used to excite the sample. Laser induced spin dynamics are investigated using the pump-probe technique. An open question is the evolution of the orbital momentum transferred from light to the medium, which defines the fundamental time limit on magnetic switching. In order to get insight into the magnetization dynamics we treat small quantum mechanical systems. In our work we begin from the investigation of a hydrogen atom excited by a femtosecond gauss-shaped polarized laser pulse. The connection between light and spin are introduced due to the spin-orbit coupling of the excited level. Solving the time-dependent Schroedinger equation using the Volterra iteration method we study the temporal behavior of spin and orbital momentum during and after the application of the pump and probe laser pulses. We are thankful for the financial support of the FANTOMAS project.

[1] A. V. Kimel et al., Nature 435, 655 (2005)