Berlin 2008 – scientific programme
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MA: Fachverband Magnetismus
MA 32: Postersession II: Spinstruct./Phase Trans. (1-10); Spinelectronics (11-15); Thin Films (16 - 36); Particles/Clusters (37-45); Multiferroics (46-54); Spindynamics/Spin Torque (55 - 76); Post Deadlines (77-79)
MA 32.57: Poster
Friday, February 29, 2008, 11:15–14:00, Poster E
Magnetization dynamics triggered by THz magnetic field pulses — •Jakob Walowski1, Zhao Wang1, Benjamin Lenk1, Malte Scherff1, Markus Münzenberg1, Mihail I. Lepsa2, and Arno Förster3 — 1IV. Physikalisches Institut, Universität Göttingen, Germany — 2Forschungszentrum Jülich (IBN-1) — 3Fachhochschule Aachen
A gapped Al strip line structured on low temperature GaAs delivers a metal-semiconductor-metal contact, which acts as a fast photo conductive switch. Using ultrashort light pulses (∼60 fs) from a Ti:Sapphire laser (pump beam), excites the carriers of the semiconductor (GaAs) and induces short electric pulses. A short magnetic pulse (1−5 ps, ∼400 mT, ∼20 mA depending on the gap shape) is generated during the current. This pulse triggers the magnetization dynamics of a thin film structured on top of the Al strip line. Changing the path length of the laser pump beam one can probe the magnetization dynamics by recording the Kerr rotation up to 1 ns after excitation (TRMOKE).
Increasing the area of the contact, by structuring the strip line interruption in a finger like shape, increases the current pulse and therewith the field pulse strength and delivers shorter pulses. A sub 10 ps response of the magnetic film is shown.
Research supported by DFG SPP 1133