Regensburg 2000 – scientific programme

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AM: Magnetismus

AM 1: Mikromagnetismus, Magnetisierungsprozesse und Domänenstrukturen I

AM 1.7: Talk

Monday, March 27, 2000, 11:15–11:30, H10

Magnetization Dynamics in a Small Cobalt Dot — •Yves Acremann, Danilo Pescia, and Christian Back — Laboratorium für Festkörperphysik,Eidgenössische Technische Hochschule Zürich, CH-8093 Zürich, Switzerland

We have used time-resolved scanning Kerr microscopy to study the response of the magnetization in a single, lithographically patterned Co disk when subjected to fast rise time magnetic field pulses. A 20 nm thick Co dot of 6 micron diameter is placed in a lithographically defined single turn coil. Fast perpendicular field pulses with sub 100 ps risetimes are generated using an optical switch.

The initial fast rise time causes the magnetization to tilt out of the plane of the film. The film subsequently relaxes back into the plane, showing damped oscillatory behavior. In addition to simple time domain measurements we can also monitor a nonuniform spatial evolution of the magnetization by recording images at a fixed position in time.