Dresden 2003 – wissenschaftliches Programm

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MA: Magnetismus

MA 10: Magnetische Abbildungsverfahren

MA 10.8: Vortrag

Dienstag, 25. März 2003, 12:00–12:15, HSZ/04

TIME-RESOLVED WIDE-FIELD KERR MICROSCOPY — •Dmitry Chumakov, Jeffrey McCord, Rudolf Schäfer, and Ludwig Schultz — IFW-Dresden, Helmholtzstr. 20, 01069 Dresden

In this presentation we share our first results on time-resolved wide-field imaging of fast magnetization processes in thin film elements. We use a stroboscopic technique to image the magnetization reversal as the elements are exposed to a pulsed magnetic field in the nanosecond timescale. The system is based on a conventional Kerr microscope with a gated CCD camera providing a temporal resolution down to 200 ps. The precession of magnetic moments causes strong differences between quasistatic and dynamic reversal processes. We compare these two kinds of magnetization switching for different element shapes and excitation fields. In all cases well-defined domain structures are observed. However, the exact way of domain generation and breakdown is different. In the quasistatic case we observe a collapse of concertina structure by domain wall movement, in the dynamic case a No-dqmeltingNo-dq of the concertina with the passage of time is found.