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MA: Fachverband Magnetismus
MA 6: Invited Talks Hehn / Eimüller
MA 6.2: Hauptvortrag
Montag, 23. März 2009, 14:30–15:00, HSZ 04
Magnetic imaging at the limits of space and time — •Thomas Eimüller1,2, Wei He1, Jie Li1, Min-Sang Lee1, Björn Redeker1, and Stefan Buschhorn3 — 1Nachwuchsgruppe Magnetische Mikroskopie, Ruhr-Universität Bochum, 44780 Bochum — 2Hochschule Kempten, University of Applied Sciences, Bahnhofstr. 61, 87435 Kempten — 3Institut für Experimentalphysik IV, Ruhr-Universität Bochum, 44780 Bochum
Magnetic technology, driven by "smaller and faster" aims for magnetic imaging methods that obtain simultaneously a high spatial and temporal resolution. For decades this was the domain of optical microscopy. However, recently synchrotron techniques emerged which combine a lateral resolution down to 15 nm with elemental, chemical, spin, and orbital selectivity. Full field (TXM) and scanning (STXM) transmission x-ray microscopy as well as photoemission electron microscopy (X-PEEM) have been used for dynamic magnetic imaging.
Nevertheless, the highest temporal resolution, down to about 200 fs can be obtained by femtosecond laser scanning Kerr microscopy. All-optical two-colour pump-probe experiments reveal variations in the magnetization dynamic of different magnetic dots in arrays. The large temporal resolution enables us to observe higher harmonics of spin waves and nonlinear coupling phenomena in permalloy films. Special coating techniques allow studying the magnetization dynamics of dots with a size below the optical diffraction limit.
Financial support by the DFG via project SFB491-N1 is gratefully acknowledged.