Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

MA: Fachverband Magnetismus

MA 35: Spin-Dynamics / Spin-Torque IV

MA 35.1: Vortrag

Donnerstag, 26. März 2009, 15:15–15:30, HSZ 04

Ultrafast Demagnetization of Lanthanide-Doped Permalloy Thin Films Studied with Time-Resolved Magneto-Optics — •Ilie Radu1,2, Matthias Kiessling1, Georg Woltersdorf1, Alexey Melnikov3, Uwe Bovensiepen3, Jan-Ulrich Thiele4, and Christian Back11Regensburg University, Regensburg, Germany — 2BESSY GmbH, Berlin, Germany — 3Free University Berlin, Berlin, Germany — 4Hitachi Global Storage, San Jose, CA, USA

The fs laser-induced magnetization dynamics of Permalloy thin films doped with Ho and Gd impurities is investigated by time-resolved magneto-optical Kerr effect. Varying the Ho concentration from 0% to 8% we observe a gradual change of the demagnetization time constant from approximately 60 fs to about 150 fs. In contrast, concentrations of Gd up to 15% do not affect the time scale of the demagnetization process. These results are at variance with recent theoretical work [1], that proposes a laser-induced demagnetization mechanism based on impurity- or phonon-assisted spin-flip scattering. We propose a demagnetization mechanism which relies on the strong magnetic inertia of the rare-earth dopant within the framework of the so-called slow relaxing impurity model [2,3].

[1] B. Koopmans et al., PRL 95, 267207 (2005); [2] J.H. van Vleck and R. Orbach, PRL 11, 65 (1963); [3] G. Woltersdorf et al., arXiv:0802.3206v2

100% | Bildschirmansicht | English Version | Kontakt/Impressum/Datenschutz
DPG-Physik > DPG-Verhandlungen > 2009 > Dresden