Berlin 2012 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MA: Fachverband Magnetismus
MA 23: Magnetization / Demagnetization Dynamics II
MA 23.6: Vortrag
Mittwoch, 28. März 2012, 11:00–11:15, H 1012
Magnetic Anisotropy and Damping of Rare-Earth Doped Permalloy — •Christoph Zollitsch1, Fredrik Hocke1, Mathias Weiler1, Rudolf Gross1,2, Georg Woltersdorf3, Jahn-Ulrich Thiele4, Sebastian T.B. Goennenwein1, and Hans Huebl1 — 1Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching — 2Physik-Department, Technische Universität München, Garching — 3Physik-Department, Universität Regensburg, Regensburg — 4Seagate Technology, Fremont, CA, USA
Understanding and engineering the magnetization damping of magnetic materials is of considerable interest both from a fundamental physics perspective and for applications. Of particular importance are low damping materials such as Permalloy (Ni80Fe20) and Yttrium Iron Garnet. We study the temperature dependent behavior of the ferromagnetic resonance (FMR) of Ni80Fe20 doped with 1at.% Ho. At room-temperature the FMR dispersion is not altered by the dopant. The latter only leads to an increased damping with respect to the undoped Ni80Fe20 as expected in the frame of the slow relaxation mechanism [1]. At around 100 K the FMR is suppressed due to the efficient damping by the Ho dopant. In the temperature regime below 100 K which was previously not studied, the dispersion shifts to higher frequencies by 14 GHz, while the damping reduces to its initial magnitude. This is attributed to an increase in the magnetic moment of Ho in combination with its thermal population.
[1] G. Woltersdorf, et al., Phys. Rev. Lett. 102, 257602 (2009)