Regensburg 2013 – scientific programme

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DS: Fachverband Dünne Schichten

DS 25: Focus Session: Magnetic Damping Phenomena in Thin Films and Nanostructures (jointly with MA)

DS 25.5: Topical Talk

Wednesday, March 13, 2013, 17:00–17:30, H10

Spin dynamics and relaxation in ferrimagnets — Frank Schlickeiser, Sönke Wienholdt, Denise Hinzke, and •Ulrich Nowak — Universität Konstanz, 78457 Konstanz, Germany

Recent experiments on all-optical switching in GdFeCo [1] have focused much attention on the spin dynamics of ferrimagnets. The understanding of relaxation mechanisms is here even more complicated than in a ferromagnet due to the fact that the two sublattices of the ferrimagnet can exchange energy and angular momentum without dissipation, keeping the total energy and angular momentum constant.

We discuss the theory of the dynamics of ferrimagnets on different length scales, ranging from microscopic spin models to mesoscopic descriptions with a two-sublattice Landau-Lifshitz-Bloch equation. Our results for the temperature dependence of the frequencies and effective damping parameters of the normal modes represent a generalization and improvement of formetwo-sublatticer approximated solutions [2]. Furthermore, we discuss the role of angular momentum conservation and dissipation for the recently discovered transient ferromagnetic-like state [3 ] and for the pure thermal switching of ferrimagnets [4].

This work received funding from the EC (Collaborative Project FEMTOSPIN) and from the CAP at the University of Konstanz.

[1] K. Vahaplar et al., Phys. Rev. Lett. 103, 117201 (2009).

[2] F. Schlickeiser et al., Phys. Rev. B, in press.

[3] I. Radu et al., Nature 472, 205 (2011).

[4] T. A. Ostler et al., Nat. Commun. 3, 666 (2012).