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MA: Fachverband Magnetismus

MA 43: Magnetization Dynamics II of 3

MA 43.6: Vortrag

Donnerstag, 14. März 2013, 16:15–16:30, H22

Theory of Thermal Magnetization Switching in Rare-Earth-based Ferrimagnets — •Sönke Wienholdt¹, Denise Hinzke¹, Karel Carva², Peter Oppeneer³, and Ulrich Nowak¹ — ¹University of Konstanz, Germany — ²Charles University in Prague, Czech Republic — ³Uppsala University, Sweden

Recently it was demonstrated that a linearly polarized laser pulse is able to reverse the magnetization in ferrimagnetic GdFeCo on a purely thermal basis within a ps time scale [1,2]. Thermal opto-magnetic switching has so far only been obtained in rare-earth-based ferrimagnets like GdFeCo [1,2]. Hence it is assumed that the antiferromagnetic exchange interaction plays a role. Additionally the substanstially different demagnetization times of rare earths (RE) and transition metals (TM) [3,4] seems to be crucial [1,2]. Nevertheless the general mechanisms, especially the role of the highly non-equilibrium transient ferromagnetic-like state, are still up for debate. We developed an atomistic multi-band spin model for RE-based ferrimagnets, where we distinguish between d- and f-electrons in the RE [5]. Our numerical results show a transient ferromagnetic-like state of the right magnitude as well as the switching of the sublattices. We explain the origin of this by dissipationless dynamics occuring on a timescale below one ps.

[1] I. Radu et al., Nature 472, 205 (2011) [2] T.A. Ostler et al., Nat. Comm. 3, 666 (2012) [3] B. Koopmans et al., Nat. Mat. 9, 259 (2009) [4] M. Wietstruk et al., Phys Rev Lett. 106, 127401 (2011) [5] S. Wienholdt et al., submitted