Regensburg 2010 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 14: Spin Dynamics / Spin Torque I
MA 14.3: Vortrag
Mittwoch, 24. März 2010, 10:15–10:30, H10
Magnetisation dynamics of ferrimagnets close to the compensation point — •Ulrich Nowak1, Thomas Ostler2, Denise Hinzke1, Stefan Gerlach1, and Roy W. Chantrell2 — 1Universität Konstanz, 78457 Konstanz — 2University of York, York YO10 5DD, U. K.
Recently it was demonstrated that a circularly polarised laser pulse in the 100 femtosecond range is able to reverse the magnetisation of the ferrimagnet GdFeCo [1,2]. It was concluded that the laser pulse leads to a combined magnetic field and heat pulse, resulting in the magnetisation switching [3]. However, so far this so-called opto-magnetic writing was only successfully demonstrated for the above class of materials. The reason for this restriction is not clear though it was speculated that the special properties of a ferrimagnet close to its compensation point could be relevant.
Therefore we investigate the dynamics of a ferrimagnet close to its angular momentum compensation point by means of computer simulations. We solve the stochastic Landau-Lifshitz-Gilbert equation for a generic, atomistic model of a ferrimagnet. The temperature dependence of the precession frequency as well as the effective damping constant is investigated. The results are compared with earlier analytical results as well as recent experiments [5].
[1] A. V. Kimel et al., Nature 435, 655 (2005) [2] C. D. Stanciu et al., Phys. Rev. Lett. 99, 047601 (2007) [3] K. Vahaplar et al., Phys. Rev. Lett. 103, 117201 (2009) [4] N. Kazantseva et al., Europhys. Lett. 86, 27006 (2009) [5] C. D. Stanciu et al., Phys. Rev. B, 73, 220402 (2006).