Berlin 2012 – scientific programme

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MA: Fachverband Magnetismus

MA 26: Micromagnetism / Computational Magnetics

MA 26.4: Talk

Wednesday, March 28, 2012, 11:30–11:45, H 0112

Temperature dependence of normal modes of ferrimagnets — •Frank Schlickeiser¹, Unai Atxitia², Soenke Wienholdt¹, Denise Hinzke¹, Oksana Chubykalo-Fesenko², and Ulrich Nowak¹ — ¹University of Konstanz, Germany — ²Institute of material science Madrid, Spain

Recently, opto magnetic writing using a circularly polarised laser pulse in the 40 femtosecond range was successfully demonstrated [1-3]. It is assumed that the magnetisation switching is forced by a combination of a heat pulse and a magnetic field created due to the inverse Faraday effect. However, so far this effect has only been found for a special class of materials as the ferrimagnet GdFeCo. The reason for this restriction is not fully understood yet and therefore of great interest. We investigate the dynamics of a ferrimagnet by means of computer simulations as well as analytically, where the behaviour of the precession frequency as well as the effective damping parameter of the ferromagnetic and exchange mode is investigated. Both approaches coincide well for different strengths of an external magnetic field as well as for different strengths of an uni axial anisotropy. Our results, representing a generalisation and improvement of former approximated solutions (e.g.[4]), therefore build a basis for a better theoretical comparison to recent experiments[5]. [1] C.D.Stanciu et al., Phys. Rev. Lett.99, 047601 (2007), [2] A.V. Kimel, C. D. et al., Nature 435, 655 (2010), [3] K.Vahaplar et al., Phys. Rev. Lett. 103, 117201 (2009), [4] R.Wangsness, Phys. Rev. B 93, 68 (1954), [5] C.D.Stanciu et al., Phys. Rev. B 73 , 220402 (2006).