Dresden 2011 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 31: Magnetization Dynamics III

MA 31.1: Vortrag

Mittwoch, 16. März 2011, 11:00–11:15, HSZ 403

Atomistic Simulations of the Dynamaics of Antiferromagnets and Ferrimagnets — •Sönke Wienholdt¹, Frank Schlickeiser¹, Oksana Chubykalo-Fesenko², and Ulrich Nowak¹ — ¹Universität Konstanz, Germany — ²Instituto de Ciencia de Materiales de Madrid, Spain

So far, ultrafast all-optical magnetization switching has been demonstrated experimentally only in ferrimagnetic materials like GdFeCo[1]. A reason for this restriction seems to be the antiferromagnetic coupling of the two sub-lattices in these materials, which may lead to completely different dynamics as compared to a ferromagnet, combined with a strong, ultrashort magnetic field pulse induced by the inverse Faraday effect [2]. Also the heating by the laser pulse is assumed to play a crucial role in this process and it was speculated that the special properties of the ferrimagnet close to the compensation point could be relevant [3].

To understand the dynamics in these materials, we perform atomistic simulations of antiferromagnets as well as ferrimagnets, driven either by extern magnetic field pulses or variation of the spin temperature. We calculate the effective frequencies and damping parameters, compare them with experimental findings[4] and analytical results and investigate possible switching mechanisms as well as their typical timescales. [1] C.D. Stanciu et al., Phys. Rev. Lett., 99 (047601), 2007 [2] A.V. Kimel et al., Nature Physics, 5 (727 - 731), 2009 [3] K. Vahaplar et al., Phys. Rev. Lett. 103 (117201), 2009 [4] C.D. Stanciu et al., Phys. Rev. B, 73 (220402), 2006