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Femtosecond opto-magnetism : A key to novel mechanism of spin reorientation

This seminar demonstrate the discovery of novel mechanisms of spin-reorientation by the control of magnetism with light.

le 2 mars 2010

le mardi 02 mars 2010 à 10h30
Université de Versailles St-Quentin
Bâtiment Fermat
45 av. des Etats-Unis, 78000 Versailles
The demand for the ever-increasing speed of information storage and manipulation has
triggered an intense search for ways to control the magnetization of a medium by means other
than magnetic fields. The control of magnetism by light is one of the promising approaches to
this problem, because such methods may access timescales of a picosecond or less [1].
Can light directly and nonthermally magnetize a medium? In my lecture I will  demonstrate that the effect of an ultrashort circularly polarized optical pulse on a magnetic system is equivalent to the effect of an equally short magnetic field pulse with strengths up to few Tesla [2-5]. Using such short pulses of effective magnetic field we were able to discover novel mechanisms of spin-reorientation [6,7]. Finally, I will demonstrate that using two single
subpicosecond laser pulses it is possible to do both all-optical recording and reading on an
ultrashort time scale. The magnetic information was recorded by a subpicosecond laser pulse
and read-out by a similarly short pulse after 30 ps, which is the fastest ”write-read” event
demonstrated for magnetic recording medium so far. [6].

[1] A. V. Kimel et al, Nature 429 850 (2004).
[2] A. V. Kimel et al., Nature 435 655 (2005).
[3] F. Hansteen et al, Phys. Rev. Lett. 95 047402 (2005).
[4] A. V. Kimel et al., Laser & Photonics Rev. 1 275 (2007).
[5] C. D. Stanciu et al, Phys. Rev Lett. 99 047601 (2007); Patent PCT/NL2006/000264.
[6] K. Vahaplar et al, Phys. Rev Lett 103, 117201 (2009).
[7] A. V. Kimel et al, Nature-Physics 5 727 (2009).
Informations complémentaires
Séminaire présenté par A. V. Kimel de l'Institut des Molécules et Matériaux à Nijmegen, en Hollande

Contacts :
Joseph Scola - Enseignant en physique-environnement
Tél. : 01 39 25 46 69