Berlin 2012 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 40: PhD Student Symposium: "Spintronics on the Way to modern Storage Technology I", Organization: "Univ. Mainz team"

MA 40.3: Vortrag

Donnerstag, 29. März 2012, 11:00–11:15, BH 243

Revealing the significance of heating in the all-optical switching process — •Sabine Alebrand, Daniel Steil, Alexander Haßdenteufel, Mirko Cinchetti, and Martin Aeschlimann — Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67653 Kaiserslautern, Germany

It is well known that it is possible to switch the magnetic state of a ferrimagnetic GdFeCo sample all-optically, i.e. just by using one single circularly polarized laser pulse and without any additional external magnetic field [1]. In principle the laser pulse may fulfil two functions: delivering helicity and heating up the sample. Up to now it is still controversially discussed in literature if heating is necessary for the all-optical switching process [2,3].

To shed light on this issue: (i) we consider the dependence of the minimum laser fluence needed to obtain switching on the repetition rate of the laser pulses; and (ii) discuss the results of σ-π experiments using one circularly pulse (acting as angular momentum source) and a linearly polarized pulse (acting as a heating pulse). We show that it is possible to switch all-optically by the combination of both pulses although the fluence of the circularly polarized laser pulse is below the minimum fluence threshold (determined for switching with only one circularly polarized pulse). Both of our experiments clearly favour the fact that heating contributes to the switching process.

[1] Stanciu et al. PRL 99, 047601, 2007 [2] Kirilyuk et al., Rev. of Mod. Phys. 82, 2010 [3] Vahaplar et al., PRL 103, 117201, 2009