Regensburg 2013 – scientific programme

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MA: Fachverband Magnetismus

MA 33: Magnetization Dynamics I of 3

MA 33.2: Talk

Thursday, March 14, 2013, 09:45–10:00, H22

Thermally assisted all-optical helicity dependent magnetic switching in Fe_100-xTb_x films — Alexander Hassdenteufel¹, Birgit Hebler¹, Christian Schubert¹, •Andreas Liebig¹, Martin Teich^2,3, Manfred Helm^2,3, Martin Aeschlimann⁴, Manfred Albrecht¹, and Rudolf Bratschitsch¹ — ¹Institute of Physics, Chemnitz University of Technology, D-09107 Chemnitz (Germany) — ²Helmholtz Zentrum Dresden Rossendorf, P. O. Box 510119, D-01314 Dresden (Germany) — ³Technische Universität Dresden, D-01062 Dresden (Germany) — ⁴Department of Physics and Research Center Optimas, University of Kaiserslautern, D-67663 Kaiserslautern (Germany)

Magnetization switching is at the heart of both modern information storage technology and fundamental science. Ultrafast laser pulses are promising to explore and finally reach the ultimate speed limit of this process. We present all-optical switching (AOS) in amorphous ferrimagnetic Fe_100-xTb_x alloy films with circularly polarized laser pulses. A Tb content of 22 to 34 at.% is necessary for AOS to occur. Outside this composition range pure thermal demagnetization is observed. AOS occurs not only below and above the magnetic compensation temperataure (T_comp), but also in samples without T_comp. We find that AOS is associated with laser heating up to the Curie temperature. AOS is intimately linked to a low remanent sample magnetization M_R. Above a threshold magnetization of 220 emu/cc helicity dependent AOS is replaced by pure thermal demagnetization.