Regensburg 2013 – scientific programme
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MA: Fachverband Magnetismus
MA 33: Magnetization Dynamics I of 3
MA 33.4: Talk
Thursday, March 14, 2013, 10:15–10:30, H22
Ultrafast magnetic dynamics in the metallic 4f antiferromagnet Holmium — •Christoph Trabant1,2,3, Niko Pontius2, Hartmut Zabel4, Alexander Föhlisch2,3, and Christian Schüßler-Langeheine2 — 1II. Physikalisches Institut, Universität zu Köln — 2Institut für Methoden und Instrumentierung der Synchrotronstrahlung, Helmholtz-Zentrum Berlin — 3Institut für Physik und Astronomie, Universität Potsdam — 4Institut für Experimentalphysik / Festkörperphysik, Ruhr Universität Bochum
We studied the laser induced fs magnetic dynamics of a metallic 4f antiferromagentic Holmium thin film. The dynamics was mapped using the strong resonant x-ray scattering signal of the helical magnetic (00τ) superstructure reflection. We found a fast quenching of the magnetic order on a ∼ 200 fs timescale which is essentially independent of the applied laser fluence. Comparing this demagnetization time and those of the the 4f ferromagnets Terbium and Gadolinium (750 fs each) [1] to their respective atomic magnetic moment (Gd: 7.55 µ B, Tb: 9.3 µ B, and Ho: 10.6 µ B) leads to the conclusion that the time constant does not scale with the size of the magnetic moment as proposed for ferromagnets. The optical pump xray probe measurements have been performed at the FEMTOSPEX facility at BESSY II. Supported by the BMBF through contract 05K10PK2.
[1] M. Wietstruk, et al.: PRL 106, 127401 (2011).