Dresden 2014 – scientific programme
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MA: Fachverband Magnetismus
MA 55: Poster II
MA 55.40: Poster
Friday, April 4, 2014, 10:30–13:30, P2
Element-specific magnetization dynamics in Gd doped Ni81Fe19 films — •Ruslan Salikhov3, Radu Abrudan1, Florian Römer3, Florin Radu2, Ralf Meckenstock3, Hartmut Zabel1, and Michael Farle3 — 1Ruhr-Universität Bochum, Germany — 2Helmholtz Zentrum Berlin, Germany — 3Universität Duisburg-Essen, Germany
We have studied magnetization dynamics in Ni81Fe19 films doped by Gd with different concentrations (5, 9 and 13 at.%) using ferromagnetic resonance (FMR) [1] and time-resolved x-ray resonant magnetic scattering (tr-XRMS) implemented at the Helmholtz Zentrum Berlin [2]. At room temperature two antiferromagnetically coupled sublattices Fe (Ni) and Gd show identical response after magnetic field pulse excitation, having similar Landau-Lifshitz (LL) relaxation rate (λ) and precessional frequency (f). The FMR dimensionless damping parameter α increases with increasing Gd content. However, λ obtained from the tr-XRMS shows the opposite trend with increasing Gd concentration. At low temperatures (100 and 50 K) we have found that Fe and Gd sublattices precess noncollinear (with different precessional angles in respect to initial state). Noncollinear precession of the Fe and Gd magnetic moments accompanied with increase in both λ and f. Our results will be discussed in the frame of the "s-d exchange model" [3] and the "slow relaxing" impurity model [4].
[1] F. Römer et al., APL. 100, 092402 (2012). [2] R. Salikhov et al., PRB 86, 144422 (2012). [3] B. Heinrich et al., Phys. Stat. Sol. 23, 501 (1967). [4] G. Woltersdorf et al., PRL. 102, 257602 (2009).