Regensburg 1998 – wissenschaftliches Programm

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AM: Magnetismus

AM 8: Elektronentheorie und Modelle geordneter Spinstrukturen

AM 8.2: Vortrag

Dienstag, 24. März 1998, 10:30–10:45, H23

Theory of femtosecond spin dynamics in ferromagnet nickel: Intrinsic properties — •W. Hübner and G. P. Zhang — Max-Planck Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle/Saale

The spin dynamics in Ni is studied by an exact diagonalization method on the ultrafast time scale. It is shown that the femtosecond relaxation of the magneto-optical response results from exchange interaction and spin-orbit coupling. Each of the two mechanisms affects the relaxation process differently. In this report, we will address how intrinsic parameters affect the spin dynamics. Those intrinsic parameters are (i) Coulomb interaction U, (ii) exchange interaction J, (iii) exchange anisotropy Δ J, (iv) SOC λ, and (v) band structure E(K). We find that the intrinsic spin dynamics occurs during about 10 fs. Comparing our theoretical results with all the existing experimental data, we suggest that there is still room to accelerate the spin dynamics. A very short spin dynamics, less than 100 fs, is possible, as some indications have been shown in a recent experiment [1].

[1] E. Beaurepaire, M. Maret, V. Halte, J.-C. Merle, A. Daunois, and J. -Y. Bigot, unpublished.