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MA: Fachverband Magnetismus
MA 43: Magnetization Dynamics II of 3
MA 43.4: Talk
Thursday, March 14, 2013, 15:45–16:00, H22
Unified theory of ultrafast femtosecond and picosecond spin dynamics in the three-center magnetic cluster Ni3Na2 — •Georgios Lefkidis1, Hongping Xiang1,2, and Wolfgang Hübner1 — 1Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, Germany — 2Department of Physics and Astronomy, California State University, Northridge, USA
Using ab initio quantum chemistry, varying the interatomic distances, and including spin-orbit coupling and a static external magnetic field, we investigate the laser-induced, ultrafast magnetic switching in Ni3Na2 [1,2]. Our studies yield a very accurate bond-length sensor based on spin dynamics, as well as a unified picture of subpicosecond, laser-induced and picosecond, phonon-induced spin-flip processes.
Specifically we find that the geometric distortions lead to magnetic phases in the cluster, in which the strongly localized spins exhibit different orientations and hence respond differently to laser pulses. At the critical interatomic distances the spins undergo a sudden reorientation (spin-phonon scattering). This scattering is indirect and mediated through an energetically higher-lying electronic state.
Finally, to completely unify the laser-induced and the phonon-induced processes we calculate their longitudinal and transverse relaxation times and draw an analogy to classical precessional switching.
[1] H. P. Xiang, G. Lefkidis, and W. Hübner, Phys. Rev. B 86, 134402 (2012)
[2] H. P. Xiang, G. Lefkidis, and W. Hübner, J. Supercond. Nov. Magn. (in press) (2012)