Dresden 2014 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 43: Magnetization Dynamics III

MA 43.2: Vortrag

Donnerstag, 3. April 2014, 15:15–15:30, HSZ 401

Spin Dephasing and Magnetization Damping due to electron-phonon scattering in a ferrimagnetic s-d model — Alexander Baral and •Hans-Christian Schneider — University of Kaiserslautern and Research Center OPTIMAS

We calculate the spin dynamics in a model of itinerant carriers coupled antiferromagnetically to a macrospin ("ferrimagnetic s-d model") due to the coupling to a phonon bath in the presence of spin-orbit coupling. Using a mean-field approximation for the s-d model, we derive Boltzmann scattering integrals for the distributions and spin coherences for the case of a antiferromagnetic exchange splitting, which is complicated by dynamical changes of the longitudinal and transversal magnetization directions. We assume the spin-orbit coupling to be of the Rashba form so that the resulting model describes a form of Elliot-Yafet type electron-phonon scattering within an equation of motion formalism. We extrapolate dephasing- and magnetization times and draw a comparison to phenomenological equations such as Landau-Lifshitz (LL) [1] or Landau-Lifshitz-Gilbert (LLG) [2]. We then analyze the magnetization precession and relaxation of the antiferromagnetically coupled carrier spins and macrospin in an anisotropy field [3] and find a carrier mediated dephasing of the macrospin via mean-field coupling.

[1] L. D. Landau and E. M. Lifshitz, Phys. Z. Sowjet., vol. 8, pp. 153-169 (1935).

[2] T. L. Gilbert, IEEE Transactions on Magnetics, vol. 40(6), pp. 3443-3449 (2004).

[3] Y.Tserkovnyak, Applied Phys. Lett Vol.84, Number 25 (2004).