Regensburg 2016 – scientific programme

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MA: Fachverband Magnetismus

MA 44: Spininjection / Spin currents in heterostructures

MA 44.8: Talk

Thursday, March 10, 2016, 17:00–17:15, H31

Boltzmann-equation model for spin-dependent transport on ultrashort timescales — •Dennis Michael Nenno and Hans Christian Schneider — Physics Department and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern

Spin-polarized currents have been shown to play an important role in ultrafast demagnetization [1,2,3].

We use a spin-resolved Boltzmann equation to simulate charge and spin dynamics in an iron/gold hetero-structure. The excitation conditions are modeled after the ultrashort laser excitation as in Ref. [1].

The dynamical equation is solved using numerical methods originally applied in plasma physics in a reduced phase space in order to limit the computational cost. Scattering effects are included at the level of the relaxation time approximation. This calculation accounts for microscopic effects such as a k-dependent excitation and deviations from the equilibrium distribution. We study the influence of different excitation spectra injected from the ferromagnetic iron layer into the adjacent nonmagnetic gold slab and their influence on the resulting spin and charge dynamics. In additon, we compare the results with the macroscopic wave-diffusion equations for spin and charge transport [3].
[1] A. Melnikov et al., Phys. Rev. Lett. 107, 076601 (2011).
[2] M. Battiato, K. Carva, and P. M. Oppeneer, Phys. Rev. B 86, 024404 (2012).
[3] S. Kaltenborn, Y. H. Zhu, and H. .C. Schneider, Phys. Rev. B 85, 235101 (2012)