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MA: Fachverband Magnetismus

MA 28: Spin-dependent Transport Phenomena

MA 28.8: Vortrag

Donnerstag, 25. März 2010, 17:15–17:30, H3

Macroscopic theory for time-dependent noncollinear spin transport — •Steffen Kaltenborn, Yao-Hui Zhu, and Hans Christian Schneider — Department of Physics and Research Center OPTIMAS, TU Kaiserslautern

We employ a macroscopic theory based on the semiclassical Boltzmann equation for the spin-density matrix to analyze the propagation of signals encoded in a spin current, which flows through a multilayer structure with noncollinear magnetization and spin directions. [1] We find that, due to the wave-like character of spin currents, modifications of pure spin-diffusion dynamics may result, depending on the signal time-scale (or frequency). In particular, we determine the finite spin-signal propagation velocity, which is not possible in the framework of the spin-diffusion equation, and numerically study the dynamics of a pure spin current pumped into a nonmagnetic Cu layer by a precessing magnetization in an adjacent ferromagnetic permalloy layer for precession frequencies ranging from GHz to THz. Extensions of the theory to nanostructures will be discussed.

[1] Y.-H. Zhu, B. Hillebrands, and H. C. Schneider, Phys. Rev. B 79, 214412 (2009)