Dresden 2014 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 55: Poster II

MA 55.8: Poster

Freitag, 4. April 2014, 10:30–13:30, P2

Enhancement of spin currents by three-magnon splitting — Oleksandr Dzyapko¹, Hidekazu Kurebayashi², Vladislav E. Demidov¹, •Michael Evelt¹, and Sergej O. Demokritov¹ — ¹Institute for Applied Physics, University of Muenster, Germany — ²Cavendish Laboratory, University of Cambridge, United Kingdom

The effect of spin-pumping offers a perfect possibility to generate pure spin currents in a layered system of ferromagnetic and normal metals by excitation of spin precession in the ferromagnet. Vice versa, detecting the spin current using the inverse spin-Hall effect (ISHE) allows investigation of magnetic dynamics.
Here we report on the examination of the spin pumping in yttrium iron garnet (YIG)/Pt bilayers for different thickness of YIG. We show that the efficiency of the spin-current generation can be significantly enhanced by three-magnon splitting in YIG. This is only allowed for particular intervals of applied magnetic fields depending on the thickness of the ferromagnetic film (energy conservation). Our results show that for all samples with allowed three-magnon splitting an enhancement of the spin current generation is observed in a certain frequency region. The cut-off frequencies characterizing the region of the enhancement correlate perfectly with the theoretically predicted frequency for the latter process, confirming the experimental claims [1,2] that three-magnon splitting is responsible for the observed amplification.
H. Kurebayashi, O. Dzyapko, et al, Nature Mater. 10, 660 (2011) [2] O. Dzyapko, H. Kurebayashi, et al, Applied Physics Letters 102, 252409 (2013)