There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
Abstract
The dependence of the spin-pumping effect on the yttrium iron garnet (Y3Fe5O12, YIG)
thickness detected by the inverse spin Hall effect (ISHE) has been investigated quantitatively.
Due to the spin-pumping effect driven by the magnetization precession in the ferrimagnetic
insulator YIG film a spin-polarized electron current is injected into the Pt layer.
This spin current is transformed into electrical charge current by means of the ISHE.
An increase of the ISHE-voltage with increasing film thickness is observed and compared
to the theoretically expected behavior. The effective damping parameter of the YIG/Pt
samples is found to be enhanced with decreasing YIG film thickness. The investigated
samples exhibit a spin mixing conductance of g=(7.43 \pm 0.36) \times 10^{18} m^{-2}
and a spin Hall angle of theta_{ISHE} = 0.009 \pm 0.0008. Furthermore, the influence
of nonlinear effects on the generated voltage and on the Gilbert damping parameter
at high excitation powers are revealed. It is shown that for small YIG film thicknesses
a broadening of the linewidth due to nonlinear effects at high excitation powers is
suppressed because of a lack of nonlinear multi-magnon scattering channels. We have
found that the variation of the spin-pumping efficiency for thick YIG samples exhibiting
pronounced nonlinear effects is much smaller than the nonlinear enhancement of the
damping.