Spin-pumping generates pure spin currents in normal metals at the ferromagnet (F)/normal metal (N) interface. The efficiency of spin-pumping is given by the spin mixing conductance, which depends on N and the F/N interface. We directly study the spin-pumping through an MgO tunnel-barrier using the inverse spin Hall effect, which couples spin and charge currents and provides a direct electrical detection of spin currents in the normal metal. We find that spin-pumping is suppressed by the tunnel-barrier, which is contrary to recent studies that suggest that the spin mixing conductance can be enhanced by a tunnel-barrier inserted at the interface.
@article{arxiv.0911.3182,
title = {Suppression of spin-pumping by a MgO tunnel-barrier},
author = {O. Mosendz and J. E. Pearson and F. Y. Fradin and S. D. Bader and A. Hoffmann},
journal= {arXiv preprint arXiv:0911.3182},
year = {2015}
}