We studied the spin injection in a NiFe(Py)/Si system using broadband ferromagnetic resonance spectroscopy. The Gilbert damping parameter of the Py layer on top of the Si channel was determined as a function of the Si doping concentration and Py layer thickness. For fixed Py thickness we observed an increase of the Gilbert damping parameter with decreasing resistivity of the Si channel. For a fixed Si doping concentration we measured an increasing Gilbert damping parameter for decreasing Py layer thickness. No increase of the Gilbert damping parameter was found Py/Si samples with an insulating interlayer. We attribute our observations to an enhanced spin injection into the low-resistivity Si by spin pumping.
@article{arxiv.1704.07006,
title = {Spin injection into silicon detected by broadband ferromagnetic resonance spectroscopy},
author = {Ryo Ohshima and Stefan Klingler and Sergey Dushenko and Yuichiro Ando and Mathias Weiler and Hans Huebl and Teruya Shinjo and Sebastian T. B. Goennenwein and Masashi Shiraishi},
journal= {arXiv preprint arXiv:1704.07006},
year = {2017}
}