Marcham, M. K., Shelford, L. R., Cavill, S. A., Keatley, P. S., Yu, W., Shafer, P., …Hicken, R. J. (2013). Phase-resolved x-ray ferromagnetic resonance measurements of spin pumping in spin valve structures. Physical review B: Condensed matter and materials physics, 87(18), https://doi.org/10.1103/physrevb.87.180403