  We use electrical detection, in combination with microwave transmission, to
investigate both resonant and non-resonant magnon-photon coupling at room
temperature. Spin pumping in a dynamically coupled magnon-photon system is
found to be distinctly different from previous experiments. Characteristic
coupling features such as modes anti-crossing, line width evolution, peculiar
line shape, and resonance broadening are systematically measured and
consistently analyzed by a theoretical model set on the foundation of classical
electrodynamic coupling. Our experimental and theoretical approach pave the way
for pursuing microwave coherent manipulation of pure spin current via the
combination of spin pumping and magnon-photon coupling.
