  We show here theoretically and experimentally that a Rashba-split electron
state inside a ferromagnet can efficiently convert a dynamical spin
accumulation into an electrical voltage. The effect is understood to stem from
the Rashba splitting but with a symmetry linked to the magnetization direction.
It is experimentally measured by spin pumping in a CoFeB/MgO structure where it
is found to be as efficient as the inverse spin Hall effect at play when Pt
replaces MgO, with the extra advantage of not affecting the damping in the
ferromagnet.
