  We show that the resonant coupling of phonons and magnons can be exploited to
generate spin currents at room temperature. Surface acoustic wave (SAW) pulses
with a frequency of 1.55 GHz and duration of 300 ns provide coherent elastic
waves in a ferromagnetic thin film/normal metal (Co/Pt) bilayer. We use the
inverse spin Hall voltage in the Pt as a measure for the spin current and
record its evolution as a function of time and external magnetic field
magnitude and orientation. Our experiments show that a spin current is
generated in the exclusive presence of a resonant elastic excitation. This
establishes acoustic spin pumping as a resonant analogue to the spin Seebeck
effect.
