  Spin current has emerged as a leading candidate for manipulation of spins in
a nano-magnet. We here experimentally show another utility of spin current viz.
it can be used for generation of phonons. Within the same experimental setup,
we also demonstrate the inverse effect of generation of spin current by
phonons. To demonstrate them, we measured the scattering-matrix of a two-port
device with interdigital transducers as one port and array of Ni/Pt lines as
second port on piezoelectric substrate. The off-diagonal elements which
correspond to transmission between the ports, were found to have 180 degree
relative phase shift. The transmission of electrical signal from port 2 to 1
corresponds to generation of phonons from spin-current, while transmission from
port 1 to 2 corresponds to the inverse effect. These results could be useful
for designing spin-current based gyrators.
