  The angular momentum interconversion between electron spin and other type of
angular momenta is useful to develop new spintronic functionalities. The
conversions from the angular momentum of photon and mechanical rotation to
ferromagnetic spin moment have been well studied. While the recent studies
theoretically suggested circular vibration of atoms works as angular momentum
of phonon, the direct experimental demonstration of conversion to spin moments
remains to be performed. Here we demonstrate that the phonon angular momentum
of surface acoustic wave can control the magnetization of a ferromagnetic Ni
film by means of the phononic-to-electronic conversion of angular momentum in
Ni/LiNbO$_3$ hybrid device. This result clearly shows the phonon angular
momentum is useful to further fictionalize spintronic devices.
