  We examine the mechanical rotation of a levitated magnetic particle that is
induced by ferromagnetic resonance under microwave irradiation. We show that
two stable solutions appear in a certain range of parameters by bifurcation
when the rotation frequency is comparable to the microwave frequency. This
phenomenon originates from the coexistence of the Barnett and the Einstein-de
Haas effects. We also reveal that this measurement is sensitive to the strength
of the spin-rotation coupling. Our work provides a platform for accessing a
microscopic relaxation process from spin to macroscopic rotation.
