Parametric excitation of magnetization oscillations controlled by pure spin current

We report an experimental investigation of parametric excitation of magnetization oscillations in a permalloy microdisk in the presence of a pure spin current. The latter is generated by an adjacent Pt layer due to the spin Hall effect. We demonstrate that the spin torque induced by the pure spin current can significantly reduce the threshold for parametric instability, and modify the frequency range of the parametrically excited oscillation at a given pumping power. Our results show that pure spin currents can be utilized for stimulation and control of nonlinear dynamic magnetic phenomena in microscopic structures.