Geometric phase control of a spin-torque oscillator

We show that the phase of a spin-torque oscillator generically acquires a geometric contribution on slow and cyclic variation of the parameters that govern its dynamics. As an example, we compute the geometric phase that results from a cyclic excursion of the magnitude of the external field and the current. We consider thermal phase fluctuations and conclude that the geometric phase should be experimentally observable at room temperature with current set-ups. We briefly comment on arrays of spin-torque oscillators and possible applications.