Nonlinear self-phase-locking effect in an array of current-driven magnetic nanocontacts

We show that in an array of magnetic nanocontacts driven by spin-polarized current a self-phase-locking effect can lead to a regime in which all the contacts are generating microwave oscillations with the same frequency and phase, and coherent addition of microwave power generated by individual nanocontacts is possible. The mechanism of this self-phase-locking effect is strongly nonlinear, while the frequency band of phase locking is an order of magnitude larger than in the usual coupled generators and depends on the direction of the bias magnetic field applied to the nanocontacts.