  We report the experimental observation of mutual synchronization of magnetic
nanooscillators driven by pure spin current generated by nonlocal spin
injection. We show that the oscillators efficiently synchronize due to the
direct spatial overlap of the dynamical modes excited by spin current, which is
facilitated by the large size of the auto-oscillation area inherent to these
devices. The synchronization occurs within an interval of the driving current
determined by the competition between the dynamic nonlinearity that facilitates
synchronization, and the short-wavelength magnetic fluctuations enhanced by the
spin current that suppress synchronization. The demonstrated synchronization
effects can be utilized to control the spatial and spectral characteristics of
the dynamical states induced by spin currents.
