  This paper micromagnetically studies the magnetization dynamics driven by the
spin-Hall effect in a Platinum/Permalloy bi-layer. For a certain field and
current range, the excitation of a uniform mode, characterized by a power with
a spatial distribution in the whole ferromagnetic cross section, is observed.
We suggest to use the ferromagnet of the bi-layer as basis for the realization
of an array of spin-torque oscillators (STOs): the Permalloy ferromagnet will
act as shared free layer, whereas the spacers and the polarizers are built on
top of it. Following this strategy, the frequency of the uniform mode will be
the same for the whole device, creating an intrinsic synchronization. The
synchronization of an array of parallely connected STOs will allow to increase
the output power, as necessary for technological applications.
