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 distribu
tion 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.
Integrated power and linewidth of a propagating and a self-localized spin wave modes excited by spin-polarized current in an obliquely magnetized magnetic nanocontact are studied experimentally as functions of the angle $theta_e$ between the external
bias magnetic field and the nanocontact plane. It is found that the power of the propagating mode monotonically increases with $theta_e$, while the power of the self-localized mode has a broad maximum near $theta_e = 40$ deg, and exponentially vanishes near the critical angle $theta_e = 58$ deg, at which the localized mode disappears. The linewidth of the propagating mode in the interval of angles $58<theta_e<90$ deg, where only this mode is excited, is adequtely described by the existing theory, while in the angular interval where both modes can exist the observed linewidth of both modes is substantially broadened due to the telegraph switching between the modes. Numetical simulations and an approximate analytical model give good semi-quantitative description of the observed results.
