Spin Currents and Nonlinear Dynamics of Vortex Spin Torque Nano-Oscillators

Vortex spin torque nano-oscillators (STNOs) are multilayer spin-valve magnetic nanopillars, in which the magnetic layers (one or both) contain a magnetic vortex, the dynamics of which provides microwave radiation. In vortex STNOs, it was possible to achieve a high microwave signal power (on the order of 1 μW) and a relatively narrow linewidth (several hundreds of kHz). To further increase the power and improve the spectral characteristics of vortex STNOs, the collective dynamics and synchronization conditions in the ensembles of such nanostructures are studied. The subject of this review is the latest achievements in the field of physics and technology of vortex STNOs.