Nonlinear Behavior and Mode Coupling in Spin-Transfer Nano-Oscillators

By investigating thoroughly the tunable behavior of coupled modes, we highlight how it provides a means to tune the properties of spin-transfer nano-oscillators.We first demonstrate that the main features of the microwave signal associated with coupled vortex dynamics, i.e., frequency, spectral coherence, critical current, and mode localization, depend drastically on the relative vortex core polarities. Second, we report a large reduction of the nonlinear linewidth broadening obtained by changing the effective damping through the control of the core configuration. Such a level of control on the nonlinear behavior reinforces our choice to exploit the microwave properties of collective modes for applications in advanced spintronics devices for integrated telecommunication concerns