Tuning the Mutual Synchronization of Electrically Coupled Spin-Torque Oscillators by Selecting the Vortex Dynamic Regime

Abstract

In this study, the synchronization ability of vortex-based spin-torque nano-oscillators is investigated for three different dynamical regimes: the fundamental gyrotropic mode, the dynamic C-state, and the transition regime characterized by stochastic switching between the gyrotropic mode and the dynamic C-state. By combining injection locking at 2f and mutual synchronization experiments between two oscillators, it is shown that the ability to synchronize is larger in the transition regime than in the gyrotropic mode. By slightly tuning the injected dc current, this transition regime, which is highly efficient at synchronization, evolves into a dynamic state with no ability to synchronize. Thus, the synchronization range can be tuned, and the synchronized state can be easily switched on and off by selecting the dynamic regime. These results are promising for applications requiring large-scale networks of synchronized oscillators, where tuning the synchronization range and controlling the synchronized state are important features, such as neuromorphic computing and broadband microwave communication