Efficient Synchronization of Dipolarly Coupled Vortex-Based Spin Transfer Nano-Oscillators

TL;DR

This paper demonstrates that dipolar interactions can effectively synchronize vortex-based spin transfer nano-oscillators, even with frequency mismatches, with synchronization efficiency controlled by vortex magnetic configurations.

Contribution

It introduces dipolar coupling as a new efficient synchronization mechanism for vortex-based spin transfer nano-oscillators, supported by experimental, analytical, and simulation results.

Findings

Dipolar interaction effectively synchronizes neighboring oscillators.

Synchronization occurs despite significant frequency mismatch.

Magnetic vortex configuration controls coupling efficiency.

Abstract

Due to their nonlinear properties, spin transfer nano-oscillators can easily adapt their frequency to external stimuli. This makes them interesting model systems to study the effects of synchronization and brings some opportunities to improve their microwave characteristics in view of their applications in information and communication technologies and to design innovative computing architectures. So far, mutual synchronization of spin transfer nano-oscillators through propagating spin-waves and exchange coupling in a common magnetic layer has been demonstrated. Here we show that the dipolar interaction is also an efficient mechanism to synchronize neighbouring oscillators. We experimentally study a pair of vortex-based spin-transfer nano-oscillators, in which mutual synchronization can be achieved despite a significant frequency mismatch between oscillators. Importantly, the coupling efficiency is controlled by the magnetic configuration of the vortices, as confirmed by an analytical model highlighting the physics at play in the synchronization process as well as by micromagnetic simulations.