Selective control of vortex polarities by microwave field in two robustly synchronized spin-torque nano-oscillators

TL;DR

This paper demonstrates selective vortex core polarity control in coupled spin-torque nano-oscillators using microwave fields, enabling manipulation of their synchronization states for potential applications in oscillator networks.

Contribution

It introduces a method for selective vortex polarity switching in coupled STNOs, affecting their synchronization, with experimental validation and potential for extension to larger networks.

Findings

Successful microwave-assisted vortex polarity switching.

Control over synchronization and desynchronization states.

Reduction in linewidth and coherent output enhancement.

Abstract

Manipulating operation states of coupled spin-torque nano-oscillators (STNOs), including their synchronization, is essential for applications such as complex oscillator networks. In this work we experimentally demonstrate selective control of two coupled vortex STNOs through microwave-assisted switching of their vortex core polarities. First, the two oscillators are shown to synchronize due to dipolar interaction in a broad frequency range tuned by external biasing field. Coherent output is demonstrated along with strong linewidth reduction. Then, we show individual vortex polarity control of each oscillator, which leads to synchronization/desynchronization due to accompanied frequency shift. Our methods can be easily extended to multiple-element coupled oscillator networks.