Enhancing the injection locking range of spin torque oscillators through mutual coupling

TL;DR

This paper demonstrates that mutual electrical coupling between spin-torque nano-oscillators significantly enhances their locking range to external signals, with potential applications in designing sensitive oscillator arrays.

Contribution

It experimentally and numerically shows how mutual coupling increases locking range, providing insights for improved spin-torque oscillator array design.

Findings

Locking range increased by a factor of 1.64 due to mutual coupling

Experimental and numerical analysis of locking range evolution

Mechanisms of locking range enhancement uncovered

Abstract

We investigate how the ability of the vortex oscillation mode of a spin-torque nano-oscillator to lock to an external microwave signal is modified when it is coupled to another oscillator. We show experimentally that mutual electrical coupling can lead to locking range enhancements of a factor 1.64. Furthermore, we analyze the evolution of the locking range as a function of the coupling strength through experiments and numerical simulations. By uncovering the mechanisms at stake in the locking range enhancement, our results will be useful for designing spin-torque nano-oscillators arrays with high sensitivities to external microwave stimuli.