Coupling efficiency for phase locking of a spin transfer oscillator to a microwave current

TL;DR

This paper investigates how spin transfer nano-oscillators (STNOs) lock their phase to external microwave signals, analyzing the coupling strength based on intrinsic oscillator parameters to optimize power output.

Contribution

It introduces a method to extract coupling strength from experimental data using phase dynamics, linking it to intrinsic properties of STNOs.

Findings

Coupling strength depends on oscillator power, linewidth, and current agility.

Phase locking behavior can be predicted from intrinsic parameters.

Optimization of emitted power in arrays is achievable through understanding coupling trends.

Abstract

The phase locking behavior of spin transfer nano-oscillators (STNOs) to an external microwave signal is experimentally studied as a function of the STNO intrinsic parameters. We extract the coupling strength from our data using the derived phase dynamics of a forced STNO. The predicted trends on the coupling strength for phase locking as a function of intrinsic features of the oscillators i.e. power, linewidth, agility in current, are central to optimize the emitted power in arrays of mutually coupled STNOs.