A quasi-linear spin-torque nano-oscillator via enhanced negative feedback of power fluctuations

TL;DR

This paper introduces a method to enhance spin torque nano-oscillators by using power-dependent negative feedback, resulting in more linear and coherent oscillations with tunability at room temperature.

Contribution

The paper presents a novel feedback approach to significantly improve the linearity and coherence of spin torque nano-oscillators, enabling better performance at room temperature.

Findings

Achieved highly coherent room temperature STNOs.

Demonstrated weak non-linear coupling of power and phase fluctuations.

Maintained tunability while enhancing coherence.

Abstract

We report an approach to improving the performance of spin torque nano-oscillators (STNOs) that utilizes power-dependent negative feedback to achieve a significantly enhanced dynamic damping. In combination with a sufficiently slow variation of frequency with power this can result in a quasi-linear STNO, with very weak non-linear coupling of power and phase fluctuations over a range of bias current and field. An implementation of this approach that utilizes a non-uniform spin-torque demonstrates that highly coherent room temperature STNOs can be achieved while retaining a significant tunability.