Injection locking at 2f of spin torque oscillators under influence of thermal noise

TL;DR

This paper investigates how thermal noise affects injection locking at twice the frequency of spin torque oscillators, demonstrating control of phase noise through current adjustments in experiments, simulations, and models.

Contribution

It provides a comprehensive analysis of noise effects in spin torque nano oscillators and proposes methods to reduce phase noise via current control, combining experimental, numerical, and analytical approaches.

Findings

Higher reference currents are needed for phase locking under noise.

Phase noise can be controlled by adjusting the reference microwave current.

Increasing bias current reduces phase noise within feasible limits.

Abstract

Experiments, numerical simulations and an analytic model were developed to elucidate the effects of noise in the synchronized state of a tunnel junction based spin torque nano oscillator (STNO). It is demonstrated that in the in plane magnetized structure, while the frequency is locked, much higher reference currents are needed to reduce the noise by phase locking. Our analysis shows that it is possible to control the phase noise by the reference microwave current (IRF) and that it can be further reduced by increasing the bias current (IDC) of the oscillator, keeping the reference current in feasible limits for applications.