Synchronization of spin-transfer oscillators driven by stimulated microwave currents

TL;DR

This paper demonstrates that networks of magnetically uncoupled spin-transfer oscillators can be synchronized in frequency and phase through microwave current coupling, significantly enhancing emitted microwave power.

Contribution

It introduces a novel simulation approach showing current-induced synchronization in electrically connected spin-transfer oscillators, improving understanding of their collective dynamics.

Findings

Oscillators can synchronize in frequency and phase

Synchronization enhances microwave power output

Mechanism explains narrow spectra in isolated oscillators

Abstract

We have simulated the non-linear dynamics of networks of spin-transfer oscillators. The oscillators are magnetically uncoupled but electrically connected in series. We use a modified Landau-Lifschitz- Gilbert equation to describe the motion of each oscillator in the presence of the oscillations of all the others. We show that the oscillators of the network can be synchronized not only in frequency but also in phase. The coupling is due to the microwave components of the current induced in each oscillator by the oscillations in all the other oscillators. Our results show how the emitted microwave power of spin-transfer oscillators can be considerably enhanced by current-induced synchronization in an electrically connected network. We also discuss the possible application of our synchronization mechanism to the interpretation of the surprisingly narrow microwave spectrum in some isolated spin-transfer oscillators.