Intrinsic synchronization of an array of spin-torque oscillators driven by the spin-Hall effect

TL;DR

This study demonstrates that a bi-layer of Platinum and Permalloy can intrinsically synchronize an array of spin-torque oscillators driven by the spin-Hall effect, potentially enhancing output power for technological use.

Contribution

Proposes using a Platinum/Permalloy bi-layer as a shared free layer to achieve intrinsic synchronization of multiple spin-torque oscillators via the spin-Hall effect.

Findings

Uniform mode excitation observed in micromagnetic simulations

Frequency synchronization across the array achieved

Potential for increased output power in oscillator arrays

Abstract

This paper micromagnetically studies the magnetization dynamics driven by the spin-Hall effect in a Platinum/Permalloy bi-layer. For a certain field and current range, the excitation of a uniform mode, characterized by a power with a spatial distribution in the whole ferromagnetic cross section, is observed. We suggest to use the ferromagnet of the bi-layer as basis for the realization of an array of spin-torque oscillators (STOs): the Permalloy ferromagnet will act as shared free layer, whereas the spacers and the polarizers are built on top of it. Following this strategy, the frequency of the uniform mode will be the same for the whole device, creating an intrinsic synchronization. The synchronization of an array of parallely connected STOs will allow to increase the output power, as necessary for technological applications.