Designing large arrays of interacting spin-torque nano-oscillators for microwave information processing

TL;DR

This paper presents the design and analysis of large arrays of spin-torque nano-oscillators with evenly spaced frequencies and uniform sensitivity, optimized for microwave signal processing and neuromorphic computing applications.

Contribution

It introduces analytical and numerical methods to engineer spin-torque nano-oscillator arrays with specific frequency spacing and synchronization properties, including size and frequency range estimations.

Findings

Arrays of hundreds of oscillators can be fabricated within nanofabrication constraints.

Optimized arrays can cover several hundred MHz with uniform sensitivity.

Design guidelines for equally-spaced frequency and synchronization bandwidths are provided.

Abstract

Arrays of spin-torque nano-oscillators are promising for broadband microwave signal detection and processing, as well as for neuromorphic computing. In many of these applications, the oscillators should be engineered to have equally-spaced frequencies and equal sensitivity to microwave inputs. Here we design spin-torque nano-oscillator arrays with these rules and estimate their optimum size for a given sensitivity, as well as the frequency range that they cover. For this purpose, we explore analytically and numerically conditions to obtain vortex spin-torque nano-oscillators with equally-spaced gyrotropic oscillation frequencies and having all similar synchronization bandwidths to input microwave signals. We show that arrays of hundreds of oscillators covering ranges of several hundred MHz can be built taking into account nanofabrication constraints.