Ultra-large mutually synchronized networks of 10 nm spin Hall nano-oscillators

TL;DR

This paper reports the creation of ultra-large, synchronized networks of spin Hall nano-oscillators with over 100,000 units, demonstrating record power and quality factors, advancing their potential for communication and computing.

Contribution

Demonstrated the largest mutually synchronized SHNO network of up to 105,000 units using ultra-narrow nano-constrictions, with insights into frequency tunability and array size effects.

Findings

Achieved record network size of 105,000 SHNOs.

Microwave power and quality factor scale linearly with network size.

Frequency-current tunability strongly depends on array size due to magnon interactions.

Abstract

While mutually interacting spin Hall nano-oscillators (SHNOs) hold great promise for wireless communication, neural networks, neuromorphic computing, and Ising machines, the highest number of synchronized SHNOs remains limited to $N$ = 64. Using ultra-narrow 10 and 20-nm nano-constrictions in W-Ta/CoFeB/MgO trilayers, we demonstrate mutually synchronized SHNO networks of up to $N$ = 105,000. The microwave power and quality factor scale as $N$ with new record values of 9 nW and $1.04 \times 10^6$, respectively. An unexpectedly strong array size dependence of the frequency-current tunability is explained by magnon exchange between nano-constrictions and magnon losses at the array edges, further corroborated by micromagnetic simulations and Brillouin light scattering microscopy. Our results represent a significant step towards viable SHNO network applications in wireless communication and unconventional computing.