Robust Mutual Synchronization in Long Spin Hall Nano-oscillator Chains.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37450893.
- Also identified by DOI 10.1021/acs.nanolett.3c02036 and PMC identifier 10375588.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Mutual synchronization of <i>N</i> serially connected spintronic nano-oscillators boosts their coherence by <i>N</i> and peak power by <i>N</i><sup>2</sup>. Increasing the number of synchronized nano-oscillators in chains holds significance for improved signal quality and emerging applications such as oscillator based unconventional computing. We successfully fabricate spin Hall nano-oscillator chains with up to 50 serially connected nanoconstrictions using W/NiFe, W/CoFeB/MgO, and NiFe/Pt stacks. Our experiments demonstrate robust and complete mutual synchronization of 21 nanoconstrictions at an operating frequency of 10 GHz, achieving line widths <134 kHz and quality factors >79,000. As the number of mutually synchronized oscillators increases, we observe a quadratic increase in peak power, resulting in 400-fold higher peak power in long chains compared to individual nanoconstrictions. While chains longer than 21 nanoconstrictions also achieve complete mutual synchronization, it is less robust, and their signal quality does not improve significantly, as they tend to break into partially synchronized states.