Spin wave-driven variable-phase mutual synchronization in spin Hall nano-oscillators

Abstract

Spin-orbit torque can drive auto-oscillations of propagating spin wave (PSW) modes in nano-constriction spin Hall nano-oscillators (SHNOs). These modes allow both long-range coupling and the potential of controlling its phase -- critical aspect for nano-magnonics, spin wave logic, and Ising machines. Here, we demonstrate PSW-driven variable-phase coupling between two nano-constriction SHNOs and study how their separation and the PSW wave vector impact their mutual synchronization. In addition to ordinary in-phase mutual synchronization, we observe, using both electrical measurements and phase-resolved $\mu -$Brillouin Light Scattering microscopy, mutual synchronization with a phase that can be tuned from 0 to $\pi$ using the drive current or the applied field. Micromagnetic simulations corroborate the experiments and visualize how the PSW patterns in the bridge connecting the two nano-constrictions govern the coupling. These results advance the capabilities of mutually synchronized SHNOs and open up new possibilities for applications in spin wave logic, unconventional computing, and Ising Machines.

19 pages

References in corpus (12)

• Roadmap of spin-orbit torques
• Roadmap on Spin-Wave Computing
• Memristive control of mutual SHNO synchronization for neuromorphic computing
• CoFeB Thickness Dependence of Thermal Stability Factor in CoFeB/MgO Perpendicular Magnetic Tunnel Junctions
• Spin-orbit-torque magnonics
• Giant voltage control of spin Hall nano-oscillator damping
• Robust mutual synchronization in long spin Hall nano-oscillator chains
• Energy-efficient W${}_{\text{100-x}}$Ta${}_{\text{x}}$/CoFeB/MgO spin Hall nano-oscillators
• Nanoconstriction spin-Hall oscillator with perpendicular magnetic anisotropy
• Stimulated amplification of propagating spin waves
• Non-hermiticity in spintronics: oscillation death in coupled spintronic nano-oscillators through emerging exceptional points
• Voltage control of frequency, effective damping and threshold current in nano-constriction-based spin Hall nano-oscillators

Cited by in corpus (4)

• Ultra-low-current-density single-layer magnetic Weyl semimetal spin Hall nano-oscillators
• Symmetry Enhanced Unconventional Spin Current Anisotropy in a Collinear Antiferromagnet
• Metrics for spin-based computing
• Spin-wave emission with current-controlled frequency by a PMA-based spin-Hall oscillator