|
Spin Hall nano-oscillator (SHNO) [1] devices hold great promise as extremely compact, broad-band, and versatile microwave oscillators and have unique opportunities for magnonic devices. SHNOs exhibit a strong nonlinearity, which increases their phase noise, but at the same time, strengthens their propensity for injection locking [2] to external sources, and ultimately the possibility of mutual synchronization.
Here, we present the first experimental demonstration of the mutual synchronization of nano-constriction SHNOs [3] and the recent progress in the mutual synchronization of such devices. The mutual synchronization is observed both as a strong increase in the power and coherence of the electrically measured microwave signal. The mutual synchronization is also optically probed using scanning micro-focused Brillouin light scattering microscopy (µ-BLS), providing the first direct imaging of synchronized nano-magnetic oscillators. By tailoring the connection region between the nano-constrictions, we have been able to synchronize SHNOs separated by up to 4 micrometers, and we have demonstrated mutual synchronization of as many as nine SHNOs; we will show as well the ability to synchronize a much larger number of such devices 100 NC-SHNOs so far.
We will discuss as will the perspectives of our results on mutual synchronization of SHNOs, and how it opens up a direct route for the design of very large SHNO based oscillator networks and pave the way for many research and application opportunities where coherent phase locking is needed, in particular, energy efficient spin wave computing on the nanoscale as spintronic “neuromorphic computing”.
[1] V. E. Demidov, et al., Nature Mater. 11, 1028 (2012) V. E. Demidov, et al., Appl. Phys. Lett. 105, 172410 (2014).
[2] V. E. Demidov, et al., Nat. Commun. 5, 3179 (2014).
[3] A. A. Awad, et al., Nat. Phys. 13, 292–299, (2017).
|
