Voltage-control of effective damping in spin Hall nano-oscillators

Constriction-based spin Hall nano-oscillators (SHNOs) [1] have attracted interest for their non-linear behavior [2] exhibiting ultra-wide microwave frequency tunability [3], mutual synchronization in chains [4] and 2D arrays [5], and voltage enabled frequency manipulation [6]. The latter provides an efficient path for the implementation of neuromorphic and quantum-like computing applications, such as Ising Machines [7]. In this work, we use micromagnetic simulations to explore voltage gate geometries for controlling SHNOs and obtain strong qualitative and quantitative changes in effective damping as a function of gate placement. We speculate that these effects are due to spin-wave localization and reflection at the voltage gate interfaces and the product of a change in magnetic anisotropy as a result of the applied electric field.

[1] T. Chen et al. Proc. IEEE,104(10):1919–1945, Oct 2016.

[2] M. Dvornik et al. Physical Review Applied,9(1):014017, Jan 2018.

[3] M. Zahedinejad et al. Applied Physics Letters, 112(13):132404, 2018.

[4] A. A. Awad et al. Nat. Phys., 13(Nov):292–299, 2017.1

[5] M. Zahedinejad et al. Nat. Nanotechnol. 15(1):47–52, Jan 2020.

[6] H. Fulara et al. Nature Communications, 11(1):1–7, Dec 2020.

[7] A. Houshang et al. arXiv:2006.02236. 2020