Stochastic generation in a Josephson-like antiferromagnetic spin Hall oscillator driven by a pure AC current

TL;DR

This paper numerically demonstrates that a pure AC current can induce chaotic and stochastic magnetization dynamics in a Josephson-like antiferromagnetic spin Hall oscillator, with potential applications in spintronic random signal sources.

Contribution

It reveals how specific AC current parameters can generate stochastic regimes in an AFM SHO, advancing the understanding of chaotic dynamics in spintronic devices.

Findings

Chaotic magnetization dynamics can be excited by pure AC current.

Stochastic regimes depend on the ratio of frequency to amplitude of the AC current.

Potential applications in ultra-fast probabilistic computing and secure communications.

Abstract

We demonstrate numerically that a pure time-harmonic bias AC current of some particular amplitude $\tau_f$ and angular frequency $\omega_f$ can excite the chaotic magnetization dynamics in a Josephson-like antiferromagnetic (AFM) spin Hall oscillator (SHO) having a biaxial magnetic anisotropy of an AFM layer. The nature of such a stochastic generation regime in a Josephson-like AFM SHO could be explained by the random hopping of the SHO's work point between several quasi-stable states under the action of applied AC current. We revealed that depending on the $\omega_f/\tau_f$ ratio several stochastic generation regimes interspersed with regular generation regimes can be achieved in an AFM SHO that can be used in spintronic sources of random signals and various nano-scale devices utilizing random signals including the spintronic p-bit device considered in this paper. The obtained results are important for the development and optimization of spintronic devices able to generate and process (sub-)THz-frequency random signals promising for ultra-fast probabilistic computing, cryptography, secure communications, etc.