Spin-orbit torque driven antiferromagnetic oscillator

Antiferromagnets offer a promising pathway toward robust and ultrafast spintronic devices due to their intrinsically zero net magnetic moment and exchangeenhanced spin dynamics. Here, we demonstrate a spin-orbit torque (SOT)-driven oscillator based on a nanoconstriction patterned from a synthetic antiferromagnet (SAF). Spin rectification measurements reveal SOT-driven excitations of both optical and acoustic modes, along with additional resonances that emerge above a threshold DC current near the spin-flop transition. These resonances originate from self-sustained oscillations whose chirality is determined by the polarity of the driving DC current, and which can injection-lock to the detection frequency. Macrospin and micromagnetic simulations corroborate the existence of these chiral self-oscillations and predict chaotic dynamics near the spin-flop regime, experimentally indicated as the sudden onset of multiple oscillation modes above a DC threshold current.