Current-driven spin oscillations in noncollinear antiferromagnetic tunnel junctions

This study investigates the fascinating reality of noncollinear antiferromagnet ${\mathrm{Mn}}_{3}\mathrm{Pt}$ thin film and its potential applications in spintronic devices, particularly in the context of all-antiferromagnetic tunnel junctions. By employing atomic-scale Landau-Lifshitz-Gilbert (LLG) simulations, we explored the spin dynamics driven by spin transfer torque (STT) in a ${\mathrm{Mn}}_{3}\mathrm{Pt}$-based all-antiferromagnetic tunnel junction. The investigation revealed an intriguing phenomenon: a spin-flop transition occurring within the ${\mathrm{Mn}}_{3}\mathrm{Pt}$ sublattices under the influence of STT. This transition involves a transformation from a triangular antiparallel alignment to a quasiparallel configuration, demonstrating the complex dynamics achievable through STT manipulation. Importantly, the study identifies magnetic anisotropy as a key determinant of the stability of the spin-flop process, highlighting that larger magnetic anisotropy leads to a more robust transition. Furthermore, through frequency analyses conducted via simulations and theoretical considerations, the study elucidates the presence of terahertz oscillations. Notably, the frequency of these oscillations exhibits a linear increase with the increase of current density. These findings not only deepen our understanding of the oscillation properties of noncollinear antiferromagnets but also pave the way for potential applications in high-frequency spin oscillators.