Synthetic antiferromagnets (SAFs) have attracted considerable interest for high-frequency device applications due to their ultrafast dynamical characteristics. While most theoretical models treat SAFs as uniform macrospins, the localized oscillation and precession dynamics of antiferromagnetically coupled domain walls (DWs) remain largely unexplored in regimes beyond the conventional Walker breakdown paradigm. Here, using a one-dimensional collective-coordinate ($q\text{−}\psi$) DW model, we systematically investigate the oscillation and precession of DWs in SAFs. We reveal that these dynamics emerge specifically during the chirality-breaking transition of the upper-layer DW, as it transforms between Néel and Bloch configurations—a mechanism distinct from the classical Walker scenario. We demonstrate that high oscillation frequencies are achieved when the Dzyaloshinskii-Moriya interaction effective fields in the two layers differ significantly, while the dampinglike spin-orbit torque (SOT) fields remain closely matched. Moreover, by introducing a fieldlike SOT effective field along the $z$ direction through geometric engineering, the frequency can be linearly enhanced, offering a clear pathway toward THz operation. These findings provide not only a deeper understanding of chiral symmetry breaking in DW dynamics but also practical strategies for designing high-frequency DW oscillators based on SAFs.

Close

PrevNext

View figure in article

• Domain walls
• Dzyaloshinskii-Moriya interaction
• Spin-orbit torque
• Synthetic antiferromagnetic multilayers
• Landau-Lifschitz-Gilbert equation