Deterministic Control and Reversible Interconversion of Multiple Magnetic Domain States in a Synthetic Antiferromagnet

Synthetic antiferromagnets (SAFs) are pivotal for high-density spintronic applications, prized for their ultrafast dynamics and negligible stray fields. However, the deterministic control and reversible interconversion among multiple distinct domain states within a single SAF system remains a challenge. Here, we demonstrate the programmable formation and transformation of a rich portfolio of magnetic domain configurations in a perpendicularly magnetized Ta/[Pt/Co]3/Ru/[Co/Pt]3/Ta multilayer. While sweeping an external magnetic field can stabilize various states, including single-layer ferromagnetic (FM) skyrmion bubbles and SAF skyrmion bubbles, it is insufficient to achieve a pure, uniformly magnetized antiparallel SAF state. By synergistically applying magnetic fields and current pulses, we achieve comprehensive control: (i) reversible switching between SAF skyrmion bubbles and a pure antiparallel SAF state with controlled polarity, (ii) interconversion between SAF and FM skyrmion bubbles, and (iii) transformation between two polarization variants of SAF skyrmion bubbles. Furthermore, current pulses facilitate the transition to a saturated state at a significantly reduced magnetic field. This comprehensive toolkit for domain state manipulation establishes a robust pathway toward developing reconfigurable multistate magnetic memory and logic devices.