Time-resolved imaging of antiferromagnetic skyrmion interactions

Abstract

Quantifying particle interactions is central to understanding and controlling collective dynamics in particle-based devices such as those comprising skyrmion ensembles. Here we directly visualize, in real time, the nanosecond current-driven dynamics of an antiferromagnetic skyrmion lattice. By tuning the spin–orbit torque relative to local pinning, we identify two regimes: an incoherent flow, where mobile skyrmions are driven toward pinned neighbours undergoing compression followed by a recoil, and a coherent flow regime, where the lattice translates uniformly. We use an inverse analysis method based on the Thiele equation to extract an exponentially decaying antiferromagnetic skyrmion interaction potential, which is in agreement with simulation results. At higher current densities, the lattice exhibits coherent motion free from detectable Hall and inertial effects or dynamical deformation, and this enables robust ultrafast operation. These findings establish a quantitative framework for antiferromagnetic skyrmion interactions and demonstrate deterministic control of their collective dynamics, even in the incoherent flow regime, thereby providing potential applications for multiskyrmion spintronic devices.