Dislocation-templated antiferromagnetic domains in epitaxial NiO
Controlling antiferromagnetic domains is essential for spintronics, yet deterministic manipulation remains challenging due to their lack of net magnetization. Here, we utilize scanning electron microscopy electron channeling contrast imaging (ECCI) to demonstrate a robust structural memory effect in epitaxial NiO/MgO(001), where antiferromagnetic twin-domain walls (DWs) are deterministically pinned at the nanoscale by interface dislocation networks. Thermal cycling across the Neel temperature reveals that while DW contrast completely vanishes in the paramagnetic phase, the features re-emerge at identical spatial locations upon cooling. Diffraction-vector-dependent ECCI demonstrates that domain contrast stems from localized rhombohedral magnetostrictive strain fields. By tracking a film thickness series from 23 to 60 nm, we resolve an explicit transition in oxide relaxation mechanics. A primary slip system initiates strain relaxation via interface misfit dislocations (MDs) tracking along <100>. At greater thicknesses, rising critical strain prompts threading segments to cross-slip onto secondary or higher-index planes, depositing a wavy network of zig-zag MD lines deviated toward <110>. Quantitative image analysis reveals that DW area fractions directly track the local density and spatial configuration of the evolving MD networks, providing a framework for defect-engineering antiferromagnetic textures using one-dimensional defects.