Ru spacer thickness dependences of the domain nucleation and growth in Co/Ru/Co synthetic antiferromagnet

The relative orientation of Co magnetization vectors in a Co/Ru/Co/Ta structure varies gradually from parallel to antiparallel orientation as a function of Ru thickness varying from 0 to 1.0 nm. At intermediate average Ru thicknesses from 0.2 to 0.35 nm, the sandwich ground states were characterized by non-collinear magnetization orientations. Real-time magneto-optical indicator film images reveal either 180° or non-180° domain wall nucleation and motion processes. For non-180° domain walls, magnetization reversal was observed to proceed incrementally with each cycle of an AC field.