  We examine the combined effects of interlayer exchange coupling (IEC) and the
interfacial Dzyaloshinskii-Moriya Interaction (DMI) on the structure of
magnetic domain walls in fully compensated synthetic anti-ferromagnets (SAFs).
Ir-based SAFs with ferromagnetic (FM) layers based on [Pt/(Co/Ni)M]N were
characterized by Lorentz transmission electron microscopy (LTEM). The
multi-layer design of the individual ferromagnetic layers enables control of
the interfacial Dzyaloshinskii-Moriya interaction (via 'M') and, in turn, the
structure and chirality of domain walls (DWs). We compare the Fresnel-mode LTEM
images in SAF designs with only a change in the purported strength of the DMI.
The existence of anti-ferromagnetically coupled Dzyaloshinskii domain walls
(DWs) in a high DMI SAF is confirmed through application of in-situ
perpendicular magnetic field and sample tilt. This conclusion is based on a
unique set of conditions required to observe contrast in Fresnel-mode LTEM,
which we outline in this document.
