  Antiferromagnetic materials present us with rich and exciting physics, which
we can exploit to open new avenues in spintronic device applications. We
explore perpendicularly magnetized exchange biased systems of Pt/Co/IrMn and
Pt/Co/FeMn, where the crossover from paramagnetic to antiferromagnetic behavior
in the IrMn and FeMn layers is accessed by varying the thickness. We
demonstrate, through magneto-optical imaging, that the magnetic domain
morphology of the ferromagnetic Co layer is influenced by the N${\'e}$el order
of the antiferromagnet (AFM) layers. We relate these variations to the
anisotropy energy of the AFM layer and the ferromagnet-antiferromagnet (FM-AFM)
inter-layer exchange coupling. We also quantify the interfacial
Dzyaloshinskii-Moriya interaction (DMI) in these systems by Brillouin light
scattering spectroscopy. The DMI remains unchanged, within experimental
uncertainty, for different phases of the AFM layers, which allows us to
conclude that the DMI is largely insensitive to both AFM spin order and
exchange bias. Understanding such fundamental mechanisms is crucial for the
development of future devices employing chiral spin textures, such as
N${\'e}$el domain walls and skyrmions, in FM-AFM heterostructures.
