Magnetic structures with an out of plane magnetic moment can be found in the latest generation hard disk drive. Interactions between a material with controllable out of plane moment and a loop of soft magnetic material form the key components to a new type of magnetic storage call race track memory. In both cases the 90 degree magnetic domain walls is a prominent feature, used either as a means of writing a 180 degree domain wall which acts as a bit of information or to stabilise the process of writing the memory bit. We wish to employ our mastery over FePt and FeRh along with the new developments in PNR instrumentation at ISIS to map the phase diagram of the 90 degree domain wall formed near the interface as a function of field.