Through the exploration and development of candidate materials it was discovered that a a variety of transition metals could be coupled together via a range og non-magnetic materials to produce several synthetic ferrimagnets (SFiM). These SFiM exhibited a wide range of magnetic properties were the optimum SFiM was achieved through coupling the A1 FePt phase to Co via a non-magnetic Ru layer. From the development of these optimum SFiM structures it was found that the multi-layered structures were much more thermally robust in comparison to the tri-layer structures. Through structural analysis it was discovered that this thermal stability was not a result of interlayer mixing or grain growth. Therefore it was demostrated that a variety of SFiM structures could be produced for applications such as all optical switching.