Exchange-coupled FePt/Fe bilayers with perpendicular magnetization

We have realized perpendicular hard/soft bilayers with exchange-spring behavior, based on FePt-L1_0 and Fe. Studying the magnetization process as a function of the soft-layer thickness, two different coupling regimes have been identified, i.e., the rigid-magnet and exchange-spring regimes. High values of the maximum energy product (12.4 MGOe) and remanent magnetization (750 emu/cm) have been found in the exchange-coupled bilayers.