Controlling magnetic configuration in soft–hard bilayers probed by polarized neutron reflectometry

Hard/soft magnetic bilayer thin films have been widely used in data storage technologies and permanent magnet applications. The configuration response to temperatures fields these heterostructures are considered be highly dependent on the interfacial coupling. However, intrinsic properties of each layers, such as saturation magnetization layer thickness, also strongly influence configuration. Changing parameters provides an effective method tailor composite magnets. Here, we use polarized neutron reflectometry (PNR) experimentally probe configurations hard/soft films: L10-FePt/A1-FePt, [Co/Pd]/CoPd, [Co/Pt]/FeNi, L10-FePt/Fe, all which a perpendicular anisotropy hard layer. These were designed with different soft thicknesses (tsoft thard) (Mssoft Mshard). influences in-plane field (Hip) temperature (T) studied using L10-FePt/A1-FePt sample. Comparing PNR results micromagnetic simulations reveals that is tsoft, Mssoft, external factors (Hip T) has relatively weak dependence thard Mshard. Key among results, for layers rigidly coupled out-of-plane direction then undergo transition relax in-plane. This can delayed larger tsoft by decreasing Mssoft. Understanding critical designing functional magnets