The goal of this research is to grow oriented periodic multilayer thin films and characterize relationships between their ferromagnetic properties, interfacial structure and composition. Two model experimental systems, manganese/gold and iron/platinum, are being examined. Direct correlations are established between the structural and compositional evolution of the interphase interfaces and magnetic properties as a function of selected incremental annealing treatments. Experimental techniques include transmission electron microscopy, X-ray diffraction, vibrating sample and torque magnetometer, and ferromagnetic resonance. DC sputtering is used to create the multilayer films, which are a new class of materials offering the potential of possessing unique properties not attainable in other materials.