In-plane anisotropy and coupling in Fe/Ag superlattices

We studied the magnetic properties of Fe/Ag superlattices grown by molecular beam epitaxy (MBE) on MgO(001) single crystals. The Fe thickness is fixed at 20 Å and the Ag thickness varied from 7 to 20 Å. Epitaxial quality and superlattice structure were verified by reflection high-energy electron diffraction (RHEED) and X-ray diffraction (XRD). The magnetization measurements in the temperature range of 5–300 K revealed the presence of in-plane uniaxial anisotropy. Ferromagnetic resonance (FMR) measurements performed at room temperature (RT) with a magnetic field applied perpendicularly to the film plane confirmed the easy axis in the film plane and showed a spacer thickness-dependent ferromagnetic exchange coupling.