EXCHANGE COUPLING IN FE/CU, PD, AG, AU/FE TRILAYERS

Epitaxial trilayer Fe/Cu, Pd, Ag, Au/Fe structures have been grown by MBE. The growth of bcc Fe(001), Cu(001), lattice expanded fcc Pd(001) and fcc Ag(001) and Au(001) layers were monitored and characterized by RHEED patterns and RHEED intensity oscillations. Ferromagnetic Resonance (FMR) and Surface Magneto-Optical Kerr Effect (SMOKE) were used to investigate the exchange coupling in these trilayers using a wide range of Cu, Pd, Ag and Au interlayer thicknesses. It is shown that Cu and Pd interlayers exhibit long range antiferromagnetic coupling. Both interlayers exhibit unique oscillatory behavior. The exchange coupling through bcc Cu exhibits only one crossover to antiferromagnetic coupling. The strength of the antiferromagnetic coupling reveals an oscillatory behavior with periodicity of 10 monolayers. In the region of ferromagnetic coupling the exchange coupling through lattice expanded fcc Pd shows an oscillatory behavior with periodicity of 4 monolayers. Ag(001) interlayers show a rapid decrease in the ferromagnetic coupling with increasing Ag interlayer thickness. Au(001) interlayers behave similarly to those of Ag(001). However a weak antiferromagnetic coupling was observed in Au(001).