INTERLAYER COUPLING IN EPITAXIAL FE(110)/AG(111) MULTILAYERS

We have detected a possible oscillatory interlayer coupling in Fe(110)/Ag(111) mulilayers grown by molecular beam epitaxy. The oscillation period is between 5 and 9 ML. The coupling was examined using a site-specific Mossbauer spectroscopy technique to determine the spin-wave spectrum at the first two monolayers of the Fe(110) surface. As the interlayer exchange decreases, the spin-wave spectrum softens, resulting in a faster decrease in the nuclear hyperfine field with temperature. At an interlayer thickness of 6 ML, the coupling is so strong that the spin-wave spectrum appears almost bulk-like.