Two-monolayer oscillations in the antiferromagnetic exchange coupling through Mn in Fe/Mn/Fe sandwich structures

Abstract

Oscillations with a period corresponding to two Mn monolayers (ML's) were measured in the antiferromagnetic exchange coupling between ultrathin Fe layers and bulk Fe single-crystal whiskers separated by epitaxial Mn layers. The films were deposited by molecular-beam epitaxy. Electron diffraction showed that the Mn grew monolayer by monolayer in a body-centered-tetragonal structure (a=2.87 \AA{}, c=3.27 \AA{}) up to 15--25 ML's. The coupling was determined using the magneto-optic Kerr effect. It was antiferromagnetic for all thicknesses above 4--7 ML's Mn, with five strong peaks in the 0--0.2 mJ/${\mathrm{m}}^{2}$ range.