Abstract
A microscopic magnetic antiphase domain structure has been observed in a single-crystal Gd-Y superlattice by neutron diffraction. Furthermore, this long-range antiferromagnetic correlation is found to occur in a multibilayer, in which each bilayer consists of NGd ferromagnetic atomic planes of Gd followed by NY planes of nonmagnetic Y, for NY=NGd=10 but not for NY=6 or 20. This oscillatory behavior is consistent with recent theoretical speculation that the Gd moments are coupled through the intervening Y via the Ruderman-Kittel-Kasuya- Yosida interaction. © 1986 The American Physical Society.